/*
 * 统一数据访问层
 *
 * 默认走本地数据层，方便网页端离线演示。
 * 页面带 ?demo=0 时切换到真实后端，供之后继续联调。
 */
(() => {
  'use strict';

  const API_BASE = `${location.origin}/api`;
  const SOURCE_KEY = 'youthome:web:dataSource';
  const SOURCE_VERSION_KEY = 'youthome:web:sourceDefault:v2';
  const TOKEN_KEY = 'youthome:web:accessToken';
  const USER_KEY = 'youthome:web:authUser';

  const demoMode = new URLSearchParams(location.search).get('demo');
  if (demoMode === '0') {
    localStorage.setItem(SOURCE_KEY, 'api');
    localStorage.setItem(SOURCE_VERSION_KEY, 'true');
    if ((sessionStorage.getItem(TOKEN_KEY) || localStorage.getItem(TOKEN_KEY) || '').startsWith('local-')) {
      [localStorage, sessionStorage].forEach((storage) => {
        storage.removeItem(TOKEN_KEY);
        storage.removeItem(USER_KEY);
      });
    }
  } else {
    if (demoMode === '1' || localStorage.getItem(SOURCE_VERSION_KEY) !== 'true') {
      localStorage.setItem(SOURCE_KEY, 'local');
      localStorage.setItem(SOURCE_VERSION_KEY, 'true');
    }
    if (localStorage.getItem(SOURCE_KEY) === 'local') {
      const existingToken = sessionStorage.getItem(TOKEN_KEY) || localStorage.getItem(TOKEN_KEY) || '';
      if (existingToken && !existingToken.startsWith('local-')) {
        [localStorage, sessionStorage].forEach((storage) => {
          storage.removeItem(TOKEN_KEY);
          storage.removeItem(USER_KEY);
        });
      }
      window.YouthomeLocal?.useDemoAccount();
    }
  }

  const source = () => (localStorage.getItem(SOURCE_KEY) === 'local' ? 'local' : 'api');
  const isLocal = () => source() === 'local';
  const token = () => sessionStorage.getItem(TOKEN_KEY) || localStorage.getItem(TOKEN_KEY);
  const currentUser = () => {
    try { return JSON.parse(sessionStorage.getItem(USER_KEY) || localStorage.getItem(USER_KEY) || 'null'); }
    catch (error) { return null; }
  };
  const applicationKey = () => `youthome:web:activityApplications:${currentUser()?.id || 'guest'}`;
  const applicationRecords = () => {
    try { return JSON.parse(localStorage.getItem(applicationKey()) || '[]'); }
    catch (error) { return []; }
  };
  const clearSession = () => {
    localStorage.removeItem(TOKEN_KEY);
    localStorage.removeItem(USER_KEY);
    sessionStorage.removeItem(TOKEN_KEY);
    sessionStorage.removeItem(USER_KEY);
  };

  const request = async (path, options = {}) => {
    if (isLocal()) {
      if (!window.YouthomeLocal) throw new Error('本地数据层未加载，请刷新页面重试');
      return window.YouthomeLocal.request(path, options);
    }
    const headers = { ...(options.headers || {}) };
    if (token()) headers.access_token = token();
    const isForm = options.body instanceof FormData;
    if (options.body && !isForm) headers['Content-Type'] = 'application/json';
    let response;
    try {
      response = await fetch(`${API_BASE}${path}`, {
        ...options,
        headers,
        signal: AbortSignal.timeout(isForm ? 600000 : 20000)
      });
    } catch (error) {
      throw new Error(error.name === 'TimeoutError' ? '请求超时，请稍后重试' : '无法连接后端，请稍后重试');
    }
    let result;
    try { result = await response.json(); }
    catch (error) { throw new Error(`请求失败（HTTP ${response.status}）`); }
    if (response.status === 401) {
      clearSession();
      throw new Error('登录已失效，请重新登录');
    }
    if (!response.ok || (typeof result.code === 'number' && result.code !== 200)) {
      throw new Error(result.message || `请求失败（HTTP ${response.status}）`);
    }
    return Object.prototype.hasOwnProperty.call(result, 'data') ? result.data : result;
  };

  // 后端头像字段是资源 key（如 man1），不是可直接访问的 URL
  const avatarUrl = (value) => {
    if (!value || typeof value !== 'string') return '';
    if (/^(https?:|data:image\/|\.\.\/|<)/.test(value)) return value;
    return '';
  };

  const me = () => currentUser();

  window.YouthomeApi = {
    source,
    isLocal,
    setSource(value) {
      localStorage.setItem(SOURCE_KEY, value === 'local' ? 'local' : 'api');
      localStorage.setItem(SOURCE_VERSION_KEY, 'true');
    },
    token,
    currentUser,
    applicationRecords,
    saveApplication(record) {
      const records = applicationRecords().filter((item) => item.activityId !== record.activityId);
      records.push(record);
      localStorage.setItem(applicationKey(), JSON.stringify(records));
    },
    removeApplication(activityId) {
      localStorage.setItem(applicationKey(), JSON.stringify(applicationRecords().filter((item) => item.activityId !== activityId)));
    },
    clearSession,
    request,
    get: (path) => request(path),
    post: (path, body) => request(path, { method: 'POST', ...(body === undefined ? {} : { body: JSON.stringify(body) }) }),
    delete: (path) => request(path, { method: 'DELETE' }),
    avatarUrl,
    updateSessionUser(patch) {
      const storage = sessionStorage.getItem(USER_KEY) ? sessionStorage : localStorage;
      const merged = { ...(currentUser() || {}), ...patch };
      storage.setItem(USER_KEY, JSON.stringify(merged));
      return merged;
    },

    async profile() {
      if (isLocal()) return window.YouthomeLocal?.account?.() || null;
      const user = me();
      if (!user) return null;
      return request(`/users/profile?userId=${encodeURIComponent(user.id)}`);
    },
    async points() {
      if (isLocal()) return Number(window.YouthomeLocal?.account?.()?.points || 0);
      const data = await request('/profile/points');
      return Number(data?.points ?? 0);
    },
    async checkIn() {
      if (isLocal()) return null;
      return request('/campus/points/check-in', { method: 'POST' });
    },
    async followStats() {
      if (isLocal()) {
        const account = window.YouthomeLocal?.account?.();
        return { followingCount: window.YouthomeLocal?.following?.().length || 0, followersCount: account?.fans || 0 };
      }
      const user = me();
      if (!user) return { followingCount: 0, followersCount: 0 };
      return request(`/users/follow-status?userId=${encodeURIComponent(user.id)}`);
    },
    async favorites() {
      if (isLocal()) return window.YouthomeLocal.bucketMoments('favorites');
      const data = await request('/campus/moments/favorites?page=1&size=50');
      return data?.items || [];
    },
    async following() {
      if (isLocal()) return window.YouthomeLocal.following().map((nickname) => ({ nickname }));
      const user = me();
      if (!user) return [];
      const data = await request(`/users/following?userId=${encodeURIComponent(user.id)}&page=1&size=50`);
      return data?.items || [];
    },
    async toggleFollow(userId) {
      if (isLocal() || !userId) return null;
      return request(`/users/follow?userId=${encodeURIComponent(userId)}`, { method: 'POST' });
    },
    async joinedActivities() {
      if (isLocal()) return window.YouthomeLocal.joinedActivities();
      const data = await request('/campus/activities/joined?page=1&size=50');
      return data?.items || [];
    },
    async registrations() {
      if (isLocal()) return [];
      const data = await request('/campus/activities/registrations/mine');
      return Array.isArray(data) ? data : (data?.items || []);
    },
    async cancelRegistration(id) {
      return request(`/campus/activities/registrations/${encodeURIComponent(id)}`, { method: 'DELETE' });
    },
    async joinActivity(id, remark = '') {
      if (isLocal()) return null;
      const query = remark ? `?remark=${encodeURIComponent(remark)}` : '';
      return request(`/campus/activities/${encodeURIComponent(id)}/applications${query}`, { method: 'POST' });
    },
    async quitActivity(id) {
      if (isLocal()) return window.YouthomeLocal.leaveActivity(id);
      return request(`/campus/activities/quit?id=${encodeURIComponent(id)}`, { method: 'DELETE' });
    },
    async mallProducts() {
      if (isLocal()) return [];
      const data = await request('/campus/mall/products');
      return data?.items || [];
    },
    async purchase(productId) {
      return request('/campus/mall/purchase', { method: 'POST', body: JSON.stringify({ productId }) });
    }
  };
})();