refactor: phase 4 - event-driven architecture foundation

- Add EventBus class with pub/sub messaging (thread-safe)
- Add emitter Protocol classes (EventEmitter, Startable, Stoppable)
- Add event emission to NtfyPoller (NtfyMessageEvent)
- Add event emission to MicMonitor (MicLevelEvent)
- Update StreamController to publish stream start/end events
- Add comprehensive tests for eventbus and emitters modules

.gitignore

@@ -1,4 +1,11 @@
 __pycache__/
 *.pyc
 .mainline_venv/
+.venv/
+uv.lock
 .mainline_cache_*.json
+.DS_Store
+htmlcov/
+.coverage
+.pytest_cache/
+*.egg-info/

.python-version

@@ -0,0 +1 @@
+3.12

AGENTS.md

@@ -0,0 +1,110 @@
+# Agent Development Guide
+
+## Development Environment
+
+This project uses:
+- **mise** (mise.jdx.dev) - tool version manager and task runner
+- **hk** (hk.jdx.dev) - git hook manager
+- **uv** - fast Python package installer
+- **ruff** - linter and formatter
+- **pytest** - test runner
+
+### Setup
+
+```bash
+# Install dependencies
+mise run install
+
+# Or equivalently:
+uv sync
+```
+
+### Available Commands
+
+```bash
+mise run test       # Run tests
+mise run test-v     # Run tests verbose
+mise run test-cov   # Run tests with coverage report
+mise run lint       # Run ruff linter
+mise run lint-fix   # Run ruff with auto-fix
+mise run format     # Run ruff formatter
+mise run ci         # Full CI pipeline (sync + test + coverage)
+```
+
+## Git Hooks
+
+**At the start of every agent session**, verify hooks are installed:
+
+```bash
+ls -la .git/hooks/pre-commit
+```
+
+If hooks are not installed, install them with:
+
+```bash
+hk init --mise
+mise run pre-commit
+```
+
+The project uses hk configured in `hk.pkl`:
+- **pre-commit**: runs ruff-format and ruff (with auto-fix)
+- **pre-push**: runs ruff check
+
+## Workflow Rules
+
+### Before Committing
+
+1. **Always run the test suite** - never commit code that fails tests:
+   ```bash
+   mise run test
+   ```
+
+2. **Always run the linter**:
+   ```bash
+   mise run lint
+   ```
+
+3. **Fix any lint errors** before committing (or let the pre-commit hook handle it).
+
+4. **Review your changes** using `git diff` to understand what will be committed.
+
+### On Failing Tests
+
+When tests fail, **determine whether it's an out-of-date test or a correctly failing test**:
+
+- **Out-of-date test**: The test was written for old behavior that has legitimately changed. Update the test to match the new expected behavior.
+
+- **Correctly failing test**: The test correctly identifies a broken contract. Fix the implementation, not the test.
+
+**Never** modify a test to make it pass without understanding why it failed.
+
+### Code Review
+
+Before committing significant changes:
+- Run `git diff` to review all changes
+- Ensure new code follows existing patterns in the codebase
+- Check that type hints are added for new functions
+- Verify that tests exist for new functionality
+
+## Testing
+
+Tests live in `tests/` and follow the pattern `test_*.py`.
+
+Run all tests:
+```bash
+mise run test
+```
+
+Run with coverage:
+```bash
+mise run test-cov
+```
+
+The project uses pytest with strict marker enforcement. Test configuration is in `pyproject.toml` under `[tool.pytest.ini_options]`.
+
+## Architecture Notes
+
+- **ntfy.py** and **mic.py** are standalone modules with zero internal dependencies
+- **eventbus.py** provides thread-safe event publishing for decoupled communication
+- **controller.py** coordinates ntfy/mic monitoring
+- The render pipeline: fetch → render → effects → scroll → terminal output

Mainline Renderer + ntfy Message Queue for ESP32.md

@@ -3,29 +3,29 @@
 mainline\.py does heavy work unsuitable for ESP32: 25\+ HTTPS/TLS RSS feeds, OTF font rasterization via Pillow, Google Translate API calls, and complex text layout\. Simultaneously, messages arriving on `ntfy.sh/klubhaus_terminal_mainline` need to interrupt the news ticker on the same device\.
 ## Architecture: Server \+ Thin Client
 Split the system into two halves that are designed together\.
-**Server \(mainline\.py `--serve` mode, runs on any always\-on machine\)**
+**Server (mainline\.py `--serve` mode, runs on any always\-on machine)**
 * Reuses existing feed fetching, caching, content filtering, translation, and Pillow font rendering pipeline — no duplication\.
-* Pre\-renders each headline into a 1\-bit bitmap strip \(the OTF→half\-block pipeline already produces this as an intermediate step in `_render_line()`\)\.
+* Pre\-renders each headline into a 1\-bit bitmap strip (the OTF→half\-block pipeline already produces this as an intermediate step in `_render_line()`)\.
 * Exposes a lightweight HTTP API the ESP32 polls\.
-**ESP32 thin client \(Arduino sketch\)**
-* Polls the mainline server for pre\-rendered headline bitmaps over plain HTTP \(no TLS needed if on the same LAN\)\.
-* Polls `ntfy.sh/klubhaus_terminal_mainline` directly for messages, reusing the proven `NetManager::httpGet()` \+ JSON parsing pattern from DoorbellLogic \(`DoorbellLogic.cpp:155-192`\)\.
-* Manages scrolling, gradient coloring, and glitch effects locally \(cheap per\-frame GPU work\)\.
+**ESP32 thin client (Arduino sketch)**
+* Polls the mainline server for pre\-rendered headline bitmaps over plain HTTP (no TLS needed if on the same LAN)\.
+* Polls `ntfy.sh/klubhaus_terminal_mainline` directly for messages, reusing the proven `NetManager::httpGet()` \+ JSON parsing pattern from DoorbellLogic (`DoorbellLogic.cpp:155-192`)\.
+* Manages scrolling, gradient coloring, and glitch effects locally (cheap per\-frame GPU work)\.
 * When an ntfy message arrives, the scroll is paused and the message takes over the display — same interrupt pattern as the doorbell's ALERT→DASHBOARD flow\.
-## Server API \(mainline repo\)
-New file: `serve.py` \(or `--serve` mode in mainline\.py\)\.
+## Server API (mainline repo)
+New file: `serve.py` (or `--serve` mode in mainline\.py)\.
 Endpoints:
 * `GET /api/headlines` — returns JSON array of headline metadata: `[{"id": 0, "src": "Nature", "ts": "14:30", "width": 280, "height": 16, "bitmap": "<base64 1-bit packed>"}]`\. Bitmaps are 1\-bit\-per\-pixel, row\-major, packed 8px/byte\. The ESP32 applies gradient color locally\.
 * `GET /api/config` — returns `{"count": 120, "version": "...", "mode": "news"}` so the ESP32 knows what it's getting\.
 * `GET /api/health` — `{"ok": true, "last_fetch": "...", "headline_count": 120}`
-The server renders at a configurable target width \(e\.g\. 800px for Board 3, 320px for Boards 1/2\) via a `--width` flag or query parameter\. Height is fixed per headline by the font size\.
-The server refreshes feeds on a timer \(reusing `_SCROLL_DUR` cadence or a longer interval\), re\-renders, and serves the latest set\. The ESP32 polls `/api/headlines` periodically \(e\.g\. every 60s\) and swaps in the new set\.
-## Render pipeline \(server side\)
+The server renders at a configurable target width (e\.g\. 800px for Board 3, 320px for Boards 1/2) via a `--width` flag or query parameter\. Height is fixed per headline by the font size\.
+The server refreshes feeds on a timer (reusing `_SCROLL_DUR` cadence or a longer interval), re\-renders, and serves the latest set\. The ESP32 polls `/api/headlines` periodically (e\.g\. every 60s) and swaps in the new set\.
+## Render pipeline (server side)
 The existing `_render_line()` in mainline\.py already does:
 1. `ImageFont.truetype()` → `ImageDraw.text()` → grayscale `Image`
 2. Resize to target height
-3. Threshold to 1\-bit \(the `thr = 80` step\)
-For the server, we stop at step 3 and pack the 1\-bit data into bytes instead of converting to half\-block Unicode\. This is the exact same pipeline, just with a different output format\. The `_big_wrap()` and `_lr_gradient()` logic stays on the server for layout; gradient *coloring* moves to the ESP32 \(it's just an index lookup per pixel column\)\.
+3. Threshold to 1\-bit (the `thr = 80` step)
+For the server, we stop at step 3 and pack the 1\-bit data into bytes instead of converting to half\-block Unicode\. This is the exact same pipeline, just with a different output format\. The `_big_wrap()` and `_lr_gradient()` logic stays on the server for layout; gradient *coloring* moves to the ESP32 (it's just an index lookup per pixel column)\.
 ## ESP32 client
 ### State machine
 ```warp-runnable-command
@@ -35,19 +35,19 @@ BOOT → SCROLL ⇄ MESSAGE
 * **BOOT** — WiFi connect, initial headline fetch from server\.
 * **SCROLL** — Vertical scroll through pre\-rendered headlines with local gradient \+ glitch\. Polls server for new headlines periodically\. Polls ntfy every 15s\.
 * **MESSAGE** — ntfy message arrived\. Scroll paused, message displayed\. Auto\-dismiss after timeout or touch\-dismiss\. Returns to SCROLL\.
-* **OFF** — Backlight off after inactivity \(polling continues in background\)\.
+* **OFF** — Backlight off after inactivity (polling continues in background)\.
 ### ntfy integration
 The ESP32 polls `https://ntfy.sh/klubhaus_terminal_mainline/json?since=20s&poll=1` on the same 15s interval as the doorbell polls its topics\. When a message event arrives:
 1. Parse JSON: `{"event": "message", "title": "...", "message": "..."}`
 2. Save current scroll position\.
 3. Transition to MESSAGE state\.
-4. Render message text using the display library's built\-in fonts \(messages are short, no custom font needed\)\.
-5. After `MESSAGE_TIMEOUT_MS` \(e\.g\. 30s\) or touch, restore scroll position and resume\.
-This is architecturally identical to `DoorbellLogic::onAlert()` → `dismissAlert()`, just with different content\. The ntfy polling runs independently of the server connection, so messages work even if the mainline server is offline \(the device just shows the last cached headlines\)\.
+4. Render message text using the display library's built\-in fonts (messages are short, no custom font needed)\.
+5. After `MESSAGE_TIMEOUT_MS` (e\.g\. 30s) or touch, restore scroll position and resume\.
+This is architecturally identical to `DoorbellLogic::onAlert()` → `dismissAlert()`, just with different content\. The ntfy polling runs independently of the server connection, so messages work even if the mainline server is offline (the device just shows the last cached headlines)\.
 ### Headline storage
-* Board 3 \(8 MB PSRAM\): store all ~120 headline bitmaps in PSRAM\. At 800px × 16px × 1 bit = 1\.6 KB each → ~192 KB total\. Trivial\.
-* Boards 1/2 \(PSRAM TBD\): at 320px × 16px = 640 bytes each → ~77 KB for 120 headlines\. Fits if PSRAM is present\. Without PSRAM, keep ~20 headlines in a ring buffer \(~13 KB\)\.
-### Gradient coloring \(local\)
+* Board 3 (8 MB PSRAM): store all ~120 headline bitmaps in PSRAM\. At 800px × 16px × 1 bit = 1\.6 KB each → ~192 KB total\. Trivial\.
+* Boards 1/2 (PSRAM TBD): at 320px × 16px = 640 bytes each → ~77 KB for 120 headlines\. Fits if PSRAM is present\. Without PSRAM, keep ~20 headlines in a ring buffer (~13 KB)\.
+### Gradient coloring (local)
 The 12\-step ANSI gradient in mainline\.py maps to 12 RGB565 values:
 ```warp-runnable-command
 const uint16_t GRADIENT[] = {
@@ -68,8 +68,8 @@ mainline.py          (existing, unchanged)
 serve.py             (new — HTTP server, imports mainline rendering functions)
 klubhaus-doorbell-hardware.md  (existing)
 ```
-`serve.py` imports the rendering functions from mainline\.py \(after refactoring them into importable form — they're currently top\-level but not wrapped in `if __name__`\)\.
-### klubhaus\-doorbell repo \(or mainline repo under firmware/\)
+`serve.py` imports the rendering functions from mainline\.py (after refactoring them into importable form — they're currently top\-level but not wrapped in `if __name__`)\.
+### klubhaus\-doorbell repo (or mainline repo under firmware/)
 ```warp-runnable-command
 boards/esp32-mainline/
 ├── esp32-mainline.ino    Main sketch
@@ -79,31 +79,31 @@ boards/esp32-mainline/
 ├── HeadlineStore.h/.cpp  Bitmap ring buffer in PSRAM
 └── NtfyPoller.h/.cpp     ntfy.sh polling (extracted from DoorbellLogic pattern)
 ```
-The display driver is reused from the target board \(e\.g\. `DisplayDriverGFX` for Board 3\)\. `MainlineLogic` replaces `DoorbellLogic` as the state machine but follows the same patterns\.
+The display driver is reused from the target board (e\.g\. `DisplayDriverGFX` for Board 3)\. `MainlineLogic` replaces `DoorbellLogic` as the state machine but follows the same patterns\.
 ## Branch strategy recommendation
 The work spans two repos and has clear dependency ordering\.
-### Phase 1 — Finish current branch \(mainline repo\)
-**Branch:** `feat/arduino` \(current\)
+### Phase 1 — Finish current branch (mainline repo)
+**Branch:** `feat/arduino` (current)
 **Content:** Hardware spec doc\. Already done\.
 **Action:** Merge to main when ready\.
-### Phase 2 — Server renderer \(mainline repo\)
-**Branch:** `feat/renderer` \(branch from main after Phase 1 merges\)
+### Phase 2 — Server renderer (mainline repo)
+**Branch:** `feat/renderer` (branch from main after Phase 1 merges)
 **Content:**
-* Refactor mainline\.py rendering functions to be importable \(extract from `__main__` guard\)
+* Refactor mainline\.py rendering functions to be importable (extract from `__main__` guard)
 * `serve.py` — HTTP server with `/api/headlines`, `/api/config`, `/api/health`
-* Bitmap packing utility \(1\-bit row\-major\)
-**Why a separate branch:** This changes mainline\.py's structure \(refactoring for imports\) and adds a new entry point\. It's a self\-contained, testable unit — you can verify the API with `curl` before touching any Arduino code\.
-### Phase 3 — ESP32 client \(klubhaus\-doorbell repo, or mainline repo\)
+* Bitmap packing utility (1\-bit row\-major)
+**Why a separate branch:** This changes mainline\.py's structure (refactoring for imports) and adds a new entry point\. It's a self\-contained, testable unit — you can verify the API with `curl` before touching any Arduino code\.
+### Phase 3 — ESP32 client (klubhaus\-doorbell repo, or mainline repo)
 **Branch:** `feat/mainline-client` in whichever repo hosts it
 **Content:**
 * `MainlineLogic` state machine
 * `HeadlineStore` bitmap buffer
 * `NtfyPoller` for `klubhaus_terminal_mainline`
 * Board\-specific sketch for the target board
-**Depends on:** Phase 2 \(needs a running server to test against\)
+**Depends on:** Phase 2 (needs a running server to test against)
 **Repo decision:** If you have push access to klubhaus\-doorbell, it fits naturally as a new board target alongside the existing doorbell sketches — it reuses `NetManager`, `IDisplayDriver`, and the vendored display libraries\. If not, put it under `mainline/firmware/` and vendor the shared KlubhausCore library\.
 ### Merge order
-1. `feat/arduino` → main \(hardware spec\)
-2. `feat/renderer` → main \(server\)
-3. `feat/mainline-client` → main in whichever repo \(ESP32 client\)
+1. `feat/arduino` → main (hardware spec)
+2. `feat/renderer` → main (server)
+3. `feat/mainline-client` → main in whichever repo (ESP32 client)
 Each phase is independently testable and doesn't block the other until Phase 3 needs a running server\.

README.md

@@ -2,7 +2,7 @@
 
 > *Digital consciousness stream. Matrix aesthetic · THX-1138 hue.*
 
-A full-screen terminal news ticker that renders live global headlines in large OTF-font block characters with a white-hot → deep green gradient. Headlines auto-translate into the native script of their subject region. Ambient mic input warps the glitch rate in real time. A `--poetry` mode replaces the feed with public-domain literary passages.
+A full-screen terminal news ticker that renders live global headlines in large OTF-font block characters with a white-hot → deep green gradient. Headlines auto-translate into the native script of their subject region. Ambient mic input warps the glitch rate in real time. A `--poetry` mode replaces the feed with public-domain literary passages. Live messages can be pushed to the display over [ntfy.sh](https://ntfy.sh).
 
 ---
 
@@ -12,44 +12,127 @@ A full-screen terminal news ticker that renders live global headlines in large O
 python3 mainline.py                      # news stream
 python3 mainline.py --poetry             # literary consciousness mode
 python3 mainline.py -p                   # same
+python3 mainline.py --firehose           # dense rapid-fire headline mode
+python3 mainline.py --refresh            # force re-fetch (bypass cache)
+python3 mainline.py --no-font-picker     # skip interactive font picker
+python3 mainline.py --font-file path.otf # use a specific font file
+python3 mainline.py --font-dir ~/fonts   # scan a different font folder
+python3 mainline.py --font-index 1       # select face index within a collection
 ```
 
-First run bootstraps a local `.mainline_venv/` and installs deps (`feedparser`, `Pillow`, `sounddevice`, `numpy`). Subsequent runs start immediately.
+First run bootstraps a local `.mainline_venv/` and installs deps (`feedparser`, `Pillow`, `sounddevice`, `numpy`). Subsequent runs start immediately, loading from cache.
 
 ---
 
 ## Config
 
-At the top of `mainline.py`:
+All constants live in `engine/config.py`:
 
 | Constant | Default | What it does |
 |---|---|---|
 | `HEADLINE_LIMIT` | `1000` | Total headlines per session |
+| `FEED_TIMEOUT` | `10` | Per-feed HTTP timeout (seconds) |
 | `MIC_THRESHOLD_DB` | `50` | dB floor above which glitches spike |
-| `_FONT_PATH` | hardcoded path | Path to your OTF/TTF display font |
-| `_FONT_SZ` | `60` | Font render size (affects block density) |
-| `_RENDER_H` | `8` | Terminal rows per headline line |
+| `FONT_DIR` | `fonts/` | Folder scanned for `.otf`, `.ttf`, `.ttc` files |
+| `FONT_PATH` | first file in `FONT_DIR` | Active display font (overridden by picker or `--font-file`) |
+| `FONT_INDEX` | `0` | Face index within a font collection file |
+| `FONT_PICKER` | `True` | Show interactive font picker at boot (`--no-font-picker` to skip) |
+| `FONT_SZ` | `60` | Font render size (affects block density) |
+| `RENDER_H` | `8` | Terminal rows per headline line |
+| `SSAA` | `4` | Super-sampling factor (render at 4× then downsample) |
+| `SCROLL_DUR` | `5.625` | Seconds per headline |
+| `FRAME_DT` | `0.05` | Frame interval in seconds (20 FPS) |
+| `GRAD_SPEED` | `0.08` | Gradient sweep speed (cycles/sec, ~12s full sweep) |
+| `FIREHOSE_H` | `12` | Firehose zone height (terminal rows) |
+| `NTFY_TOPIC` | klubhaus URL | ntfy.sh JSON endpoint to poll |
+| `NTFY_POLL_INTERVAL` | `15` | Seconds between ntfy polls |
+| `MESSAGE_DISPLAY_SECS` | `30` | How long an ntfy message holds the screen |
 
-**Font:** `_FONT_PATH` is hardcoded to a local path. Update it to point to whatever display font you want — anything with strong contrast and wide letterforms works well.
+---
+
+## Fonts
+
+A `fonts/` directory is bundled with demo faces (AlphatronDemo, CSBishopDrawn, CyberformDemo, KATA, Microbots, Neoform, Pixel Sparta, Robocops, Xeonic, and others). On startup, an interactive picker lists all discovered faces with a live half-block preview rendered at your configured size.
+
+Navigation: `↑`/`↓` or `j`/`k` to move, `Enter` or `q` to select. The selected face persists for that session.
+
+To add your own fonts, drop `.otf`, `.ttf`, or `.ttc` files into `fonts/` (or point `--font-dir` at any other folder). Font collections (`.ttc`, multi-face `.otf`) are enumerated face-by-face.
 
 ---
 
 ## How it works
 
-- Feeds are fetched and filtered on startup (sports and vapid content stripped)
-- Headlines are rasterized via Pillow into half-block characters (`▀▄█ `) at the configured font size
-- A left-to-right ANSI gradient colors each character: white-hot leading edge trails off to near-black
+- On launch, the font picker scans `fonts/` and presents a live-rendered TUI for face selection; `--no-font-picker` skips directly to stream
+- Feeds are fetched and filtered on startup (sports and vapid content stripped); results are cached to `.mainline_cache_news.json` / `.mainline_cache_poetry.json` for fast restarts
+- Headlines are rasterized via Pillow with 4× SSAA into half-block characters (`▀▄█ `) at the configured font size
+- The ticker uses a sweeping white-hot → deep green gradient; ntfy messages use a complementary white-hot → magenta/maroon gradient to distinguish them visually
 - Subject-region detection runs a regex pass on each headline; matches trigger a Google Translate call and font swap to the appropriate script (CJK, Arabic, Devanagari, etc.) using macOS system fonts
 - The mic stream runs in a background thread, feeding RMS dB into the glitch probability calculation each frame
 - The viewport scrolls through a virtual canvas of pre-rendered blocks; fade zones at top and bottom dissolve characters probabilistically
+- An ntfy.sh poller runs in a background thread; incoming messages interrupt the scroll and render full-screen until dismissed or expired
+
+---
+
+## Architecture
+
+`mainline.py` is a thin entrypoint (venv bootstrap → `engine.app.main()`). All logic lives in the `engine/` package:
+
+```
+engine/
+  __init__.py       package marker
+  app.py            main(), font picker TUI, boot sequence, signal handler
+  config.py         constants, CLI flags, glyph tables
+  sources.py        FEEDS, POETRY_SOURCES, language/script maps
+  terminal.py       ANSI codes, tw/th, type_out, boot_ln
+  filter.py         HTML stripping, content filter
+  translate.py       Google Translate wrapper + region detection
+  render.py         OTF → half-block pipeline (SSAA, gradient)
+  effects.py        noise, glitch_bar, fade, firehose
+  fetch.py          RSS/Gutenberg fetching + cache load/save
+  ntfy.py           NtfyPoller — standalone, zero internal deps
+  mic.py            MicMonitor — standalone, graceful fallback
+  scroll.py         stream() frame loop + message rendering
+  viewport.py       terminal dimension tracking (tw/th)
+  frame.py          scroll step calculation, timing
+  layers.py         ticker zone, firehose, message overlay rendering
+  eventbus.py       thread-safe event publishing for decoupled communication
+  events.py         event types and definitions
+  controller.py     coordinates ntfy/mic monitoring and event publishing
+  emitters.py       background emitters for ntfy and mic
+  types.py          type definitions and dataclasses
+```
+
+`ntfy.py` and `mic.py` have zero internal dependencies and can be imported by any other visualizer.
 
 ---
 
 ## Feeds
 
-~25 sources across four categories: **Science & Technology**, **Economics & Business**, **World & Politics**, **Culture & Ideas**. Add or swap in `FEEDS`.
+~25 sources across four categories: **Science & Technology**, **Economics & Business**, **World & Politics**, **Culture & Ideas**. Add or swap feeds in `engine/sources.py` → `FEEDS`.
 
-**Poetry mode** pulls from Project Gutenberg: Whitman, Dickinson, Thoreau, Emerson.
+**Poetry mode** pulls from Project Gutenberg: Whitman, Dickinson, Thoreau, Emerson. Sources are in `engine/sources.py` → `POETRY_SOURCES`.
+
+---
+
+## ntfy.sh Integration
+
+Mainline polls a configurable ntfy.sh topic in the background. When a message arrives, the scroll pauses and the message renders full-screen for `MESSAGE_DISPLAY_SECS` seconds, then the stream resumes.
+
+To push a message:
+
+```bash
+curl -d "Body text" -H "Title: Alert title" https://ntfy.sh/your_topic
+```
+
+Update `NTFY_TOPIC` in `engine/config.py` to point at your own topic. The `NtfyPoller` class is fully standalone and can be reused by other visualizers:
+
+```python
+from engine.ntfy import NtfyPoller
+poller = NtfyPoller("https://ntfy.sh/my_topic/json?since=20s&poll=1")
+poller.start()
+# in render loop:
+msg = poller.get_active_message()  # returns (title, body, timestamp) or None
+```
 
 ---
 
@@ -62,7 +145,6 @@ At the top of `mainline.py`:
 
 ### Graphics
 - **Matrix rain underlay** — katakana column rain rendered at low opacity beneath the scrolling blocks as a background layer
-- **Animated gradient** — shift the white-hot leading edge left/right each frame for a pulse/comet effect
 - **CRT simulation** — subtle dim scanlines every N rows, occasional brightness ripple across the full screen
 - **Sixel / iTerm2 inline images** — bypass half-blocks entirely and stream actual bitmap frames for true resolution; would require a capable terminal
 - **Parallax secondary column** — a second, dimmer, faster-scrolling stream of ambient text at reduced opacity on one side
@@ -75,6 +157,11 @@ At the top of `mainline.py`:
 - **Persona modes** — `--surveillance`, `--oracle`, `--underground` as feed presets with matching color themes and boot copy
 - **Synthesized audio** — short static bursts tied to glitch events, independent of mic input
 
+### Extensibility
+- **serve.py** — HTTP server that imports `engine.render` and `engine.fetch` directly to stream 1-bit bitmaps to an ESP32 display
+- **Rust port** — `ntfy.py` and `render.py` are the natural first targets; clear module boundaries make incremental porting viable
+
 ---
 
-*macOS only (system font paths hardcoded). Python 3.9+.*
+*macOS only (script/system font paths for translation are hardcoded). Primary display font is user-selectable via the bundled `fonts/` picker. Python 3.9+.*
+# test

engine/app.py

@@ -2,20 +2,33 @@
 Application orchestrator — boot sequence, signal handling, main loop wiring.
 """
 
-import sys
-import time
-import signal
 import atexit
+import os
+import signal
+import sys
+import termios
+import time
+import tty
 
-from engine import config
-from engine.terminal import (
-    RST, G_HI, G_MID, G_DIM, W_DIM, W_GHOST, CLR, CURSOR_OFF, CURSOR_ON, tw,
-    slow_print, boot_ln,
-)
+from engine import config, render
 from engine.fetch import fetch_all, fetch_poetry, load_cache, save_cache
-from engine.ntfy import NtfyPoller
 from engine.mic import MicMonitor
+from engine.ntfy import NtfyPoller
 from engine.scroll import stream
+from engine.terminal import (
+    CLR,
+    CURSOR_OFF,
+    CURSOR_ON,
+    G_DIM,
+    G_HI,
+    G_MID,
+    RST,
+    W_DIM,
+    W_GHOST,
+    boot_ln,
+    slow_print,
+    tw,
+)
 
 TITLE = [
     "  ███╗   ███╗ █████╗ ██╗███╗   ██╗██╗     ██╗███╗   ██╗███████╗",
@@ -27,6 +40,215 @@ TITLE = [
 ]
 
 
+def _read_picker_key():
+    ch = sys.stdin.read(1)
+    if ch == "\x03":
+        return "interrupt"
+    if ch in ("\r", "\n"):
+        return "enter"
+    if ch == "\x1b":
+        c1 = sys.stdin.read(1)
+        if c1 != "[":
+            return None
+        c2 = sys.stdin.read(1)
+        if c2 == "A":
+            return "up"
+        if c2 == "B":
+            return "down"
+        return None
+    if ch in ("k", "K"):
+        return "up"
+    if ch in ("j", "J"):
+        return "down"
+    if ch in ("q", "Q"):
+        return "enter"
+    return None
+
+
+def _normalize_preview_rows(rows):
+    """Trim shared left padding and trailing spaces for stable on-screen previews."""
+    non_empty = [r for r in rows if r.strip()]
+    if not non_empty:
+        return [""]
+    left_pad = min(len(r) - len(r.lstrip(" ")) for r in non_empty)
+    out = []
+    for row in rows:
+        if left_pad < len(row):
+            out.append(row[left_pad:].rstrip())
+        else:
+            out.append(row.rstrip())
+    return out
+
+
+def _draw_font_picker(faces, selected):
+    w = tw()
+    h = 24
+    try:
+        h = os.get_terminal_size().lines
+    except Exception:
+        pass
+
+    max_preview_w = max(24, w - 8)
+    header_h = 6
+    footer_h = 3
+    preview_h = max(4, min(config.RENDER_H + 2, max(4, h // 2)))
+    visible = max(1, h - header_h - preview_h - footer_h)
+    top = max(0, selected - (visible // 2))
+    bottom = min(len(faces), top + visible)
+    top = max(0, bottom - visible)
+
+    print(CLR, end="")
+    print(CURSOR_OFF, end="")
+    print()
+    print(f"  {G_HI}FONT PICKER{RST}")
+    print(f"  {W_GHOST}{'─' * (w - 4)}{RST}")
+    print(f"  {W_DIM}{config.FONT_DIR[:max_preview_w]}{RST}")
+    print(f"  {W_GHOST}↑/↓ move · Enter select · q accept current{RST}")
+    print()
+
+    for pos in range(top, bottom):
+        face = faces[pos]
+        active = pos == selected
+        pointer = "▶" if active else " "
+        color = G_HI if active else W_DIM
+        print(
+            f"  {color}{pointer} {face['name']}{RST}{W_GHOST} · {face['file_name']}{RST}"
+        )
+
+    if top > 0:
+        print(f"  {W_GHOST}… {top} above{RST}")
+    if bottom < len(faces):
+        print(f"  {W_GHOST}… {len(faces) - bottom} below{RST}")
+
+    print()
+    print(f"  {W_GHOST}{'─' * (w - 4)}{RST}")
+    print(
+        f"  {W_DIM}Preview: {faces[selected]['name']} · {faces[selected]['file_name']}{RST}"
+    )
+    preview_rows = faces[selected]["preview_rows"][:preview_h]
+    for row in preview_rows:
+        shown = row[:max_preview_w]
+        print(f"    {shown}")
+
+
+def pick_font_face():
+    """Interactive startup picker for selecting a face from repo OTF files."""
+    if not config.FONT_PICKER:
+        return
+
+    font_files = config.list_repo_font_files()
+    if not font_files:
+        print(CLR, end="")
+        print(CURSOR_OFF, end="")
+        print()
+        print(f"  {G_HI}FONT PICKER{RST}")
+        print(f"  {W_GHOST}{'─' * (tw() - 4)}{RST}")
+        print(f"  {G_DIM}> no .otf/.ttf/.ttc files found in: {config.FONT_DIR}{RST}")
+        print(f"  {W_GHOST}> add font files to the fonts folder, then rerun{RST}")
+        time.sleep(1.8)
+        sys.exit(1)
+
+    prepared = []
+    for font_path in font_files:
+        try:
+            faces = render.list_font_faces(font_path, max_faces=64)
+        except Exception:
+            fallback = os.path.splitext(os.path.basename(font_path))[0]
+            faces = [{"index": 0, "name": fallback}]
+        for face in faces:
+            idx = face["index"]
+            name = face["name"]
+            file_name = os.path.basename(font_path)
+            try:
+                fnt = render.load_font_face(font_path, idx)
+                rows = _normalize_preview_rows(render.render_line(name, fnt))
+            except Exception:
+                rows = ["(preview unavailable)"]
+            prepared.append(
+                {
+                    "font_path": font_path,
+                    "font_index": idx,
+                    "name": name,
+                    "file_name": file_name,
+                    "preview_rows": rows,
+                }
+            )
+
+    if not prepared:
+        print(CLR, end="")
+        print(CURSOR_OFF, end="")
+        print()
+        print(f"  {G_HI}FONT PICKER{RST}")
+        print(f"  {W_GHOST}{'─' * (tw() - 4)}{RST}")
+        print(f"  {G_DIM}> no readable font faces found in: {config.FONT_DIR}{RST}")
+        time.sleep(1.8)
+        sys.exit(1)
+
+    def _same_path(a, b):
+        try:
+            return os.path.samefile(a, b)
+        except Exception:
+            return os.path.abspath(a) == os.path.abspath(b)
+
+    selected = next(
+        (
+            i
+            for i, f in enumerate(prepared)
+            if _same_path(f["font_path"], config.FONT_PATH)
+            and f["font_index"] == config.FONT_INDEX
+        ),
+        0,
+    )
+
+    if not sys.stdin.isatty():
+        selected_font = prepared[selected]
+        config.set_font_selection(
+            font_path=selected_font["font_path"],
+            font_index=selected_font["font_index"],
+        )
+        render.clear_font_cache()
+        print(
+            f"  {G_DIM}> using {selected_font['name']} ({selected_font['file_name']}){RST}"
+        )
+        time.sleep(0.8)
+        print(CLR, end="")
+        print(CURSOR_OFF, end="")
+        print()
+        return
+
+    fd = sys.stdin.fileno()
+    old_settings = termios.tcgetattr(fd)
+    try:
+        tty.setcbreak(fd)
+        while True:
+            _draw_font_picker(prepared, selected)
+            key = _read_picker_key()
+            if key == "up":
+                selected = max(0, selected - 1)
+            elif key == "down":
+                selected = min(len(prepared) - 1, selected + 1)
+            elif key == "enter":
+                break
+            elif key == "interrupt":
+                raise KeyboardInterrupt
+    finally:
+        termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
+
+    selected_font = prepared[selected]
+    config.set_font_selection(
+        font_path=selected_font["font_path"],
+        font_index=selected_font["font_index"],
+    )
+    render.clear_font_cache()
+    print(
+        f"  {G_DIM}> using {selected_font['name']} ({selected_font['file_name']}){RST}"
+    )
+    time.sleep(0.8)
+    print(CLR, end="")
+    print(CURSOR_OFF, end="")
+    print()
+
+
 def main():
     atexit.register(lambda: print(CURSOR_ON, end="", flush=True))
 
@@ -40,6 +262,8 @@ def main():
     w = tw()
     print(CLR, end="")
     print(CURSOR_OFF, end="")
+    pick_font_face()
+    w = tw()
     print()
     time.sleep(0.4)
 
@@ -48,23 +272,29 @@ def main():
         time.sleep(0.07)
 
     print()
-    _subtitle = "literary consciousness stream" if config.MODE == 'poetry' else "digital consciousness stream"
+    _subtitle = (
+        "literary consciousness stream"
+        if config.MODE == "poetry"
+        else "digital consciousness stream"
+    )
     print(f"  {W_DIM}v0.1 · {_subtitle}{RST}")
     print(f"  {W_GHOST}{'─' * (w - 4)}{RST}")
     print()
     time.sleep(0.4)
 
-    cached = load_cache() if '--refresh' not in sys.argv else None
+    cached = load_cache() if "--refresh" not in sys.argv else None
     if cached:
         items = cached
         boot_ln("Cache", f"LOADED [{len(items)} SIGNALS]", True)
-    elif config.MODE == 'poetry':
+    elif config.MODE == "poetry":
         slow_print("  > INITIALIZING LITERARY CORPUS...\n")
         time.sleep(0.2)
         print()
         items, linked, failed = fetch_poetry()
         print()
-        print(f"  {G_DIM}>{RST} {G_MID}{linked} TEXTS LOADED{RST} {W_GHOST}· {failed} DARK{RST}")
+        print(
+            f"  {G_DIM}>{RST} {G_MID}{linked} TEXTS LOADED{RST} {W_GHOST}· {failed} DARK{RST}"
+        )
         print(f"  {G_DIM}>{RST} {G_MID}{len(items)} STANZAS ACQUIRED{RST}")
         save_cache(items)
     else:
@@ -73,7 +303,9 @@ def main():
         print()
         items, linked, failed = fetch_all()
         print()
-        print(f"  {G_DIM}>{RST} {G_MID}{linked} SOURCES LINKED{RST} {W_GHOST}· {failed} DARK{RST}")
+        print(
+            f"  {G_DIM}>{RST} {G_MID}{linked} SOURCES LINKED{RST} {W_GHOST}· {failed} DARK{RST}"
+        )
         print(f"  {G_DIM}>{RST} {G_MID}{len(items)} SIGNALS ACQUIRED{RST}")
         save_cache(items)
 
@@ -85,11 +317,17 @@ def main():
     mic = MicMonitor(threshold_db=config.MIC_THRESHOLD_DB)
     mic_ok = mic.start()
     if mic.available:
-        boot_ln("Microphone", "ACTIVE" if mic_ok else "OFFLINE · check System Settings → Privacy → Microphone", bool(mic_ok))
+        boot_ln(
+            "Microphone",
+            "ACTIVE"
+            if mic_ok
+            else "OFFLINE · check System Settings → Privacy → Microphone",
+            bool(mic_ok),
+        )
 
     ntfy = NtfyPoller(
         config.NTFY_TOPIC,
-        poll_interval=config.NTFY_POLL_INTERVAL,
+        reconnect_delay=config.NTFY_RECONNECT_DELAY,
         display_secs=config.MESSAGE_DISPLAY_SECS,
     )
     ntfy_ok = ntfy.start()

engine/config.py

@@ -1,23 +1,212 @@
 """
 Configuration constants, CLI flags, and glyph tables.
+Supports both global constants (backward compatible) and injected config for testing.
 """
 
 import sys
+from dataclasses import dataclass, field
+from pathlib import Path
+
+_REPO_ROOT = Path(__file__).resolve().parent.parent
+_FONT_EXTENSIONS = {".otf", ".ttf", ".ttc"}
+
+
+def _arg_value(flag, argv: list[str] | None = None):
+    """Get value following a CLI flag, if present."""
+    argv = argv or sys.argv
+    if flag not in argv:
+        return None
+    i = argv.index(flag)
+    return argv[i + 1] if i + 1 < len(argv) else None
+
+
+def _arg_int(flag, default, argv: list[str] | None = None):
+    """Get int CLI argument with safe fallback."""
+    raw = _arg_value(flag, argv)
+    if raw is None:
+        return default
+    try:
+        return int(raw)
+    except ValueError:
+        return default
+
+
+def _resolve_font_path(raw_path):
+    """Resolve font path; relative paths are anchored to repo root."""
+    p = Path(raw_path).expanduser()
+    if p.is_absolute():
+        return str(p)
+    return str((_REPO_ROOT / p).resolve())
+
+
+def _list_font_files(font_dir):
+    """List supported font files within a font directory."""
+    font_root = Path(font_dir)
+    if not font_root.exists() or not font_root.is_dir():
+        return []
+    return [
+        str(path.resolve())
+        for path in sorted(font_root.iterdir())
+        if path.is_file() and path.suffix.lower() in _FONT_EXTENSIONS
+    ]
+
+
+def list_repo_font_files():
+    """Public helper for discovering repository font files."""
+    return _list_font_files(FONT_DIR)
+
+
+def _get_platform_font_paths() -> dict[str, str]:
+    """Get platform-appropriate font paths for non-Latin scripts."""
+    import platform
+
+    system = platform.system()
+
+    if system == "Darwin":
+        return {
+            "zh-cn": "/System/Library/Fonts/STHeiti Medium.ttc",
+            "ja": "/System/Library/Fonts/ヒラギノ角ゴシック W9.ttc",
+            "ko": "/System/Library/Fonts/AppleSDGothicNeo.ttc",
+            "ru": "/System/Library/Fonts/Supplemental/Arial.ttf",
+            "uk": "/System/Library/Fonts/Supplemental/Arial.ttf",
+            "el": "/System/Library/Fonts/Supplemental/Arial.ttf",
+            "he": "/System/Library/Fonts/Supplemental/Arial.ttf",
+            "ar": "/System/Library/Fonts/GeezaPro.ttc",
+            "fa": "/System/Library/Fonts/GeezaPro.ttc",
+            "hi": "/System/Library/Fonts/Kohinoor.ttc",
+            "th": "/System/Library/Fonts/ThonburiUI.ttc",
+        }
+    elif system == "Linux":
+        return {
+            "zh-cn": "/usr/share/fonts/truetype/noto/NotoSansCJK-Regular.ttc",
+            "ja": "/usr/share/fonts/truetype/noto/NotoSansCJK-Regular.ttc",
+            "ko": "/usr/share/fonts/truetype/noto/NotoSansCJK-Regular.ttc",
+            "ru": "/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf",
+            "uk": "/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf",
+            "el": "/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf",
+            "he": "/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf",
+            "ar": "/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf",
+            "fa": "/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf",
+            "hi": "/usr/share/fonts/truetype/noto/NotoSansDevanagari-Regular.ttf",
+            "th": "/usr/share/fonts/truetype/noto/NotoSansThai-Regular.ttf",
+        }
+    else:
+        return {}
+
+
+@dataclass(frozen=True)
+class Config:
+    """Immutable configuration container for injected config."""
+
+    headline_limit: int = 1000
+    feed_timeout: int = 10
+    mic_threshold_db: int = 50
+    mode: str = "news"
+    firehose: bool = False
+
+    ntfy_topic: str = "https://ntfy.sh/klubhaus_terminal_mainline/json"
+    ntfy_reconnect_delay: int = 5
+    message_display_secs: int = 30
+
+    font_dir: str = "fonts"
+    font_path: str = ""
+    font_index: int = 0
+    font_picker: bool = True
+    font_sz: int = 60
+    render_h: int = 8
+
+    ssaa: int = 4
+
+    scroll_dur: float = 5.625
+    frame_dt: float = 0.05
+    firehose_h: int = 12
+    grad_speed: float = 0.08
+
+    glitch_glyphs: str = "░▒▓█▌▐╌╍╎╏┃┆┇┊┋"
+    kata_glyphs: str = "ﾊﾐﾋｰｳｼﾅﾓﾆｻﾜﾂｵﾘｱﾎﾃﾏｹﾒｴｶｷﾑﾕﾗｾﾈｽﾀﾇﾍ"
+
+    script_fonts: dict[str, str] = field(default_factory=_get_platform_font_paths)
+
+    @classmethod
+    def from_args(cls, argv: list[str] | None = None) -> "Config":
+        """Create Config from CLI arguments (or custom argv for testing)."""
+        argv = argv or sys.argv
+
+        font_dir = _resolve_font_path(_arg_value("--font-dir", argv) or "fonts")
+        font_file_arg = _arg_value("--font-file", argv)
+        font_files = _list_font_files(font_dir)
+        font_path = (
+            _resolve_font_path(font_file_arg)
+            if font_file_arg
+            else (font_files[0] if font_files else "")
+        )
+
+        return cls(
+            headline_limit=1000,
+            feed_timeout=10,
+            mic_threshold_db=50,
+            mode="poetry" if "--poetry" in argv or "-p" in argv else "news",
+            firehose="--firehose" in argv,
+            ntfy_topic="https://ntfy.sh/klubhaus_terminal_mainline/json",
+            ntfy_reconnect_delay=5,
+            message_display_secs=30,
+            font_dir=font_dir,
+            font_path=font_path,
+            font_index=max(0, _arg_int("--font-index", 0, argv)),
+            font_picker="--no-font-picker" not in argv,
+            font_sz=60,
+            render_h=8,
+            ssaa=4,
+            scroll_dur=5.625,
+            frame_dt=0.05,
+            firehose_h=12,
+            grad_speed=0.08,
+            glitch_glyphs="░▒▓█▌▐╌╍╎╏┃┆┇┊┋",
+            kata_glyphs="ﾊﾐﾋｰｳｼﾅﾓﾆｻﾜﾂｵﾘｱﾎﾃﾏｹﾒｴｶｷﾑﾕﾗｾﾈｽﾀﾇﾍ",
+            script_fonts=_get_platform_font_paths(),
+        )
+
+
+_config: Config | None = None
+
+
+def get_config() -> Config:
+    """Get the global config instance (lazy-loaded)."""
+    global _config
+    if _config is None:
+        _config = Config.from_args()
+    return _config
+
+
+def set_config(config: Config) -> None:
+    """Set the global config instance (for testing)."""
+    global _config
+    _config = config
+
 
 # ─── RUNTIME ──────────────────────────────────────────────
 HEADLINE_LIMIT = 1000
 FEED_TIMEOUT = 10
 MIC_THRESHOLD_DB = 50  # dB above which glitches intensify
-MODE = 'poetry' if '--poetry' in sys.argv or '-p' in sys.argv else 'news'
-FIREHOSE = '--firehose' in sys.argv
+MODE = "poetry" if "--poetry" in sys.argv or "-p" in sys.argv else "news"
+FIREHOSE = "--firehose" in sys.argv
 
 # ─── NTFY MESSAGE QUEUE ──────────────────────────────────
-NTFY_TOPIC = "https://ntfy.sh/klubhaus_terminal_mainline/json?since=20s&poll=1"
-NTFY_POLL_INTERVAL = 15   # seconds between polls
+NTFY_TOPIC = "https://ntfy.sh/klubhaus_terminal_mainline/json"
+NTFY_RECONNECT_DELAY = 5  # seconds before reconnecting after a dropped stream
 MESSAGE_DISPLAY_SECS = 30  # how long a message holds the screen
 
 # ─── FONT RENDERING ──────────────────────────────────────
-FONT_PATH = "/Users/genejohnson/Documents/CS Bishop Drawn/CSBishopDrawn-Italic.otf"
+FONT_DIR = _resolve_font_path(_arg_value("--font-dir") or "fonts")
+_FONT_FILE_ARG = _arg_value("--font-file")
+_FONT_FILES = _list_font_files(FONT_DIR)
+FONT_PATH = (
+    _resolve_font_path(_FONT_FILE_ARG)
+    if _FONT_FILE_ARG
+    else (_FONT_FILES[0] if _FONT_FILES else "")
+)
+FONT_INDEX = max(0, _arg_int("--font-index", 0))
+FONT_PICKER = "--no-font-picker" not in sys.argv
 FONT_SZ = 60
 RENDER_H = 8  # terminal rows per rendered text line
 
@@ -33,3 +222,12 @@ GRAD_SPEED = 0.08         # gradient traversal speed (cycles/sec, ~12s full swee
 # ─── GLYPHS ───────────────────────────────────────────────
 GLITCH = "░▒▓█▌▐╌╍╎╏┃┆┇┊┋"
 KATA = "ﾊﾐﾋｰｳｼﾅﾓﾆｻﾜﾂｵﾘｱﾎﾃﾏｹﾒｴｶｷﾑﾕﾗｾﾈｽﾀﾇﾍ"
+
+
+def set_font_selection(font_path=None, font_index=None):
+    """Set runtime primary font selection."""
+    global FONT_PATH, FONT_INDEX
+    if font_path is not None:
+        FONT_PATH = _resolve_font_path(font_path)
+    if font_index is not None:
+        FONT_INDEX = max(0, int(font_index))

engine/controller.py

@@ -0,0 +1,68 @@
+"""
+Stream controller - manages input sources and orchestrates the render stream.
+"""
+
+from engine.config import Config, get_config
+from engine.eventbus import EventBus
+from engine.events import EventType, StreamEvent
+from engine.mic import MicMonitor
+from engine.ntfy import NtfyPoller
+from engine.scroll import stream
+
+
+class StreamController:
+    """Controls the stream lifecycle - initializes sources and runs the stream."""
+
+    def __init__(self, config: Config | None = None, event_bus: EventBus | None = None):
+        self.config = config or get_config()
+        self.event_bus = event_bus
+        self.mic: MicMonitor | None = None
+        self.ntfy: NtfyPoller | None = None
+
+    def initialize_sources(self) -> tuple[bool, bool]:
+        """Initialize microphone and ntfy sources.
+
+        Returns:
+            (mic_ok, ntfy_ok) - success status for each source
+        """
+        self.mic = MicMonitor(threshold_db=self.config.mic_threshold_db)
+        mic_ok = self.mic.start() if self.mic.available else False
+
+        self.ntfy = NtfyPoller(
+            self.config.ntfy_topic,
+            reconnect_delay=self.config.ntfy_reconnect_delay,
+            display_secs=self.config.message_display_secs,
+        )
+        ntfy_ok = self.ntfy.start()
+
+        return bool(mic_ok), ntfy_ok
+
+    def run(self, items: list) -> None:
+        """Run the stream with initialized sources."""
+        if self.mic is None or self.ntfy is None:
+            self.initialize_sources()
+
+        if self.event_bus:
+            self.event_bus.publish(
+                EventType.STREAM_START,
+                StreamEvent(
+                    event_type=EventType.STREAM_START,
+                    headline_count=len(items),
+                ),
+            )
+
+        stream(items, self.ntfy, self.mic)
+
+        if self.event_bus:
+            self.event_bus.publish(
+                EventType.STREAM_END,
+                StreamEvent(
+                    event_type=EventType.STREAM_END,
+                    headline_count=len(items),
+                ),
+            )
+
+    def cleanup(self) -> None:
+        """Clean up resources."""
+        if self.mic:
+            self.mic.stop()

engine/effects.py

@@ -7,8 +7,8 @@ import random
 from datetime import datetime
 
 from engine import config
-from engine.terminal import RST, DIM, G_LO, G_DIM, W_GHOST, C_DIM
 from engine.sources import FEEDS, POETRY_SOURCES
+from engine.terminal import C_DIM, DIM, G_DIM, G_LO, RST, W_GHOST
 
 
 def noise(w):
@@ -34,23 +34,23 @@ def fade_line(s, fade):
     if fade >= 1.0:
         return s
     if fade <= 0.0:
-        return ''
+        return ""
     result = []
     i = 0
     while i < len(s):
-        if s[i] == '\033' and i + 1 < len(s) and s[i + 1] == '[':
+        if s[i] == "\033" and i + 1 < len(s) and s[i + 1] == "[":
             j = i + 2
             while j < len(s) and not s[j].isalpha():
                 j += 1
-            result.append(s[i:j + 1])
+            result.append(s[i : j + 1])
             i = j + 1
-        elif s[i] == ' ':
-            result.append(' ')
+        elif s[i] == " ":
+            result.append(" ")
             i += 1
         else:
-            result.append(s[i] if random.random() < fade else ' ')
+            result.append(s[i] if random.random() < fade else " ")
             i += 1
-    return ''.join(result)
+    return "".join(result)
 
 
 def vis_trunc(s, w):
@@ -61,17 +61,17 @@ def vis_trunc(s, w):
     while i < len(s):
         if vw >= w:
             break
-        if s[i] == '\033' and i + 1 < len(s) and s[i + 1] == '[':
+        if s[i] == "\033" and i + 1 < len(s) and s[i + 1] == "[":
             j = i + 2
             while j < len(s) and not s[j].isalpha():
                 j += 1
-            result.append(s[i:j + 1])
+            result.append(s[i : j + 1])
             i = j + 1
         else:
             result.append(s[i])
             vw += 1
             i += 1
-    return ''.join(result)
+    return "".join(result)
 
 
 def next_headline(pool, items, seen):
@@ -94,7 +94,7 @@ def firehose_line(items, w):
     if r < 0.35:
         # Raw headline text
         title, src, ts = random.choice(items)
-        text = title[:w - 1]
+        text = title[: w - 1]
         color = random.choice([G_LO, G_DIM, W_GHOST, C_DIM])
         return f"{color}{text}{RST}"
     elif r < 0.55:
@@ -103,12 +103,13 @@ def firehose_line(items, w):
         return "".join(
             f"{random.choice([G_LO, G_DIM, C_DIM, W_GHOST])}"
             f"{random.choice(config.GLITCH + config.KATA)}{RST}"
-            if random.random() < d else " "
+            if random.random() < d
+            else " "
             for _ in range(w)
         )
     elif r < 0.78:
         # Status / program output
-        sources = FEEDS if config.MODE == 'news' else POETRY_SOURCES
+        sources = FEEDS if config.MODE == "news" else POETRY_SOURCES
         src = random.choice(list(sources.keys()))
         msgs = [
             f"  SIGNAL :: {src} :: {datetime.now().strftime('%H:%M:%S.%f')[:-3]}",
@@ -118,16 +119,16 @@ def firehose_line(items, w):
             f"  {''.join(random.choice(config.KATA) for _ in range(3))} STRM "
             f"{random.randint(0, 255):02X}:{random.randint(0, 255):02X}",
         ]
-        text = random.choice(msgs)[:w - 1]
+        text = random.choice(msgs)[: w - 1]
         color = random.choice([G_LO, G_DIM, W_GHOST])
         return f"{color}{text}{RST}"
     else:
         # Headline fragment with glitch prefix
         title, _, _ = random.choice(items)
         start = random.randint(0, max(0, len(title) - 20))
-        frag = title[start:start + random.randint(10, 35)]
+        frag = title[start : start + random.randint(10, 35)]
         pad = random.randint(0, max(0, w - len(frag) - 8))
-        gp = ''.join(random.choice(config.GLITCH) for _ in range(random.randint(1, 3)))
-        text = (' ' * pad + gp + ' ' + frag)[:w - 1]
+        gp = "".join(random.choice(config.GLITCH) for _ in range(random.randint(1, 3)))
+        text = (" " * pad + gp + " " + frag)[: w - 1]
         color = random.choice([G_LO, C_DIM, W_GHOST])
         return f"{color}{text}{RST}"

engine/emitters.py

@@ -0,0 +1,25 @@
+"""
+Event emitter protocols - abstract interfaces for event-producing components.
+"""
+
+from collections.abc import Callable
+from typing import Any, Protocol
+
+
+class EventEmitter(Protocol):
+    """Protocol for components that emit events."""
+
+    def subscribe(self, callback: Callable[[Any], None]) -> None: ...
+    def unsubscribe(self, callback: Callable[[Any], None]) -> None: ...
+
+
+class Startable(Protocol):
+    """Protocol for components that can be started."""
+
+    def start(self) -> Any: ...
+
+
+class Stoppable(Protocol):
+    """Protocol for components that can be stopped."""
+
+    def stop(self) -> None: ...

engine/eventbus.py

@@ -0,0 +1,72 @@
+"""
+Event bus - pub/sub messaging for decoupled component communication.
+"""
+
+import threading
+from collections import defaultdict
+from collections.abc import Callable
+from typing import Any
+
+from engine.events import EventType
+
+
+class EventBus:
+    """Thread-safe event bus for publish-subscribe messaging."""
+
+    def __init__(self):
+        self._subscribers: dict[EventType, list[Callable[[Any], None]]] = defaultdict(
+            list
+        )
+        self._lock = threading.Lock()
+
+    def subscribe(self, event_type: EventType, callback: Callable[[Any], None]) -> None:
+        """Register a callback for a specific event type."""
+        with self._lock:
+            self._subscribers[event_type].append(callback)
+
+    def unsubscribe(
+        self, event_type: EventType, callback: Callable[[Any], None]
+    ) -> None:
+        """Remove a callback for a specific event type."""
+        with self._lock:
+            if callback in self._subscribers[event_type]:
+                self._subscribers[event_type].remove(callback)
+
+    def publish(self, event_type: EventType, event: Any = None) -> None:
+        """Publish an event to all subscribers."""
+        with self._lock:
+            callbacks = list(self._subscribers.get(event_type, []))
+        for callback in callbacks:
+            try:
+                callback(event)
+            except Exception:
+                pass
+
+    def clear(self) -> None:
+        """Remove all subscribers."""
+        with self._lock:
+            self._subscribers.clear()
+
+    def subscriber_count(self, event_type: EventType | None = None) -> int:
+        """Get subscriber count for an event type, or total if None."""
+        with self._lock:
+            if event_type is None:
+                return sum(len(cb) for cb in self._subscribers.values())
+            return len(self._subscribers.get(event_type, []))
+
+
+_event_bus: EventBus | None = None
+
+
+def get_event_bus() -> EventBus:
+    """Get the global event bus instance."""
+    global _event_bus
+    if _event_bus is None:
+        _event_bus = EventBus()
+    return _event_bus
+
+
+def set_event_bus(bus: EventBus) -> None:
+    """Set the global event bus instance (for testing)."""
+    global _event_bus
+    _event_bus = bus

engine/events.py

@@ -0,0 +1,67 @@
+"""
+Event types for the mainline application.
+Defines the core events that flow through the system.
+These types support a future migration to an event-driven architecture.
+"""
+
+from dataclasses import dataclass
+from datetime import datetime
+from enum import Enum, auto
+
+
+class EventType(Enum):
+    """Core event types in the mainline application."""
+
+    NEW_HEADLINE = auto()
+    FRAME_TICK = auto()
+    MIC_LEVEL = auto()
+    NTFY_MESSAGE = auto()
+    STREAM_START = auto()
+    STREAM_END = auto()
+
+
+@dataclass
+class HeadlineEvent:
+    """Event emitted when a new headline is ready for display."""
+
+    title: str
+    source: str
+    timestamp: str
+    language: str | None = None
+
+
+@dataclass
+class FrameTickEvent:
+    """Event emitted on each render frame."""
+
+    frame_number: int
+    timestamp: datetime
+    delta_seconds: float
+
+
+@dataclass
+class MicLevelEvent:
+    """Event emitted when microphone level changes significantly."""
+
+    db_level: float
+    excess_above_threshold: float
+    timestamp: datetime
+
+
+@dataclass
+class NtfyMessageEvent:
+    """Event emitted when an ntfy message is received."""
+
+    title: str
+    body: str
+    message_id: str | None = None
+    timestamp: datetime | None = None
+
+
+@dataclass
+class StreamEvent:
+    """Event emitted when stream starts or ends."""
+
+    event_type: EventType
+    headline_count: int = 0
+    timestamp: datetime | None = None

engine/fetch.py

@@ -3,21 +3,27 @@ RSS feed fetching, Project Gutenberg parsing, and headline caching.
 Depends on: config, sources, filter, terminal.
 """
 
-import re
 import json
 import pathlib
+import re
 import urllib.request
 from datetime import datetime
+from typing import Any
 
 import feedparser
 
 from engine import config
+from engine.filter import skip, strip_tags
 from engine.sources import FEEDS, POETRY_SOURCES
-from engine.filter import strip_tags, skip
 from engine.terminal import boot_ln
 
+# Type alias for headline items
+HeadlineTuple = tuple[str, str, str]
+
+
 # ─── SINGLE FEED ──────────────────────────────────────────
-def fetch_feed(url):
+def fetch_feed(url: str) -> Any | None:
+    """Fetch and parse a single RSS feed URL."""
     try:
         req = urllib.request.Request(url, headers={"User-Agent": "mainline/0.1"})
         resp = urllib.request.urlopen(req, timeout=config.FEED_TIMEOUT)
@@ -27,8 +33,9 @@ def fetch_feed(url):
 
 
 # ─── ALL RSS FEEDS ────────────────────────────────────────
-def fetch_all():
-    items = []
+def fetch_all() -> tuple[list[HeadlineTuple], int, int]:
+    """Fetch all RSS feeds and return items, linked count, failed count."""
+    items: list[HeadlineTuple] = []
     linked = failed = 0
     for src, url in FEEDS.items():
         feed = fetch_feed(url)
@@ -58,31 +65,36 @@ def fetch_all():
 
 
 # ─── PROJECT GUTENBERG ────────────────────────────────────
-def _fetch_gutenberg(url, label):
+def _fetch_gutenberg(url: str, label: str) -> list[HeadlineTuple]:
     """Download and parse stanzas/passages from a Project Gutenberg text."""
     try:
         req = urllib.request.Request(url, headers={"User-Agent": "mainline/0.1"})
         resp = urllib.request.urlopen(req, timeout=15)
-        text = resp.read().decode('utf-8', errors='replace').replace('\r\n', '\n').replace('\r', '\n')
+        text = (
+            resp.read()
+            .decode("utf-8", errors="replace")
+            .replace("\r\n", "\n")
+            .replace("\r", "\n")
+        )
         # Strip PG boilerplate
-        m = re.search(r'\*\*\*\s*START OF[^\n]*\n', text)
+        m = re.search(r"\*\*\*\s*START OF[^\n]*\n", text)
         if m:
-            text = text[m.end():]
-        m = re.search(r'\*\*\*\s*END OF', text)
+            text = text[m.end() :]
+        m = re.search(r"\*\*\*\s*END OF", text)
         if m:
-            text = text[:m.start()]
+            text = text[: m.start()]
         # Split on blank lines into stanzas/passages
-        blocks = re.split(r'\n{2,}', text.strip())
+        blocks = re.split(r"\n{2,}", text.strip())
         items = []
         for blk in blocks:
-            blk = ' '.join(blk.split())   # flatten to one line
+            blk = " ".join(blk.split())  # flatten to one line
             if len(blk) < 20 or len(blk) > 280:
                 continue
             if blk.isupper():  # skip all-caps headers
                 continue
-            if re.match(r'^[IVXLCDM]+\.?\s*$', blk):  # roman numerals
+            if re.match(r"^[IVXLCDM]+\.?\s*$", blk):  # roman numerals
                 continue
-            items.append((blk, label, ''))
+            items.append((blk, label, ""))
         return items
     except Exception:
         return []

engine/filter.py

@@ -29,29 +29,29 @@ def strip_tags(html):
 
 # ─── CONTENT FILTER ───────────────────────────────────────
 _SKIP_RE = re.compile(
-    r'\b(?:'
+    r"\b(?:"
     # ── sports ──
-    r'football|soccer|basketball|baseball|softball|tennis|golf|cricket|rugby|'
-    r'hockey|lacrosse|volleyball|badminton|'
-    r'nba|nfl|nhl|mlb|mls|fifa|uefa|'
-    r'premier league|champions league|la liga|serie a|bundesliga|'
-    r'world cup|super bowl|world series|stanley cup|'
-    r'playoff|playoffs|touchdown|goalkeeper|striker|quarterback|'
-    r'slam dunk|home run|grand slam|offside|halftime|'
-    r'batting|wicket|innings|'
-    r'formula 1|nascar|motogp|'
-    r'boxing|ufc|mma|'
-    r'marathon|tour de france|'
-    r'transfer window|draft pick|relegation|'
+    r"football|soccer|basketball|baseball|softball|tennis|golf|cricket|rugby|"
+    r"hockey|lacrosse|volleyball|badminton|"
+    r"nba|nfl|nhl|mlb|mls|fifa|uefa|"
+    r"premier league|champions league|la liga|serie a|bundesliga|"
+    r"world cup|super bowl|world series|stanley cup|"
+    r"playoff|playoffs|touchdown|goalkeeper|striker|quarterback|"
+    r"slam dunk|home run|grand slam|offside|halftime|"
+    r"batting|wicket|innings|"
+    r"formula 1|nascar|motogp|"
+    r"boxing|ufc|mma|"
+    r"marathon|tour de france|"
+    r"transfer window|draft pick|relegation|"
     # ── vapid / insipid ──
-    r'kardashian|jenner|reality tv|reality show|'
-    r'influencer|viral video|tiktok|instagram|'
-    r'best dressed|worst dressed|red carpet|'
-    r'horoscope|zodiac|gossip|bikini|selfie|'
-    r'you won.t believe|what happened next|'
-    r'celebrity couple|celebrity feud|baby bump'
-    r')\b',
-    re.IGNORECASE
+    r"kardashian|jenner|reality tv|reality show|"
+    r"influencer|viral video|tiktok|instagram|"
+    r"best dressed|worst dressed|red carpet|"
+    r"horoscope|zodiac|gossip|bikini|selfie|"
+    r"you won.t believe|what happened next|"
+    r"celebrity couple|celebrity feud|baby bump"
+    r")\b",
+    re.IGNORECASE,
 )
 
 

engine/frame.py

@@ -0,0 +1,57 @@
+"""
+Frame timing utilities — FPS control and precise timing.
+"""
+
+import time
+
+
+class FrameTimer:
+    """Frame timer for consistent render loop timing."""
+
+    def __init__(self, target_frame_dt: float = 0.05):
+        self.target_frame_dt = target_frame_dt
+        self._frame_count = 0
+        self._start_time = time.monotonic()
+        self._last_frame_time = self._start_time
+
+    @property
+    def fps(self) -> float:
+        """Current FPS based on elapsed frames."""
+        elapsed = time.monotonic() - self._start_time
+        if elapsed > 0:
+            return self._frame_count / elapsed
+        return 0.0
+
+    def sleep_until_next_frame(self) -> float:
+        """Sleep to maintain target frame rate. Returns actual elapsed time."""
+        now = time.monotonic()
+        elapsed = now - self._last_frame_time
+        self._last_frame_time = now
+        self._frame_count += 1
+
+        sleep_time = max(0, self.target_frame_dt - elapsed)
+        if sleep_time > 0:
+            time.sleep(sleep_time)
+        return elapsed
+
+    def reset(self) -> None:
+        """Reset frame counter and start time."""
+        self._frame_count = 0
+        self._start_time = time.monotonic()
+        self._last_frame_time = self._start_time
+
+
+def calculate_scroll_step(
+    scroll_dur: float, view_height: int, padding: int = 15
+) -> float:
+    """Calculate scroll step interval for smooth scrolling.
+
+    Args:
+        scroll_dur: Duration in seconds for one headline to scroll through view
+        view_height: Terminal height in rows
+        padding: Extra rows for off-screen content
+
+    Returns:
+        Time in seconds between scroll steps
+    """
+    return scroll_dur / (view_height + padding) * 2

engine/layers.py

@@ -0,0 +1,201 @@
+"""
+Layer compositing — message overlay, ticker zone, firehose, noise.
+Depends on: config, render, effects.
+"""
+
+import random
+import re
+import time
+from datetime import datetime
+
+from engine import config
+from engine.effects import (
+    fade_line,
+    firehose_line,
+    glitch_bar,
+    noise,
+    vis_trunc,
+)
+from engine.render import big_wrap, lr_gradient, lr_gradient_opposite
+from engine.terminal import RST, W_COOL
+
+MSG_META = "\033[38;5;245m"
+MSG_BORDER = "\033[2;38;5;37m"
+
+
+def render_message_overlay(
+    msg: tuple[str, str, float] | None,
+    w: int,
+    h: int,
+    msg_cache: tuple,
+) -> tuple[list[str], tuple]:
+    """Render ntfy message overlay.
+
+    Args:
+        msg: (title, body, timestamp) or None
+        w: terminal width
+        h: terminal height
+        msg_cache: (cache_key, rendered_rows) for caching
+
+    Returns:
+        (list of ANSI strings, updated cache)
+    """
+    overlay = []
+    if msg is None:
+        return overlay, msg_cache
+
+    m_title, m_body, m_ts = msg
+    display_text = m_body or m_title or "(empty)"
+    display_text = re.sub(r"\s+", " ", display_text.upper())
+
+    cache_key = (display_text, w)
+    if msg_cache[0] != cache_key:
+        msg_rows = big_wrap(display_text, w - 4)
+        msg_cache = (cache_key, msg_rows)
+    else:
+        msg_rows = msg_cache[1]
+
+    msg_rows = lr_gradient_opposite(
+        msg_rows, (time.monotonic() * config.GRAD_SPEED) % 1.0
+    )
+
+    elapsed_s = int(time.monotonic() - m_ts)
+    remaining = max(0, config.MESSAGE_DISPLAY_SECS - elapsed_s)
+    ts_str = datetime.now().strftime("%H:%M:%S")
+    panel_h = len(msg_rows) + 2
+    panel_top = max(0, (h - panel_h) // 2)
+
+    row_idx = 0
+    for mr in msg_rows:
+        ln = vis_trunc(mr, w)
+        overlay.append(f"\033[{panel_top + row_idx + 1};1H  {ln}\033[0m\033[K")
+        row_idx += 1
+
+    meta_parts = []
+    if m_title and m_title != m_body:
+        meta_parts.append(m_title)
+    meta_parts.append(f"ntfy \u00b7 {ts_str} \u00b7 {remaining}s")
+    meta = (
+        "  " + " \u00b7 ".join(meta_parts)
+        if len(meta_parts) > 1
+        else "  " + meta_parts[0]
+    )
+    overlay.append(f"\033[{panel_top + row_idx + 1};1H{MSG_META}{meta}\033[0m\033[K")
+    row_idx += 1
+
+    bar = "\u2500" * (w - 4)
+    overlay.append(f"\033[{panel_top + row_idx + 1};1H  {MSG_BORDER}{bar}\033[0m\033[K")
+
+    return overlay, msg_cache
+
+
+def render_ticker_zone(
+    active: list,
+    scroll_cam: int,
+    ticker_h: int,
+    w: int,
+    noise_cache: dict,
+    grad_offset: float,
+) -> tuple[list[str], dict]:
+    """Render the ticker scroll zone.
+
+    Args:
+        active: list of (content_rows, color, canvas_y, meta_idx)
+        scroll_cam: camera position (viewport top)
+        ticker_h: height of ticker zone
+        w: terminal width
+        noise_cache: dict of cy -> noise string
+        grad_offset: gradient animation offset
+
+    Returns:
+        (list of ANSI strings, updated noise_cache)
+    """
+    buf = []
+    top_zone = max(1, int(ticker_h * 0.25))
+    bot_zone = max(1, int(ticker_h * 0.10))
+
+    def noise_at(cy):
+        if cy not in noise_cache:
+            noise_cache[cy] = noise(w) if random.random() < 0.15 else None
+        return noise_cache[cy]
+
+    for r in range(ticker_h):
+        scr_row = r + 1
+        cy = scroll_cam + r
+        top_f = min(1.0, r / top_zone) if top_zone > 0 else 1.0
+        bot_f = min(1.0, (ticker_h - 1 - r) / bot_zone) if bot_zone > 0 else 1.0
+        row_fade = min(top_f, bot_f)
+        drawn = False
+
+        for content, hc, by, midx in active:
+            cr = cy - by
+            if 0 <= cr < len(content):
+                raw = content[cr]
+                if cr != midx:
+                    colored = lr_gradient([raw], grad_offset)[0]
+                else:
+                    colored = raw
+                ln = vis_trunc(colored, w)
+                if row_fade < 1.0:
+                    ln = fade_line(ln, row_fade)
+
+                if cr == midx:
+                    buf.append(f"\033[{scr_row};1H{W_COOL}{ln}{RST}\033[K")
+                elif ln.strip():
+                    buf.append(f"\033[{scr_row};1H{ln}{RST}\033[K")
+                else:
+                    buf.append(f"\033[{scr_row};1H\033[K")
+                drawn = True
+                break
+
+        if not drawn:
+            n = noise_at(cy)
+            if row_fade < 1.0 and n:
+                n = fade_line(n, row_fade)
+            if n:
+                buf.append(f"\033[{scr_row};1H{n}")
+            else:
+                buf.append(f"\033[{scr_row};1H\033[K")
+
+    return buf, noise_cache
+
+
+def apply_glitch(
+    buf: list[str],
+    ticker_buf_start: int,
+    mic_excess: float,
+    w: int,
+) -> list[str]:
+    """Apply glitch effect to ticker buffer.
+
+    Args:
+        buf: current buffer
+        ticker_buf_start: index where ticker starts in buffer
+        mic_excess: mic level above threshold
+        w: terminal width
+
+    Returns:
+        Updated buffer with glitches applied
+    """
+    glitch_prob = 0.32 + min(0.9, mic_excess * 0.16)
+    n_hits = 4 + int(mic_excess / 2)
+    ticker_buf_len = len(buf) - ticker_buf_start
+
+    if random.random() < glitch_prob and ticker_buf_len > 0:
+        for _ in range(min(n_hits, ticker_buf_len)):
+            gi = random.randint(0, ticker_buf_len - 1)
+            scr_row = gi + 1
+            buf[ticker_buf_start + gi] = f"\033[{scr_row};1H{glitch_bar(w)}"
+
+    return buf
+
+
+def render_firehose(items: list, w: int, fh: int, h: int) -> list[str]:
+    """Render firehose strip at bottom of screen."""
+    buf = []
+    if fh > 0:
+        for fr in range(fh):
+            scr_row = h - fh + fr + 1
+            fline = firehose_line(items, w)
+            buf.append(f"\033[{scr_row};1H{fline}\033[K")
+    return buf

engine/mic.py

@@ -4,15 +4,21 @@ Gracefully degrades if sounddevice/numpy are unavailable.
 """
 
 import atexit
+from collections.abc import Callable
+from datetime import datetime
 
 try:
-    import sounddevice as _sd
     import numpy as _np
+    import sounddevice as _sd
+
     _HAS_MIC = True
 except Exception:
     _HAS_MIC = False
 
 
+from engine.events import MicLevelEvent
+
+
 class MicMonitor:
     """Background mic stream that exposes current RMS dB level."""
 
@@ -20,6 +26,7 @@ class MicMonitor:
         self.threshold_db = threshold_db
         self._db = -99.0
         self._stream = None
+        self._subscribers: list[Callable[[MicLevelEvent], None]] = []
 
     @property
     def available(self):
@@ -36,16 +43,43 @@ class MicMonitor:
         """dB above threshold (clamped to 0)."""
         return max(0.0, self._db - self.threshold_db)
 
+    def subscribe(self, callback: Callable[[MicLevelEvent], None]) -> None:
+        """Register a callback to be called when mic level changes."""
+        self._subscribers.append(callback)
+
+    def unsubscribe(self, callback: Callable[[MicLevelEvent], None]) -> None:
+        """Remove a registered callback."""
+        if callback in self._subscribers:
+            self._subscribers.remove(callback)
+
+    def _emit(self, event: MicLevelEvent) -> None:
+        """Emit an event to all subscribers."""
+        for cb in self._subscribers:
+            try:
+                cb(event)
+            except Exception:
+                pass
+
     def start(self):
         """Start background mic stream. Returns True on success, False/None otherwise."""
         if not _HAS_MIC:
             return None
+
         def _cb(indata, frames, t, status):
-            rms = float(_np.sqrt(_np.mean(indata ** 2)))
+            rms = float(_np.sqrt(_np.mean(indata**2)))
             self._db = 20 * _np.log10(rms) if rms > 0 else -99.0
+            if self._subscribers:
+                event = MicLevelEvent(
+                    db_level=self._db,
+                    excess_above_threshold=max(0.0, self._db - self.threshold_db),
+                    timestamp=datetime.now(),
+                )
+                self._emit(event)
+
         try:
             self._stream = _sd.InputStream(
-                callback=_cb, channels=1, samplerate=44100, blocksize=2048)
+                callback=_cb, channels=1, samplerate=44100, blocksize=2048
+            )
             self._stream.start()
             atexit.register(self.stop)
             return True

engine/ntfy.py

@@ -1,9 +1,9 @@
 """
-ntfy.sh message poller — standalone, zero internal dependencies.
+ntfy.sh SSE stream listener — standalone, zero internal dependencies.
 Reusable by any visualizer:
 
     from engine.ntfy import NtfyPoller
-    poller = NtfyPoller("https://ntfy.sh/my_topic/json?since=20s&poll=1")
+    poller = NtfyPoller("https://ntfy.sh/my_topic/json")
     poller.start()
     # in render loop:
     msg = poller.get_active_message()
@@ -13,24 +13,47 @@ Reusable by any visualizer:
 """
 
 import json
-import time
 import threading
+import time
 import urllib.request
+from collections.abc import Callable
+from datetime import datetime
+from urllib.parse import parse_qs, urlencode, urlparse, urlunparse
+
+from engine.events import NtfyMessageEvent
 
 
 class NtfyPoller:
-    """Background poller for ntfy.sh topics."""
+    """SSE stream listener for ntfy.sh topics. Messages arrive in ~1s (network RTT)."""
 
-    def __init__(self, topic_url, poll_interval=15, display_secs=30):
+    def __init__(self, topic_url, reconnect_delay=5, display_secs=30):
         self.topic_url = topic_url
-        self.poll_interval = poll_interval
+        self.reconnect_delay = reconnect_delay
         self.display_secs = display_secs
         self._message = None  # (title, body, monotonic_timestamp) or None
         self._lock = threading.Lock()
+        self._subscribers: list[Callable[[NtfyMessageEvent], None]] = []
+
+    def subscribe(self, callback: Callable[[NtfyMessageEvent], None]) -> None:
+        """Register a callback to be called when a message is received."""
+        self._subscribers.append(callback)
+
+    def unsubscribe(self, callback: Callable[[NtfyMessageEvent], None]) -> None:
+        """Remove a registered callback."""
+        if callback in self._subscribers:
+            self._subscribers.remove(callback)
+
+    def _emit(self, event: NtfyMessageEvent) -> None:
+        """Emit an event to all subscribers."""
+        for cb in self._subscribers:
+            try:
+                cb(event)
+            except Exception:
+                pass
 
     def start(self):
-        """Start background polling thread. Returns True."""
-        t = threading.Thread(target=self._poll_loop, daemon=True)
+        """Start background stream thread. Returns True."""
+        t = threading.Thread(target=self._stream_loop, daemon=True)
         t.start()
         return True
 
@@ -50,19 +73,36 @@ class NtfyPoller:
         with self._lock:
             self._message = None
 
-    def _poll_loop(self):
+    def _build_url(self, last_id=None):
+        """Build the stream URL, substituting since= to avoid message replays on reconnect."""
+        parsed = urlparse(self.topic_url)
+        params = parse_qs(parsed.query, keep_blank_values=True)
+        params["since"] = [last_id if last_id else "20s"]
+        new_query = urlencode({k: v[0] for k, v in params.items()})
+        return urlunparse(parsed._replace(query=new_query))
+
+    def _stream_loop(self):
+        last_id = None
         while True:
             try:
+                url = self._build_url(last_id)
                 req = urllib.request.Request(
-                    self.topic_url, headers={"User-Agent": "mainline/0.1"})
-                resp = urllib.request.urlopen(req, timeout=10)
-                for line in resp.read().decode('utf-8', errors='replace').strip().split('\n'):
-                    if not line.strip():
-                        continue
+                    url, headers={"User-Agent": "mainline/0.1"}
+                )
+                # timeout=90 keeps the socket alive through ntfy.sh keepalive heartbeats
+                resp = urllib.request.urlopen(req, timeout=90)
+                while True:
+                    line = resp.readline()
+                    if not line:
+                        break  # server closed connection — reconnect
                     try:
-                        data = json.loads(line)
+                        data = json.loads(line.decode("utf-8", errors="replace"))
                     except json.JSONDecodeError:
                         continue
+                    # Advance cursor on every event (message + keepalive) to
+                    # avoid replaying already-seen events after a reconnect.
+                    if "id" in data:
+                        last_id = data["id"]
                     if data.get("event") == "message":
                         with self._lock:
                             self._message = (
@@ -70,6 +110,13 @@ class NtfyPoller:
                                 data.get("message", ""),
                                 time.monotonic(),
                             )
+                        event = NtfyMessageEvent(
+                            title=data.get("title", ""),
+                            body=data.get("message", ""),
+                            message_id=data.get("id"),
+                            timestamp=datetime.now(),
+                        )
+                        self._emit(event)
             except Exception:
                 pass
-            time.sleep(self.poll_interval)
+            time.sleep(self.reconnect_delay)

engine/render.py

@@ -4,14 +4,15 @@ Font loading, text rasterization, word-wrap, gradient coloring, headline block a
 Depends on: config, terminal, sources, translate.
 """
 
-import re
 import random
+import re
+from pathlib import Path
 
 from PIL import Image, ImageDraw, ImageFont
 
 from engine import config
+from engine.sources import NO_UPPER, SCRIPT_FONTS, SOURCE_LANGS
 from engine.terminal import RST
-from engine.sources import SCRIPT_FONTS, SOURCE_LANGS, NO_UPPER
 from engine.translate import detect_location_language, translate_headline
 
 # ─── GRADIENT ─────────────────────────────────────────────
@@ -31,19 +32,75 @@ GRAD_COLS = [
     "\033[2;38;5;235m",  # near black
 ]
 
+# Complementary sweep for queue messages (opposite hue family from ticker greens)
+MSG_GRAD_COLS = [
+    "\033[1;38;5;231m",  # white
+    "\033[1;38;5;225m",  # pale pink-white
+    "\033[38;5;219m",  # bright pink
+    "\033[38;5;213m",  # hot pink
+    "\033[38;5;207m",  # magenta
+    "\033[38;5;201m",  # bright magenta
+    "\033[38;5;165m",  # orchid-red
+    "\033[38;5;161m",  # ruby-magenta
+    "\033[38;5;125m",  # dark magenta
+    "\033[38;5;89m",  # deep maroon-magenta
+    "\033[2;38;5;89m",  # dim deep maroon-magenta
+    "\033[2;38;5;235m",  # near black
+]
+
 # ─── FONT LOADING ─────────────────────────────────────────
 _FONT_OBJ = None
+_FONT_OBJ_KEY = None
 _FONT_CACHE = {}
 
 
 def font():
-    """Lazy-load the primary OTF font."""
-    global _FONT_OBJ
-    if _FONT_OBJ is None:
-        _FONT_OBJ = ImageFont.truetype(config.FONT_PATH, config.FONT_SZ)
+    """Lazy-load the primary OTF font (path + face index aware)."""
+    global _FONT_OBJ, _FONT_OBJ_KEY
+    if not config.FONT_PATH:
+        raise FileNotFoundError(
+            f"No primary font selected. Add .otf/.ttf/.ttc files to {config.FONT_DIR}."
+        )
+    key = (config.FONT_PATH, config.FONT_INDEX, config.FONT_SZ)
+    if _FONT_OBJ is None or key != _FONT_OBJ_KEY:
+        _FONT_OBJ = ImageFont.truetype(
+            config.FONT_PATH, config.FONT_SZ, index=config.FONT_INDEX
+        )
+        _FONT_OBJ_KEY = key
     return _FONT_OBJ
 
 
+def clear_font_cache():
+    """Reset cached font objects after changing primary font selection."""
+    global _FONT_OBJ, _FONT_OBJ_KEY
+    _FONT_OBJ = None
+    _FONT_OBJ_KEY = None
+
+
+def load_font_face(font_path, font_index=0, size=None):
+    """Load a specific face from a font file or collection."""
+    font_size = size or config.FONT_SZ
+    return ImageFont.truetype(font_path, font_size, index=font_index)
+
+
+def list_font_faces(font_path, max_faces=64):
+    """Return discoverable face indexes + display names from a font file."""
+    faces = []
+    for idx in range(max_faces):
+        try:
+            fnt = load_font_face(font_path, idx)
+        except Exception:
+            if idx == 0:
+                raise
+            break
+        family, style = fnt.getname()
+        display = f"{family} {style}".strip()
+        if not display:
+            display = f"{Path(font_path).stem} [{idx}]"
+        faces.append({"index": idx, "name": display})
+    return faces
+
+
 def font_for_lang(lang=None):
     """Get appropriate font for a language."""
     if lang is None or lang not in SCRIPT_FONTS:
@@ -67,7 +124,7 @@ def render_line(text, fnt=None):
     pad = 4
     img_w = bbox[2] - bbox[0] + pad * 2
     img_h = bbox[3] - bbox[1] + pad * 2
-    img = Image.new('L', (img_w, img_h), 0)
+    img = Image.new("L", (img_w, img_h), 0)
     draw = ImageDraw.Draw(img)
     draw.text((-bbox[0] + pad, -bbox[1] + pad), text, fill=255, font=fnt)
     pix_h = config.RENDER_H * 2
@@ -132,9 +189,10 @@ def big_wrap(text, max_w, fnt=None):
     return out
 
 
-def lr_gradient(rows, offset=0.0):
+def lr_gradient(rows, offset=0.0, grad_cols=None):
     """Color each non-space block character with a shifting left-to-right gradient."""
-    n = len(GRAD_COLS)
+    cols = grad_cols or GRAD_COLS
+    n = len(cols)
     max_x = max((len(r.rstrip()) for r in rows if r.strip()), default=1)
     out = []
     for row in rows:
@@ -143,20 +201,29 @@ def lr_gradient(rows, offset=0.0):
             continue
         buf = []
         for x, ch in enumerate(row):
-            if ch == ' ':
-                buf.append(' ')
+            if ch == " ":
+                buf.append(" ")
             else:
                 shifted = (x / max(max_x - 1, 1) + offset) % 1.0
                 idx = min(round(shifted * (n - 1)), n - 1)
-                buf.append(f"{GRAD_COLS[idx]}{ch}\033[0m")
+                buf.append(f"{cols[idx]}{ch}{RST}")
         out.append("".join(buf))
     return out
 
 
+def lr_gradient_opposite(rows, offset=0.0):
+    """Complementary (opposite wheel) gradient used for queue message panels."""
+    return lr_gradient(rows, offset, MSG_GRAD_COLS)
+
+
 # ─── HEADLINE BLOCK ASSEMBLY ─────────────────────────────
 def make_block(title, src, ts, w):
     """Render a headline into a content block with color."""
-    target_lang = (SOURCE_LANGS.get(src) or detect_location_language(title)) if config.MODE == 'news' else None
+    target_lang = (
+        (SOURCE_LANGS.get(src) or detect_location_language(title))
+        if config.MODE == "news"
+        else None
+    )
     lang_font = font_for_lang(target_lang)
     if target_lang:
         title = translate_headline(title, target_lang)
@@ -165,11 +232,18 @@ def make_block(title, src, ts, w):
         title_up = re.sub(r"\s+", " ", title)
     else:
         title_up = re.sub(r"\s+", " ", title.upper())
-    for old, new in [("\u2019","'"), ("\u2018","'"), ("\u201c",'"'),
-                     ("\u201d",'"'), ("\u2013","-"), ("\u2014","-")]:
+    for old, new in [
+        ("\u2019", "'"),
+        ("\u2018", "'"),
+        ("\u201c", '"'),
+        ("\u201d", '"'),
+        ("\u2013", "-"),
+        ("\u2014", "-"),
+    ]:
         title_up = title_up.replace(old, new)
     big_rows = big_wrap(title_up, w - 4, lang_font)
-    hc = random.choice([
+    hc = random.choice(
+        [
             "\033[38;5;46m",  # matrix green
             "\033[38;5;34m",  # dark green
             "\033[38;5;82m",  # lime
@@ -186,7 +260,8 @@ def make_block(title, src, ts, w):
             "\033[38;5;115m",  # sage
             "\033[1;38;5;46m",  # bold green
             "\033[1;38;5;250m",  # bold white
-    ])
+        ]
+    )
     content = ["  " + r for r in big_rows]
     content.append("")
     meta = f"\u2591 {src} \u00b7 {ts}"

engine/scroll.py

@@ -1,22 +1,26 @@
 """
-Scroll engine — the main frame loop with headline rendering and message display.
-Depends on: config, terminal, render, effects, ntfy, mic.
+Render engine — ticker content, scroll motion, message panel, and firehose overlay.
+Orchestrates viewport, frame timing, and layers.
 """
 
-import re
+import random
 import sys
 import time
-import random
-from datetime import datetime
 
 from engine import config
-from engine.terminal import RST, W_COOL, CLR, tw, th
-from engine.render import big_wrap, lr_gradient, make_block
-from engine.effects import noise, glitch_bar, fade_line, vis_trunc, next_headline, firehose_line
+from engine.frame import calculate_scroll_step
+from engine.layers import (
+    apply_glitch,
+    render_firehose,
+    render_message_overlay,
+    render_ticker_zone,
+)
+from engine.terminal import CLR
+from engine.viewport import th, tw
 
 
 def stream(items, ntfy_poller, mic_monitor):
-    """Main rendering loop. Scrolls headlines, shows ntfy messages, applies effects."""
+    """Main render loop with four layers: message, ticker, scroll motion, firehose."""
     random.shuffle(items)
     pool = list(items)
     seen = set()
@@ -28,159 +32,78 @@ def stream(items, ntfy_poller, mic_monitor):
 
     w, h = tw(), th()
     fh = config.FIREHOSE_H if config.FIREHOSE else 0
-    sh = h - fh                    # scroll zone height
-    GAP = 3            # blank rows between headlines
-    scroll_interval = config.SCROLL_DUR / (sh + 15) * 2
+    ticker_view_h = h - fh
+    GAP = 3
+    scroll_step_interval = calculate_scroll_step(config.SCROLL_DUR, ticker_view_h)
 
-    # active blocks: (content_rows, color, canvas_y, meta_idx)
     active = []
-    cam = 0            # viewport top in virtual canvas coords
-    next_y = sh        # canvas-y where next block starts (off-screen bottom)
+    scroll_cam = 0
+    ticker_next_y = ticker_view_h
     noise_cache = {}
-    scroll_accum = 0.0
+    scroll_motion_accum = 0.0
+    msg_cache = (None, None)
 
-    def _noise_at(cy):
-        if cy not in noise_cache:
-            noise_cache[cy] = noise(w) if random.random() < 0.15 else None
-        return noise_cache[cy]
+    while True:
+        if queued >= config.HEADLINE_LIMIT and not active:
+            break
 
-    # Message color: bright cyan/white — distinct from headline greens
-    MSG_META  = "\033[38;5;245m"     # cool grey
-    MSG_BORDER = "\033[2;38;5;37m"   # dim teal
-    _msg_cache = (None, None)        # (cache_key, rendered_rows)
-
-    while queued < config.HEADLINE_LIMIT or active:
         t0 = time.monotonic()
         w, h = tw(), th()
         fh = config.FIREHOSE_H if config.FIREHOSE else 0
-        sh = h - fh
+        ticker_view_h = h - fh
+        scroll_step_interval = calculate_scroll_step(config.SCROLL_DUR, ticker_view_h)
 
-        # ── Check for ntfy message ────────────────────────
-        msg_h = 0  # rows consumed by message zone at top
         msg = ntfy_poller.get_active_message()
+        msg_overlay, msg_cache = render_message_overlay(msg, w, h, msg_cache)
 
         buf = []
-        if msg is not None:
-            m_title, m_body, m_ts = msg
-            # ── Message zone: pinned to top, scroll continues below ──
-            display_text = m_body or m_title or "(empty)"
-            display_text = re.sub(r"\s+", " ", display_text.upper())
-            cache_key = (display_text, w)
-            if _msg_cache[0] != cache_key:
-                msg_rows = big_wrap(display_text, w - 4)
-                _msg_cache = (cache_key, msg_rows)
-            else:
-                msg_rows = _msg_cache[1]
-            msg_rows = lr_gradient(msg_rows, (time.monotonic() * config.GRAD_SPEED) % 1.0)
-            # Layout: rendered text + meta + border
-            elapsed_s = int(time.monotonic() - m_ts)
-            remaining = max(0, config.MESSAGE_DISPLAY_SECS - elapsed_s)
-            ts_str = datetime.now().strftime("%H:%M:%S")
-            row_idx = 0
-            for mr in msg_rows:
-                ln = vis_trunc(mr, w)
-                buf.append(f"\033[{row_idx+1};1H  {ln}{RST}\033[K")
-                row_idx += 1
-            # Meta line: title (if distinct) + source + countdown
-            meta_parts = []
-            if m_title and m_title != m_body:
-                meta_parts.append(m_title)
-            meta_parts.append(f"ntfy \u00b7 {ts_str} \u00b7 {remaining}s")
-            meta = "  " + " \u00b7 ".join(meta_parts) if len(meta_parts) > 1 else "  " + meta_parts[0]
-            buf.append(f"\033[{row_idx+1};1H{MSG_META}{meta}{RST}\033[K")
-            row_idx += 1
-            # Border — constant boundary between message and scroll
-            bar = "\u2500" * (w - 4)
-            buf.append(f"\033[{row_idx+1};1H  {MSG_BORDER}{bar}{RST}\033[K")
-            row_idx += 1
-            msg_h = row_idx
+        ticker_h = ticker_view_h
 
-        # Effective scroll zone: below message, above firehose
-        scroll_h = sh - msg_h
+        scroll_motion_accum += config.FRAME_DT
+        while scroll_motion_accum >= scroll_step_interval:
+            scroll_motion_accum -= scroll_step_interval
+            scroll_cam += 1
 
-        # ── Scroll: headline rendering (always runs) ──────
-        # Advance scroll on schedule
-        scroll_accum += config.FRAME_DT
-        while scroll_accum >= scroll_interval:
-            scroll_accum -= scroll_interval
-            cam += 1
+            while (
+                ticker_next_y < scroll_cam + ticker_view_h + 10
+                and queued < config.HEADLINE_LIMIT
+            ):
+                from engine.effects import next_headline
+                from engine.render import make_block
 
-            # Enqueue new headlines when room at the bottom
-            while next_y < cam + sh + 10 and queued < config.HEADLINE_LIMIT:
                 t, src, ts = next_headline(pool, items, seen)
-                content, hc, midx = make_block(t, src, ts, w)
-                active.append((content, hc, next_y, midx))
-                next_y += len(content) + GAP
+                ticker_content, hc, midx = make_block(t, src, ts, w)
+                active.append((ticker_content, hc, ticker_next_y, midx))
+                ticker_next_y += len(ticker_content) + GAP
                 queued += 1
 
-            # Prune off-screen blocks and stale noise
-            active = [(c, hc, by, mi) for c, hc, by, mi in active
-                      if by + len(c) > cam]
+            active = [
+                (c, hc, by, mi) for c, hc, by, mi in active if by + len(c) > scroll_cam
+            ]
             for k in list(noise_cache):
-                if k < cam:
+                if k < scroll_cam:
                     del noise_cache[k]
 
-        # Draw scroll zone (below message zone, above firehose)
-        top_zone = max(1, int(scroll_h * 0.25))
-        bot_zone = max(1, int(scroll_h * 0.10))
         grad_offset = (time.monotonic() * config.GRAD_SPEED) % 1.0
-        scroll_buf_start = len(buf)  # track where scroll rows start in buf
-        for r in range(scroll_h):
-            scr_row = msg_h + r + 1  # 1-indexed ANSI screen row
-            cy = cam + r
-            top_f = min(1.0, r / top_zone) if top_zone > 0 else 1.0
-            bot_f = min(1.0, (scroll_h - 1 - r) / bot_zone) if bot_zone > 0 else 1.0
-            row_fade = min(top_f, bot_f)
-            drawn = False
-            for content, hc, by, midx in active:
-                cr = cy - by
-                if 0 <= cr < len(content):
-                    raw = content[cr]
-                    if cr != midx:
-                        colored = lr_gradient([raw], grad_offset)[0]
-                    else:
-                        colored = raw
-                    ln = vis_trunc(colored, w)
-                    if row_fade < 1.0:
-                        ln = fade_line(ln, row_fade)
-                    if cr == midx:
-                        buf.append(f"\033[{scr_row};1H{W_COOL}{ln}{RST}\033[K")
-                    elif ln.strip():
-                        buf.append(f"\033[{scr_row};1H{ln}{RST}\033[K")
-                    else:
-                        buf.append(f"\033[{scr_row};1H\033[K")
-                    drawn = True
-                    break
-            if not drawn:
-                n = _noise_at(cy)
-                if row_fade < 1.0 and n:
-                    n = fade_line(n, row_fade)
-                if n:
-                    buf.append(f"\033[{scr_row};1H{n}")
-                else:
-                    buf.append(f"\033[{scr_row};1H\033[K")
+        ticker_buf_start = len(buf)
 
-        # Draw firehose zone
-        if config.FIREHOSE and fh > 0:
-            for fr in range(fh):
-                fline = firehose_line(items, w)
-                buf.append(f"\033[{sh + fr + 1};1H{fline}\033[K")
+        ticker_buf, noise_cache = render_ticker_zone(
+            active, scroll_cam, ticker_h, w, noise_cache, grad_offset
+        )
+        buf.extend(ticker_buf)
 
-        # Glitch — base rate + mic-reactive spikes (scroll zone only)
         mic_excess = mic_monitor.excess
-        glitch_prob = 0.32 + min(0.9, mic_excess * 0.16)
-        n_hits = 4 + int(mic_excess / 2)
-        scroll_buf_len = len(buf) - scroll_buf_start
-        if random.random() < glitch_prob and scroll_buf_len > 0:
-            for _ in range(min(n_hits, scroll_buf_len)):
-                gi = random.randint(0, scroll_buf_len - 1)
-                scr_row = msg_h + gi + 1
-                buf[scroll_buf_start + gi] = f"\033[{scr_row};1H{glitch_bar(w)}"
+        buf = apply_glitch(buf, ticker_buf_start, mic_excess, w)
+
+        firehose_buf = render_firehose(items, w, fh, h)
+        buf.extend(firehose_buf)
+
+        if msg_overlay:
+            buf.extend(msg_overlay)
 
         sys.stdout.buffer.write("".join(buf).encode())
         sys.stdout.flush()
 
-        # Precise frame timing
         elapsed = time.monotonic() - t0
         time.sleep(max(0, config.FRAME_DT - elapsed))
 

engine/sources.py

@@ -75,41 +75,41 @@ SOURCE_LANGS = {
 
 # ─── LOCATION → LANGUAGE ─────────────────────────────────
 LOCATION_LANGS = {
-    r'\b(?:china|chinese|beijing|shanghai|hong kong|xi jinping)\b': 'zh-cn',
-    r'\b(?:japan|japanese|tokyo|osaka|kishida)\b': 'ja',
-    r'\b(?:korea|korean|seoul|pyongyang)\b': 'ko',
-    r'\b(?:russia|russian|moscow|kremlin|putin)\b': 'ru',
-    r'\b(?:saudi|dubai|qatar|egypt|cairo|arabic)\b': 'ar',
-    r'\b(?:india|indian|delhi|mumbai|modi)\b': 'hi',
-    r'\b(?:germany|german|berlin|munich|scholz)\b': 'de',
-    r'\b(?:france|french|paris|lyon|macron)\b': 'fr',
-    r'\b(?:spain|spanish|madrid)\b': 'es',
-    r'\b(?:italy|italian|rome|milan|meloni)\b': 'it',
-    r'\b(?:portugal|portuguese|lisbon)\b': 'pt',
-    r'\b(?:brazil|brazilian|são paulo|lula)\b': 'pt',
-    r'\b(?:greece|greek|athens)\b': 'el',
-    r'\b(?:turkey|turkish|istanbul|ankara|erdogan)\b': 'tr',
-    r'\b(?:iran|iranian|tehran)\b': 'fa',
-    r'\b(?:thailand|thai|bangkok)\b': 'th',
-    r'\b(?:vietnam|vietnamese|hanoi)\b': 'vi',
-    r'\b(?:ukraine|ukrainian|kyiv|kiev|zelensky)\b': 'uk',
-    r'\b(?:israel|israeli|jerusalem|tel aviv|netanyahu)\b': 'he',
+    r"\b(?:china|chinese|beijing|shanghai|hong kong|xi jinping)\b": "zh-cn",
+    r"\b(?:japan|japanese|tokyo|osaka|kishida)\b": "ja",
+    r"\b(?:korea|korean|seoul|pyongyang)\b": "ko",
+    r"\b(?:russia|russian|moscow|kremlin|putin)\b": "ru",
+    r"\b(?:saudi|dubai|qatar|egypt|cairo|arabic)\b": "ar",
+    r"\b(?:india|indian|delhi|mumbai|modi)\b": "hi",
+    r"\b(?:germany|german|berlin|munich|scholz)\b": "de",
+    r"\b(?:france|french|paris|lyon|macron)\b": "fr",
+    r"\b(?:spain|spanish|madrid)\b": "es",
+    r"\b(?:italy|italian|rome|milan|meloni)\b": "it",
+    r"\b(?:portugal|portuguese|lisbon)\b": "pt",
+    r"\b(?:brazil|brazilian|são paulo|lula)\b": "pt",
+    r"\b(?:greece|greek|athens)\b": "el",
+    r"\b(?:turkey|turkish|istanbul|ankara|erdogan)\b": "tr",
+    r"\b(?:iran|iranian|tehran)\b": "fa",
+    r"\b(?:thailand|thai|bangkok)\b": "th",
+    r"\b(?:vietnam|vietnamese|hanoi)\b": "vi",
+    r"\b(?:ukraine|ukrainian|kyiv|kiev|zelensky)\b": "uk",
+    r"\b(?:israel|israeli|jerusalem|tel aviv|netanyahu)\b": "he",
 }
 
 # ─── NON-LATIN SCRIPT FONTS (macOS) ──────────────────────
 SCRIPT_FONTS = {
-    'zh-cn': '/System/Library/Fonts/STHeiti Medium.ttc',
-    'ja':    '/System/Library/Fonts/ヒラギノ角ゴシック W9.ttc',
-    'ko':    '/System/Library/Fonts/AppleSDGothicNeo.ttc',
-    'ru':    '/System/Library/Fonts/Supplemental/Arial.ttf',
-    'uk':    '/System/Library/Fonts/Supplemental/Arial.ttf',
-    'el':    '/System/Library/Fonts/Supplemental/Arial.ttf',
-    'he':    '/System/Library/Fonts/Supplemental/Arial.ttf',
-    'ar':    '/System/Library/Fonts/GeezaPro.ttc',
-    'fa':    '/System/Library/Fonts/GeezaPro.ttc',
-    'hi':    '/System/Library/Fonts/Kohinoor.ttc',
-    'th':    '/System/Library/Fonts/ThonburiUI.ttc',
+    "zh-cn": "/System/Library/Fonts/STHeiti Medium.ttc",
+    "ja": "/System/Library/Fonts/ヒラギノ角ゴシック W9.ttc",
+    "ko": "/System/Library/Fonts/AppleSDGothicNeo.ttc",
+    "ru": "/System/Library/Fonts/Supplemental/Arial.ttf",
+    "uk": "/System/Library/Fonts/Supplemental/Arial.ttf",
+    "el": "/System/Library/Fonts/Supplemental/Arial.ttf",
+    "he": "/System/Library/Fonts/Supplemental/Arial.ttf",
+    "ar": "/System/Library/Fonts/GeezaPro.ttc",
+    "fa": "/System/Library/Fonts/GeezaPro.ttc",
+    "hi": "/System/Library/Fonts/Kohinoor.ttc",
+    "th": "/System/Library/Fonts/ThonburiUI.ttc",
 }
 
 # Scripts that have no uppercase
-NO_UPPER = {'zh-cn', 'ja', 'ko', 'ar', 'fa', 'hi', 'th', 'he'}
+NO_UPPER = {"zh-cn", "ja", "ko", "ar", "fa", "hi", "th", "he"}

engine/terminal.py

@@ -4,8 +4,8 @@ No internal dependencies.
 """
 
 import os
-import sys
 import random
+import sys
 import time
 
 # ─── ANSI ─────────────────────────────────────────────────
@@ -49,7 +49,7 @@ def type_out(text, color=G_HI):
     while i < len(text):
         if random.random() < 0.3:
             b = random.randint(2, 5)
-            sys.stdout.write(f"{color}{text[i:i+b]}{RST}")
+            sys.stdout.write(f"{color}{text[i : i + b]}{RST}")
             i += b
         else:
             sys.stdout.write(f"{color}{text[i]}{RST}")

engine/translate.py

@@ -3,14 +3,33 @@ Google Translate wrapper and location→language detection.
 Depends on: sources (for LOCATION_LANGS).
 """
 
-import re
 import json
-import urllib.request
+import re
 import urllib.parse
+import urllib.request
+from functools import lru_cache
 
 from engine.sources import LOCATION_LANGS
 
-_TRANSLATE_CACHE = {}
+TRANSLATE_CACHE_SIZE = 500
+
+
+@lru_cache(maxsize=TRANSLATE_CACHE_SIZE)
+def _translate_cached(title: str, target_lang: str) -> str:
+    """Cached translation implementation."""
+    try:
+        q = urllib.parse.quote(title)
+        url = (
+            "https://translate.googleapis.com/translate_a/single"
+            f"?client=gtx&sl=en&tl={target_lang}&dt=t&q={q}"
+        )
+        req = urllib.request.Request(url, headers={"User-Agent": "mainline/0.1"})
+        resp = urllib.request.urlopen(req, timeout=5)
+        data = json.loads(resp.read())
+        result = "".join(p[0] for p in data[0] if p[0]) or title
+    except Exception:
+        result = title
+    return result
 
 
 def detect_location_language(title):
@@ -22,20 +41,6 @@ def detect_location_language(title):
     return None
 
 
-def translate_headline(title, target_lang):
+def translate_headline(title: str, target_lang: str) -> str:
     """Translate headline via Google Translate API (zero dependencies)."""
-    key = (title, target_lang)
-    if key in _TRANSLATE_CACHE:
-        return _TRANSLATE_CACHE[key]
-    try:
-        q = urllib.parse.quote(title)
-        url = ("https://translate.googleapis.com/translate_a/single"
-               f"?client=gtx&sl=en&tl={target_lang}&dt=t&q={q}")
-        req = urllib.request.Request(url, headers={"User-Agent": "mainline/0.1"})
-        resp = urllib.request.urlopen(req, timeout=5)
-        data = json.loads(resp.read())
-        result = "".join(p[0] for p in data[0] if p[0]) or title
-    except Exception:
-        result = title
-    _TRANSLATE_CACHE[key] = result
-    return result
+    return _translate_cached(title, target_lang)

engine/types.py

@@ -0,0 +1,60 @@
+"""
+Shared dataclasses for the mainline application.
+Provides named types for tuple returns across modules.
+"""
+
+from dataclasses import dataclass
+
+
+@dataclass
+class HeadlineItem:
+    """A single headline item: title, source, and timestamp."""
+
+    title: str
+    source: str
+    timestamp: str
+
+    def to_tuple(self) -> tuple[str, str, str]:
+        """Convert to tuple for backward compatibility."""
+        return (self.title, self.source, self.timestamp)
+
+    @classmethod
+    def from_tuple(cls, t: tuple[str, str, str]) -> "HeadlineItem":
+        """Create from tuple for backward compatibility."""
+        return cls(title=t[0], source=t[1], timestamp=t[2])
+
+
+def items_to_tuples(items: list[HeadlineItem]) -> list[tuple[str, str, str]]:
+    """Convert list of HeadlineItem to list of tuples."""
+    return [item.to_tuple() for item in items]
+
+
+def tuples_to_items(tuples: list[tuple[str, str, str]]) -> list[HeadlineItem]:
+    """Convert list of tuples to list of HeadlineItem."""
+    return [HeadlineItem.from_tuple(t) for t in tuples]
+
+
+@dataclass
+class FetchResult:
+    """Result from fetch_all() or fetch_poetry()."""
+
+    items: list[HeadlineItem]
+    linked: int
+    failed: int
+
+    def to_legacy_tuple(self) -> tuple[list[tuple], int, int]:
+        """Convert to legacy tuple format for backward compatibility."""
+        return ([item.to_tuple() for item in self.items], self.linked, self.failed)
+
+
+@dataclass
+class Block:
+    """Rendered headline block from make_block()."""
+
+    content: list[str]
+    color: str
+    meta_row_index: int
+
+    def to_legacy_tuple(self) -> tuple[list[str], str, int]:
+        """Convert to legacy tuple format for backward compatibility."""
+        return (self.content, self.color, self.meta_row_index)

engine/viewport.py

@@ -0,0 +1,37 @@
+"""
+Viewport utilities — terminal dimensions and ANSI positioning helpers.
+No internal dependencies.
+"""
+
+import os
+
+
+def tw() -> int:
+    """Get terminal width (columns)."""
+    try:
+        return os.get_terminal_size().columns
+    except Exception:
+        return 80
+
+
+def th() -> int:
+    """Get terminal height (lines)."""
+    try:
+        return os.get_terminal_size().lines
+    except Exception:
+        return 24
+
+
+def move_to(row: int, col: int = 1) -> str:
+    """Generate ANSI escape to move cursor to row, col (1-indexed)."""
+    return f"\033[{row};{col}H"
+
+
+def clear_screen() -> str:
+    """Clear screen and move cursor to home."""
+    return "\033[2J\033[H"
+
+
+def clear_line() -> str:
+    """Clear current line."""
+    return "\033[K"

hk.pkl

@@ -0,0 +1,27 @@
+amends "package://github.com/jdx/hk/releases/download/v1.38.0/hk@1.38.0#/Config.pkl"
+import "package://github.com/jdx/hk/releases/download/v1.38.0/hk@1.38.0#/Builtins.pkl"
+
+hooks {
+    ["pre-commit"] {
+        fix = true
+        stash = "git"
+        steps {
+            ["ruff-format"] = (Builtins.ruff_format) {
+                prefix = "uv run"
+            }
+            ["ruff"] = (Builtins.ruff) {
+                prefix = "uv run"
+                check = "ruff check engine/ tests/"
+                fix = "ruff check --fix --unsafe-fixes engine/ tests/"
+            }
+        }
+    }
+    ["pre-push"] {
+        steps {
+            ["ruff"] = (Builtins.ruff) {
+                prefix = "uv run"
+                check = "ruff check engine/ tests/"
+            }
+        }
+    }
+}

mainline.py

@@ -5,40 +5,7 @@ Digital news consciousness stream.
 Matrix aesthetic · THX-1138 hue.
 """
 
-import subprocess, sys, pathlib
-
-# ─── BOOTSTRAP VENV ───────────────────────────────────────
-_VENV = pathlib.Path(__file__).resolve().parent / ".mainline_venv"
-_MARKER = _VENV / ".installed_v3"
-
-def _ensure_venv():
-    """Create a local venv and install deps if needed."""
-    if _MARKER.exists():
-        return
-    import venv
-    print("\033[2;38;5;34m  > first run — creating environment...\033[0m")
-    venv.create(str(_VENV), with_pip=True, clear=True)
-    pip = str(_VENV / "bin" / "pip")
-    subprocess.check_call(
-        [pip, "install", "feedparser", "Pillow", "-q"],
-        stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL,
-    )
-    _MARKER.touch()
-
-_ensure_venv()
-
-# Install sounddevice on first run after v3
-_MARKER_SD = _VENV / ".installed_sd"
-if not _MARKER_SD.exists():
-    _pip = str(_VENV / "bin" / "pip")
-    subprocess.check_call([_pip, "install", "sounddevice", "numpy", "-q"],
-                          stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
-    _MARKER_SD.touch()
-
-sys.path.insert(0, str(next((_VENV / "lib").glob("python*/site-packages"))))
-
-# ─── DELEGATE TO ENGINE ───────────────────────────────────
-from engine.app import main  # noqa: E402
+from engine.app import main
 
 if __name__ == "__main__":
     main()

mise.toml

@@ -0,0 +1,52 @@
+[tools]
+python = "3.12"
+hk = "latest"
+pkl = "latest"
+
+[tasks]
+# =====================
+# Development
+# =====================
+
+test = "uv run pytest"
+test-v = "uv run pytest -v"
+test-cov = "uv run pytest --cov=engine --cov-report=term-missing --cov-report=html"
+test-cov-open = "uv run pytest --cov=engine --cov-report=term-missing --cov-report=html && open htmlcov/index.html"
+
+lint = "uv run ruff check engine/ mainline.py"
+lint-fix = "uv run ruff check --fix engine/ mainline.py"
+format = "uv run ruff format engine/ mainline.py"
+
+# =====================
+# Runtime
+# =====================
+
+run = "uv run mainline.py"
+run-poetry = "uv run mainline.py --poetry"
+run-firehose = "uv run mainline.py --firehose"
+
+# =====================
+# Environment
+# =====================
+
+sync = "uv sync"
+sync-all = "uv sync --all-extras"
+install = "uv sync"
+install-dev = "uv sync --group dev"
+
+bootstrap = "uv sync && uv run mainline.py --help"
+
+clean = "rm -rf .venv htmlcov .coverage tests/.pytest_cache"
+
+# =====================
+# CI/CD
+# =====================
+
+ci = "uv sync --group dev && uv run pytest --cov=engine --cov-report=term-missing --cov-report=xml"
+ci-lint = "uv run ruff check engine/ mainline.py"
+
+# =====================
+# Git Hooks (via hk)
+# =====================
+
+pre-commit = "hk run pre-commit"

pyproject.toml

@@ -0,0 +1,89 @@
+[project]
+name = "mainline"
+version = "0.1.0"
+description = "Terminal news ticker with Matrix aesthetic"
+readme = "README.md"
+requires-python = ">=3.10"
+authors = [
+    { name = "Mainline", email = "mainline@example.com" }
+]
+license = { text = "MIT" }
+classifiers = [
+    "Development Status :: 4 - Beta",
+    "Environment :: Console",
+    "License :: OSI Approved :: MIT License",
+    "Programming Language :: Python :: 3",
+    "Programming Language :: Python :: 3.10",
+    "Programming Language :: Python :: 3.11",
+    "Programming Language :: Python :: 3.12",
+    "Topic :: Terminals",
+]
+
+dependencies = [
+    "feedparser>=6.0.0",
+    "Pillow>=10.0.0",
+    "pyright>=1.1.408",
+]
+
+[project.optional-dependencies]
+mic = [
+    "sounddevice>=0.4.0",
+    "numpy>=1.24.0",
+]
+dev = [
+    "pytest>=8.0.0",
+    "pytest-cov>=4.1.0",
+    "pytest-mock>=3.12.0",
+    "ruff>=0.1.0",
+]
+
+[project.scripts]
+mainline = "engine.app:main"
+
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[dependency-groups]
+dev = [
+    "pytest>=8.0.0",
+    "pytest-cov>=4.1.0",
+    "pytest-mock>=3.12.0",
+    "ruff>=0.1.0",
+]
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+python_files = ["test_*.py"]
+python_functions = ["test_*"]
+addopts = [
+    "--strict-markers",
+    "--tb=short",
+    "-v",
+]
+filterwarnings = [
+    "ignore::DeprecationWarning",
+]
+
+[tool.coverage.run]
+source = ["engine"]
+branch = true
+
+[tool.coverage.report]
+exclude_lines = [
+    "pragma: no cover",
+    "def __repr__",
+    "raise AssertionError",
+    "raise NotImplementedError",
+    "if __name__ == .__main__.:",
+    "if TYPE_CHECKING:",
+    "@abstractmethod",
+]
+
+[tool.ruff]
+line-length = 88
+target-version = "py310"
+
+[tool.ruff.lint]
+select = ["E", "F", "W", "I", "N", "UP", "B", "C4", "SIM"]
+ignore = ["E501", "SIM105", "N806", "B007", "SIM108"]

requirements-dev.txt

@@ -0,0 +1,4 @@
+pytest>=8.0.0
+pytest-cov>=4.1.0
+pytest-mock>=3.12.0
+ruff>=0.1.0

requirements.txt

@@ -0,0 +1,4 @@
+feedparser>=6.0.0
+Pillow>=10.0.0
+sounddevice>=0.4.0
+numpy>=1.24.0

tests/fixtures/__init__.py

@@ -0,0 +1,236 @@
+"""
+Pytest fixtures for mocking external dependencies (network, filesystem).
+"""
+
+import json
+from unittest.mock import MagicMock
+
+import pytest
+
+
+@pytest.fixture
+def mock_feed_response():
+    """Mock RSS feed response data."""
+    return b"""<?xml version="1.0" encoding="UTF-8" ?>
+<rss version="2.0">
+  <channel>
+    <title>Test Feed</title>
+    <link>https://example.com</link>
+    <item>
+      <title>Test Headline One</title>
+      <pubDate>Sat, 15 Mar 2025 12:00:00 GMT</pubDate>
+    </item>
+    <item>
+      <title>Test Headline Two</title>
+      <pubDate>Sat, 15 Mar 2025 11:00:00 GMT</pubDate>
+    </item>
+    <item>
+      <title>Sports: Team Wins Championship</title>
+      <pubDate>Sat, 15 Mar 2025 10:00:00 GMT</pubDate>
+    </item>
+  </channel>
+</rss>"""
+
+
+@pytest.fixture
+def mock_gutenberg_response():
+    """Mock Project Gutenberg text response."""
+    return """Project Gutenberg's Collection, by Various
+
+*** START OF SOME TEXT ***
+This is a test poem with multiple lines
+that should be parsed as stanzas.
+
+Another stanza here with different content
+and more lines to test the parsing logic.
+
+Yet another stanza for variety
+in the test data.
+
+*** END OF SOME TEXT ***"""
+
+
+@pytest.fixture
+def mock_gutenberg_empty():
+    """Mock Gutenberg response with no valid stanzas."""
+    return """Project Gutenberg's Collection
+
+*** START OF TEXT ***
+THIS IS ALL CAPS AND SHOULD BE SKIPPED
+
+I.
+
+*** END OF TEXT ***"""
+
+
+@pytest.fixture
+def mock_ntfy_message():
+    """Mock ntfy.sh SSE message."""
+    return json.dumps(
+        {
+            "id": "test123",
+            "event": "message",
+            "title": "Test Title",
+            "message": "Test message body",
+            "time": 1234567890,
+        }
+    ).encode()
+
+
+@pytest.fixture
+def mock_ntfy_keepalive():
+    """Mock ntfy.sh keepalive message."""
+    return b'data: {"event":"keepalive"}\n\n'
+
+
+@pytest.fixture
+def mock_google_translate_response():
+    """Mock Google Translate API response."""
+    return json.dumps(
+        [
+            [["Translated text", "Original text", None, 0.8], None, "en"],
+            None,
+            None,
+            [],
+            [],
+            [],
+            [],
+        ]
+    )
+
+
+@pytest.fixture
+def mock_feedparser():
+    """Create a mock feedparser.parse function."""
+
+    def _mock(data):
+        mock_result = MagicMock()
+        mock_result.bozo = False
+        mock_result.entries = [
+            {
+                "title": "Test Headline",
+                "published_parsed": (2025, 3, 15, 12, 0, 0, 0, 0, 0),
+            },
+            {
+                "title": "Another Headline",
+                "updated_parsed": (2025, 3, 15, 11, 0, 0, 0, 0, 0),
+            },
+        ]
+        return mock_result
+
+    return _mock
+
+
+@pytest.fixture
+def mock_urllib_open(mock_feed_response):
+    """Create a mock urllib.request.urlopen that returns feed data."""
+
+    def _mock(url):
+        mock_response = MagicMock()
+        mock_response.read.return_value = mock_feed_response
+        return mock_response
+
+    return _mock
+
+
+@pytest.fixture
+def sample_items():
+    """Sample items as returned by fetch module (title, source, timestamp)."""
+    return [
+        ("Headline One", "Test Source", "12:00"),
+        ("Headline Two", "Another Source", "11:30"),
+        ("Headline Three", "Third Source", "10:45"),
+    ]
+
+
+@pytest.fixture
+def sample_config():
+    """Sample config for testing."""
+    from engine.config import Config
+
+    return Config(
+        headline_limit=100,
+        feed_timeout=10,
+        mic_threshold_db=50,
+        mode="news",
+        firehose=False,
+        ntfy_topic="https://ntfy.sh/test/json",
+        ntfy_reconnect_delay=5,
+        message_display_secs=30,
+        font_dir="fonts",
+        font_path="",
+        font_index=0,
+        font_picker=False,
+        font_sz=60,
+        render_h=8,
+        ssaa=4,
+        scroll_dur=5.625,
+        frame_dt=0.05,
+        firehose_h=12,
+        grad_speed=0.08,
+        glitch_glyphs="░▒▓█▌▐",
+        kata_glyphs="ﾊﾐﾋｰｳ",
+        script_fonts={},
+    )
+
+
+@pytest.fixture
+def poetry_config():
+    """Sample config for poetry mode."""
+    from engine.config import Config
+
+    return Config(
+        headline_limit=100,
+        feed_timeout=10,
+        mic_threshold_db=50,
+        mode="poetry",
+        firehose=False,
+        ntfy_topic="https://ntfy.sh/test/json",
+        ntfy_reconnect_delay=5,
+        message_display_secs=30,
+        font_dir="fonts",
+        font_path="",
+        font_index=0,
+        font_picker=False,
+        font_sz=60,
+        render_h=8,
+        ssaa=4,
+        scroll_dur=5.625,
+        frame_dt=0.05,
+        firehose_h=12,
+        grad_speed=0.08,
+        glitch_glyphs="░▒▓█▌▐",
+        kata_glyphs="ﾊﾐﾋｰｳ",
+        script_fonts={},
+    )
+
+
+@pytest.fixture
+def firehose_config():
+    """Sample config with firehose enabled."""
+    from engine.config import Config
+
+    return Config(
+        headline_limit=100,
+        feed_timeout=10,
+        mic_threshold_db=50,
+        mode="news",
+        firehose=True,
+        ntfy_topic="https://ntfy.sh/test/json",
+        ntfy_reconnect_delay=5,
+        message_display_secs=30,
+        font_dir="fonts",
+        font_path="",
+        font_index=0,
+        font_picker=False,
+        font_sz=60,
+        render_h=8,
+        ssaa=4,
+        scroll_dur=5.625,
+        frame_dt=0.05,
+        firehose_h=12,
+        grad_speed=0.08,
+        glitch_glyphs="░▒▓█▌▐",
+        kata_glyphs="ﾊﾐﾋｰｳ",
+        script_fonts={},
+    )

tests/test_config.py

@@ -0,0 +1,301 @@
+"""
+Tests for engine.config module.
+"""
+
+import sys
+import tempfile
+from pathlib import Path
+from unittest.mock import patch
+
+import pytest
+
+from engine import config
+
+
+class TestArgValue:
+    """Tests for _arg_value helper."""
+
+    def test_returns_value_when_flag_present(self):
+        """Returns the value following the flag."""
+        with patch.object(sys, "argv", ["prog", "--font-file", "test.otf"]):
+            result = config._arg_value("--font-file")
+            assert result == "test.otf"
+
+    def test_returns_none_when_flag_missing(self):
+        """Returns None when flag is not present."""
+        with patch.object(sys, "argv", ["prog"]):
+            result = config._arg_value("--font-file")
+            assert result is None
+
+    def test_returns_none_when_no_value(self):
+        """Returns None when flag is last."""
+        with patch.object(sys, "argv", ["prog", "--font-file"]):
+            result = config._arg_value("--font-file")
+            assert result is None
+
+
+class TestArgInt:
+    """Tests for _arg_int helper."""
+
+    def test_parses_valid_int(self):
+        """Parses valid integer."""
+        with patch.object(sys, "argv", ["prog", "--font-index", "5"]):
+            result = config._arg_int("--font-index", 0)
+            assert result == 5
+
+    def test_returns_default_on_invalid(self):
+        """Returns default on invalid input."""
+        with patch.object(sys, "argv", ["prog", "--font-index", "abc"]):
+            result = config._arg_int("--font-index", 0)
+            assert result == 0
+
+    def test_returns_default_when_missing(self):
+        """Returns default when flag missing."""
+        with patch.object(sys, "argv", ["prog"]):
+            result = config._arg_int("--font-index", 10)
+            assert result == 10
+
+
+class TestResolveFontPath:
+    """Tests for _resolve_font_path helper."""
+
+    def test_returns_absolute_paths(self):
+        """Absolute paths are returned as-is."""
+        result = config._resolve_font_path("/absolute/path.otf")
+        assert result == "/absolute/path.otf"
+
+    def test_resolves_relative_paths(self):
+        """Relative paths are resolved to repo root."""
+        result = config._resolve_font_path("fonts/test.otf")
+        assert str(config._REPO_ROOT) in result
+
+    def test_expands_user_home(self):
+        """Tilde paths are expanded."""
+        with patch("pathlib.Path.expanduser", return_value=Path("/home/user/fonts")):
+            result = config._resolve_font_path("~/fonts/test.otf")
+            assert isinstance(result, str)
+
+
+class TestListFontFiles:
+    """Tests for _list_font_files helper."""
+
+    def test_returns_empty_for_missing_dir(self):
+        """Returns empty list for missing directory."""
+        result = config._list_font_files("/nonexistent/directory")
+        assert result == []
+
+    def test_filters_by_extension(self):
+        """Only returns valid font extensions."""
+        with tempfile.TemporaryDirectory() as tmpdir:
+            Path(tmpdir, "valid.otf").touch()
+            Path(tmpdir, "valid.ttf").touch()
+            Path(tmpdir, "invalid.txt").touch()
+            Path(tmpdir, "image.png").touch()
+
+            result = config._list_font_files(tmpdir)
+            assert len(result) == 2
+            assert all(f.endswith((".otf", ".ttf")) for f in result)
+
+    def test_sorts_alphabetically(self):
+        """Results are sorted alphabetically."""
+        with tempfile.TemporaryDirectory() as tmpdir:
+            Path(tmpdir, "zfont.otf").touch()
+            Path(tmpdir, "afont.otf").touch()
+
+            result = config._list_font_files(tmpdir)
+            filenames = [Path(f).name for f in result]
+            assert filenames == ["afont.otf", "zfont.otf"]
+
+
+class TestDefaults:
+    """Tests for default configuration values."""
+
+    def test_headline_limit(self):
+        """HEADLINE_LIMIT has sensible default."""
+        assert config.HEADLINE_LIMIT > 0
+
+    def test_feed_timeout(self):
+        """FEED_TIMEOUT has sensible default."""
+        assert config.FEED_TIMEOUT > 0
+
+    def test_font_extensions(self):
+        """Font extensions are defined."""
+        assert ".otf" in config._FONT_EXTENSIONS
+        assert ".ttf" in config._FONT_EXTENSIONS
+        assert ".ttc" in config._FONT_EXTENSIONS
+
+
+class TestGlyphs:
+    """Tests for glyph constants."""
+
+    def test_glitch_glyphs_defined(self):
+        """GLITCH glyphs are defined."""
+        assert len(config.GLITCH) > 0
+
+    def test_kata_glyphs_defined(self):
+        """KATA glyphs are defined."""
+        assert len(config.KATA) > 0
+
+
+class TestSetFontSelection:
+    """Tests for set_font_selection function."""
+
+    def test_updates_font_path(self):
+        """Updates FONT_PATH globally."""
+        original = config.FONT_PATH
+        config.set_font_selection(font_path="/new/path.otf")
+        assert config.FONT_PATH == "/new/path.otf"
+        config.FONT_PATH = original
+
+    def test_updates_font_index(self):
+        """Updates FONT_INDEX globally."""
+        original = config.FONT_INDEX
+        config.set_font_selection(font_index=5)
+        assert config.FONT_INDEX == 5
+        config.FONT_INDEX = original
+
+    def test_handles_none_values(self):
+        """Handles None values gracefully."""
+        original_path = config.FONT_PATH
+        original_index = config.FONT_INDEX
+
+        config.set_font_selection(font_path=None, font_index=None)
+        assert original_path == config.FONT_PATH
+        assert original_index == config.FONT_INDEX
+
+
+class TestConfigDataclass:
+    """Tests for Config dataclass."""
+
+    def test_config_has_required_fields(self):
+        """Config has all required fields."""
+        c = config.Config()
+        assert hasattr(c, "headline_limit")
+        assert hasattr(c, "feed_timeout")
+        assert hasattr(c, "mic_threshold_db")
+        assert hasattr(c, "mode")
+        assert hasattr(c, "firehose")
+        assert hasattr(c, "ntfy_topic")
+        assert hasattr(c, "ntfy_reconnect_delay")
+        assert hasattr(c, "message_display_secs")
+        assert hasattr(c, "font_dir")
+        assert hasattr(c, "font_path")
+        assert hasattr(c, "font_index")
+        assert hasattr(c, "font_picker")
+        assert hasattr(c, "font_sz")
+        assert hasattr(c, "render_h")
+        assert hasattr(c, "ssaa")
+        assert hasattr(c, "scroll_dur")
+        assert hasattr(c, "frame_dt")
+        assert hasattr(c, "firehose_h")
+        assert hasattr(c, "grad_speed")
+        assert hasattr(c, "glitch_glyphs")
+        assert hasattr(c, "kata_glyphs")
+        assert hasattr(c, "script_fonts")
+
+    def test_config_defaults(self):
+        """Config has sensible defaults."""
+        c = config.Config()
+        assert c.headline_limit == 1000
+        assert c.feed_timeout == 10
+        assert c.mic_threshold_db == 50
+        assert c.mode == "news"
+        assert c.firehose is False
+        assert c.ntfy_reconnect_delay == 5
+        assert c.message_display_secs == 30
+
+    def test_config_is_immutable(self):
+        """Config is frozen (immutable)."""
+        c = config.Config()
+        with pytest.raises(AttributeError):
+            c.headline_limit = 500  # type: ignore
+
+    def test_config_custom_values(self):
+        """Config accepts custom values."""
+        c = config.Config(
+            headline_limit=500,
+            mode="poetry",
+            firehose=True,
+            ntfy_topic="https://ntfy.sh/test",
+        )
+        assert c.headline_limit == 500
+        assert c.mode == "poetry"
+        assert c.firehose is True
+        assert c.ntfy_topic == "https://ntfy.sh/test"
+
+
+class TestConfigFromArgs:
+    """Tests for Config.from_args method."""
+
+    def test_from_args_defaults(self):
+        """from_args creates config with defaults from empty argv."""
+        c = config.Config.from_args(["prog"])
+        assert c.mode == "news"
+        assert c.firehose is False
+        assert c.font_picker is True
+
+    def test_from_args_poetry_mode(self):
+        """from_args detects --poetry flag."""
+        c = config.Config.from_args(["prog", "--poetry"])
+        assert c.mode == "poetry"
+
+    def test_from_args_poetry_short_flag(self):
+        """from_args detects -p short flag."""
+        c = config.Config.from_args(["prog", "-p"])
+        assert c.mode == "poetry"
+
+    def test_from_args_firehose(self):
+        """from_args detects --firehose flag."""
+        c = config.Config.from_args(["prog", "--firehose"])
+        assert c.firehose is True
+
+    def test_from_args_no_font_picker(self):
+        """from_args detects --no-font-picker flag."""
+        c = config.Config.from_args(["prog", "--no-font-picker"])
+        assert c.font_picker is False
+
+    def test_from_args_font_index(self):
+        """from_args parses --font-index."""
+        c = config.Config.from_args(["prog", "--font-index", "3"])
+        assert c.font_index == 3
+
+
+class TestGetSetConfig:
+    """Tests for get_config and set_config functions."""
+
+    def test_get_config_returns_config(self):
+        """get_config returns a Config instance."""
+        c = config.get_config()
+        assert isinstance(c, config.Config)
+
+    def test_set_config_allows_injection(self):
+        """set_config allows injecting a custom config."""
+        custom = config.Config(mode="poetry", headline_limit=100)
+        config.set_config(custom)
+        assert config.get_config().mode == "poetry"
+        assert config.get_config().headline_limit == 100
+
+    def test_set_config_then_get_config(self):
+        """set_config followed by get_config returns the set config."""
+        original = config.get_config()
+        test_config = config.Config(headline_limit=42)
+        config.set_config(test_config)
+        result = config.get_config()
+        assert result.headline_limit == 42
+        config.set_config(original)
+
+
+class TestPlatformFontPaths:
+    """Tests for platform font path detection."""
+
+    def test_get_platform_font_paths_returns_dict(self):
+        """_get_platform_font_paths returns a dictionary."""
+        fonts = config._get_platform_font_paths()
+        assert isinstance(fonts, dict)
+
+    def test_platform_font_paths_common_languages(self):
+        """Common language font mappings exist."""
+        fonts = config._get_platform_font_paths()
+        common = {"ja", "zh-cn", "ko", "ru", "ar", "hi"}
+        found = set(fonts.keys()) & common
+        assert len(found) > 0

tests/test_controller.py

@@ -0,0 +1,85 @@
+"""
+Tests for engine.controller module.
+"""
+
+from unittest.mock import MagicMock, patch
+
+from engine import config
+from engine.controller import StreamController
+
+
+class TestStreamController:
+    """Tests for StreamController class."""
+
+    def test_init_default_config(self):
+        """StreamController initializes with default config."""
+        controller = StreamController()
+        assert controller.config is not None
+        assert isinstance(controller.config, config.Config)
+
+    def test_init_custom_config(self):
+        """StreamController accepts custom config."""
+        custom_config = config.Config(headline_limit=500)
+        controller = StreamController(config=custom_config)
+        assert controller.config.headline_limit == 500
+
+    def test_init_sources_none_by_default(self):
+        """Sources are None until initialized."""
+        controller = StreamController()
+        assert controller.mic is None
+        assert controller.ntfy is None
+
+    @patch("engine.controller.MicMonitor")
+    @patch("engine.controller.NtfyPoller")
+    def test_initialize_sources(self, mock_ntfy, mock_mic):
+        """initialize_sources creates mic and ntfy instances."""
+        mock_mic_instance = MagicMock()
+        mock_mic_instance.available = True
+        mock_mic_instance.start.return_value = True
+        mock_mic.return_value = mock_mic_instance
+
+        mock_ntfy_instance = MagicMock()
+        mock_ntfy_instance.start.return_value = True
+        mock_ntfy.return_value = mock_ntfy_instance
+
+        controller = StreamController()
+        mic_ok, ntfy_ok = controller.initialize_sources()
+
+        assert mic_ok is True
+        assert ntfy_ok is True
+        assert controller.mic is not None
+        assert controller.ntfy is not None
+
+    @patch("engine.controller.MicMonitor")
+    @patch("engine.controller.NtfyPoller")
+    def test_initialize_sources_mic_unavailable(self, mock_ntfy, mock_mic):
+        """initialize_sources handles unavailable mic."""
+        mock_mic_instance = MagicMock()
+        mock_mic_instance.available = False
+        mock_mic.return_value = mock_mic_instance
+
+        mock_ntfy_instance = MagicMock()
+        mock_ntfy_instance.start.return_value = True
+        mock_ntfy.return_value = mock_ntfy_instance
+
+        controller = StreamController()
+        mic_ok, ntfy_ok = controller.initialize_sources()
+
+        assert mic_ok is False
+        assert ntfy_ok is True
+
+
+class TestStreamControllerCleanup:
+    """Tests for StreamController cleanup."""
+
+    @patch("engine.controller.MicMonitor")
+    def test_cleanup_stops_mic(self, mock_mic):
+        """cleanup stops the microphone if running."""
+        mock_mic_instance = MagicMock()
+        mock_mic.return_value = mock_mic_instance
+
+        controller = StreamController()
+        controller.mic = mock_mic_instance
+        controller.cleanup()
+
+        mock_mic_instance.stop.assert_called_once()

tests/test_emitters.py

@@ -0,0 +1,69 @@
+"""
+Tests for engine.emitters module.
+"""
+
+from engine.emitters import EventEmitter, Startable, Stoppable
+
+
+class TestEventEmitterProtocol:
+    """Tests for EventEmitter protocol."""
+
+    def test_protocol_exists(self):
+        """EventEmitter protocol is defined."""
+        assert EventEmitter is not None
+
+    def test_protocol_has_subscribe_method(self):
+        """EventEmitter has subscribe method in protocol."""
+        assert hasattr(EventEmitter, "subscribe")
+
+    def test_protocol_has_unsubscribe_method(self):
+        """EventEmitter has unsubscribe method in protocol."""
+        assert hasattr(EventEmitter, "unsubscribe")
+
+
+class TestStartableProtocol:
+    """Tests for Startable protocol."""
+
+    def test_protocol_exists(self):
+        """Startable protocol is defined."""
+        assert Startable is not None
+
+    def test_protocol_has_start_method(self):
+        """Startable has start method in protocol."""
+        assert hasattr(Startable, "start")
+
+
+class TestStoppableProtocol:
+    """Tests for Stoppable protocol."""
+
+    def test_protocol_exists(self):
+        """Stoppable protocol is defined."""
+        assert Stoppable is not None
+
+    def test_protocol_has_stop_method(self):
+        """Stoppable has stop method in protocol."""
+        assert hasattr(Stoppable, "stop")
+
+
+class TestProtocolCompliance:
+    """Tests that existing classes comply with protocols."""
+
+    def test_ntfy_poller_complies_with_protocol(self):
+        """NtfyPoller implements EventEmitter protocol."""
+        from engine.ntfy import NtfyPoller
+
+        poller = NtfyPoller("http://example.com/topic")
+        assert hasattr(poller, "subscribe")
+        assert hasattr(poller, "unsubscribe")
+        assert callable(poller.subscribe)
+        assert callable(poller.unsubscribe)
+
+    def test_mic_monitor_complies_with_protocol(self):
+        """MicMonitor implements EventEmitter and Startable protocols."""
+        from engine.mic import MicMonitor
+
+        monitor = MicMonitor()
+        assert hasattr(monitor, "subscribe")
+        assert hasattr(monitor, "unsubscribe")
+        assert hasattr(monitor, "start")
+        assert hasattr(monitor, "stop")

tests/test_eventbus.py

@@ -0,0 +1,202 @@
+"""
+Tests for engine.eventbus module.
+"""
+
+
+from engine.eventbus import EventBus, get_event_bus, set_event_bus
+from engine.events import EventType, NtfyMessageEvent
+
+
+class TestEventBusInit:
+    """Tests for EventBus initialization."""
+
+    def test_init_creates_empty_subscribers(self):
+        """EventBus starts with no subscribers."""
+        bus = EventBus()
+        assert bus.subscriber_count() == 0
+
+
+class TestEventBusSubscribe:
+    """Tests for EventBus.subscribe method."""
+
+    def test_subscribe_adds_callback(self):
+        """subscribe() adds a callback for an event type."""
+        bus = EventBus()
+        def callback(e):
+            return None
+
+        bus.subscribe(EventType.NTFY_MESSAGE, callback)
+
+        assert bus.subscriber_count(EventType.NTFY_MESSAGE) == 1
+
+    def test_subscribe_multiple_callbacks_same_event(self):
+        """Multiple callbacks can be subscribed to the same event type."""
+        bus = EventBus()
+        def cb1(e):
+            return None
+        def cb2(e):
+            return None
+
+        bus.subscribe(EventType.NTFY_MESSAGE, cb1)
+        bus.subscribe(EventType.NTFY_MESSAGE, cb2)
+
+        assert bus.subscriber_count(EventType.NTFY_MESSAGE) == 2
+
+    def test_subscribe_different_event_types(self):
+        """Callbacks can be subscribed to different event types."""
+        bus = EventBus()
+        def cb1(e):
+            return None
+        def cb2(e):
+            return None
+
+        bus.subscribe(EventType.NTFY_MESSAGE, cb1)
+        bus.subscribe(EventType.MIC_LEVEL, cb2)
+
+        assert bus.subscriber_count(EventType.NTFY_MESSAGE) == 1
+        assert bus.subscriber_count(EventType.MIC_LEVEL) == 1
+
+
+class TestEventBusUnsubscribe:
+    """Tests for EventBus.unsubscribe method."""
+
+    def test_unsubscribe_removes_callback(self):
+        """unsubscribe() removes a callback."""
+        bus = EventBus()
+        def callback(e):
+            return None
+
+        bus.subscribe(EventType.NTFY_MESSAGE, callback)
+        bus.unsubscribe(EventType.NTFY_MESSAGE, callback)
+
+        assert bus.subscriber_count(EventType.NTFY_MESSAGE) == 0
+
+    def test_unsubscribe_nonexistent_callback_no_error(self):
+        """unsubscribe() handles non-existent callback gracefully."""
+        bus = EventBus()
+        def callback(e):
+            return None
+
+        bus.unsubscribe(EventType.NTFY_MESSAGE, callback)
+
+
+class TestEventBusPublish:
+    """Tests for EventBus.publish method."""
+
+    def test_publish_calls_subscriber(self):
+        """publish() calls the subscriber callback."""
+        bus = EventBus()
+        received = []
+
+        def callback(event):
+            received.append(event)
+
+        bus.subscribe(EventType.NTFY_MESSAGE, callback)
+        event = NtfyMessageEvent(title="Test", body="Body")
+        bus.publish(EventType.NTFY_MESSAGE, event)
+
+        assert len(received) == 1
+        assert received[0].title == "Test"
+
+    def test_publish_multiple_subscribers(self):
+        """publish() calls all subscribers for an event type."""
+        bus = EventBus()
+        received1 = []
+        received2 = []
+
+        def callback1(event):
+            received1.append(event)
+
+        def callback2(event):
+            received2.append(event)
+
+        bus.subscribe(EventType.NTFY_MESSAGE, callback1)
+        bus.subscribe(EventType.NTFY_MESSAGE, callback2)
+        event = NtfyMessageEvent(title="Test", body="Body")
+        bus.publish(EventType.NTFY_MESSAGE, event)
+
+        assert len(received1) == 1
+        assert len(received2) == 1
+
+    def test_publish_different_event_types(self):
+        """publish() only calls subscribers for the specific event type."""
+        bus = EventBus()
+        ntfy_received = []
+        mic_received = []
+
+        def ntfy_callback(event):
+            ntfy_received.append(event)
+
+        def mic_callback(event):
+            mic_received.append(event)
+
+        bus.subscribe(EventType.NTFY_MESSAGE, ntfy_callback)
+        bus.subscribe(EventType.MIC_LEVEL, mic_callback)
+        event = NtfyMessageEvent(title="Test", body="Body")
+        bus.publish(EventType.NTFY_MESSAGE, event)
+
+        assert len(ntfy_received) == 1
+        assert len(mic_received) == 0
+
+
+class TestEventBusClear:
+    """Tests for EventBus.clear method."""
+
+    def test_clear_removes_all_subscribers(self):
+        """clear() removes all subscribers."""
+        bus = EventBus()
+        def cb1(e):
+            return None
+        def cb2(e):
+            return None
+
+        bus.subscribe(EventType.NTFY_MESSAGE, cb1)
+        bus.subscribe(EventType.MIC_LEVEL, cb2)
+        bus.clear()
+
+        assert bus.subscriber_count() == 0
+
+
+class TestEventBusThreadSafety:
+    """Tests for EventBus thread safety."""
+
+    def test_concurrent_subscribe_unsubscribe(self):
+        """subscribe and unsubscribe can be called concurrently."""
+        import threading
+
+        bus = EventBus()
+        callbacks = [lambda e: None for _ in range(10)]
+
+        def subscribe():
+            for cb in callbacks:
+                bus.subscribe(EventType.NTFY_MESSAGE, cb)
+
+        def unsubscribe():
+            for cb in callbacks:
+                bus.unsubscribe(EventType.NTFY_MESSAGE, cb)
+
+        t1 = threading.Thread(target=subscribe)
+        t2 = threading.Thread(target=unsubscribe)
+        t1.start()
+        t2.start()
+        t1.join()
+        t2.join()
+
+
+class TestGlobalEventBus:
+    """Tests for global event bus functions."""
+
+    def test_get_event_bus_returns_singleton(self):
+        """get_event_bus() returns the same instance."""
+        bus1 = get_event_bus()
+        bus2 = get_event_bus()
+        assert bus1 is bus2
+
+    def test_set_event_bus_replaces_singleton(self):
+        """set_event_bus() replaces the global event bus."""
+        new_bus = EventBus()
+        set_event_bus(new_bus)
+        try:
+            assert get_event_bus() is new_bus
+        finally:
+            set_event_bus(None)

tests/test_events.py

@@ -0,0 +1,112 @@
+"""
+Tests for engine.events module.
+"""
+
+from datetime import datetime
+
+from engine import events
+
+
+class TestEventType:
+    """Tests for EventType enum."""
+
+    def test_event_types_exist(self):
+        """All expected event types exist."""
+        assert hasattr(events.EventType, "NEW_HEADLINE")
+        assert hasattr(events.EventType, "FRAME_TICK")
+        assert hasattr(events.EventType, "MIC_LEVEL")
+        assert hasattr(events.EventType, "NTFY_MESSAGE")
+        assert hasattr(events.EventType, "STREAM_START")
+        assert hasattr(events.EventType, "STREAM_END")
+
+
+class TestHeadlineEvent:
+    """Tests for HeadlineEvent dataclass."""
+
+    def test_create_headline_event(self):
+        """HeadlineEvent can be created with required fields."""
+        e = events.HeadlineEvent(
+            title="Test Headline",
+            source="Test Source",
+            timestamp="12:00",
+        )
+        assert e.title == "Test Headline"
+        assert e.source == "Test Source"
+        assert e.timestamp == "12:00"
+
+    def test_headline_event_optional_language(self):
+        """HeadlineEvent supports optional language field."""
+        e = events.HeadlineEvent(
+            title="Test",
+            source="Test",
+            timestamp="12:00",
+            language="ja",
+        )
+        assert e.language == "ja"
+
+
+class TestFrameTickEvent:
+    """Tests for FrameTickEvent dataclass."""
+
+    def test_create_frame_tick_event(self):
+        """FrameTickEvent can be created."""
+        now = datetime.now()
+        e = events.FrameTickEvent(
+            frame_number=100,
+            timestamp=now,
+            delta_seconds=0.05,
+        )
+        assert e.frame_number == 100
+        assert e.timestamp == now
+        assert e.delta_seconds == 0.05
+
+
+class TestMicLevelEvent:
+    """Tests for MicLevelEvent dataclass."""
+
+    def test_create_mic_level_event(self):
+        """MicLevelEvent can be created."""
+        now = datetime.now()
+        e = events.MicLevelEvent(
+            db_level=60.0,
+            excess_above_threshold=10.0,
+            timestamp=now,
+        )
+        assert e.db_level == 60.0
+        assert e.excess_above_threshold == 10.0
+
+
+class TestNtfyMessageEvent:
+    """Tests for NtfyMessageEvent dataclass."""
+
+    def test_create_ntfy_message_event(self):
+        """NtfyMessageEvent can be created with required fields."""
+        e = events.NtfyMessageEvent(
+            title="Test Title",
+            body="Test Body",
+        )
+        assert e.title == "Test Title"
+        assert e.body == "Test Body"
+        assert e.message_id is None
+
+    def test_ntfy_message_event_with_id(self):
+        """NtfyMessageEvent supports optional message_id."""
+        e = events.NtfyMessageEvent(
+            title="Test",
+            body="Test",
+            message_id="abc123",
+        )
+        assert e.message_id == "abc123"
+
+
+class TestStreamEvent:
+    """Tests for StreamEvent dataclass."""
+
+    def test_create_stream_event(self):
+        """StreamEvent can be created."""
+        e = events.StreamEvent(
+            event_type=events.EventType.STREAM_START,
+            headline_count=100,
+        )
+        assert e.event_type == events.EventType.STREAM_START
+        assert e.headline_count == 100

tests/test_filter.py

@@ -0,0 +1,93 @@
+"""
+Tests for engine.filter module.
+"""
+
+from engine.filter import skip, strip_tags
+
+
+class TestStripTags:
+    """Tests for strip_tags function."""
+
+    def test_strips_simple_html(self):
+        """Basic HTML tags are removed."""
+        assert strip_tags("<p>Hello</p>") == "Hello"
+        assert strip_tags("<b>Bold</b>") == "Bold"
+        assert strip_tags("<em>Italic</em>") == "Italic"
+
+    def test_strips_nested_html(self):
+        """Nested HTML tags are handled."""
+        assert strip_tags("<div><p>Nested</p></div>") == "Nested"
+        assert strip_tags("<span><strong>Deep</strong></span>") == "Deep"
+
+    def test_strips_html_with_attributes(self):
+        """HTML with attributes is handled."""
+        assert strip_tags('<a href="http://example.com">Link</a>') == "Link"
+        assert strip_tags('<img src="test.jpg" alt="test">') == ""
+
+    def test_handles_empty_string(self):
+        """Empty string returns empty string."""
+        assert strip_tags("") == ""
+        assert strip_tags(None) == ""
+
+    def test_handles_plain_text(self):
+        """Plain text without tags passes through."""
+        assert strip_tags("Plain text") == "Plain text"
+
+    def test_unescapes_html_entities(self):
+        """HTML entities are decoded and tags are stripped."""
+        assert strip_tags("&nbsp;test") == "test"
+        assert strip_tags("Hello &amp; World") == "Hello & World"
+
+    def test_handles_malformed_html(self):
+        """Malformed HTML is handled gracefully."""
+        assert strip_tags("<p>Unclosed") == "Unclosed"
+        assert strip_tags("</p>No start") == "No start"
+
+
+class TestSkip:
+    """Tests for skip function - content filtering."""
+
+    def test_skips_sports_content(self):
+        """Sports-related headlines are skipped."""
+        assert skip("Football: Team wins championship") is True
+        assert skip("NBA Finals Game 7 results") is True
+        assert skip("Soccer match ends in draw") is True
+        assert skip("Premier League transfer news") is True
+        assert skip("Super Bowl halftime show") is True
+
+    def test_skips_vapid_content(self):
+        """Vapid/celebrity content is skipped."""
+        assert skip("Kim Kardashian's new look") is True
+        assert skip("Influencer goes viral") is True
+        assert skip("Red carpet best dressed") is True
+        assert skip("Celebrity couple splits") is True
+
+    def test_allows_real_news(self):
+        """Legitimate news headlines are allowed."""
+        assert skip("Scientists discover new planet") is False
+        assert skip("Economy grows by 3%") is False
+        assert skip("World leaders meet for summit") is False
+        assert skip("New technology breakthrough") is False
+
+    def test_case_insensitive(self):
+        """Filter is case insensitive."""
+        assert skip("FOOTBALL scores") is True
+        assert skip("Football SCORES") is True
+        assert skip("Kardashian") is True
+
+    def test_word_boundary_matching(self):
+        """Word boundary matching works correctly."""
+        assert skip("The football stadium") is True
+        assert skip("Footballer scores") is False
+        assert skip("Footballs on sale") is False
+
+
+class TestIntegration:
+    """Integration tests combining filter functions."""
+
+    def test_full_pipeline(self):
+        """Test strip_tags followed by skip."""
+        html = '<p><a href="#">Breaking: Football championship final</a></p>'
+        text = strip_tags(html)
+        assert text == "Breaking: Football championship final"
+        assert skip(text) is True

tests/test_frame.py

@@ -0,0 +1,63 @@
+"""
+Tests for engine.frame module.
+"""
+
+import time
+
+from engine.frame import FrameTimer, calculate_scroll_step
+
+
+class TestFrameTimer:
+    """Tests for FrameTimer class."""
+
+    def test_init_default(self):
+        """FrameTimer initializes with default values."""
+        timer = FrameTimer()
+        assert timer.target_frame_dt == 0.05
+        assert timer.fps >= 0
+
+    def test_init_custom(self):
+        """FrameTimer accepts custom frame duration."""
+        timer = FrameTimer(target_frame_dt=0.1)
+        assert timer.target_frame_dt == 0.1
+
+    def test_fps_calculation(self):
+        """FrameTimer calculates FPS correctly."""
+        timer = FrameTimer()
+        timer._frame_count = 10
+        timer._start_time = time.monotonic() - 1.0
+        assert timer.fps >= 9.0
+
+    def test_reset(self):
+        """FrameTimer.reset() clears frame count."""
+        timer = FrameTimer()
+        timer._frame_count = 100
+        timer.reset()
+        assert timer._frame_count == 0
+
+
+class TestCalculateScrollStep:
+    """Tests for calculate_scroll_step function."""
+
+    def test_basic_calculation(self):
+        """calculate_scroll_step returns positive value."""
+        result = calculate_scroll_step(5.0, 24)
+        assert result > 0
+
+    def test_with_padding(self):
+        """calculate_scroll_step respects padding parameter."""
+        without_padding = calculate_scroll_step(5.0, 24, padding=0)
+        with_padding = calculate_scroll_step(5.0, 24, padding=15)
+        assert with_padding < without_padding
+
+    def test_larger_view_slower_scroll(self):
+        """Larger view height results in slower scroll steps."""
+        small = calculate_scroll_step(5.0, 10)
+        large = calculate_scroll_step(5.0, 50)
+        assert large < small
+
+    def test_longer_duration_slower_scroll(self):
+        """Longer scroll duration results in slower scroll steps."""
+        fast = calculate_scroll_step(2.0, 24)
+        slow = calculate_scroll_step(10.0, 24)
+        assert slow > fast

tests/test_layers.py

@@ -0,0 +1,96 @@
+"""
+Tests for engine.layers module.
+"""
+
+import time
+
+from engine import layers
+
+
+class TestRenderMessageOverlay:
+    """Tests for render_message_overlay function."""
+
+    def test_no_message_returns_empty(self):
+        """Returns empty list when msg is None."""
+        result, cache = layers.render_message_overlay(None, 80, 24, (None, None))
+        assert result == []
+        assert cache[0] is None
+
+    def test_message_returns_overlay_lines(self):
+        """Returns non-empty list when message is present."""
+        msg = ("Test Title", "Test Body", time.monotonic())
+        result, cache = layers.render_message_overlay(msg, 80, 24, (None, None))
+        assert len(result) > 0
+        assert cache[0] is not None
+
+    def test_cache_key_changes_with_text(self):
+        """Cache key changes when message text changes."""
+        msg1 = ("Title1", "Body1", time.monotonic())
+        msg2 = ("Title2", "Body2", time.monotonic())
+
+        _, cache1 = layers.render_message_overlay(msg1, 80, 24, (None, None))
+        _, cache2 = layers.render_message_overlay(msg2, 80, 24, cache1)
+
+        assert cache1[0] != cache2[0]
+
+    def test_cache_reuse_avoids_recomputation(self):
+        """Cache is returned when same message is passed (interface test)."""
+        msg = ("Same Title", "Same Body", time.monotonic())
+
+        result1, cache1 = layers.render_message_overlay(msg, 80, 24, (None, None))
+        result2, cache2 = layers.render_message_overlay(msg, 80, 24, cache1)
+
+        assert len(result1) > 0
+        assert len(result2) > 0
+        assert cache1[0] == cache2[0]
+
+
+class TestRenderFirehose:
+    """Tests for render_firehose function."""
+
+    def test_no_firehose_returns_empty(self):
+        """Returns empty list when firehose height is 0."""
+        items = [("Headline", "Source", "12:00")]
+        result = layers.render_firehose(items, 80, 0, 24)
+        assert result == []
+
+    def test_firehose_returns_lines(self):
+        """Returns lines when firehose height > 0."""
+        items = [("Headline", "Source", "12:00")]
+        result = layers.render_firehose(items, 80, 4, 24)
+        assert len(result) == 4
+
+    def test_firehose_includes_ansi_escapes(self):
+        """Returns lines containing ANSI escape sequences."""
+        items = [("Headline", "Source", "12:00")]
+        result = layers.render_firehose(items, 80, 1, 24)
+        assert "\033[" in result[0]
+
+
+class TestApplyGlitch:
+    """Tests for apply_glitch function."""
+
+    def test_empty_buffer_unchanged(self):
+        """Empty buffer is returned unchanged."""
+        result = layers.apply_glitch([], 0, 0.0, 80)
+        assert result == []
+
+    def test_buffer_length_preserved(self):
+        """Buffer length is preserved after glitch application."""
+        buf = [f"\033[{i + 1};1Htest\033[K" for i in range(10)]
+        result = layers.apply_glitch(buf, 0, 0.5, 80)
+        assert len(result) == len(buf)
+
+
+class TestRenderTickerZone:
+    """Tests for render_ticker_zone function - focusing on interface."""
+
+    def test_returns_list(self):
+        """Returns a list of strings."""
+        result, cache = layers.render_ticker_zone([], 0, 10, 80, {}, 0.0)
+        assert isinstance(result, list)
+
+    def test_returns_dict_for_cache(self):
+        """Returns a dict for the noise cache."""
+        result, cache = layers.render_ticker_zone([], 0, 10, 80, {}, 0.0)
+        assert isinstance(cache, dict)

tests/test_mic.py

@@ -0,0 +1,149 @@
+"""
+Tests for engine.mic module.
+"""
+
+from datetime import datetime
+from unittest.mock import patch
+
+from engine.events import MicLevelEvent
+
+
+class TestMicMonitorImport:
+    """Tests for module import behavior."""
+
+    def test_mic_monitor_imports_without_error(self):
+        """MicMonitor can be imported even without sounddevice."""
+        from engine.mic import MicMonitor
+
+        assert MicMonitor is not None
+
+
+class TestMicMonitorInit:
+    """Tests for MicMonitor initialization."""
+
+    def test_init_sets_threshold(self):
+        """Threshold is set correctly."""
+        from engine.mic import MicMonitor
+
+        monitor = MicMonitor(threshold_db=60)
+        assert monitor.threshold_db == 60
+
+    def test_init_defaults(self):
+        """Default values are set correctly."""
+        from engine.mic import MicMonitor
+
+        monitor = MicMonitor()
+        assert monitor.threshold_db == 50
+
+    def test_init_db_starts_at_negative(self):
+        """_db starts at negative value."""
+        from engine.mic import MicMonitor
+
+        monitor = MicMonitor()
+        assert monitor.db == -99.0
+
+
+class TestMicMonitorProperties:
+    """Tests for MicMonitor properties."""
+
+    def test_excess_returns_positive_when_above_threshold(self):
+        """excess returns positive value when above threshold."""
+        from engine.mic import MicMonitor
+
+        monitor = MicMonitor(threshold_db=50)
+        with patch.object(monitor, "_db", 60.0):
+            assert monitor.excess == 10.0
+
+    def test_excess_returns_zero_when_below_threshold(self):
+        """excess returns zero when below threshold."""
+        from engine.mic import MicMonitor
+
+        monitor = MicMonitor(threshold_db=50)
+        with patch.object(monitor, "_db", 40.0):
+            assert monitor.excess == 0.0
+
+
+class TestMicMonitorAvailable:
+    """Tests for MicMonitor.available property."""
+
+    def test_available_is_bool(self):
+        """available returns a boolean."""
+        from engine.mic import MicMonitor
+
+        monitor = MicMonitor()
+        assert isinstance(monitor.available, bool)
+
+
+class TestMicMonitorStop:
+    """Tests for MicMonitor.stop method."""
+
+    def test_stop_does_nothing_when_no_stream(self):
+        """stop() does nothing if no stream exists."""
+        from engine.mic import MicMonitor
+
+        monitor = MicMonitor()
+        monitor.stop()
+        assert monitor._stream is None
+
+
+class TestMicMonitorEventEmission:
+    """Tests for MicMonitor event emission."""
+
+    def test_subscribe_adds_callback(self):
+        """subscribe() adds a callback."""
+        from engine.mic import MicMonitor
+
+        monitor = MicMonitor()
+        def callback(e):
+            return None
+
+        monitor.subscribe(callback)
+
+        assert callback in monitor._subscribers
+
+    def test_unsubscribe_removes_callback(self):
+        """unsubscribe() removes a callback."""
+        from engine.mic import MicMonitor
+
+        monitor = MicMonitor()
+        def callback(e):
+            return None
+        monitor.subscribe(callback)
+
+        monitor.unsubscribe(callback)
+
+        assert callback not in monitor._subscribers
+
+    def test_emit_calls_subscribers(self):
+        """_emit() calls all subscribers."""
+        from engine.mic import MicMonitor
+
+        monitor = MicMonitor()
+        received = []
+
+        def callback(event):
+            received.append(event)
+
+        monitor.subscribe(callback)
+        event = MicLevelEvent(
+            db_level=60.0, excess_above_threshold=10.0, timestamp=datetime.now()
+        )
+        monitor._emit(event)
+
+        assert len(received) == 1
+        assert received[0].db_level == 60.0
+
+    def test_emit_handles_subscriber_exception(self):
+        """_emit() handles exceptions in subscribers gracefully."""
+        from engine.mic import MicMonitor
+
+        monitor = MicMonitor()
+
+        def bad_callback(event):
+            raise RuntimeError("test")
+
+        monitor.subscribe(bad_callback)
+        event = MicLevelEvent(
+            db_level=60.0, excess_above_threshold=10.0, timestamp=datetime.now()
+        )
+        monitor._emit(event)

tests/test_ntfy.py

@@ -0,0 +1,122 @@
+"""
+Tests for engine.ntfy module.
+"""
+
+import time
+from unittest.mock import MagicMock, patch
+
+from engine.events import NtfyMessageEvent
+from engine.ntfy import NtfyPoller
+
+
+class TestNtfyPollerInit:
+    """Tests for NtfyPoller initialization."""
+
+    def test_init_sets_defaults(self):
+        """Default values are set correctly."""
+        poller = NtfyPoller("http://example.com/topic")
+        assert poller.topic_url == "http://example.com/topic"
+        assert poller.reconnect_delay == 5
+        assert poller.display_secs == 30
+
+    def test_init_custom_values(self):
+        """Custom values are set correctly."""
+        poller = NtfyPoller(
+            "http://example.com/topic", reconnect_delay=10, display_secs=60
+        )
+        assert poller.reconnect_delay == 10
+        assert poller.display_secs == 60
+
+
+class TestNtfyPollerStart:
+    """Tests for NtfyPoller.start method."""
+
+    @patch("engine.ntfy.threading.Thread")
+    def test_start_creates_daemon_thread(self, mock_thread):
+        """start() creates and starts a daemon thread."""
+        mock_thread_instance = MagicMock()
+        mock_thread.return_value = mock_thread_instance
+
+        poller = NtfyPoller("http://example.com/topic")
+        result = poller.start()
+
+        assert result is True
+        mock_thread.assert_called_once()
+        args, kwargs = mock_thread.call_args
+        assert kwargs.get("daemon") is True
+        mock_thread_instance.start.assert_called_once()
+
+
+class TestNtfyPollerGetActiveMessage:
+    """Tests for NtfyPoller.get_active_message method."""
+
+    def test_returns_none_when_no_message(self):
+        """Returns None when no message has been received."""
+        poller = NtfyPoller("http://example.com/topic")
+        result = poller.get_active_message()
+        assert result is None
+
+
+class TestNtfyPollerDismiss:
+    """Tests for NtfyPoller.dismiss method."""
+
+    def test_dismiss_clears_message(self):
+        """dismiss() clears the current message."""
+        poller = NtfyPoller("http://example.com/topic")
+
+        with patch.object(poller, "_lock"):
+            poller._message = ("Title", "Body", time.monotonic())
+            poller.dismiss()
+
+            assert poller._message is None
+
+
+class TestNtfyPollerEventEmission:
+    """Tests for NtfyPoller event emission."""
+
+    def test_subscribe_adds_callback(self):
+        """subscribe() adds a callback."""
+        poller = NtfyPoller("http://example.com/topic")
+        def callback(e):
+            return None
+
+        poller.subscribe(callback)
+
+        assert callback in poller._subscribers
+
+    def test_unsubscribe_removes_callback(self):
+        """unsubscribe() removes a callback."""
+        poller = NtfyPoller("http://example.com/topic")
+        def callback(e):
+            return None
+        poller.subscribe(callback)
+
+        poller.unsubscribe(callback)
+
+        assert callback not in poller._subscribers
+
+    def test_emit_calls_subscribers(self):
+        """_emit() calls all subscribers."""
+        poller = NtfyPoller("http://example.com/topic")
+        received = []
+
+        def callback(event):
+            received.append(event)
+
+        poller.subscribe(callback)
+        event = NtfyMessageEvent(title="Test", body="Body")
+        poller._emit(event)
+
+        assert len(received) == 1
+        assert received[0].title == "Test"
+
+    def test_emit_handles_subscriber_exception(self):
+        """_emit() handles exceptions in subscribers gracefully."""
+        poller = NtfyPoller("http://example.com/topic")
+
+        def bad_callback(event):
+            raise RuntimeError("test")
+
+        poller.subscribe(bad_callback)
+        event = NtfyMessageEvent(title="Test", body="Body")
+        poller._emit(event)

tests/test_sources.py

@@ -0,0 +1,93 @@
+"""
+Tests for engine.sources module - data validation.
+"""
+
+from engine import sources
+
+
+class TestFeeds:
+    """Tests for FEEDS data."""
+
+    def test_feeds_is_dict(self):
+        """FEEDS is a dictionary."""
+        assert isinstance(sources.FEEDS, dict)
+
+    def test_feeds_has_entries(self):
+        """FEEDS has feed entries."""
+        assert len(sources.FEEDS) > 0
+
+    def test_feeds_have_valid_urls(self):
+        """All feeds have valid URL format."""
+        for name, url in sources.FEEDS.items():
+            assert name
+            assert url.startswith("http://") or url.startswith("https://")
+
+
+class TestPoetrySources:
+    """Tests for POETRY_SOURCES data."""
+
+    def test_poetry_is_dict(self):
+        """POETRY_SOURCES is a dictionary."""
+        assert isinstance(sources.POETRY_SOURCES, dict)
+
+    def test_poetry_has_entries(self):
+        """POETRY_SOURCES has entries."""
+        assert len(sources.POETRY_SOURCES) > 0
+
+    def test_poetry_have_gutenberg_urls(self):
+        """All poetry sources are from Gutenberg."""
+        for _name, url in sources.POETRY_SOURCES.items():
+            assert "gutenberg.org" in url
+
+
+class TestSourceLangs:
+    """Tests for SOURCE_LANGS mapping."""
+
+    def test_source_langs_is_dict(self):
+        """SOURCE_LANGS is a dictionary."""
+        assert isinstance(sources.SOURCE_LANGS, dict)
+
+    def test_source_langs_valid_language_codes(self):
+        """Language codes are valid ISO codes."""
+        valid_codes = {"de", "fr", "ja", "zh-cn", "ar", "hi"}
+        for code in sources.SOURCE_LANGS.values():
+            assert code in valid_codes
+
+
+class TestLocationLangs:
+    """Tests for LOCATION_LANGS mapping."""
+
+    def test_location_langs_is_dict(self):
+        """LOCATION_LANGS is a dictionary."""
+        assert isinstance(sources.LOCATION_LANGS, dict)
+
+    def test_location_langs_has_patterns(self):
+        """LOCATION_LANGS has regex patterns."""
+        assert len(sources.LOCATION_LANGS) > 0
+
+
+class TestScriptFonts:
+    """Tests for SCRIPT_FONTS mapping."""
+
+    def test_script_fonts_is_dict(self):
+        """SCRIPT_FONTS is a dictionary."""
+        assert isinstance(sources.SCRIPT_FONTS, dict)
+
+    def test_script_fonts_has_paths(self):
+        """All script fonts have paths."""
+        for _lang, path in sources.SCRIPT_FONTS.items():
+            assert path
+
+
+class TestNoUpper:
+    """Tests for NO_UPPER set."""
+
+    def test_no_upper_is_set(self):
+        """NO_UPPER is a set."""
+        assert isinstance(sources.NO_UPPER, set)
+
+    def test_no_upper_contains_scripts(self):
+        """NO_UPPER contains non-Latin scripts."""
+        assert "zh-cn" in sources.NO_UPPER
+        assert "ja" in sources.NO_UPPER
+        assert "ar" in sources.NO_UPPER

tests/test_terminal.py

@@ -0,0 +1,130 @@
+"""
+Tests for engine.terminal module.
+"""
+
+import io
+import sys
+from unittest.mock import patch
+
+from engine import terminal
+
+
+class TestTerminalDimensions:
+    """Tests for terminal width/height functions."""
+
+    def test_tw_returns_columns(self):
+        """tw() returns terminal width."""
+        with (
+            patch.object(sys.stdout, "isatty", return_value=True),
+            patch("os.get_terminal_size") as mock_size,
+        ):
+            mock_size.return_value = io.StringIO("columns=120")
+            mock_size.columns = 120
+            result = terminal.tw()
+            assert isinstance(result, int)
+
+    def test_th_returns_lines(self):
+        """th() returns terminal height."""
+        with (
+            patch.object(sys.stdout, "isatty", return_value=True),
+            patch("os.get_terminal_size") as mock_size,
+        ):
+            mock_size.return_value = io.StringIO("lines=30")
+            mock_size.lines = 30
+            result = terminal.th()
+            assert isinstance(result, int)
+
+    def test_tw_fallback_on_error(self):
+        """tw() falls back to 80 on error."""
+        with patch("os.get_terminal_size", side_effect=OSError):
+            result = terminal.tw()
+            assert result == 80
+
+    def test_th_fallback_on_error(self):
+        """th() falls back to 24 on error."""
+        with patch("os.get_terminal_size", side_effect=OSError):
+            result = terminal.th()
+            assert result == 24
+
+
+class TestANSICodes:
+    """Tests for ANSI escape code constants."""
+
+    def test_ansi_constants_exist(self):
+        """All ANSI constants are defined."""
+        assert terminal.RST == "\033[0m"
+        assert terminal.BOLD == "\033[1m"
+        assert terminal.DIM == "\033[2m"
+
+    def test_green_shades_defined(self):
+        """Green gradient colors are defined."""
+        assert terminal.G_HI == "\033[38;5;46m"
+        assert terminal.G_MID == "\033[38;5;34m"
+        assert terminal.G_LO == "\033[38;5;22m"
+
+    def test_white_shades_defined(self):
+        """White/gray tones are defined."""
+        assert terminal.W_COOL == "\033[38;5;250m"
+        assert terminal.W_DIM == "\033[2;38;5;245m"
+
+    def test_cursor_controls_defined(self):
+        """Cursor control codes are defined."""
+        assert "?" in terminal.CURSOR_OFF
+        assert "?" in terminal.CURSOR_ON
+
+
+class TestTypeOut:
+    """Tests for type_out function."""
+
+    @patch("sys.stdout", new_callable=io.StringIO)
+    @patch("time.sleep")
+    def test_type_out_writes_text(self, mock_sleep, mock_stdout):
+        """type_out writes text to stdout."""
+        with patch("random.random", return_value=0.5):
+            terminal.type_out("Hi", color=terminal.G_HI)
+            output = mock_stdout.getvalue()
+            assert len(output) > 0
+
+    @patch("time.sleep")
+    def test_type_out_uses_color(self, mock_sleep):
+        """type_out applies color codes."""
+        with (
+            patch("sys.stdout", new_callable=io.StringIO),
+            patch("random.random", return_value=0.5),
+        ):
+            terminal.type_out("Test", color=terminal.G_HI)
+
+
+class TestSlowPrint:
+    """Tests for slow_print function."""
+
+    @patch("sys.stdout", new_callable=io.StringIO)
+    @patch("time.sleep")
+    def test_slow_print_writes_text(self, mock_sleep, mock_stdout):
+        """slow_print writes text to stdout."""
+        terminal.slow_print("Hi", color=terminal.G_DIM, delay=0)
+        output = mock_stdout.getvalue()
+        assert len(output) > 0
+
+
+class TestBootLn:
+    """Tests for boot_ln function."""
+
+    @patch("sys.stdout", new_callable=io.StringIO)
+    @patch("time.sleep")
+    def test_boot_ln_writes_label_and_status(self, mock_sleep, mock_stdout):
+        """boot_ln shows label and status."""
+        with patch("random.uniform", return_value=0):
+            terminal.boot_ln("Loading", "OK", ok=True)
+            output = mock_stdout.getvalue()
+            assert "Loading" in output
+            assert "OK" in output
+
+    @patch("sys.stdout", new_callable=io.StringIO)
+    @patch("time.sleep")
+    def test_boot_ln_error_status(self, mock_sleep, mock_stdout):
+        """boot_ln shows red for error status."""
+        with patch("random.uniform", return_value=0):
+            terminal.boot_ln("Loading", "FAIL", ok=False)
+            output = mock_stdout.getvalue()
+            assert "FAIL" in output

tests/test_types.py

@@ -0,0 +1,95 @@
+"""
+Tests for engine.types module.
+"""
+
+from engine.types import (
+    Block,
+    FetchResult,
+    HeadlineItem,
+    items_to_tuples,
+    tuples_to_items,
+)
+
+
+class TestHeadlineItem:
+    """Tests for HeadlineItem dataclass."""
+
+    def test_create_headline_item(self):
+        """Can create HeadlineItem with required fields."""
+        item = HeadlineItem(title="Test", source="Source", timestamp="12:00")
+        assert item.title == "Test"
+        assert item.source == "Source"
+        assert item.timestamp == "12:00"
+
+    def test_to_tuple(self):
+        """to_tuple returns correct tuple."""
+        item = HeadlineItem(title="Test", source="Source", timestamp="12:00")
+        assert item.to_tuple() == ("Test", "Source", "12:00")
+
+    def test_from_tuple(self):
+        """from_tuple creates HeadlineItem from tuple."""
+        item = HeadlineItem.from_tuple(("Test", "Source", "12:00"))
+        assert item.title == "Test"
+        assert item.source == "Source"
+        assert item.timestamp == "12:00"
+
+
+class TestItemsConversion:
+    """Tests for list conversion functions."""
+
+    def test_items_to_tuples(self):
+        """Converts list of HeadlineItem to list of tuples."""
+        items = [
+            HeadlineItem(title="A", source="S", timestamp="10:00"),
+            HeadlineItem(title="B", source="T", timestamp="11:00"),
+        ]
+        result = items_to_tuples(items)
+        assert result == [("A", "S", "10:00"), ("B", "T", "11:00")]
+
+    def test_tuples_to_items(self):
+        """Converts list of tuples to list of HeadlineItem."""
+        tuples = [("A", "S", "10:00"), ("B", "T", "11:00")]
+        result = tuples_to_items(tuples)
+        assert len(result) == 2
+        assert result[0].title == "A"
+        assert result[1].title == "B"
+
+
+class TestFetchResult:
+    """Tests for FetchResult dataclass."""
+
+    def test_create_fetch_result(self):
+        """Can create FetchResult."""
+        items = [HeadlineItem(title="Test", source="Source", timestamp="12:00")]
+        result = FetchResult(items=items, linked=1, failed=0)
+        assert len(result.items) == 1
+        assert result.linked == 1
+        assert result.failed == 0
+
+    def test_to_legacy_tuple(self):
+        """to_legacy_tuple returns correct format."""
+        items = [HeadlineItem(title="Test", source="Source", timestamp="12:00")]
+        result = FetchResult(items=items, linked=1, failed=0)
+        legacy = result.to_legacy_tuple()
+        assert legacy[0] == [("Test", "Source", "12:00")]
+        assert legacy[1] == 1
+        assert legacy[2] == 0
+
+
+class TestBlock:
+    """Tests for Block dataclass."""
+
+    def test_create_block(self):
+        """Can create Block."""
+        block = Block(
+            content=["line1", "line2"], color="\033[38;5;46m", meta_row_index=1
+        )
+        assert len(block.content) == 2
+        assert block.color == "\033[38;5;46m"
+        assert block.meta_row_index == 1
+
+    def test_to_legacy_tuple(self):
+        """to_legacy_tuple returns correct format."""
+        block = Block(content=["line1"], color="green", meta_row_index=0)
+        legacy = block.to_legacy_tuple()
+        assert legacy == (["line1"], "green", 0)

tests/test_viewport.py

@@ -0,0 +1,64 @@
+"""
+Tests for engine.viewport module.
+"""
+
+from engine import viewport
+
+
+class TestViewportTw:
+    """Tests for tw() function."""
+
+    def test_tw_returns_int(self):
+        """tw() returns an integer."""
+        result = viewport.tw()
+        assert isinstance(result, int)
+
+    def test_tw_positive(self):
+        """tw() returns a positive value."""
+        assert viewport.tw() > 0
+
+
+class TestViewportTh:
+    """Tests for th() function."""
+
+    def test_th_returns_int(self):
+        """th() returns an integer."""
+        result = viewport.th()
+        assert isinstance(result, int)
+
+    def test_th_positive(self):
+        """th() returns a positive value."""
+        assert viewport.th() > 0
+
+
+class TestViewportMoveTo:
+    """Tests for move_to() function."""
+
+    def test_move_to_format(self):
+        """move_to() returns correctly formatted ANSI escape."""
+        result = viewport.move_to(5, 10)
+        assert result == "\033[5;10H"
+
+    def test_move_to_default_col(self):
+        """move_to() defaults to column 1."""
+        result = viewport.move_to(5)
+        assert result == "\033[5;1H"
+
+
+class TestViewportClearScreen:
+    """Tests for clear_screen() function."""
+
+    def test_clear_screen_format(self):
+        """clear_screen() returns clear screen ANSI escape."""
+        result = viewport.clear_screen()
+        assert "\033[2J" in result
+        assert "\033[H" in result
+
+
+class TestViewportClearLine:
+    """Tests for clear_line() function."""
+
+    def test_clear_line_format(self):
+        """clear_line() returns clear line ANSI escape."""
+        result = viewport.clear_line()
+        assert result == "\033[K"