// ═══════════════════════════════════════════════════════════
// MNEMOSYNE — Memory Connection Panel
// ═══════════════════════════════════════════════════════════
//
// Interactive panel for browsing, adding, and removing memory
// connections. Opens as a sub-panel from MemoryInspect when
// a memory crystal is selected.
//
// Usage from app.js:
//   MemoryConnections.init({
//     onNavigate: fn(memId),        // fly to another memory
//     onConnectionChange: fn(memId, newConnections) // update hooks
//   });
//   MemoryConnections.show(memData, allMemories);
//   MemoryConnections.hide();
//
// Depends on: SpatialMemory (for updateMemory + highlightMemory)
// ═══════════════════════════════════════════════════════════

const MemoryConnections = (() => {
  let _panel = null;
  let _onNavigate = null;
  let _onConnectionChange = null;
  let _currentMemId = null;
  let _hoveredConnId = null;

  // ─── INIT ────────────────────────────────────────────────
  function init(opts = {}) {
    _onNavigate = opts.onNavigate || null;
    _onConnectionChange = opts.onConnectionChange || null;
    _panel = document.getElementById('memory-connections-panel');
    if (!_panel) {
      console.warn('[MemoryConnections] Panel element #memory-connections-panel not found in DOM');
    }
  }

  // ─── SHOW ────────────────────────────────────────────────
  function show(memData, allMemories) {
    if (!_panel || !memData) return;

    _currentMemId = memData.id;
    const connections = memData.connections || [];
    const connectedSet = new Set(connections);

    // Build lookup for connected memories
    const memLookup = {};
    (allMemories || []).forEach(m => { memLookup[m.id] = m; });

    // Connected memories list
    let connectedHtml = '';
    if (connections.length > 0) {
      connectedHtml = connections.map(cid => {
        const cm = memLookup[cid];
        const label = cm ? _truncate(cm.content || cid, 40) : cid;
        const cat = cm ? cm.category : '';
        const strength = cm ? Math.round((cm.strength || 0.7) * 100) : 70;
        return `
          <div class="mc-conn-item" data-memid="${_esc(cid)}">
            <div class="mc-conn-info">
              <span class="mc-conn-label" title="${_esc(cid)}">${_esc(label)}</span>
              <span class="mc-conn-meta">${_esc(cat)} · ${strength}%</span>
            </div>
            <div class="mc-conn-actions">
              <button class="mc-btn mc-btn-nav" data-nav="${_esc(cid)}" title="Navigate to memory">⮞</button>
              <button class="mc-btn mc-btn-remove" data-remove="${_esc(cid)}" title="Remove connection">✕</button>
            </div>
          </div>`;
      }).join('');
    } else {
      connectedHtml = '<div class="mc-empty">No connections yet</div>';
    }

    // Find nearby unconnected memories (same region, then other regions)
    const suggestions = _findSuggestions(memData, allMemories, connectedSet);
    let suggestHtml = '';
    if (suggestions.length > 0) {
      suggestHtml = suggestions.map(s => {
        const label = _truncate(s.content || s.id, 36);
        const cat = s.category || '';
        const proximity = s._proximity || '';
        return `
          <div class="mc-suggest-item" data-memid="${_esc(s.id)}">
            <div class="mc-suggest-info">
              <span class="mc-suggest-label" title="${_esc(s.id)}">${_esc(label)}</span>
              <span class="mc-suggest-meta">${_esc(cat)} · ${_esc(proximity)}</span>
            </div>
            <button class="mc-btn mc-btn-add" data-add="${_esc(s.id)}" title="Add connection">+</button>
          </div>`;
      }).join('');
    } else {
      suggestHtml = '<div class="mc-empty">No nearby memories to connect</div>';
    }

    _panel.innerHTML = `
      <div class="mc-header">
        <span class="mc-title">⬡ Connections</span>
        <button class="mc-close" id="mc-close-btn" aria-label="Close connections panel">✕</button>
      </div>
      <div class="mc-section">
        <div class="mc-section-label">LINKED (${connections.length})</div>
        <div class="mc-conn-list" id="mc-conn-list">${connectedHtml}</div>
      </div>
      <div class="mc-section">
        <div class="mc-section-label">SUGGESTED</div>
        <div class="mc-suggest-list" id="mc-suggest-list">${suggestHtml}</div>
      </div>
    `;

    // Wire close button
    _panel.querySelector('#mc-close-btn')?.addEventListener('click', hide);

    // Wire navigation buttons
    _panel.querySelectorAll('[data-nav]').forEach(btn => {
      btn.addEventListener('click', () => {
        if (_onNavigate) _onNavigate(btn.dataset.nav);
      });
    });

    // Wire remove buttons
    _panel.querySelectorAll('[data-remove]').forEach(btn => {
      btn.addEventListener('click', () => _removeConnection(btn.dataset.remove));
    });

    // Wire add buttons
    _panel.querySelectorAll('[data-add]').forEach(btn => {
      btn.addEventListener('click', () => _addConnection(btn.dataset.add));
    });

    // Wire hover highlight for connection items
    _panel.querySelectorAll('.mc-conn-item').forEach(item => {
      item.addEventListener('mouseenter', () => _highlightConnection(item.dataset.memid));
      item.addEventListener('mouseleave', _clearConnectionHighlight);
    });

    _panel.style.display = 'flex';
    requestAnimationFrame(() => _panel.classList.add('mc-visible'));
  }

  // ─── HIDE ────────────────────────────────────────────────
  function hide() {
    if (!_panel) return;
    _clearConnectionHighlight();
    _panel.classList.remove('mc-visible');
    const onEnd = () => {
      _panel.style.display = 'none';
      _panel.removeEventListener('transitionend', onEnd);
    };
    _panel.addEventListener('transitionend', onEnd);
    setTimeout(() => { if (_panel) _panel.style.display = 'none'; }, 350);
    _currentMemId = null;
  }

  // ─── SUGGESTION ENGINE ──────────────────────────────────
  function _findSuggestions(memData, allMemories, connectedSet) {
    if (!allMemories) return [];

    const suggestions = [];
    const pos = memData.position || [0, 0, 0];
    const sameRegion = memData.category || 'working';

    for (const m of allMemories) {
      if (m.id === memData.id) continue;
      if (connectedSet.has(m.id)) continue;

      const mpos = m.position || [0, 0, 0];
      const dist = Math.sqrt(
        (pos[0] - mpos[0]) ** 2 +
        (pos[1] - mpos[1]) ** 2 +
        (pos[2] - mpos[2]) ** 2
      );

      // Categorize proximity
      let proximity = 'nearby';
      if (m.category === sameRegion) {
        proximity = dist < 5 ? 'same region · close' : 'same region';
      } else {
        proximity = dist < 10 ? 'adjacent' : 'distant';
      }

      suggestions.push({ ...m, _dist: dist, _proximity: proximity });
    }

    // Sort: same region first, then by distance
    suggestions.sort((a, b) => {
      const aSame = a.category === sameRegion ? 0 : 1;
      const bSame = b.category === sameRegion ? 0 : 1;
      if (aSame !== bSame) return aSame - bSame;
      return a._dist - b._dist;
    });

    return suggestions.slice(0, 8); // Cap at 8 suggestions
  }

  // ─── CONNECTION ACTIONS ─────────────────────────────────
  function _addConnection(targetId) {
    if (!_currentMemId) return;

    // Get current memory data via SpatialMemory
    const allMems = typeof SpatialMemory !== 'undefined' ? SpatialMemory.getAllMemories() : [];
    const current = allMems.find(m => m.id === _currentMemId);
    if (!current) return;

    const conns = [...(current.connections || [])];
    if (conns.includes(targetId)) return;

    conns.push(targetId);

    // Update SpatialMemory
    if (typeof SpatialMemory !== 'undefined') {
      SpatialMemory.updateMemory(_currentMemId, { connections: conns });
    }

    // Also create reverse connection on target
    const target = allMems.find(m => m.id === targetId);
    if (target) {
      const targetConns = [...(target.connections || [])];
      if (!targetConns.includes(_currentMemId)) {
        targetConns.push(_currentMemId);
        SpatialMemory.updateMemory(targetId, { connections: targetConns });
      }
    }

    if (_onConnectionChange) _onConnectionChange(_currentMemId, conns);

    // Re-render panel
    const updatedMem = { ...current, connections: conns };
    show(updatedMem, allMems);
  }

  function _removeConnection(targetId) {
    if (!_currentMemId) return;

    const allMems = typeof SpatialMemory !== 'undefined' ? SpatialMemory.getAllMemories() : [];
    const current = allMems.find(m => m.id === _currentMemId);
    if (!current) return;

    const conns = (current.connections || []).filter(c => c !== targetId);

    if (typeof SpatialMemory !== 'undefined') {
      SpatialMemory.updateMemory(_currentMemId, { connections: conns });
    }

    // Also remove reverse connection
    const target = allMems.find(m => m.id === targetId);
    if (target) {
      const targetConns = (target.connections || []).filter(c => c !== _currentMemId);
      SpatialMemory.updateMemory(targetId, { connections: targetConns });
    }

    if (_onConnectionChange) _onConnectionChange(_currentMemId, conns);

    const updatedMem = { ...current, connections: conns };
    show(updatedMem, allMems);
  }

  // ─── 3D HIGHLIGHT ───────────────────────────────────────
  function _highlightConnection(memId) {
    _hoveredConnId = memId;
    if (typeof SpatialMemory !== 'undefined') {
      SpatialMemory.highlightMemory(memId);
    }
  }

  function _clearConnectionHighlight() {
    if (_hoveredConnId && typeof SpatialMemory !== 'undefined') {
      SpatialMemory.clearHighlight();
    }
    _hoveredConnId = null;
  }

  // ─── HELPERS ────────────────────────────────────────────
  function _esc(str) {
    return String(str)
      .replace(/&/g, '&amp;')
      .replace(/</g, '&lt;')
      .replace(/>/g, '&gt;')
      .replace(/"/g, '&quot;');
  }

  function _truncate(str, n) {
    return str.length > n ? str.slice(0, n - 1) + '\u2026' : str;
  }

  function isOpen() {
    return _panel != null && _panel.style.display !== 'none';
  }

  return { init, show, hide, isOpen };
})();

export { MemoryConnections };