window.C2CStore = (function() {
  const API_BASE = window.C2C_API_BASE || '/api';
  const TOKEN_KEY = 'c2c_token';
  const USER_KEY = 'c2c_user';

  function getStore(key, fallback) {
    try {
      const raw = localStorage.getItem(key);
      return raw ? JSON.parse(raw) : (fallback || []);
    } catch (e) {
      return fallback || [];
    }
  }

  function setStore(key, value) {
    try {
      localStorage.setItem(key, JSON.stringify(value));
    } catch (e) {
      console.warn('localStorage 写入失败', e);
    }
    return value;
  }

  function upsertById(key, item, max) {
    const list = getStore(key, []);
    const next = [item, ...list.filter(x => String(x.id) !== String(item.id))];
    const clipped = max ? next.slice(0, max) : next;
    return setStore(key, clipped);
  }

  function removeById(key, id) {
    const list = getStore(key, []);
    return setStore(key, list.filter(x => String(x.id) !== String(id)));
  }

  function seedIfEmpty(key, data) {
    const list = getStore(key, []);
    if (list.length) return list;
    return setStore(key, data || []);
  }

  function clearStore(key) {
    return setStore(key, []);
  }

  function formatDate(ts) {
    if (!ts) return '刚刚';
    const d = new Date(ts);
    const now = new Date();
    const diff = now - d;
    const day = 24 * 60 * 60 * 1000;
    if (diff < 60 * 1000) return '刚刚';
    if (diff < 60 * 60 * 1000) return Math.floor(diff / 60000) + ' 分钟前';
    if (diff < day) return Math.floor(diff / 3600000) + ' 小时前';
    if (diff < day * 7) return Math.floor(diff / day) + ' 天前';
    return `${d.getMonth() + 1}/${d.getDate()}`;
  }

  function toast(msg) {
    let el = document.getElementById('toast');
    if (!el) {
      el = document.createElement('div');
      el.id = 'toast';
      el.className = 'toast';
      document.body.appendChild(el);
    }
    el.textContent = msg;
    el.classList.add('show');
    clearTimeout(window.__c2cToastTimer);
    window.__c2cToastTimer = setTimeout(() => el.classList.remove('show'), 2200);
  }

  function setToken(token) {
    if (token) localStorage.setItem(TOKEN_KEY, token);
    else localStorage.removeItem(TOKEN_KEY);
  }

  function getToken() {
    return localStorage.getItem(TOKEN_KEY) || '';
  }

  function setCurrentUser(user) {
    if (!user) {
      localStorage.removeItem(USER_KEY);
      localStorage.removeItem('c2c_currentUser');
      return null;
    }
    setStore(USER_KEY, user);
    localStorage.setItem('c2c_currentUser', user.username || '');
    return user;
  }

  function getCurrentUser() {
    try {
      return JSON.parse(localStorage.getItem(USER_KEY) || 'null');
    } catch (e) {
      return null;
    }
  }

  function logout() {
    setToken('');
    setCurrentUser(null);
  }

  async function api(path, options) {
    const opts = options || {};
    const headers = Object.assign({}, opts.headers || {});
    const token = getToken();
    if (token) headers.Authorization = 'Bearer ' + token;
    const hasBody = opts.body !== undefined && opts.body !== null;
    const isFormData = typeof FormData !== 'undefined' && opts.body instanceof FormData;
    if (hasBody && !isFormData && !headers['Content-Type']) {
      headers['Content-Type'] = 'application/json';
    }
    const res = await fetch(API_BASE + path, Object.assign({}, opts, { headers }));
    let data = null;
    try {
      data = await res.json();
    } catch (e) {
      data = null;
    }
    if (!res.ok) {
      const err = new Error((data && data.error) || '请求失败');
      err.status = res.status;
      err.payload = data;
      throw err;
    }
    return data;
  }

  async function fetchMe() {
    const data = await api('/me');
    if (data && data.user) setCurrentUser(data.user);
    return data && data.user;
  }

  function requireLogin(nextUrl) {
    if (getToken()) return true;
    const target = nextUrl || location.href;
    location.href = 'login.html?next=' + encodeURIComponent(target);
    return false;
  }

  function getNextUrl(defaultUrl) {
    const q = new URLSearchParams(location.search);
    return q.get('next') || defaultUrl || 'circle.html';
  }

  return {
    API_BASE,
    TOKEN_KEY,
    USER_KEY,
    getStore,
    setStore,
    upsertById,
    removeById,
    seedIfEmpty,
    clearStore,
    formatDate,
    toast,
    api,
    setToken,
    getToken,
    setCurrentUser,
    getCurrentUser,
    fetchMe,
    logout,
    requireLogin,
    getNextUrl
  };
})();