import { useI18n } from 'vue-i18n';
import { SUPPORTED_LOCALES, LOCALE_UI_LABELS, type Locale } from '@thebet365/shared';
import api from '../api';
import { useAuthStore } from '../stores/auth';
import { ensurePlayerLocale } from '../i18n';

const STORAGE_KEY = 'locale';
const COOKIE_MAX_AGE = 365 * 24 * 60 * 60;

export const APP_LOCALES = SUPPORTED_LOCALES.map((code) => ({
  code,
  label: LOCALE_UI_LABELS[code] ?? code,
}));

function persistLocale(code: string) {
  localStorage.setItem(STORAGE_KEY, code);
  document.cookie = `${STORAGE_KEY}=${encodeURIComponent(code)};path=/;max-age=${COOKIE_MAX_AGE};SameSite=Lax`;
}

export function useAppLocale() {
  const i18n = useI18n({ useScope: 'global' });
  const { locale } = i18n;
  const auth = useAuthStore();

  function applyLocale(code: string) {
    if (!(SUPPORTED_LOCALES as readonly string[]).includes(code)) return;
    locale.value = code;
    persistLocale(code);
  }

  async function setLocale(code: string) {
    if (!(SUPPORTED_LOCALES as readonly string[]).includes(code)) return;
    if (locale.value === code) return;

    if (auth.token) {
      try {
        await api.post('/player/language', { locale: code });
        if (auth.user) {
          auth.user = { ...auth.user, locale: code };
          localStorage.setItem('user', JSON.stringify(auth.user));
        }
      } catch {
        /* 离线或 token 过期时仍保留本地语言 */
      }
    }
    await ensurePlayerLocale(i18n, code as Locale);
    applyLocale(code);
  }

  /** 将当前语言同步到后端，仅在有 token 时执行，不修改本地 locale */
  async function syncLocaleToBackend() {
    if (!auth.token) return;
    try {
      await api.post('/player/language', { locale: locale.value });
      if (auth.user) {
        auth.user = { ...auth.user, locale: locale.value };
        localStorage.setItem('user', JSON.stringify(auth.user));
      }
    } catch {
      /* ignore */
    }
  }

  async function initFromUser(userLocale?: string | null) {
    if (userLocale && (SUPPORTED_LOCALES as readonly string[]).includes(userLocale)) {
      await ensurePlayerLocale(i18n, userLocale as Locale);
      applyLocale(userLocale);
    }
  }

  return { locales: APP_LOCALES, setLocale, applyLocale, initFromUser, syncLocaleToBackend };
}