/**
 * Hook for Picture-in-Picture with canvas-based rich display.
 * v0.13.4 TASK-APLSH-001: Enhanced PiP with track info overlay & dynamic cover updates.
 *
 * Uses a canvas rendered to a captureStream video for richer PiP content
 * (cover art + track title + artist), falling back to simple poster-based PiP.
 */

import { useCallback, useEffect, useRef, useState } from 'react';

interface PiPTrackInfo {
  title: string;
  artist: string;
  cover?: string | null;
}

export function usePictureInPicture(coverUrl?: string | null) {
  const videoRef = useRef<HTMLVideoElement | null>(null);
  const canvasRef = useRef<HTMLCanvasElement | null>(null);
  const animFrameRef = useRef<number | null>(null);
  const trackInfoRef = useRef<PiPTrackInfo>({ title: '', artist: '', cover: coverUrl });
  const coverImageRef = useRef<HTMLImageElement | null>(null);
  const [isPiPActive, setIsPiPActive] = useState(false);

  const isSupported =
    typeof document !== 'undefined' &&
    'pictureInPictureEnabled' in document &&
    document.pictureInPictureEnabled;

  // Create offscreen canvas once
  useEffect(() => {
    if (!isSupported) return;
    const canvas = document.createElement('canvas');
    canvas.width = 320;
    canvas.height = 320;
    canvasRef.current = canvas;

    return () => {
      if (animFrameRef.current) cancelAnimationFrame(animFrameRef.current);
      canvasRef.current = null;
    };
  }, [isSupported]);

  // Render canvas frame with cover + text
  const renderFrame = useCallback(() => {
    const canvas = canvasRef.current;
    if (!canvas) return;
    const ctx = canvas.getContext('2d');
    if (!ctx || typeof ctx.fillText !== 'function') return;

    const { title, artist } = trackInfoRef.current;
    const img = coverImageRef.current;
    const W = canvas.width;
    const H = canvas.height;

    // Background
    ctx.fillStyle = '#0c0c0f';
    ctx.fillRect(0, 0, W, H);

    // Cover art (centered, with padding)
    if (img && img.complete && img.naturalWidth > 0) {
      const size = 200;
      const x = (W - size) / 2;
      const y = 24;
      ctx.save();
      ctx.beginPath();
      if (typeof ctx.roundRect === 'function') {
        ctx.roundRect(x, y, size, size, 12);
      } else {
        ctx.rect(x, y, size, size);
      }
      ctx.clip();
      ctx.drawImage(img, x, y, size, size);
      ctx.restore();
    }

    // Title
    ctx.fillStyle = '#f0ede8';
    ctx.font = 'bold 16px Inter, system-ui, sans-serif';
    ctx.textAlign = 'center';
    ctx.textBaseline = 'top';
    const titleY = 240;
    const maxTextWidth = W - 32;
    const truncatedTitle = truncateText(ctx, title || 'No track', maxTextWidth);
    ctx.fillText(truncatedTitle, W / 2, titleY);

    // Artist
    ctx.fillStyle = '#a8a4a0';
    ctx.font = '13px Inter, system-ui, sans-serif';
    const truncatedArtist = truncateText(ctx, artist || 'Unknown Artist', maxTextWidth);
    ctx.fillText(truncatedArtist, W / 2, titleY + 24);
  }, []);

  // Animate canvas → video when PiP is active
  useEffect(() => {
    if (!isPiPActive) {
      if (animFrameRef.current) cancelAnimationFrame(animFrameRef.current);
      return;
    }

    const loop = () => {
      renderFrame();
      animFrameRef.current = requestAnimationFrame(loop);
    };
    // Render at ~4fps is enough for mostly-static content
    const interval = setInterval(() => {
      renderFrame();
    }, 250);

    return () => {
      clearInterval(interval);
      if (animFrameRef.current) cancelAnimationFrame(animFrameRef.current);
    };
  }, [isPiPActive, renderFrame]);

  // Update cover image when URL changes
  useEffect(() => {
    trackInfoRef.current.cover = coverUrl;
    if (coverUrl) {
      const img = new Image();
      img.crossOrigin = 'anonymous';
      img.src = coverUrl;
      img.onload = () => {
        coverImageRef.current = img;
        renderFrame();
      };
    } else {
      coverImageRef.current = null;
      renderFrame();
    }

    // Also update poster on the video element for simple PiP fallback
    const video = videoRef.current;
    if (video && coverUrl) {
      video.poster = coverUrl;
    }
  }, [coverUrl, renderFrame]);

  const updateTrackInfo = useCallback(
    (info: PiPTrackInfo) => {
      trackInfoRef.current = info;
      if (info.cover && info.cover !== coverImageRef.current?.src) {
        const img = new Image();
        img.crossOrigin = 'anonymous';
        img.src = info.cover;
        img.onload = () => {
          coverImageRef.current = img;
          renderFrame();
        };
      }
      renderFrame();
    },
    [renderFrame],
  );

  const togglePiP = useCallback(async () => {
    const video = videoRef.current;
    if (!video || !isSupported) return;

    try {
      if (document.pictureInPictureElement) {
        await document.exitPictureInPicture();
        setIsPiPActive(false);
      } else {
        // Try canvas-based PiP first for richer display
        const canvas = canvasRef.current;
        if (canvas && 'captureStream' in canvas) {
          try {
            renderFrame();
            const stream = (canvas as HTMLCanvasElement & { captureStream(fps?: number): MediaStream }).captureStream(4);
            video.srcObject = stream;
            await video.play();
          } catch {
            // Fallback: simple poster-based PiP
            video.srcObject = null;
          }
        }

        await video.requestPictureInPicture();
        setIsPiPActive(true);
      }
    } catch {
      setIsPiPActive(false);
    }
  }, [isSupported, renderFrame]);

  const setVideoRef = useCallback(
    (el: HTMLVideoElement | null) => {
      videoRef.current = el;
      if (el) {
        if (coverUrl) el.poster = coverUrl;
        // Provide silent video as fallback src
        if (!el.src && !el.srcObject) {
          const silentVideo =
            'data:video/webm;base64,GkXfo59ChoEBQveBAULygQRC84EIQoKEd2VibUKHgQRChYECGFOAZwH/w0BZ/5ZQZ+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BAeBhkO+BA';
          el.src = silentVideo;
        }

        el.addEventListener('leavepictureinpicture', () => {
          setIsPiPActive(false);
          // Clean up canvas stream
          el.srcObject = null;
        });
      }
    },
    [coverUrl],
  );

  return { setVideoRef, togglePiP, isPiPActive, isSupported, updateTrackInfo };
}

function truncateText(ctx: CanvasRenderingContext2D, text: string, maxWidth: number): string {
  if (ctx.measureText(text).width <= maxWidth) return text;
  let t = text;
  while (t.length > 0 && ctx.measureText(t + '…').width > maxWidth) {
    t = t.slice(0, -1);
  }
  return t + '…';
}