import Taro from '@tarojs/taro';

const TAB_PAGES = new Set([
  '/pages/home/index',
  '/pages/stores/index',
  '/pages/benefit/index',
  '/pages/mine/index',
]);

let loginNavigationPending = false;

function isLoginPageActive(): boolean {
  const pages = Taro.getCurrentPages();
  const current = pages[pages.length - 1] as { route?: string } | undefined;
  return !!current?.route?.includes('pages/login/');
}

function currentPagePath(): string {
  const pages = Taro.getCurrentPages();
  const cur = pages[pages.length - 1] as
    | { route?: string; options?: Record<string, string | undefined> }
    | undefined;
  if (!cur?.route) return '';
  const path = cur.route.startsWith('/') ? cur.route : `/${cur.route}`;
  if (path.includes('/pages/login/')) return '';
  const opts = cur.options ?? {};
  const qs = Object.entries(opts)
    .filter(([, v]) => v != null && v !== '')
    .map(([k, v]) => `${encodeURIComponent(k)}=${encodeURIComponent(String(v))}`)
    .join('&');
  return qs ? `${path}?${qs}` : path;
}

/** 跳转登录页；默认带回当前页作为 return */
export function goLogin(returnPath?: string, extras?: Record<string, string>) {
  if (loginNavigationPending || isLoginPageActive()) return;
  const returnTo = returnPath ?? currentPagePath();
  const parts: string[] = [];
  if (returnTo) parts.push(`return=${encodeURIComponent(returnTo)}`);
  if (extras) {
    for (const [key, value] of Object.entries(extras)) {
      if (value) parts.push(`${encodeURIComponent(key)}=${encodeURIComponent(value)}`);
    }
  }
  const url = parts.length ? `/pages/login/index?${parts.join('&')}` : '/pages/login/index';
  loginNavigationPending = true;
  void Taro.navigateTo({ url })
    .catch(() => Taro.redirectTo({ url }))
    .finally(() => {
      // 等路由栈稳定后再释放，拦截同一轮请求触发的重复登录跳转。
      setTimeout(() => {
        loginNavigationPending = false;
      }, 500);
    });
}

/** 登录成功后回到 return 页，或回退 / 首页 */
export function finishLoginNavigate(returnTo?: string) {
  const raw = (returnTo || '').trim();
  let target = '';
  try {
    target = raw ? decodeURIComponent(raw) : '';
  } catch {
    target = raw;
  }
  // 防止 return 仍指向登录页造成死循环
  const pathOnly = target.split('?')[0];
  if (!pathOnly || pathOnly.includes('/pages/login')) {
    Taro.reLaunch({ url: '/pages/home/index' });
    return;
  }

  if (TAB_PAGES.has(pathOnly)) {
    Taro.switchTab({ url: pathOnly }).catch(() => {
      Taro.reLaunch({ url: pathOnly });
    });
    return;
  }
  if (pathOnly.startsWith('/pages/')) {
    Taro.redirectTo({ url: target }).catch(() => {
      Taro.reLaunch({ url: pathOnly });
    });
    return;
  }

  Taro.reLaunch({ url: '/pages/home/index' });
}

/**
 * 账号合并后强制整页刷新，避免旧会话栈 / 旧用户缓存继续提示绑定手机号。
 * H5：按当前路径推算出落地 URL 后 location.replace；小程序：reLaunch。
 */
export function forceReloadAfterAccountMerge(returnTo?: string) {
  const raw = (returnTo || '').trim();
  let target = '';
  try {
    target = raw ? decodeURIComponent(raw) : '';
  } catch {
    target = raw;
  }
  const pathOnly = target.split('?')[0];
  const safePath =
    pathOnly && pathOnly.startsWith('/pages/') && !pathOnly.includes('/pages/login')
      ? target
      : '/pages/home/index';
  const launchPath = safePath.split('?')[0];

  if (process.env.TARO_ENV === 'h5' && typeof window !== 'undefined') {
    const { origin, pathname, search } = window.location;
    const marker = '/pages/';
    const idx = pathname.indexOf(marker);
    let href: string;
    if (idx >= 0) {
      href = `${origin}${pathname.slice(0, idx)}${safePath}`;
    } else if (window.location.hash.includes('/pages/')) {
      href = `${origin}${pathname}${search}#${safePath}`;
    } else {
      const base = pathname.replace(/\/$/, '') || '';
      href = `${origin}${base}${safePath.startsWith('/') ? safePath : `/${safePath}`}`;
    }
    window.location.replace(href);
    return;
  }

  if (TAB_PAGES.has(launchPath)) {
    Taro.reLaunch({ url: launchPath });
    return;
  }
  Taro.reLaunch({ url: safePath.startsWith('/') ? safePath : `/${safePath}` });
}