// Auth & Profile Management System — Server-backed (SQLite via /api/auth/)
// Falls back to localStorage if server is unavailable.
window.PvZAuth = (function () {
  const CURRENT_USER_KEY = 'pvz_current_user';
  const LOCAL_DATA_KEY   = 'pvz_local_data';    // local fallback cache
  const API_BASE         = '/api/auth';

  /* ─── Simple djb2 hash (same as before, for backward-compat) ─── */
  function hashPassword(str) {
    let h = 0;
    for (let i = 0; i < str.length; i++) {
      h = ((h << 5) - h) + str.charCodeAt(i);
      h |= 0;
    }
    return h.toString(16);
  }

  /* ─── Default blank profile ─── */
  function getDefaultData() {
    return {
      coins: 150,
      level: 1,
      maxUnlockedLevel: 1,
      highScore: 0,
      theme: 'classic',
      upgrades:    { extraSlot: false, hasRake: false },
      materials:   { bioHumus: 10, scrapMetal: 5, sunEssence: 20, crystals: 0 },
      plantLevels: { peashooter: 1, sunflower: 1, wallnut: 1, potatomine: 1,
                     repeater: 1, snowpea: 1, chomper: 1 },
      perks:       { magnetism: 0, startSun: 0, fastCool: 0, hardyRoots: 0, luckyDrop: 0 },
      zenGarden: {
        pots: [
          { id: 0, plantType: 'sunflower', stage: 2, thirstTimer: 0, needsFertilizer: false, happyTimer: 60, coinTimer: 5 },
          { id: 1, plantType: 'peashooter', stage: 1, thirstTimer: 0, needsFertilizer: false, happyTimer: 45, coinTimer: 8 },
          { id: 2, plantType: null, stage: 0, thirstTimer: 0, needsFertilizer: false, happyTimer: 0, coinTimer: 20 },
          { id: 3, plantType: null, stage: 0, thirstTimer: 0, needsFertilizer: false, happyTimer: 0, coinTimer: 20 },
          { id: 4, plantType: null, stage: 0, thirstTimer: 0, needsFertilizer: false, happyTimer: 0, coinTimer: 20 },
          { id: 5, plantType: null, stage: 0, thirstTimer: 0, needsFertilizer: false, happyTimer: 0, coinTimer: 20 }
        ],
        fertilizerCount: 5,
        chocolateCount: 2,
        snail: { x: 100, targetX: 300, dir: 1, isAwake: true, sleepTimer: 120, boostTimer: 0 },
        lastVisit: Date.now()
      },
      treeOfWisdom: { height: 0, cheats: {} },
      achievements: {}
    };
  }

  /* ─── In-memory current user data ─── */
  let _cachedData = null;

  function localSave(data) {
    try { localStorage.setItem(LOCAL_DATA_KEY, JSON.stringify(data)); } catch (_) {}
  }
  function localLoad() {
    try { return JSON.parse(localStorage.getItem(LOCAL_DATA_KEY) || 'null'); } catch (_) { return null; }
  }

  /* ─── Non-blocking server call ─── */
  async function apiPost(endpoint, body) {
    try {
      const resp = await fetch(`${API_BASE}/${endpoint}`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify(body)
      });
      return await resp.json();
    } catch (e) {
      return { success: false, message: 'Сервер недоступен' };
    }
  }

  /* ─── Debounced save (prevents save storms on rapid updates) ─── */
  let _saveTimer = null;
  function scheduleSave() {
    if (_saveTimer) clearTimeout(_saveTimer);
    _saveTimer = setTimeout(() => {
      const user = localStorage.getItem(CURRENT_USER_KEY);
      if (!user || user === 'Гость' || !_cachedData) return;
      apiPost('save', { username: user, data: _cachedData });
    }, 1500);
  }

  return {
    /* ── Public API ── */

    getCurrentUser() {
      return localStorage.getItem(CURRENT_USER_KEY) || 'Гость';
    },

    isGuest() {
      const u = localStorage.getItem(CURRENT_USER_KEY);
      return !u || u === 'Гость';
    },

    getDefaultData,

    /**
     * Login or auto-register.
     * Synchronous return with provisional localStorage data;
     * server response loaded asynchronously and applied via callback.
     */
    login(username, password, onServerResponse = null) {
      username = (username || '').trim();
      if (!username) return { success: false, message: 'Введите имя пользователя' };
      if (username.toLowerCase() === 'гость') {
        this.loginAsGuest();
        return { success: true, user: 'Гость' };
      }

      const pwdHash = hashPassword(password);

      // Optimistically set local session
      localStorage.setItem(CURRENT_USER_KEY, username);
      _cachedData = getDefaultData();
      localSave(_cachedData);

      // Async server auth
      apiPost('login', { username, passwordHash: pwdHash }).then(res => {
        if (res && res.success && res.data) {
          // Merge defaults + server data
          const def = getDefaultData();
          _cachedData = {
            ...def, ...res.data,
            upgrades:    { ...def.upgrades,    ...(res.data.upgrades    || {}) },
            materials:   { ...def.materials,   ...(res.data.materials   || {}) },
            plantLevels: { ...def.plantLevels, ...(res.data.plantLevels || {}) },
            perks:       { ...def.perks,       ...(res.data.perks       || {}) },
            zenGarden: res.data.zenGarden
              ? { ...def.zenGarden, ...res.data.zenGarden,
                  pots: res.data.zenGarden.pots || def.zenGarden.pots,
                  snail: { ...def.zenGarden.snail, ...(res.data.zenGarden.snail || {}) }
                }
              : def.zenGarden,
            treeOfWisdom: res.data.treeOfWisdom || def.treeOfWisdom,
            achievements: res.data.achievements || {}
          };
          localSave(_cachedData);
          if (typeof onServerResponse === 'function') onServerResponse(_cachedData);
          // Notify game engine to reload profile
          if (window.GameEngine && window._pvzEngine) {
            window._pvzEngine.loadUserData();
          }
        } else if (res && !res.success) {
          // Wrong password — kick back to guest
          if (res.message && res.message.includes('пароль')) {
            localStorage.setItem(CURRENT_USER_KEY, 'Гость');
            _cachedData = null;
            if (typeof onServerResponse === 'function') onServerResponse(null, res.message);
          }
        }
      });

      return { success: true, user: username, pending: true };
    },

    loginAsGuest() {
      localStorage.setItem(CURRENT_USER_KEY, 'Гость');
      _cachedData = null;
      localSave(null);
      return { success: true, user: 'Гость' };
    },

    logout() {
      // Flush any pending save first
      if (_saveTimer) { clearTimeout(_saveTimer); _saveTimer = null; }
      const user = this.getCurrentUser();
      if (user !== 'Гость' && _cachedData) {
        apiPost('save', { username: user, data: _cachedData });
      }
      this.loginAsGuest();
    },

    getUserData() {
      if (this.isGuest()) return getDefaultData();

      if (_cachedData) return _cachedData;

      // Try local cache (sync fallback while server loads)
      const local = localLoad();
      if (local) {
        _cachedData = local;
        return local;
      }

      _cachedData = getDefaultData();
      return _cachedData;
    },

    saveUserData(data) {
      if (this.isGuest()) return; // Guests are not persisted

      _cachedData = _cachedData
        ? { ..._cachedData, ...data }
        : { ...getDefaultData(), ...data };

      localSave(_cachedData); // instant local write
      scheduleSave();         // debounced server sync
    },

    /** Force immediate server save (call on game-over / victory) */
    flushSave() {
      if (this.isGuest() || !_cachedData) return;
      if (_saveTimer) { clearTimeout(_saveTimer); _saveTimer = null; }
      apiPost('save', { username: this.getCurrentUser(), data: _cachedData });
    }
  };
})();