refactor: Change firehose from a drifting overlay to a fixed bottom strip and message display from a top-pinned section to a centered overlay.

Reviewed-on: #11

README.md

@@ -2,54 +2,112 @@
 
 > *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).
 
 ---
 
 ## Run
 
 ```bash
-python3 mainline.py            # news stream
-python3 mainline.py --poetry   # literary consciousness mode
-python3 mainline.py -p         # same
+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)
 ```
 
-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_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 |
+| `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.
+**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.
 
 ---
 
 ## 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
+- 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
+- A left-to-right ANSI gradient colors each character: white-hot leading edge trails off to near-black; the gradient sweeps continuously across the full scroll canvas
 - 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/
+  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
+  app.py          main(), boot sequence, signal handler
+```
+
+`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 +120,6 @@ 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 +132,10 @@ 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+.*

engine/scroll.py

@@ -1,5 +1,5 @@
 """
-Scroll engine — the main frame loop with headline rendering and message display.
+Render engine — ticker content, scroll motion, message panel, and firehose overlay.
 Depends on: config, terminal, render, effects, ntfy, mic.
 """
 
@@ -16,7 +16,7 @@ from engine.effects import noise, glitch_bar, fade_line, vis_trunc, next_headlin
 
 
 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()
@@ -28,16 +28,21 @@ 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
+    ticker_view_h = h - fh         # reserve fixed firehose strip at bottom
     GAP = 3            # blank rows between headlines
-    scroll_interval = config.SCROLL_DUR / (sh + 15) * 2
+    scroll_step_interval = config.SCROLL_DUR / (ticker_view_h + 15) * 2
 
-    # active blocks: (content_rows, color, canvas_y, meta_idx)
+    # Taxonomy:
+    # - message: centered ntfy overlay panel
+    # - ticker: large headline text content
+    # - scroll: upward camera motion applied to ticker content
+    # - firehose: fixed carriage-return style strip pinned at bottom
+    # Active ticker 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     # viewport top in virtual canvas coords
+    ticker_next_y = ticker_view_h  # canvas-y where next block starts (off-screen bottom)
     noise_cache = {}
-    scroll_accum = 0.0
+    scroll_motion_accum = 0.0
 
     def _noise_at(cy):
         if cy not in noise_cache:
@@ -53,16 +58,17 @@ def stream(items, ntfy_poller, mic_monitor):
         t0 = time.monotonic()
         w, h = tw(), th()
         fh = config.FIREHOSE_H if config.FIREHOSE else 0
-        sh = h - fh
+        ticker_view_h = h - fh
 
         # ── Check for ntfy message ────────────────────────
-        msg_h = 0  # rows consumed by message zone at top
+        msg_h = 0
+        msg_overlay = []
         msg = ntfy_poller.get_active_message()
 
         buf = []
         if msg is not None:
             m_title, m_body, m_ts = msg
-            # ── Message zone: pinned to top, scroll continues below ──
+            # ── Message overlay: centered in the viewport ──
             display_text = m_body or m_title or "(empty)"
             display_text = re.sub(r"\s+", " ", display_text.upper())
             cache_key = (display_text, w)
@@ -76,10 +82,12 @@ def stream(items, ntfy_poller, mic_monitor):
             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  # meta + border
+            panel_top = max(0, (h - panel_h) // 2)
             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")
+                msg_overlay.append(f"\033[{panel_top + row_idx + 1};1H  {ln}{RST}\033[K")
                 row_idx += 1
             # Meta line: title (if distinct) + source + countdown
             meta_parts = []
@@ -87,49 +95,46 @@ def stream(items, ntfy_poller, mic_monitor):
                 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")
+            msg_overlay.append(f"\033[{panel_top + row_idx + 1};1H{MSG_META}{meta}{RST}\033[K")
             row_idx += 1
-            # Border — constant boundary between message and scroll
+            # Border — constant boundary under message panel
             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
+            msg_overlay.append(f"\033[{panel_top + row_idx + 1};1H  {MSG_BORDER}{bar}{RST}\033[K")
 
-        # Effective scroll zone: below message, above firehose
-        scroll_h = sh - msg_h
+        # Ticker draws above the fixed firehose strip; message is a centered overlay.
+        ticker_h = ticker_view_h - msg_h
 
-        # ── 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
+        # ── Ticker content + scroll motion (always runs) ──
+        scroll_motion_accum += config.FRAME_DT
+        while scroll_motion_accum >= scroll_step_interval:
+            scroll_motion_accum -= scroll_step_interval
+            scroll_cam += 1
 
             # Enqueue new headlines when room at the bottom
-            while next_y < cam + sh + 10 and queued < config.HEADLINE_LIMIT:
+            while ticker_next_y < scroll_cam + ticker_view_h + 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]
+                      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))
+        # Draw ticker zone (above fixed firehose strip)
+        top_zone = max(1, int(ticker_h * 0.25))
+        bot_zone = max(1, int(ticker_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
+        ticker_buf_start = len(buf)  # track where ticker rows start in buf
+        for r in range(ticker_h):
+            scr_row = r + 1  # 1-indexed ANSI screen row
+            cy = scroll_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
+            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:
@@ -160,22 +165,24 @@ def stream(items, ntfy_poller, mic_monitor):
                 else:
                     buf.append(f"\033[{scr_row};1H\033[K")
 
-        # 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")
-
-        # Glitch — base rate + mic-reactive spikes (scroll zone only)
+        # Glitch — base rate + mic-reactive spikes (ticker 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)}"
+        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)}"
+
+        if config.FIREHOSE and 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")
+        if msg_overlay:
+            buf.extend(msg_overlay)
 
         sys.stdout.buffer.write("".join(buf).encode())
         sys.stdout.flush()