"""
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