(() => {
  'use strict';

  const POLL_MS = 1000;
  const $ = (id) => document.getElementById(id);
  let itemNames = {};
  let lastInventorySignature = '';
  let lastState = null;

  const escapeHTML = (value) => String(value ?? '').replace(/[&<>"']/g, (ch) => ({
    '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;', "'": '&#39;'
  })[ch]);

  function prettyName(name) {
    return String(name || 'unknown item').replace(/^minecraft:/, '')
      .replaceAll('_', ' ').replace(/\b\w/g, (letter) => letter.toUpperCase());
  }

  function vectorText(pos) {
    if (!pos) return '—';
    if (typeof pos === 'object' && ['x', 'y', 'z'].every((key) => key in pos)) {
      return `${Number(pos.x).toFixed(1)}, ${Number(pos.y).toFixed(1)}, ${Number(pos.z).toFixed(1)}`;
    }
    const match = String(pos).match(/-?\d+(?:\.\d+)?/g);
    return match && match.length >= 3 ? match.slice(0, 3).join(', ') : String(pos);
  }

  function dimensionName(name) {
    return String(name || 'unknown').replace(/^minecraft:/, '').replaceAll('_', ' ').toUpperCase();
  }

  function formatMode(mode) {
    const modes = {0: 'Survival', 1: 'Creative', 2: 'Adventure', 3: 'Spectator'};
    return modes[mode] || (mode == null ? '—' : String(mode));
  }

  function textureCandidates(name) {
    const id = String(name || '').replace(/^minecraft:/, '').toLowerCase();
    if (!/^[a-z0-9_]+$/.test(id) || id === 'air') return [];
    // Prefer bundled icons, then the same-origin asset proxy. The external
    // sources remain a last resort for uncached items on older bot processes.
    const local = `/static/item-icons/${encodeURIComponent(id)}.png`;
    const proxy = `/api/item-icon/${encodeURIComponent(id)}`;
    const root = 'https://assets.mcasset.cloud/26.3/assets/minecraft/textures';
    const paths = [`item/${id}.png`, `block/${id}.png`];
    const simplified = id.replace(/_(slab|stairs|wall|fence_gate|fence|door|trapdoor|button|pressure_plate|sign|hanging_sign|carpet|banner|bed|candle)$/, '');
    if (simplified !== id) paths.push(`block/${simplified}.png`, `item/${simplified}.png`);
    return [local, proxy, ...[...new Set(paths)].map((path) => `${root}/${path}`)];
  }

  function renderItemIcon(img, fallback, itemName) {
    const candidates = textureCandidates(itemName);
    let index = 0;
    const tryNext = () => {
      if (index >= candidates.length) {
        img.remove();
        fallback.hidden = false;
        fallback.textContent = prettyName(itemName).slice(0, 2).toUpperCase();
        return;
      }
      img.src = candidates[index++];
    };
    img.onerror = tryNext;
    img.onload = () => { fallback.hidden = true; };
    tryNext();
  }

  function inventorySignature(inv, partial) {
    return JSON.stringify([Boolean(partial), Object.entries(inv || {}).map(([slot, item]) => [
      slot, item && item.present, item && item.item_id, item && item.item_count
    ])]);
  }

  function renderInventory(state) {
    const inv = state.inv || {};
    const signature = inventorySignature(inv, state.inventory_partial);
    if (signature === lastInventorySignature) return;
    lastInventorySignature = signature;

    const grid = $('inventory-grid');
    const items = [];
    let stackCount = 0;
    let totalCount = 0;
    for (let slot = 0; slot < 46; slot++) {
      const item = inv[String(slot)] || inv[slot];
      if (item && item.present) {
        stackCount++;
        totalCount += Number(item.item_count || 0);
      }
      items.push({slot, item});
    }

    grid.innerHTML = items.map(({slot, item}) => {
      const present = Boolean(item && item.present);
      const itemId = present ? item.item_id : null;
      const name = present ? (itemNames[String(itemId)] || `item_${itemId}`) : '';
      const count = present ? Number(item.item_count || 0) : 0;
      const title = present ? `${prettyName(name)} × ${count} (id ${itemId}, slot ${slot})` : `Empty slot ${slot}`;
      return `<div class="inventory-slot${present ? ' occupied' : ''}${slot >= 36 && slot <= 44 ? ' hotbar-slot' : ''}"
        title="${escapeHTML(title)}" aria-label="${escapeHTML(title)}">
        <span class="slot-number">${slot}</span>
        ${present ? `<span class="item-art"><img alt="" loading="lazy"><span class="icon-fallback" hidden></span></span>
          <span class="stack-count">${count > 1 ? count : ''}</span>` : ''}
      </div>`;
    }).join('');

    items.forEach(({slot, item}) => {
      if (!item || !item.present) return;
      const icon = grid.children[slot]?.querySelector('img');
      const fallback = grid.children[slot]?.querySelector('.icon-fallback');
      if (icon && fallback) renderItemIcon(icon, fallback, itemNames[String(item.item_id)] || `item_${item.item_id}`);
    });

    $('inventory-count').textContent = `${totalCount} items`;
    $('inventory-slots').textContent = `${stackCount} / 46 slots`;
    $('inventory-warning').hidden = !state.inventory_partial;
  }

  function renderPlayers(state) {
    const players = Object.values(state.players || {});
    $('player-count').textContent = String(players.length);
    if (!players.length) {
      $('player-list').innerHTML = '<div class="empty-state">No player data in range</div>';
      return;
    }
    $('player-list').innerHTML = players.map((player) => {
      const uuid = String(player.player_uuid || '');
      const name = state.player_names?.[uuid] || state.player_names?.[uuid.toLowerCase()] || `Player ${player.entity_id}`;
      const pos = [player.x, player.y, player.z].map((n) => Number(n).toFixed(0)).join(', ');
      return `<div class="player-row"><span class="player-avatar">${escapeHTML(name.slice(0, 1).toUpperCase())}</span>
        <span class="player-name">${escapeHTML(name)}</span><span class="player-pos">${escapeHTML(pos)}</span></div>`;
    }).join('');
  }

  function render(state) {
    lastState = state;
    const online = Boolean(state.connected) && state.connection_status === 'in_game';
    const pill = $('connection-pill');
    pill.classList.toggle('is-online', online);
    pill.classList.toggle('is-offline', !online);
    pill.querySelector('span').textContent = online ? 'ONLINE' : (state.connection_status || 'OFFLINE').toUpperCase();

    $('bot-name').textContent = state.name || 'Mosfet';
    $('session-subtitle').textContent = online
      ? `${formatMode(state.game_mode)} mode · protocol 777 · AuthMe session active`
      : `Connection state: ${state.connection_status || 'disconnected'}`;
    $('position').textContent = vectorText(state.pos || state.player_position);
    $('dimension').textContent = dimensionName(state.dimension);

    const health = state.health == null ? NaN : Number(state.health);
    const food = state.food == null ? NaN : Number(state.food);
    const saturation = state.food_saturation == null
      ? NaN : Number(state.food_saturation);
    $('health-value').textContent = Number.isFinite(health)
      ? Number(health.toFixed(1)).toString() : '—';
    $('food-value').textContent = Number.isFinite(food) ? String(food) : '—';
    $('food-saturation').textContent = Number.isFinite(saturation)
      ? `Saturation ${saturation.toFixed(2)}` : 'Saturation —';
    $('health-meter').style.width = `${Math.max(0, Math.min(100, (health || 0) * 5))}%`;
    $('food-meter').style.width = `${Math.max(0, Math.min(100, (food || 0) * 5))}%`;

    const movement = state.movement_status || (state.path?.length ? 'following_path' : 'idle');
    $('movement-value').textContent = String(movement).replaceAll('_', ' ').toUpperCase();
    $('movement-detail').textContent = state.path?.length ? `${state.path.length} nodes remaining` : 'No active path';
    $('chunk-count').textContent = state.chunk_state?.loaded ?? '—';
    const center = state.chunk_state?.center;
    $('chunk-detail').textContent = center ? `Center ${center[0]}, ${center[1]} · radius ${state.chunk_state.radius ?? '—'}` : 'Waiting for world data';
    $('game-mode').textContent = formatMode(state.game_mode);
    $('job-state').textContent = prettyName(state.job_state || 'idle').toUpperCase();
    $('path-length').textContent = String(state.path?.length || 0);
    $('entity-count').textContent = `${Object.keys(state.mobs || {}).length} mobs · ${Object.keys(state.objects || {}).length} drops`;
    $('afk-state').textContent = state.afk ? 'YES' : 'NO';
    $('movement-error').hidden = !state.movement_error;
    $('movement-error').textContent = state.movement_error ? `Movement error: ${state.movement_error}` : '';

    renderInventory(state);
    renderPlayers(state);
    $('last-update').textContent = `Updated ${new Date().toLocaleTimeString()}`;
  }

  async function loadItems() {
    try {
      const response = await fetch('/api/items', {cache: 'force-cache'});
      if (response.ok) itemNames = await response.json();
      if (lastState) {
        lastInventorySignature = '';
        renderInventory(lastState);
      }
    } catch (_) {
      // Inventory still renders with numeric IDs if the name endpoint is absent.
    }
  }

  async function poll() {
    try {
      const response = await fetch('/api/global', {cache: 'no-store'});
      if (!response.ok) throw new Error(`API ${response.status}`);
      render(await response.json());
    } catch (error) {
      const pill = $('connection-pill');
      pill.classList.add('is-offline');
      pill.classList.remove('is-online');
      pill.querySelector('span').textContent = 'API OFFLINE';
      $('session-subtitle').textContent = 'Cannot reach the bot web API';
      $('last-update').textContent = `Last update failed · ${error.message}`;
    }
  }

  loadItems();
  poll();
  window.setInterval(poll, POLL_MS);
})();