// ═══════════════════════════════════════════
//  PROJECT MNEMOSYNE — TIMELINE SCRUBBER
// ═══════════════════════════════════════════
//
// Horizontal timeline bar overlay for scrolling through fact history.
// Crystals outside the visible time window fade out.
//
// Issue: #1169
// ═══════════════════════════════════════════

const TimelineScrubber = (() => {
  let _container = null;
  let _bar = null;
  let _handle = null;
  let _labels = null;
  let _spatialMemory = null;
  let _rangeStart = 0;       // 0-1 normalized
  let _rangeEnd = 1;         // 0-1 normalized
  let _minTimestamp = null;
  let _maxTimestamp = null;
  let _active = false;

  const PRESETS = {
    'hour': { label: 'Last Hour', ms: 3600000 },
    'day':  { label: 'Last Day', ms: 86400000 },
    'week': { label: 'Last Week', ms: 604800000 },
    'all':  { label: 'All Time', ms: Infinity }
  };

  // ─── INIT ──────────────────────────────────────────
  function init(spatialMemory) {
    _spatialMemory = spatialMemory;
    _buildDOM();
    _computeTimeRange();
    console.info('[Mnemosyne] Timeline scrubber initialized');
  }

  function _buildDOM() {
    _container = document.createElement('div');
    _container.id = 'mnemosyne-timeline';
    _container.style.cssText = `
      position: fixed; bottom: 0; left: 0; right: 0; height: 48px;
      background: rgba(5, 5, 16, 0.85); border-top: 1px solid #1a2a4a;
      z-index: 1000; display: flex; align-items: center; padding: 0 16px;
      font-family: monospace; font-size: 12px; color: #8899aa;
      backdrop-filter: blur(8px); transition: opacity 0.3s;
    `;

    // Preset buttons
    const presetDiv = document.createElement('div');
    presetDiv.style.cssText = 'display: flex; gap: 8px; margin-right: 16px;';
    Object.entries(PRESETS).forEach(([key, preset]) => {
      const btn = document.createElement('button');
      btn.textContent = preset.label;
      btn.style.cssText = `
        background: #0a0f28; border: 1px solid #1a2a4a; color: #4af0c0;
        padding: 4px 8px; cursor: pointer; font-family: monospace; font-size: 11px;
        border-radius: 3px; transition: background 0.2s;
      `;
      btn.onmouseenter = () => btn.style.background = '#1a2a4a';
      btn.onmouseleave = () => btn.style.background = '#0a0f28';
      btn.onclick = () => _applyPreset(key);
      presetDiv.appendChild(btn);
    });
    _container.appendChild(presetDiv);

    // Timeline bar
    _bar = document.createElement('div');
    _bar.style.cssText = `
      flex: 1; height: 20px; background: #0a0f28; border: 1px solid #1a2a4a;
      border-radius: 3px; position: relative; cursor: pointer; margin: 0 8px;
    `;

    // Handle (draggable range selector)
    _handle = document.createElement('div');
    _handle.style.cssText = `
      position: absolute; top: 0; left: 0%; width: 100%; height: 100%;
      background: rgba(74, 240, 192, 0.15); border-left: 2px solid #4af0c0;
      border-right: 2px solid #4af0c0; cursor: ew-resize;
    `;
    _bar.appendChild(_handle);
    _container.appendChild(_bar);

    // Labels
    _labels = document.createElement('div');
    _labels.style.cssText = 'min-width: 200px; text-align: right; font-size: 11px;';
    _labels.textContent = 'All Time';
    _container.appendChild(_labels);

    // Drag handling
    let dragging = null;
    _handle.addEventListener('mousedown', (e) => {
      dragging = { startX: e.clientX, startLeft: parseFloat(_handle.style.left) || 0, startWidth: parseFloat(_handle.style.width) || 100 };
      e.preventDefault();
    });
    document.addEventListener('mousemove', (e) => {
      if (!dragging) return;
      const barRect = _bar.getBoundingClientRect();
      const dx = (e.clientX - dragging.startX) / barRect.width * 100;
      let newLeft = Math.max(0, Math.min(100 - dragging.startWidth, dragging.startLeft + dx));
      _handle.style.left = newLeft + '%';
      _rangeStart = newLeft / 100;
      _rangeEnd = (newLeft + dragging.startWidth) / 100;
      _applyFilter();
    });
    document.addEventListener('mouseup', () => { dragging = null; });

    document.body.appendChild(_container);
  }

  function _computeTimeRange() {
    if (!_spatialMemory) return;
    const memories = _spatialMemory.getAllMemories();
    if (memories.length === 0) return;

    let min = Infinity, max = -Infinity;
    memories.forEach(m => {
      const t = new Date(m.timestamp || 0).getTime();
      if (t < min) min = t;
      if (t > max) max = t;
    });
    _minTimestamp = min;
    _maxTimestamp = max;
  }

  function _applyPreset(key) {
    const preset = PRESETS[key];
    if (!preset) return;

    if (preset.ms === Infinity) {
      _rangeStart = 0;
      _rangeEnd = 1;
    } else {
      const now = Date.now();
      const range = _maxTimestamp - _minTimestamp;
      if (range <= 0) return;
      const cutoff = now - preset.ms;
      _rangeStart = Math.max(0, (cutoff - _minTimestamp) / range);
      _rangeEnd = 1;
    }

    _handle.style.left = (_rangeStart * 100) + '%';
    _handle.style.width = ((_rangeEnd - _rangeStart) * 100) + '%';
    _labels.textContent = preset.label;
    _applyFilter();
  }

  function _applyFilter() {
    if (!_spatialMemory) return;
    const range = _maxTimestamp - _minTimestamp;
    if (range <= 0) return;

    const startMs = _minTimestamp + range * _rangeStart;
    const endMs = _minTimestamp + range * _rangeEnd;

    _spatialMemory.getCrystalMeshes().forEach(mesh => {
      const ts = new Date(mesh.userData.createdAt || 0).getTime();
      if (ts >= startMs && ts <= endMs) {
        mesh.visible = true;
        // Smooth restore
        if (mesh.material) mesh.material.opacity = mesh.userData._savedOpacity || mesh.material.opacity;
      } else {
        // Fade out
        if (mesh.material) {
          mesh.userData._savedOpacity = mesh.userData._savedOpacity || mesh.material.opacity;
          mesh.material.opacity = 0.02;
        }
      }
    });

    // Update label with date range
    const startStr = new Date(startMs).toLocaleDateString();
    const endStr = new Date(endMs).toLocaleDateString();
    _labels.textContent = startStr + ' — ' + endStr;
  }

  function update() {
    _computeTimeRange();
  }

  function show() {
    if (_container) _container.style.display = 'flex';
    _active = true;
  }

  function hide() {
    if (_container) _container.style.display = 'none';
    _active = false;
    // Restore all crystals
    if (_spatialMemory) {
      _spatialMemory.getCrystalMeshes().forEach(mesh => {
        mesh.visible = true;
        if (mesh.material && mesh.userData._savedOpacity) {
          mesh.material.opacity = mesh.userData._savedOpacity;
        }
      });
    }
  }

  function isActive() { return _active; }

  return { init, update, show, hide, isActive };
})();

export { TimelineScrubber };