import axios from 'axios';
import { ElMessage } from "element-plus";
import router from "@/router";

/** 后端统一响应包装：code === 200 表示业务成功 */
export interface ApiResponse<T = any> {
    code: number;
    message?: string;
    data: T;
}

const baseURL = import.meta.env.VITE_BASE_URL;

// 默认 30s：普通 CRUD 足够；AI 聚合等长耗时接口需在 api 层显式覆写 timeout
const DEFAULT_TIMEOUT = 30_000;

const axiosInstance = axios.create({
    baseURL,
    timeout: DEFAULT_TIMEOUT,
    withCredentials: true
});

const handleError = (error: any) => {

    // 401 未授权（HTTP 层）：token 过期或未登录
    if (error?.response?.status === 401) {
        localStorage.removeItem("isLoggedIn");
        router.push("/login");
        return Promise.reject(error);
    }

    // 401 未授权（业务层）：后端 GlobalExceptionHandler 返回 code=401
    if (error && typeof error === "object" && error.code === 401) {
        localStorage.removeItem("isLoggedIn");
        router.push("/login");
        return Promise.reject(error);
    }

    // 其他业务异常（如 code !== 200）透传，由调用方自行提示
    if (error && typeof error === "object" && "code" in error && !error.response) {
        return Promise.reject(error);
    }

    if (error.response) {
        const backendMessage = error.response?.data?.message;
        ElMessage.error(backendMessage || "请求失败了，请稍后再试");
    } else if (error.request) {
        ElMessage.error("请求失败了，请检查网络后重试");
    } else {
        ElMessage.error("请求失败了，请稍后再试");
    }
    throw new Error("请求失败了，请稍后再试");
};

const validateResponse = (res: any) => {
    const result = res.data;
    if (result.code !== 200) {
        ElMessage.error(result.message || '请求失败');
        return Promise.reject(result);
    }
    return result;
};

const get = <T = any>(
    url: string,
    params: Record<string, any> = {},
    config: Record<string, any> = {},
): Promise<ApiResponse<T>> =>
    axiosInstance.get(url, { params, ...config })
        .then(validateResponse)
        .catch(handleError);

const post = <T = any>(
    url: string,
    data: any = null,
    config: Record<string, any> = {},
): Promise<ApiResponse<T>> =>
    axiosInstance.post(url, data, config)
        .then(validateResponse)
        .catch(handleError);

const put = <T = any>(
    url: string,
    data: any,
    config: Record<string, any> = {},
): Promise<ApiResponse<T>> =>
    axiosInstance.put(url, data, config)
        .then(validateResponse)
        .catch(handleError);

const del = <T = any>(
    url: string,
    params: Record<string, any> = {},
    config: Record<string, any> = {},
): Promise<ApiResponse<T>> =>
    axiosInstance.delete(url, { params, ...config })
        .then(validateResponse)
        .catch(handleError);

const requestNotImplemented = () => {
    ElMessage.error("该功能暂不可用，请刷新后重试");
    throw new Error("该功能暂不可用，请刷新后重试");
};

const request = (method: string, url: string, paramsOrData: any) => {
    switch (method.toLowerCase()) {
        case 'get': return get(url, paramsOrData);
        case 'post': return post(url, paramsOrData);
        case 'put': return put(url, paramsOrData);
        case 'delete': return del(url, paramsOrData);
        default: return requestNotImplemented();
    }
};

export default { get, post, put, del, request };