import axios from 'axios';
import { ElMessage } from 'element-plus';
import { useUserStore } from '../store/user';
import router from '../router';

const service = axios.create({
  baseURL: import.meta.env.VITE_API_BASE_URL || '/api', // Use /api as default proxy prefix
  timeout: 10000,
});

// Request Interceptor
service.interceptors.request.use(
  (config) => {
    const userStore = useUserStore();
    if (userStore.token) {
      config.headers['Authorization'] = `Bearer ${userStore.token}`;
    }
    return config;
  },
  (error) => {
    return Promise.reject(error);
  }
);

// Response Interceptor
service.interceptors.response.use(
  (response) => {
    const res = response.data;
    // Backend standard format: { code: number, msg: string, data: any }
    // Accept code 0 or 2xx as success
    if (res.code === 0 || (res.code >= 200 && res.code < 300)) {
      return res.data;
    } else {
      // If backend returns code !== 0/2xx but HTTP status is 200
      ElMessage.error(res.msg || '请求失败');
      return Promise.reject(new Error(res.msg || 'Error'));
    }
  },
  (error) => {
    const userStore = useUserStore();
    let message = error.message;
    
    if (error.response) {
      const { status, data } = error.response;
      // Backend error response format: { code: number, msg: string, data: null }
      message = data?.msg || message;
      
      if (status === 401) {
        // Token expired or invalid
        userStore.logout();
        router.push(`/login?redirect=${encodeURIComponent(router.currentRoute.value.fullPath)}`);
        ElMessage.error(message || '登录状态已过期，请重新登录');
        return Promise.reject(new Error('Unauthorized'));
      } else if (status === 403) {
        ElMessage.error(message || '没有权限执行该操作');
      } else {
         ElMessage.error(message || '请求失败');
      }
    } else {
      ElMessage.error(message || '网络连接异常');
    }
    return Promise.reject(error);
  }
);

export default service;