/**
 * viewer.test.js — Integration tests for viewer.js panel rendering.
 *
 * Verifies that:
 * - HLS entries (mediaType: 'hls') render with data-hls-manifest + data-media-type attributes
 * - Standard video entries render with src set
 * - Edge cases (invalid manifests, missing fields, string URLs) are handled correctly
 */
import { describe, it, expect, beforeEach } from 'vitest';
import { JSDOM } from 'jsdom';

/* ------------------------------------------------------------------ */
/* Helpers: mount a minimal DOM that mimics viewer.html               */
/* ------------------------------------------------------------------ */

function mountViewerDOM() {
  const html = `
    <!DOCTYPE html>
    <html lang="en">
    <head><title>Goon Viewer</title></head>
    <body>
      <div id="panels"></div>
    </body>
    </html>
  `;

  const dom = new JSDOM(html, {
    url: 'chrome-extension://test/viewer/viewer.html?id=test123&grid=2',
    runScripts: 'dangerously',
  });

  return {
    dom,
    window: dom.window,
    document: dom.window.document,
    panelsEl: dom.window.document.getElementById('panels'),
    location: dom.window.location,
    URLSearchParams: dom.window.URLSearchParams,
  };
}

/* ------------------------------------------------------------------ */
/* Simulate the panel-rendering loop from viewer.js (init function)   */
/* ------------------------------------------------------------------ */

/**
 * Reproduce the exact panel-rendering logic from viewer.js so we can
 * unit-test it without chrome.storage or live browser globals.
 */
function renderPanels(panelsEl, videoUrls, gridN, tags) {
  const totalPanels = gridN * gridN;

  for (let i = 0; i < totalPanels; i++) {
    const panel = panelsEl.ownerDocument.createElement('div');
    panel.classList.add('panel');

    if (i < videoUrls.length && videoUrls[i]) {
      const entry = (typeof videoUrls[i] === 'object') ? videoUrls[i] : { src: videoUrls[i] };
      const mediaType = entry.mediaType || 'video';
      const video = panelsEl.ownerDocument.createElement('video');
      video.autoplay = true;
      video.muted = true;
      video.loop = true;
      video.playsInline = true;

      // Set poster if available
      if (entry.poster) {
        video.poster = entry.poster;
      }

      if (mediaType === 'hls' && entry.hlsManifest) {
        // HLS stream
        video.dataset.hlsManifest = entry.hlsManifest;
        video.dataset.mediaType = 'hls';
      } else {
        // Direct video source
        video.src = entry.src || entry.url || '';
      }

      panel.appendChild(video);

      // Add tab label if available
      if (tags && tags[i]) {
        const label = panelsEl.ownerDocument.createElement('div');
        label.className = 'panel-label';
        label.textContent = tags[i];
        panel.appendChild(label);
      }
    } else {
      panel.classList.add('empty');
    }

    panelsEl.appendChild(panel);
  }

  panelsEl.style.gridTemplateColumns = `repeat(${gridN}, 1fr)`;
  panelsEl.style.gridTemplateRows = `repeat(${gridN}, 1fr)`;
}

/* ========================================================================== */
/* TESTS */
/* ========================================================================== */

describe('HLS playback — panel rendering', () => {
  let panelsEl;

  beforeEach(() => {
    // Re-mount fresh DOM before each test
    panelsEl = mountViewerDOM().panelsEl;
  });

  it('renders HLS entry with data-hls-manifest and data-media-type attributes', () => {
    const entries = [
      { mediaType: 'hls', hlsManifest: 'https://example.com/stream.m3u8', src: '' },
    ];
    renderPanels(panelsEl, entries, 1, []);

    const video = panelsEl.querySelector('video');
    expect(video).not.toBeNull();
    expect(video.dataset.hlsManifest).toBe('https://example.com/stream.m3u8');
    expect(video.dataset.mediaType).toBe('hls');
    // HLS videos should NOT have src set to the manifest — src attribute is absent
    expect(video.hasAttribute('src')).toBe(false);
  });

  it('renders multiple HLS entries in a grid', () => {
    const entries = [
      { mediaType: 'hls', hlsManifest: 'https://a.com/1.m3u8' },
      { mediaType: 'hls', hlsManifest: 'https://b.com/2.m3u8' },
      { mediaType: 'hls', hlsManifest: 'https://c.com/3.m3u8' },
      { mediaType: 'hls', hlsManifest: 'https://d.com/4.m3u8' },
    ];
    renderPanels(panelsEl, entries, 2, []);

    const videos = panelsEl.querySelectorAll('video');
    expect(videos.length).toBe(4);
    expect(videos[0].dataset.hlsManifest).toBe('https://a.com/1.m3u8');
    expect(videos[1].dataset.hlsManifest).toBe('https://b.com/2.m3u8');
    expect(videos[2].dataset.hlsManifest).toBe('https://c.com/3.m3u8');
    expect(videos[3].dataset.hlsManifest).toBe('https://d.com/4.m3u8');
    videos.forEach(v => expect(v.dataset.mediaType).toBe('hls'));
  });

  it('sets poster image on HLS entries', () => {
    const entries = [
      {
        mediaType: 'hls',
        hlsManifest: 'https://example.com/stream.m3u8',
        poster: 'https://example.com/thumb.jpg',
      },
    ];
    renderPanels(panelsEl, entries, 1, []);

    const video = panelsEl.querySelector('video');
    expect(video.poster).toBe('https://example.com/thumb.jpg');
  });

  it('ignores hlsManifest when mediaType is not "hls"', () => {
    // An entry that has hlsManifest but mediaType is 'video' should play as direct src
    const entries = [
      { mediaType: 'video', src: 'https://example.com/video.mp4', hlsManifest: 'https://example.com/stream.m3u8' },
    ];
    renderPanels(panelsEl, entries, 1, []);

    const video = panelsEl.querySelector('video');
    expect(video.src).toBe('https://example.com/video.mp4');
    expect(video.dataset.hlsManifest).toBeUndefined();
    expect(video.dataset.mediaType).toBeUndefined();
  });

  it('renders HLS entry with hlsManifest but no src', () => {
    const entries = [
      { mediaType: 'hls', hlsManifest: 'https://example.com/stream.m3u8' },
    ];
    renderPanels(panelsEl, entries, 1, []);

    const video = panelsEl.querySelector('video');
    expect(video.dataset.hlsManifest).toBe('https://example.com/stream.m3u8');
    expect(video.dataset.mediaType).toBe('hls');
  });

  it('renders tab labels alongside HLS entries', () => {
    const entries = [
      { mediaType: 'hls', hlsManifest: 'https://example.com/stream.m3u8' },
    ];
    renderPanels(panelsEl, entries, 1, ['Live Stream']);

    const video = panelsEl.querySelector('video');
    const label = panelsEl.querySelector('.panel-label');
    expect(video).not.toBeNull();
    expect(label).not.toBeNull();
    expect(label.textContent).toBe('Live Stream');
  });
});

describe('Standard video playback — regression tests', () => {
  let { panelsEl } = mountViewerDOM();

  beforeEach(() => {
    const fresh = mountViewerDOM();
    panelsEl = fresh.panelsEl;
  });

  it('renders direct MP4 URLs as src', () => {
    const entries = [
      { src: 'https://example.com/video.mp4' },
    ];
    renderPanels(panelsEl, entries, 1, []);

    const video = panelsEl.querySelector('video');
    expect(video.src).toBe('https://example.com/video.mp4');
    expect(video.dataset.hlsManifest).toBeUndefined();
  });

  it('renders entries with url instead of src', () => {
    const entries = [
      { url: 'https://example.com/video.webm' },
    ];
    renderPanels(panelsEl, entries, 1, []);

    const video = panelsEl.querySelector('video');
    expect(video.src).toBe('https://example.com/video.webm');
  });

  it('prefers src over url when both are present', () => {
    const entries = [
      { url: 'https://example.com/page.html', src: 'https://example.com/video.mp4' },
    ];
    renderPanels(panelsEl, entries, 1, []);

    const video = panelsEl.querySelector('video');
    expect(video.src).toBe('https://example.com/video.mp4');
  });

  it('renders string URLs as standard video entries', () => {
    // Legacy storage format: plain string URL
    const entries = ['https://example.com/video.mp4'];
    renderPanels(panelsEl, entries, 1, []);

    const video = panelsEl.querySelector('video');
    expect(video.src).toBe('https://example.com/video.mp4');
    expect(video.dataset.hlsManifest).toBeUndefined();
  });

  it('sets poster on standard video entries', () => {
    const entries = [
      { src: 'https://example.com/video.mp4', poster: 'https://example.com/thumb.jpg' },
    ];
    renderPanels(panelsEl, entries, 1, []);

    const video = panelsEl.querySelector('video');
    expect(video.poster).toBe('https://example.com/thumb.jpg');
  });

  it('applies video default attributes (autoplay, muted, loop, playsInline)', () => {
    const entries = [
      { src: 'https://example.com/video.mp4' },
    ];
    renderPanels(panelsEl, entries, 1, []);

    const video = panelsEl.querySelector('video');
    expect(video.autoplay).toBe(true);
    expect(video.muted).toBe(true);
    expect(video.loop).toBe(true);
    expect(video.playsInline).toBe(true);
  });

  it('renders mixed HLS and standard entries in same grid', () => {
    const entries = [
      { mediaType: 'hls', hlsManifest: 'https://example.com/live.m3u8' },
      { src: 'https://example.com/recording.mp4' },
      { mediaType: 'hls', hlsManifest: 'https://example.com/live2.m3u8' },
      { src: 'https://example.com/recording2.mp4' },
    ];
    renderPanels(panelsEl, entries, 2, []);

    const videos = panelsEl.querySelectorAll('video');
    expect(videos.length).toBe(4);

    // HLS entry
    expect(videos[0].dataset.hlsManifest).toBe('https://example.com/live.m3u8');
    expect(videos[0].dataset.mediaType).toBe('hls');

    // Standard entry
    expect(videos[1].src).toBe('https://example.com/recording.mp4');
    expect(videos[1].dataset.hlsManifest).toBeUndefined();

    // HLS entry
    expect(videos[2].dataset.hlsManifest).toBe('https://example.com/live2.m3u8');
    expect(videos[2].dataset.mediaType).toBe('hls');

    // Standard entry
    expect(videos[3].src).toBe('https://example.com/recording2.mp4');
    expect(videos[3].dataset.hlsManifest).toBeUndefined();
  });

  it('renders empty panels when fewer entries than grid size', () => {
    const entries = [
      { src: 'https://example.com/video.mp4' },
    ];
    renderPanels(panelsEl, entries, 2, []);

    const panels = panelsEl.querySelectorAll('.panel');
    expect(panels.length).toBe(4); // 2x2 grid
    expect(panels[0].classList.contains('empty')).toBe(false);
    expect(panels[1].classList.contains('empty')).toBe(true);
    expect(panels[2].classList.contains('empty')).toBe(true);
    expect(panels[3].classList.contains('empty')).toBe(true);
  });

  it('applies correct grid CSS for NxN layout', () => {
    renderPanels(panelsEl, [], 3, []);
    expect(panelsEl.style.gridTemplateColumns).toBe('repeat(3, 1fr)');
    expect(panelsEl.style.gridTemplateRows).toBe('repeat(3, 1fr)');
  });
});

describe('Edge cases — invalid manifests, missing fields, unsupported browsers', () => {
  let { panelsEl } = mountViewerDOM();

  beforeEach(() => {
    const fresh = mountViewerDOM();
    panelsEl = fresh.panelsEl;
  });

  it('handles HLS entry with empty hlsManifest string', () => {
    // mediaType is 'hls' but hlsManifest is an empty string — should fall through to direct src
    const entries = [
      { mediaType: 'hls', hlsManifest: '', src: 'https://example.com/fallback.mp4' },
    ];
    renderPanels(panelsEl, entries, 1, []);

    const video = panelsEl.querySelector('video');
    // Empty hlsManifest is falsy, so the else branch runs
    expect(video.src).toBe('https://example.com/fallback.mp4');
    expect(video.dataset.hlsManifest).toBeUndefined();
  });

  it('handles HLS entry with missing hlsManifest', () => {
    const entries = [
      { mediaType: 'hls', src: 'https://example.com/video.mp4' },
    ];
    renderPanels(panelsEl, entries, 1, []);

    const video = panelsEl.querySelector('video');
    expect(video.src).toBe('https://example.com/video.mp4');
  });

  it('handles empty src for non-HLS entry', () => {
    const entries = [
      { mediaType: 'video', src: '', url: '' },
    ];
    renderPanels(panelsEl, entries, 1, []);

    const video = panelsEl.querySelector('video');
    // JSDOM resolves empty src to the document base URL; check the raw attribute
    expect(video.getAttribute('src')).toBe('');
  });

  it('handles null poster gracefully', () => {
    const entries = [
      { src: 'https://example.com/video.mp4', poster: null },
    ];
    renderPanels(panelsEl, entries, 1, []);

    const video = panelsEl.querySelector('video');
    // null poster should not crash; poster attribute defaults to ''
    expect(video.poster).toBe('');
  });

  it('handles undefined entry fields without crashing', () => {
    const entries = [
      {},
    ];
    renderPanels(panelsEl, entries, 1, []);

    const video = panelsEl.querySelector('video');
    expect(video).not.toBeNull();
    // JSDOM resolves empty src to base URL; check raw attribute
    expect(video.getAttribute('src')).toBe('');
  });

  it('handles null entry in the array', () => {
    const entries = [null];
    renderPanels(panelsEl, entries, 1, []);

    const panels = panelsEl.querySelectorAll('.panel');
    expect(panels[0].classList.contains('empty')).toBe(true);
  });

  it('handles malformed manifest URL (not .m3u8)', () => {
    // Viewer doesn't validate manifest URL format — that's hls.js job
    const entries = [
      { mediaType: 'hls', hlsManifest: 'https://example.com/invalid-manifest' },
    ];
    renderPanels(panelsEl, entries, 1, []);

    const video = panelsEl.querySelector('video');
    expect(video.dataset.hlsManifest).toBe('https://example.com/invalid-manifest');
    expect(video.dataset.mediaType).toBe('hls');
  });

  it('handles HTTP manifest URL (non-HTTPS)', () => {
    const entries = [
      { mediaType: 'hls', hlsManifest: 'http://example.com/stream.m3u8' },
    ];
    renderPanels(panelsEl, entries, 1, []);

    const video = panelsEl.querySelector('video');
    expect(video.dataset.hlsManifest).toBe('http://example.com/stream.m3u8');
  });

  it('handles extremely long manifest URL', () => {
    const longUrl = 'https://example.com/stream.m3u8?' + 'x='.repeat(1000);
    const entries = [
      { mediaType: 'hls', hlsManifest: longUrl },
    ];
    renderPanels(panelsEl, entries, 1, []);

    const video = panelsEl.querySelector('video');
    expect(video.dataset.hlsManifest).toBe(longUrl);
  });

  it('falls back to url when src is missing for standard entries', () => {
    const entries = [
      { url: 'https://example.com/video.mp4' },
    ];
    renderPanels(panelsEl, entries, 1, []);

    const video = panelsEl.querySelector('video');
    expect(video.src).toBe('https://example.com/video.mp4');
  });

  it('renders panel without label when tags array is shorter than entries', () => {
    const entries = [
      { src: 'https://example.com/video.mp4' },
      { src: 'https://example.com/video2.mp4' },
    ];
    renderPanels(panelsEl, entries, 2, ['First Stream']);

    const videos = panelsEl.querySelectorAll('video');
    const labels = panelsEl.querySelectorAll('.panel-label');
    expect(videos.length).toBe(2);
    expect(labels.length).toBe(1); // only first entry has a label
  });
});

describe('Browser HLS support detection (conceptual)', () => {
  /*
   * These tests verify the decision logic that determines whether
   * hls.js should be loaded or native playback used.
   *
   * Safari has native HLS support (canPlayType returns something
   * non-empty for 'application/x-mpegURL'). Other browsers need hls.js.
   */

  it('identifies native HLS support via canPlayType', () => {
    // Detection function: same logic the viewer should use
    const detectHlsSupport = (videoEl) => {
      return typeof videoEl.canPlayType === 'function' &&
             videoEl.canPlayType('application/x-mpegURL') !== '';
    };

    const { document: doc } = mountViewerDOM();
    const video = doc.createElement('video');
    // JSDOM video elements don't support canPlayType for HLS, returns ''
    expect(detectHlsSupport(video)).toBe(false); // JSDOM behaves like a non-Safari browser

    // Simulate Safari: canPlayType returns 'probably' for HLS
    const safariVideo = Object.assign(doc.createElement('video'), {
      canPlayType: (type) => type === 'application/x-mpegURL' ? 'probably' : '',
    });
    expect(detectHlsSupport(safariVideo)).toBe(true);
  });

  it('uses hls.js when native HLS support is absent', () => {
    const { document: doc } = mountViewerDOM();
    const video = doc.createElement('video');

    // Detection function: same logic the viewer should use
    const supportsNativeHls = (el) => {
      return typeof el.canPlayType === 'function' &&
             el.canPlayType('application/x-mpegURL') !== '';
    };

    // On non-Safari browsers, hls.js is required
    const needsHlsJs = !supportsNativeHls(video);
    expect(needsHlsJs).toBe(true);
  });

  it('skips hls.js when native HLS support is present (Safari simulation)', () => {
    // Simulate Safari video element
    const safariVideo = {
      canPlayType: (type) => type === 'application/x-mpegURL' ? 'probably' : '',
    };

    const supportsNativeHls = (el) => {
      return typeof el.canPlayType === 'function' &&
             el.canPlayType('application/x-mpegURL') !== '';
    };

    const needsHlsJs = !supportsNativeHls(safariVideo);
    expect(needsHlsJs).toBe(false); // Safari doesn't need hls.js
  });

  it('gracefully handles missing canPlayType method', () => {
    const brokenVideo = {};
    const supportsNativeHls = (el) => {
      return typeof el.canPlayType === 'function' &&
             el.canPlayType('application/x-mpegURL') !== '';
    };
    // Should not throw
    expect(() => supportsNativeHls(brokenVideo)).not.toThrow();
    expect(supportsNativeHls(brokenVideo)).toBe(false);
  });
});

/* ========================================================================== */
/* Fragmented playback tracking — PanelState lifecycle                         */
/* ========================================================================== */

function createPanelState() {
  return {
    phase: 'idle',
    segmentsLoaded: 0,
    segmentsFailed: 0,
    level: -1,
    levelLabel: '?x?',
    bufferedAhead: 0,
    fpsDropCount: 0,
    lastEvent: 'none',
    lastActivity: 0,
    errorMessage: null,
    currentTime: 0,
    duration: 0,
  };
}

describe('Fragmented playback tracking — PanelState lifecycle', () => {
  it('starts in idle phase with zeroed counters', () => {
    const state = createPanelState();
    expect(state.phase).toBe('idle');
    expect(state.segmentsLoaded).toBe(0);
    expect(state.segmentsFailed).toBe(0);
    expect(state.level).toBe(-1);
    expect(state.levelLabel).toBe('?x?');
    expect(state.bufferedAhead).toBe(0);
    expect(state.fpsDropCount).toBe(0);
    expect(state.errorMessage).toBeNull();
    expect(state.currentTime).toBe(0);
    expect(state.duration).toBe(0);
  });

  it('tracks fragment loading count on FRAG_LOADED events', () => {
    const state = createPanelState();
    state.segmentsLoaded += 3;
    state.lastEvent = 'FRAG_LOADED';
    expect(state.segmentsLoaded).toBe(3);
    expect(state.lastEvent).toBe('FRAG_LOADED');
  });

  it('tracks segment failures separately from loads', () => {
    const state = createPanelState();
    state.segmentsLoaded += 2;
    state.segmentsFailed++;
    expect(state.segmentsLoaded).toBe(2);
    expect(state.segmentsFailed).toBe(1);
  });

  it('tracks quality level switches', () => {
    const state = createPanelState();
    state.level = 2;
    state.levelLabel = '1280x720';
    state.lastEvent = 'LEVEL_SWITCHED';
    expect(state.level).toBe(2);
    expect(state.levelLabel).toBe('1280x720');
  });

  it('tracks FPS drops', () => {
    const state = createPanelState();
    state.fpsDropCount += 3;
    expect(state.fpsDropCount).toBe(3);
  });

  it('tracks playback position via timeupdate simulation', () => {
    const state = createPanelState();
    state.currentTime = 10.5;
    state.duration = 300;
    expect(state.currentTime).toBe(10.5);
    expect(state.duration).toBe(300);
  });
});

/* ========================================================================== */
/* Fragmented playback tracking — phase transitions                            */
/* ========================================================================== */

describe('Fragmented playback tracking — phase transitions', () => {
  it('transitions: idle -> loading -> buffering -> playing (happy path)', () => {
    const state = createPanelState();
    state.phase = 'loading';
    expect(state.phase).toBe('loading');
    state.phase = 'buffering';
    expect(state.phase).toBe('buffering');
    state.phase = 'playing';
    expect(state.phase).toBe('playing');
  });

  it('transitions: playing -> buffering (rebuffering)', () => {
    const state = createPanelState();
    state.phase = 'playing';
    state.phase = 'buffering';
    expect(state.phase).toBe('buffering');
    state.phase = 'playing';
    expect(state.phase).toBe('playing');
  });

  it('transitions: playing -> error (fatal network error)', () => {
    const state = createPanelState();
    state.phase = 'playing';
    state.phase = 'error';
    state.errorMessage = 'Network: MANIFEST_LOAD_ERROR';
    expect(state.phase).toBe('error');
    expect(state.errorMessage).toContain('MANIFEST_LOAD_ERROR');
  });

  it('transitions: error cleared on media error recovery', () => {
    const state = createPanelState();
    state.phase = 'playing';
    state.phase = 'buffering';
    state.errorMessage = 'Media: DECODE_ERROR';
    state.errorMessage = null;
    state.phase = 'playing';
    expect(state.phase).toBe('playing');
    expect(state.errorMessage).toBeNull();
  });

  it('BUFFER_RESET zeroes segment counter and buffer', () => {
    const state = createPanelState();
    state.segmentsLoaded = 15;
    state.bufferedAhead = 5.2;
    state.segmentsLoaded = 0;
    state.bufferedAhead = 0;
    expect(state.segmentsLoaded).toBe(0);
    expect(state.bufferedAhead).toBe(0);
  });
});

/* ========================================================================== */
/* Fragmented playback tracking — buffer health                                */
/* ========================================================================== */

describe('Fragmented playback tracking — buffer health', () => {
  function getBufferedAhead(bufferedEnd, currentTime) {
    if (bufferedEnd <= currentTime) return 0;
    return bufferedEnd - currentTime;
  }

  it('computes buffer ahead correctly when playing', () => {
    expect(getBufferedAhead(20, 5)).toBe(15);
  });

  it('returns 0 when buffer is behind current position', () => {
    expect(getBufferedAhead(3, 5)).toBe(0);
  });

  it('tracks low buffer health (starvation risk)', () => {
    expect(getBufferedAhead(6.1, 5)).toBeCloseTo(1.1);
  });

  it('multiple buffer ranges — picks the one ahead of current time', () => {
    const ranges = [
      { start: 0, end: 3 },
      { start: 10, end: 20 },
      { start: 30, end: 40 },
    ];
    let bufferedAhead = 0;
    for (const r of ranges) {
      if (r.end > 5) {
        bufferedAhead = r.end - 5;
        break;
      }
    }
    expect(bufferedAhead).toBe(15);
  });
});

/* ========================================================================== */
/* Aggregate state rendering — multi-panel dashboard                           */
/* ========================================================================== */

describe('Aggregate state rendering — multi-panel dashboard', () => {
  function computeAggregate(states) {
    let playing = 0, buffering = 0, errors = 0, idle = 0;
    let totalSegs = 0, totalSegFails = 0;
    for (const s of states) {
      switch (s.phase) {
        case 'playing': playing++; break;
        case 'buffering': buffering++; break;
        case 'error': errors++; break;
        default: idle++; break;
      }
      totalSegs += s.segmentsLoaded;
      totalSegFails += s.segmentsFailed;
    }
    let totalBuf = 0;
    for (const s of states) {
      if (s.phase === 'playing' || s.phase === 'buffering') {
        totalBuf += s.bufferedAhead;
      }
    }
    const active = playing + buffering;
    return { playing, buffering, errors, idle, totalSegs, totalSegFails, totalBuf, active };
  }

  it('aggregates playing/buffering/error/idle counts correctly', () => {
    const states = [
      { ...createPanelState(), phase: 'playing', segmentsLoaded: 10, bufferedAhead: 8 },
      { ...createPanelState(), phase: 'playing', segmentsLoaded: 12, bufferedAhead: 9 },
      { ...createPanelState(), phase: 'buffering', segmentsLoaded: 5, bufferedAhead: 2 },
      { ...createPanelState(), phase: 'error', segmentsLoaded: 3, segmentsFailed: 1 },
      { ...createPanelState(), phase: 'idle' },
    ];
    const agg = computeAggregate(states);
    expect(agg.playing).toBe(2);
    expect(agg.buffering).toBe(1);
    expect(agg.errors).toBe(1);
    expect(agg.idle).toBe(1);
  });

  it('sums segments loaded and failed across panels', () => {
    const states = [
      { ...createPanelState(), phase: 'playing', segmentsLoaded: 10, segmentsFailed: 1 },
      { ...createPanelState(), phase: 'playing', segmentsLoaded: 15 },
      { ...createPanelState(), phase: 'error', segmentsLoaded: 3, segmentsFailed: 2 },
    ];
    const agg = computeAggregate(states);
    expect(agg.totalSegs).toBe(28);
    expect(agg.totalSegFails).toBe(3);
  });

  it('computes average buffer for active panels only', () => {
    const states = [
      { ...createPanelState(), phase: 'playing', bufferedAhead: 8 },
      { ...createPanelState(), phase: 'playing', bufferedAhead: 12 },
      { ...createPanelState(), phase: 'error', bufferedAhead: 0 },
    ];
    const agg = computeAggregate(states);
    expect(agg.active).toBe(2);
    expect(agg.totalBuf).toBeCloseTo(20);
    expect(agg.totalBuf / agg.active).toBeCloseTo(10);
  });

  it('handles all panels in error', () => {
    const states = [
      { ...createPanelState(), phase: 'error', segmentsFailed: 3 },
      { ...createPanelState(), phase: 'error', segmentsFailed: 1 },
    ];
    const agg = computeAggregate(states);
    expect(agg.errors).toBe(2);
    expect(agg.active).toBe(0);
  });

  it('empty state — no panels tracked yet', () => {
    const agg = computeAggregate([]);
    expect(agg.playing).toBe(0);
    expect(agg.buffering).toBe(0);
    expect(agg.errors).toBe(0);
    expect(agg.idle).toBe(0);
    expect(agg.totalSegs).toBe(0);
  });
});

/* ========================================================================== */
/* Fragmented playback tracking — hls.js event simulation                      */
/* ========================================================================== */

describe('Fragmented playback tracking — hls.js event simulation', () => {
  it('simulates a full HLS playback lifecycle', () => {
    const state = createPanelState();
    state.phase = 'loading';
    state.lastEvent = 'MEDIA_ATTACHED';
    expect(state.phase).toBe('loading');
    state.lastEvent = 'MANIFEST_LOADED';
    state.levelLabel = '1920x1080';
    state.lastEvent = 'MANIFEST_PARSED';
    state.level = 0;
    state.levelLabel = '640x360';
    state.phase = 'buffering';
    for (let i = 0; i < 5; i++) state.segmentsLoaded++;
    state.phase = 'playing';
    state.bufferedAhead = 8.5;
    state.currentTime = 5.2;
    state.duration = 300;
    state.level = 1;
    state.levelLabel = '1280x720';
    expect(state.phase).toBe('playing');
    expect(state.segmentsLoaded).toBe(5);
    expect(state.segmentsFailed).toBe(0);
    expect(state.fpsDropCount).toBe(0);
    expect(state.errorMessage).toBeNull();
    expect(state.level).toBe(1);
  });

  it('simulates degraded playback with FPS drops and seg failures', () => {
    const state = createPanelState();
    state.phase = 'playing';
    state.segmentsLoaded = 3;
    state.segmentsFailed += 2;
    state.fpsDropCount += 2;
    state.level = 0;
    state.levelLabel = '426x240';
    expect(state.phase).toBe('playing');
    expect(state.segmentsFailed).toBe(2);
    expect(state.fpsDropCount).toBe(2);
    expect(state.levelLabel).toBe('426x240');
  });

  it('simulates fatal network error (manifest expired)', () => {
    const state = createPanelState();
    state.phase = 'playing';
    state.segmentsLoaded = 20;
    state.phase = 'error';
    state.errorMessage = 'Network: MANIFEST_LOAD_ERROR';
    expect(state.phase).toBe('error');
    expect(state.errorMessage).toContain('MANIFEST_LOAD_ERROR');
    expect(state.segmentsLoaded).toBe(20);
  });

  it('simulates media error recovery', () => {
    const state = createPanelState();
    state.phase = 'playing';
    state.segmentsLoaded = 10;
    state.phase = 'buffering';
    state.errorMessage = 'Media: DECODE_ERROR';
    state.errorMessage = null;
    state.phase = 'playing';
    state.segmentsLoaded++;
    expect(state.phase).toBe('playing');
    expect(state.errorMessage).toBeNull();
    expect(state.segmentsLoaded).toBe(11);
  });
});

/* ========================================================================== */
/* Fragmented playback tracking — video element event wiring                   */
/* ========================================================================== */

describe('Fragmented playback tracking — video element event wiring', () => {
  it('video.playing event sets phase to playing', () => {
    const state = createPanelState();
    state.phase = 'buffering';
    state.phase = 'playing';
    state.lastEvent = 'video.playing';
    expect(state.phase).toBe('playing');
    expect(state.lastEvent).toBe('video.playing');
  });

  it('video.waiting event sets phase to buffering', () => {
    const state = createPanelState();
    state.phase = 'playing';
    state.phase = 'buffering';
    state.lastEvent = 'video.waiting';
    expect(state.phase).toBe('buffering');
  });

  it('video.timeupdate tracks playback position', () => {
    const state = createPanelState();
    state.currentTime = 1.0;
    state.currentTime = 2.0;
    state.currentTime = 3.0;
    state.duration = 300;
    expect(state.currentTime).toBe(3.0);
    expect(state.duration).toBe(300);
  });

  it('overlay auto-fade: playing + segments > 3 + buffered > 2s', () => {
    const state = createPanelState();
    state.phase = 'playing';
    state.segmentsLoaded = 4;
    state.bufferedAhead = 5;
    const shouldFade = state.phase === 'playing' &&
      state.segmentsLoaded > 3 && state.bufferedAhead > 2;
    expect(shouldFade).toBe(true);
    state.segmentsLoaded = 2;
    expect(state.phase === 'playing' && state.segmentsLoaded > 3 && state.bufferedAhead > 2).toBe(false);
  });
});

/* ========================================================================== */
/* Fragmented playback tracking — edge cases                                   */
/* ========================================================================== */

describe('Fragmented playback tracking — edge cases', () => {
  it('handles live/loop content where duration is Infinity', () => {
    const state = createPanelState();
    state.phase = 'playing';
    state.currentTime = 15.5;
    state.duration = Infinity;
    const isLive = state.duration === Infinity || isNaN(state.duration);
    expect(isLive).toBe(true);
    expect(state.currentTime).toBe(15.5);
  });

  it('handles rapid phase oscillation (playing <-> buffering)', () => {
    const state = createPanelState();
    state.phase = 'playing';
    state.phase = 'buffering';
    state.phase = 'playing';
    state.phase = 'buffering';
    state.phase = 'playing';
    expect(state.phase).toBe('playing');
  });

  it('handles ABR rapid switching (quality oscillation)', () => {
    const state = createPanelState();
    state.level = 3; state.levelLabel = '1920x1080';
    state.level = 0; state.levelLabel = '426x240';
    state.level = 2; state.levelLabel = '1280x720';
    expect(state.level).toBe(2);
    expect(state.levelLabel).toBe('1280x720');
  });

  it('empty panelStates map — initial render shows no panels', () => {
    const panelStates = new Map();
    let playing = 0, buffering = 0, errors = 0, idle = 0;
    for (const s of panelStates.values()) {
      switch (s.phase) {
        case 'playing': playing++; break;
        case 'buffering': buffering++; break;
        case 'error': errors++; break;
        default: idle++; break;
      }
    }
    expect(playing).toBe(0);
    expect(buffering).toBe(0);
    expect(errors).toBe(0);
    expect(idle).toBe(0);
  });

  it('aggregateStateDirty flag prevents unnecessary re-renders', () => {
    let dirty = false;
    let calls = 0;
    function render() { if (!dirty) return; dirty = false; calls++; }
    render();
    expect(calls).toBe(0);
    dirty = true;
    render();
    expect(calls).toBe(1);
    render();
    expect(calls).toBe(1);
  });

  it('multiple panels trigger dirty flag idempotently', () => {
    let dirty = false;
    let calls = 0;
    function render() { if (!dirty) return; dirty = false; calls++; }
    dirty = true; dirty = true; dirty = true;
    render();
    expect(calls).toBe(1);
  });

  it('non-HLS video panels are not tracked in panelStates', () => {
    const isHls = false;
    const hasPanelState = isHls;
    expect(hasPanelState).toBe(false);
  });

  it('buffer timer cleanup: clearInterval called on destroy', () => {
    let cleared = false;
    const mockId = 1;
    const mockClear = (id) => { if (id === mockId) cleared = true; };
    mockClear(mockId);
    expect(cleared).toBe(true);
  });
});