/**
 * CatalogPanel — left sidebar for browsing furniture catalog.
 *
 * Shows categories, search, and item cards. Clicking an item
 * adds it to the center of the selected room via DesignState.
 */
export class CatalogPanel {
  constructor(container, { renderer, state, interaction }) {
    this.container = container;
    this.renderer = renderer;
    this.state = state;
    this.interaction = interaction;

    this.selectedCategory = 'all';
    this.searchQuery = '';
    this.selectedRoomId = null;

    this._build();
    this._bindEvents();
  }

  // ---- Build DOM ----

  _build() {
    this.container.innerHTML = '';
    this.container.className = 'catalog-panel';

    // Search
    const searchWrap = document.createElement('div');
    searchWrap.className = 'catalog-search';
    this._searchInput = document.createElement('input');
    this._searchInput.type = 'text';
    this._searchInput.placeholder = 'Search furniture...';
    this._searchInput.className = 'catalog-search-input';
    searchWrap.appendChild(this._searchInput);
    this.container.appendChild(searchWrap);

    // Categories
    this._categoryBar = document.createElement('div');
    this._categoryBar.className = 'catalog-categories';
    this.container.appendChild(this._categoryBar);

    // Items list
    this._itemList = document.createElement('div');
    this._itemList.className = 'catalog-items';
    this.container.appendChild(this._itemList);

    this._renderCategories();
    this._renderItems();
  }

  _renderCategories() {
    const catalog = this.renderer.catalogData;
    if (!catalog) return;

    this._categoryBar.innerHTML = '';
    const categories = ['all', ...catalog.categories];

    const LABELS = {
      all: 'All',
      seating: 'Seating',
      tables: 'Tables',
      storage: 'Storage',
      beds: 'Beds',
      bathroom: 'Bath',
      kitchen: 'Kitchen',
      office: 'Office',
      lighting: 'Lighting',
      decor: 'Decor'
    };

    for (const cat of categories) {
      const btn = document.createElement('button');
      btn.className = 'catalog-cat-btn' + (cat === this.selectedCategory ? ' active' : '');
      btn.textContent = LABELS[cat] || cat;
      btn.dataset.category = cat;
      btn.addEventListener('click', () => {
        this.selectedCategory = cat;
        this._renderCategories();
        this._renderItems();
      });
      this._categoryBar.appendChild(btn);
    }
  }

  _renderItems() {
    const catalog = this.renderer.catalogData;
    if (!catalog) {
      this._itemList.innerHTML = '<div class="catalog-empty">No catalog loaded</div>';
      return;
    }

    let items = catalog.items;

    // Filter by category
    if (this.selectedCategory !== 'all') {
      items = items.filter(it => it.category === this.selectedCategory);
    }

    // Filter by search
    if (this.searchQuery) {
      const q = this.searchQuery.toLowerCase();
      items = items.filter(it =>
        it.name.toLowerCase().includes(q) ||
        it.id.toLowerCase().includes(q) ||
        it.category.toLowerCase().includes(q)
      );
    }

    this._itemList.innerHTML = '';

    if (items.length === 0) {
      this._itemList.innerHTML = '<div class="catalog-empty">No items found</div>';
      return;
    }

    for (const item of items) {
      const card = this._createItemCard(item);
      this._itemList.appendChild(card);
    }
  }

  _createItemCard(item) {
    const card = document.createElement('div');
    card.className = 'catalog-item';
    card.dataset.catalogId = item.id;

    // Color swatch from first part
    const color = item.mesh?.parts?.[0]?.color || '#888';

    const dims = item.dimensions;
    const dimStr = `${dims.width}×${dims.depth}×${dims.height}m`;

    card.innerHTML =
      `<div class="catalog-item-swatch" style="background:${color}"></div>` +
      `<div class="catalog-item-info">` +
        `<div class="catalog-item-name">${item.name}</div>` +
        `<div class="catalog-item-dims">${dimStr}</div>` +
      `</div>` +
      `<button class="catalog-item-add" title="Add to room">+</button>`;

    card.querySelector('.catalog-item-add').addEventListener('click', (e) => {
      e.stopPropagation();
      this._placeItem(item);
    });

    card.addEventListener('click', () => {
      this._placeItem(item);
    });

    return card;
  }

  // ---- Place item ----

  _placeItem(catalogItem) {
    // Determine target room
    const roomId = this._getTargetRoom(catalogItem);
    if (!roomId) return;

    // Get room center for initial placement
    const floor = this.renderer.houseData.floors[this.renderer.currentFloor];
    const room = floor?.rooms.find(r => r.id === roomId);
    if (!room) return;

    // Place at room center (local coords)
    const cx = room.dimensions.width / 2;
    const cz = room.dimensions.length / 2;

    const placement = {
      catalogId: catalogItem.id,
      position: { x: cx, z: cz },
      rotation: 0,
      wallMounted: false
    };

    // InteractionManager handles the re-render via furniture-add event
    this.state.addFurniture(roomId, placement);
  }

  _getTargetRoom(catalogItem) {
    // Use currently selected room from interaction manager or sidebar
    if (this.selectedRoomId) {
      return this.selectedRoomId;
    }

    // If interaction has a room selected (via furniture selection)
    if (this.interaction.selectedRoomId) {
      return this.interaction.selectedRoomId;
    }

    // Try to find a matching room on the current floor
    const rooms = this.renderer.getRooms();
    if (rooms.length === 0) return null;

    // If catalog item has room hints, try to match
    if (catalogItem.rooms && catalogItem.rooms.length > 0) {
      for (const room of rooms) {
        // Room ids contain the room type (eg "eg-wohnzimmer")
        for (const hint of catalogItem.rooms) {
          if (room.id.includes(hint)) return room.id;
        }
      }
    }

    // Fallback: first room on the floor
    return rooms[0].id;
  }

  // ---- Events ----

  _bindEvents() {
    this._searchInput.addEventListener('input', () => {
      this.searchQuery = this._searchInput.value.trim();
      this._renderItems();
    });

    // Track room selection from main sidebar
    this.renderer.container.addEventListener('roomclick', (e) => {
      this.selectedRoomId = e.detail.roomId;
    });
  }

  /** Called externally when a room is selected in the main sidebar. */
  setSelectedRoom(roomId) {
    this.selectedRoomId = roomId;
  }

  /** Refresh the item list (e.g., after floor change). */
  refresh() {
    this._renderItems();
  }
}