// Inventory Home App - Items & Locations (No Prices)

(function () {
  const STORAGE_KEY = 'inventory_home_v1';
  const DEFAULT_LOCATIONS = ['Kitchen', 'Living Room', 'Garage', 'Bedroom', 'Bathroom', 'Office'];
  const DEFAULT_ITEMS = [
    { name: 'Coffee Beans', location: 'Kitchen', qty: 2, notes: 'Medium roast' },
    { name: 'Toothpaste', location: 'Bathroom', qty: 1, notes: '' },
    { name: 'AA Batteries', location: 'Office', qty: 8, notes: '' },
    { name: 'Light Bulbs', location: 'Garage', qty: 4, notes: 'LED 9W' },
  ];

  const $ = (sel, root = document) => root.querySelector(sel);
  const $$ = (sel, root = document) => [...root.querySelectorAll(sel)];

  let state = {
    locations: [],
    items: [],
    filter: { q: '', location: 'all' },
    sort: 'updated_desc',
    editingItemId: null,
  };

  // DOM references
  const locationListEl = $('#locationList');
  const locationCountEl = $('#locationCount');
  const addLocationForm = $('#addLocationForm');
  const newLocationName = $('#newLocationName');

  const searchInput = $('#searchInput');
  const filterLocation = $('#filterLocation');
  const sortSelect = $('#sortSelect');
  const addItemBtn = $('#addItemBtn');

  const itemList = $('#itemList');
  const emptyState = $('#emptyState');
  const statsText = $('#statsText');

  const itemModal = $('#itemModal');
  const modalBackdrop = $('#modalBackdrop');
  const itemForm = $('#itemForm');
  const itemModalTitle = $('#itemModalTitle');
  const closeItemModal = $('#closeItemModal');
  const cancelItemBtn = $('#cancelItemBtn');

  const itemName = $('#itemName');
  const itemLocation = $('#itemLocation');
  const itemQty = $('#itemQty');
  const itemNotes = $('#itemNotes');

  const exportBtn = $('#exportBtn');
  const importFile = $('#importFile');
  const resetBtn = $('#resetBtn');

  // Initialize
  loadState();
  ensureDefaults();
  renderAll();

  // Event listeners
  addLocationForm.addEventListener('submit', (e) => {
    e.preventDefault();
    const name = newLocationName.value.trim();
    if (!name) return;
    addLocation(name);
    newLocationName.value = '';
  });

  searchInput.addEventListener('input', (e) => {
    state.filter.q = e.target.value;
    renderItems();
  });

  filterLocation.addEventListener('change', (e) => {
    state.filter.location = e.target.value;
    renderItems();
  });

  sortSelect.addEventListener('change', (e) => {
    state.sort = e.target.value;
    renderItems();
  });

  addItemBtn.addEventListener('click', () => openItemModal());

  [modalBackdrop, closeItemModal, cancelItemBtn].forEach((el) =>
    el.addEventListener('click', closeItemModalHandler)
  );
  document.addEventListener('keydown', (e) => {
    if (e.key === 'Escape' && !itemModal.classList.contains('hidden')) closeItemModalHandler();
  });

  itemForm.addEventListener('submit', (e) => {
    e.preventDefault();
    const payload = {
      name: itemName.value.trim(),
      location: itemLocation.value,
      qty: Number(itemQty.value || 0),
      notes: itemNotes.value.trim(),
    };
    if (!payload.name) {
      alert('Please enter a name.');
      return;
    }
    if (state.editingItemId) {
      updateItem(state.editingItemId, payload);
    } else {
      addItem(payload);
    }
    closeItemModal();
  });

  exportBtn.addEventListener('click', () => {
    const data = {
      locations: state.locations,
      items: state.items,
      exportedAt: new Date().toISOString(),
      version: 1,
    };
    const blob = new Blob([JSON.stringify(data, null, 2)], { type: 'application/json' });
    const url = URL.createObjectURL(blob);
    const a = document.createElement('a');
    a.href = url;
    a.download = `inventory-home-${new Date().toISOString().slice(0, 10)}.json`;
    document.body.appendChild(a);
    a.click();
    a.remove();
    URL.revokeObjectURL(url);
  });

  importFile.addEventListener('change', async (e) => {
    const file = e.target.files?.[0];
    if (!file) return;
    try {
      const text = await file.text();
      const json = JSON.parse(text);
      if (!Array.isArray(json.items) || !Array.isArray(json.locations)) {
        throw new Error('Invalid file format.');
      }
      // Basic validation for item fields
      const items = json.items
        .filter((it) => it && typeof it.name === 'string')
        .map((it) => ({
          id: it.id || uid(),
          name: String(it.name).trim(),
          location: String(it.location || 'Unassigned'),
          qty: Number(it.qty || 0),
          notes: String(it.notes || ''),
          createdAt: it.createdAt || new Date().toISOString(),
          updatedAt: it.updatedAt || new Date().toISOString(),
        }));
      // Ensure locations include all referenced and import as provided
      const locSet = new Set(json.locations.map((l) => String(l)));
      items.forEach((it) => locSet.add(it.location));
      const locations = Array.from(locSet);
      state.items = items;
      state.locations = locations;
      persistState();
      renderAll();
      alert('Import completed.');
    } catch (err) {
      console.error(err);
      alert('Failed to import file.');
    } finally {
      e.target.value = '';
    }
  });

  resetBtn.addEventListener('click', () => {
    if (!confirm('Reset all data to defaults? This cannot be undone.')) return;
    localStorage.removeItem(STORAGE_KEY);
    state.locations = [];
    state.items = [];
    ensureDefaults(true);
    renderAll();
  });

  // Delegated events for locations
  locationListEl.addEventListener('click', (e) => {
    const btn = e.target.closest('button[data-action]');
    if (!btn) return;
    const id = btn.getAttribute('data-id');
    const action = btn.getAttribute('data-action');
    if (action === 'rename') {
      const newName = prompt('Rename location:', btn.getAttribute('data-name') || '');
      if (newName && newName.trim()) {
        renameLocation(id, newName.trim());
      }
    } else if (action === 'delete') {
      if (!confirm('Delete this location? Items will be moved to "Unassigned".')) return;
      deleteLocation(id);
    }
  });

  // Delegated events for items
  itemList.addEventListener('click', (e) => {
    const btn = e.target.closest('button[data-item-id]');
    if (!btn) return;
    const id = btn.getAttribute('data-item-id');
    const action = btn.getAttribute('data-action');
    if (action === 'edit') {
      const item = state.items.find((it) => it.id === id);
      if (item) openItemModal(item);
    } else if (action === 'delete') {
      if (confirm('Delete this item?')) {
        deleteItem(id);
      }
    }
  });

  itemList.addEventListener('change', (e) => {
    const select = e.target.closest('select[data-item-id][data-field="location"]');
    if (select) {
      const id = select.getAttribute('data-item-id');
      const newLoc = select.value;
      updateItem(id, { location: newLoc });
    }
  });

  itemList.addEventListener('input', (e) => {
    const input = e.target.closest('input[data-item-id][data-field="qty"]');
    if (input) {
      const id = input.getAttribute('data-item-id');
      const val = Math.max(0, Math.floor(Number(input.value || 0)));
      updateItem(id, { qty: val });
    }
  });

  // Core functions
  function loadState() {
    const raw = localStorage.getItem(STORAGE_KEY);
    if (raw) {
      try {
        const data = JSON.parse(raw);
        state.locations = Array.isArray(data.locations) ? data.locations : [];
        state.items = Array.isArray(data.items) ? data.items : [];
        return;
      } catch {
        // fall through
      }
    }
    // empty by default
    state.locations = [];
    state.items = [];
  }

  function persistState() {
    localStorage.setItem(
      STORAGE_KEY,
      JSON.stringify({
        locations: state.locations,
        items: state.items,
        updatedAt: new Date().toISOString(),
      })
    );
  }

  function ensureDefaults(force = false) {
    let changed = false;
    if (state.locations.length === 0 || force) {
      state.locations = DEFAULT_LOCATIONS.slice();
      changed = true;
    }
    if (state.items.length === 0 || force) {
      const now = new Date().toISOString();
      state.items = DEFAULT_ITEMS.map((it) => ({
        id: uid(),
        name: it.name,
        location: it.location,
        qty: it.qty,
        notes: it.notes,
        createdAt: now,
        updatedAt: now,
      }));
      changed = true;
    }
    if (changed) persistState();
  }

  function uid() {
    return 'id-' + Date.now().toString(36) + '-' + Math.random().toString(36).slice(2, 8);
  }

  function addLocation(name) {
    if (state.locations.includes(name)) {
      alert('Location already exists.');
      return;
    }
    state.locations.push(name);
    persistState();
    renderLocations();
    populateLocationFilters();
  }

  function renameLocation(oldName, newName) {
    if (state.locations.includes(newName)) {
      alert('A location with that name already exists.');
      return;
    }
    const idx = state.locations.indexOf(oldName);
    if (idx === -1) return;
    state.locations[idx] = newName;
    // Reassign items
    state.items = state.items.map((it) =>
      it.location === oldName ? { ...it, location: newName, updatedAt: new Date().toISOString() } : it
    );
    persistState();
    renderAll();
  }

  function deleteLocation(name) {
    const idx = state.locations.indexOf(name);
    if (idx === -1) return;
    state.locations.splice(idx, 1);
    // Reassign items to Unassigned
    const unassigned = 'Unassigned';
    if (!state.locations.includes(unassigned)) state.locations.push(unassigned);
    state.items = state.items.map((it) =>
      it.location === name ? { ...it, location: unassigned, updatedAt: new Date().toISOString() } : it
    );
    persistState();
    renderAll();
  }

  function addItem({ name, location, qty, notes }) {
    const now = new Date().toISOString();
    const item = {
      id: uid(),
      name,
      location: location || 'Unassigned',
      qty: Number(qty || 0),
      notes: notes || '',
      createdAt: now,
      updatedAt: now,
    };
    if (!state.locations.includes(item.location)) {
      state.locations.push(item.location);
    }
    state.items.push(item);
    persistState();
    renderItems();
    populateLocationFilters();
    renderLocations();
  }

  function updateItem(id, updates) {
    const idx = state.items.findIndex((it) => it.id === id);
    if (idx === -1) return;
    const prev = state.items[idx];
    const next = { ...prev, ...updates, updatedAt: new Date().toISOString() };
    if (next.location && !state.locations.includes(next.location)) {
      state.locations.push(next.location);
    }
    state.items[idx] = next;
    persistState();
    renderItems();
    populateLocationFilters();
    renderLocations();
  }

  function deleteItem(id) {
    const idx = state.items.findIndex((it) => it.id === id);
    if (idx === -1) return;
    state.items.splice(idx, 1);
    persistState();
    renderItems();
  }

  function openItemModal(item) {
    if (item) {
      state.editingItemId = item.id;
      itemModalTitle.textContent = 'Edit Item';
      itemName.value = item.name;
      itemQty.value = String(item.qty);
      itemNotes.value = item.notes || '';
    } else {
      state.editingItemId = null;
      itemModalTitle.textContent = 'Add Item';
      itemName.value = '';
      itemQty.value = '1';
      itemNotes.value = '';
    }
    populateLocationSelects();
    if (item) itemLocation.value = item.location;
    itemModal.classList.remove('hidden');
    itemName.focus();
  }

  function closeItemModalHandler() {
    itemModal.classList.add('hidden');
    state.editingItemId = null;
    itemForm.reset();
  }

  // Renderers
  function renderAll() {
    renderLocations();
    populateLocationFilters();
    renderItems();
  }

  function renderLocations() {
    locationListEl.innerHTML = '';
    const totalItems = state.items.length;
    locationCountEl.textContent = `${totalItems} total`;

    const counts = countBy(state.items, (it) => it.location);
    const sorted = [...state.locations].sort((a, b) => a.localeCompare(b));

    for (const name of sorted) {
      const li = document.createElement('div');
      li.className = 'flex items-center justify-between rounded-md border border-gray-200 bg-gray-50 px-3 py-2';
      li.innerHTML = `
        <div class="min-w-0">
          <div class="text-sm font-medium text-gray-900 truncate">${escapeHtml(name)}</div>
          <div class="text-xs text-gray-500">${counts[name] || 0} items</div>
        </div>
        <div class="flex items-center gap-1">
          <button data-action="rename" data-id="${escapeAttr(name)}" data-name="${escapeAttr(name)}" class="rounded-md border border-gray-300 bg-white px-2 py-1 text-xs text-gray-600 hover:bg-gray-100" title="Rename">Rename</button>
          <button data-action="delete" data-id="${escapeAttr(name)}" class="rounded-md border border-red-300 bg-white px-2 py-1 text-xs text-red-600 hover:bg-red-50" title="Delete">Delete</button>
        </div>
      `;
      locationListEl.appendChild(li);
    }
  }

  function populateLocationFilters() {
    const current = filterLocation.value;
    filterLocation.innerHTML = `<option value="all">All locations</option>`;
    const sorted = [...state.locations].sort((a, b) => a.localeCompare(b));
    for (const name of sorted) {
      const opt = document.createElement('option');
      opt.value = name;
      opt.textContent = name;
      filterLocation.appendChild(opt);
    }
    filterLocation.value = state.filter.location || current || 'all';
    populateLocationSelects();
  }

  function populateLocationSelects() {
    itemLocation.innerHTML = '';
    const sorted = [...state.locations].sort((a, b) => a.localeCompare(b));
    for (const name of sorted) {
      const opt = document.createElement('option');
      opt.value = name;
      opt.textContent = name;
      itemLocation.appendChild(opt);
    }
  }

  function renderItems() {
    const q = (state.filter.q || '').toLowerCase();
    const loc = state.filter.location || 'all';

    let items = state.items.slice();

    if (q) {
      items = items.filter((it) => it.name.toLowerCase().includes(q) || (it.notes || '').toLowerCase().includes(q));
    }
    if (loc !== 'all') {
      items = items.filter((it) => it.location === loc);
    }

    items = sortItems(items, state.sort);

    itemList.innerHTML = '';
    if (items.length === 0) {
      emptyState.classList.remove('hidden');
    } else {
      emptyState.classList.add('hidden');
    }

    for (const it of items) {
      const li = document.createElement('li');
      li.className = 'p-4 sm:p-5 flex flex-col sm:flex-row sm:items-center sm:justify-between gap-3';
      li.innerHTML = `
        <div class="min-w-0">
          <div class="flex items-center gap-2 flex-wrap">
            <h3 class="text-sm font-semibold text-gray-900">${escapeHtml(it.name)}</h3>
            <span class="inline-flex items-center rounded-full bg-gray-100 px-2 py-0.5 text-xs font-medium text-gray-700">${escapeHtml(it.location)}</span>
          </div>
          ${it.notes ? `<p class="mt-1 text-sm text-gray-600">${escapeHtml(it.notes)}</p>` : ''}
          <p class="mt-1 text-xs text-gray-500">Updated ${formatRelative(it.updatedAt)}</p>
        </div>
        <div class="flex items-center gap-3">
          <label class="text-sm text-gray-600">
            Qty
            <input data-field="qty" data-item-id="${it.id}" type="number" min="0" step="1" value="${it.qty}"
              class="ml-1 w-20 rounded-md border-gray-300 text-sm focus:border-blue-500 focus:ring-blue-500" />
          </label>
          <label class="text-sm text-gray-600">
            Location
            <select data-field="location" data-item-id="${it.id}"
              class="ml-1 w-36 rounded-md border-gray-300 text-sm focus:border-blue-500 focus:ring-blue-500">
            </select>
          </label>
          <div class="flex items-center gap-2">
            <button data-action="edit" data-item-id="${it.id}" class="rounded-md border border-gray-300 bg-white px-3 py-2 text-sm text-gray-700 hover:bg-gray-50">Edit</button>
            <button data-action="delete" data-item-id="${it.id}" class="rounded-md border border-red-300 bg-white px-3 py-2 text-sm text-red-600 hover:bg-red-50">Delete</button>
          </div>
        </div>
      `;
      itemList.appendChild(li);
    }

    // Populate each item's location select
    $$('select[data-field="location"][data-item-id]', itemList).forEach((sel) => {
      const id = sel.getAttribute('data-item-id');
      const item = state.items.find((x) => x.id === id);
      if (!item) return;
      sel.innerHTML = '';
      const sorted = [...state.locations].sort((a, b) => a.localeCompare(b));
      for (const name of sorted) {
        const opt = document.createElement('option');
        opt.value = name;
        opt.textContent = name;
        if (name === item.location) opt.selected = true;
        sel.appendChild(opt);
      }
    });

    statsText.textContent = `${items.length} item${items.length === 1 ? '' : 's'}`;
  }

  function sortItems(items, sortKey) {
    const byName = (a, b) => a.name.localeCompare(b.name);
    const byQty = (a, b) => a.qty - b.qty;
    const byCreated = (a, b) => new Date(b.createdAt) - new Date(a.createdAt);
    const byUpdated = (a, b) => new Date(b.updatedAt) - new Date(a.updatedAt);

    switch (sortKey) {
      case 'name_asc':
        return items.sort(byName);
      case 'name_desc':
        return items.sort((a, b) => byName(b, a));
      case 'qty_asc':
        return items.sort(byQty);
      case 'qty_desc':
        return items.sort((a, b) => byQty(b, a));
      case 'created_desc':
        return items.sort(byCreated);
      case 'updated_desc':
      default:
        return items.sort(byUpdated);
    }
  }

  // Utils
  function countBy(arr, fn) {
    return arr.reduce((acc, cur) => {
      const key = fn(cur);
      acc[key] = (acc[key] || 0) + 1;
      return acc;
    }, {});
  }

  function formatRelative(iso) {
    try {
      const d = new Date(iso);
      const diff = Date.now() - d.getTime();
      const sec = Math.floor(diff / 1000);
      if (sec < 10) return 'just now';
      if (sec < 60) return `${sec}s ago`;
      const min = Math.floor(sec / 60);
      if (min < 60) return `${min}m ago`;
      const hr = Math.floor(min / 60);
      if (hr < 24) return `${hr}h ago`;
      const day = Math.floor(hr / 24);
      if (day < 7) return `${day}d ago`;
      return d.toLocaleDateString();
    } catch {
      return '';
    }
  }

  function escapeHtml(s) {
    return String(s)
      .replaceAll('&', '&amp;')
      .replaceAll('<', '&lt;')
      .replaceAll('>', '&gt;')
      .replaceAll('"', '&quot;')
      .replaceAll("'", '&#039;');
  }
  function escapeAttr(s) {
    return escapeHtml(s).replaceAll('"', '&quot;');
  }
})();