const SESSION_KEY = 'tkmind_session';
const { createUuid, SESSION_COOKIE_NAME } = require('./config');
const { clearLegalConsent } = require('./legal-consent');

let apiBaseUrl = '';
let cookie = '';

function buildSessionCookie(token) {
  const value = String(token ?? '').trim();
  if (!value) return '';
  return `${SESSION_COOKIE_NAME}=${encodeURIComponent(value)}`;
}

function applySessionToken(token) {
  const nextCookie = buildSessionCookie(token);
  if (!nextCookie) return;
  cookie = nextCookie;
  const previous = getStoredSession() || {};
  saveSession({ ...previous, cookie: nextCookie });
}

function restoreSessionCookie() {
  try {
    const session = wx.getStorageSync(SESSION_KEY);
    if (session?.cookie) {
      cookie = session.cookie;
    }
  } catch {
    // Ignore storage read errors during cold start.
  }
}

restoreSessionCookie();

function setApiBaseUrl(value) {
  apiBaseUrl = String(value || '').replace(/\/$/, '');
}

function getMiniProgramAppId() {
  try {
    return wx.getAccountInfoSync?.()?.miniProgram?.appId || '';
  } catch {
    return '';
  }
}

function isTouristMode() {
  const appId = getMiniProgramAppId();
  return !appId || appId === 'touristappid';
}

function getApiBaseUrl() {
  return apiBaseUrl;
}

function formatRequestError(res, url) {
  const status = Number(res.statusCode || 0);
  const code = res.data?.error?.code || '';
  const serverMessage = res.data?.message || res.data?.error?.message || '';
  if (status === 403 && code === 'csrf_failed') {
    if (/m\.tkmind\.cn/i.test(apiBaseUrl)) {
      return '线上 Portal 尚未部署小程序登录接口（403 来源校验失败）。请先用账号密码登录，或改用本地 Portal 联调。';
    }
    return serverMessage || '请求被服务器拒绝（来源校验失败）';
  }
  if (status === 404) {
    return '登录接口不存在，请重启本地 Portal（pnpm dev）后再试';
  }
  if (serverMessage) return serverMessage;
  if (status === 503) return '服务暂不可用，请稍后重试或使用账号密码登录';
  if (status === 405) {
    return `接口不支持当前请求方法，请检查 API_BASE_URL 是否指向 Portal：${url}`;
  }
  return `请求失败 (${status || 'network'})`;
}

function getStoredSession() {
  const session = wx.getStorageSync(SESSION_KEY);
  if (session && typeof session === 'object') {
    cookie = session.cookie || cookie;
    return session;
  }
  return null;
}

function saveSession(session) {
  cookie = session?.cookie || cookie;
  wx.setStorageSync(SESSION_KEY, session || {});
}

function clearSession() {
  cookie = '';
  wx.removeStorageSync(SESSION_KEY);
}

function normalizeSetCookie(headers = {}) {
  const raw = headers['Set-Cookie'] || headers['set-cookie'];
  if (!raw) return '';
  const items = Array.isArray(raw) ? raw : [String(raw)];
  let sessionCookie = '';
  for (const item of items) {
    const firstPart = String(item).trim().split(';')[0].trim();
    const separator = firstPart.indexOf('=');
    if (separator <= 0) continue;
    const name = firstPart.slice(0, separator);
    const value = firstPart.slice(separator + 1);
    if (name === SESSION_COOKIE_NAME && value) {
      sessionCookie = `${name}=${value}`;
    }
  }
  return sessionCookie;
}

function persistLoginResult(result, loginType) {
  if (result?.sessionToken) {
    applySessionToken(result.sessionToken);
  }
  saveSession({
    cookie,
    user: result?.user || null,
    loginType,
  });
  const app = getApp?.();
  if (app && result?.user) {
    app.globalData.user = result.user;
  }
}

function request(path, options = {}) {
  const url = /^https?:\/\//i.test(path) ? path : `${apiBaseUrl}${path}`;
  const header = {
    Accept: 'application/json',
    ...(options.body ? { 'Content-Type': 'application/json' } : {}),
    ...(cookie ? { Cookie: cookie } : {}),
    ...(options.header || {})
  };

  return new Promise((resolve, reject) => {
    wx.request({
      url,
      method: options.method || 'GET',
      data: options.body == null ? undefined : options.body,
      header,
      timeout: options.timeout || 20000,
      success(res) {
        const nextCookie = normalizeSetCookie(res.header);
        if (nextCookie) {
          cookie = nextCookie;
          const previous = getStoredSession() || {};
          saveSession({ ...previous, cookie });
        }
        const status = Number(res.statusCode || 0);
        if (status >= 200 && status < 300) {
          resolve(res.data);
          return;
        }
        const message = formatRequestError(res, url);
        const error = new Error(message);
        error.status = status;
        error.body = res.data;
        reject(error);
      },
      fail(err) {
        reject(new Error(err?.errMsg || '网络请求失败'));
      }
    });
  });
}

function portalRequest(path, options = {}) {
  return request(path, options);
}

function apiRequest(path, options = {}) {
  return request(`/api${path}`, options);
}

async function checkAuth() {
  return portalRequest('/auth/status');
}

async function getMe() {
  return portalRequest('/auth/me');
}

async function loginWithPassword(username, password) {
  const result = await portalRequest('/auth/login', {
    method: 'POST',
    body: { username, password }
  });
  persistLoginResult(result, 'password');
  return result;
}

function wxLogin() {
  return new Promise((resolve, reject) => {
    wx.login({
      success(res) {
        if (res.code) resolve(res.code);
        else reject(new Error('微信登录未返回 code'));
      },
      fail(err) {
        reject(new Error(err?.errMsg || '微信登录失败'));
      }
    });
  });
}

async function loginWithWechatCode(loginPath) {
  if (isTouristMode()) {
    throw new Error(
      '当前是游客模式（无 AppID 关联）。请在微信开发者工具用 AppID wx3e79ecd530c88da4 重新导入项目，并确认登录 DevTools 的微信号已是该小程序管理员。'
    );
  }
  const code = await wxLogin();
  const result = await portalRequest(loginPath, {
    method: 'POST',
    body: { code }
  });
  persistLoginResult(result, 'wechat');
  return result;
}

async function logout() {
  try {
    await portalRequest('/auth/logout', { method: 'POST' });
  } finally {
    clearSession();
    clearLegalConsent();
  }
}

async function listSessions(options = {}) {
  const limit = options.limit || 30;
  const cursor = options.cursor ? `&cursor=${encodeURIComponent(options.cursor)}` : '';
  return apiRequest(`/sessions?limit=${encodeURIComponent(limit)}${cursor}`);
}

async function loadSession(sessionId) {
  return apiRequest(`/sessions/${encodeURIComponent(sessionId)}`);
}

async function createAgentRun(input = {}) {
  const body = {
    ...input,
    request_id: input.request_id || createUuid(),
  };
  if (!body.session_id) {
    delete body.session_id;
  }
  const result = await apiRequest('/agent/runs', {
    method: 'POST',
    body,
    timeout: 60000
  });
  return result?.run ?? result;
}

async function getAgentRun(runId) {
  const result = await apiRequest(`/agent/runs/${encodeURIComponent(runId)}`);
  return result?.run ?? result;
}

async function listMindSpacePages(options = {}) {
  const limit = options.limit || 30;
  const offset = options.offset || 0;
  return apiRequest(
    `/mindspace/v1/pages?limit=${encodeURIComponent(limit)}&offset=${encodeURIComponent(offset)}`
  );
}

module.exports = {
  setApiBaseUrl,
  getApiBaseUrl,
  getMiniProgramAppId,
  isTouristMode,
  getStoredSession,
  saveSession,
  clearSession,
  checkAuth,
  getMe,
  loginWithPassword,
  loginWithWechatCode,
  logout,
  listSessions,
  loadSession,
  createAgentRun,
  getAgentRun,
  listMindSpacePages
};