import axios from 'axios';
import type {
    AxiosInstance,
    AxiosRequestConfig,
    AxiosResponse,
    InternalAxiosRequestConfig,
} from 'axios';
import { envConfig } from '@/config/env';
import { authToken } from '@/services/authToken';

declare module 'axios' {
    export interface AxiosRequestConfig {
        /** 401 刷新重放标记，防止无限重试 */
        _retried?: boolean;
    }
}

const apiClient: AxiosInstance = axios.create({
    baseURL: envConfig.apiBaseUrl,
    timeout: 30000,
    // 不设全局 Content-Type：axios 1.x 遇到「默认 JSON 头 + FormData」会把表单转成 JSON 发送，
    // 导致素材上传等表单接口解析失败。对象请求体 axios 会自动补 JSON 头。
});

// access token 仅在内存中短暂持有（docs/api/conventions.md §1），每次请求动态附加 Bearer 头
apiClient.interceptors.request.use((config: InternalAxiosRequestConfig) => {
    const token = authToken.get();
    if (token) {
        config.headers.Authorization = `Bearer ${token}`;
    }
    return config;
});

// 认证接口自身的失败不进入刷新流程
const AUTH_PATHS = ['/auth/login', '/auth/register', '/auth/refresh', '/auth/logout'];

let refreshTask: Promise<string | null> | null = null;

/** 并发 401 只触发一次刷新请求；刷新依赖 HttpOnly refresh cookie */
function refreshAccessToken(): Promise<string | null> {
    refreshTask ??= apiClient
        .post('/auth/refresh')
        .then((res) => {
            const token = unwrapEnvelope<{ access_token: string }>(res).access_token;
            authToken.set(token);
            return token;
        })
        .catch(() => {
            authToken.clear();
            return null;
        })
        .finally(() => {
            refreshTask = null;
        });
    return refreshTask;
}

apiClient.interceptors.response.use(
    (response) => response,
    async (error) => {
        if (envConfig.debug) {
            console.error('请求失败:', error.response?.data || error.message);
        }
        const config = error.config as AxiosRequestConfig | undefined;
        const url = config?.url ?? '';
        const isAuthPath = AUTH_PATHS.some((path) => url.includes(path));
        // access token 过期时用 refresh cookie 换新 token 并重放一次；
        // 刷新失败说明会话已失效，整页跳转登录页（后续可换成路由内跳转并保留来源）
        if (error.response?.status === 401 && config && !config._retried && !isAuthPath) {
            config._retried = true;
            const token = await refreshAccessToken();
            if (token) {
                return apiClient.request(config);
            }
            window.location.assign('/login');
        }
        return Promise.reject(error);
    }
);

/**
 * 统一解包强制响应信封：成功为 { data: T }，204 No Content 无响应体
 * （docs/api/conventions.md §3.1）。服务层泛型 T 指业务负载本身；
 * 列表接口使用 getList 保留分页 meta。
 */
function unwrapEnvelope<T>(response: AxiosResponse): T {
    const body = response.data as { data?: unknown } | undefined;
    if (body === null || body === undefined) {
        return undefined as T;
    }
    return body.data as T;
}

/** 列表响应信封为 { data: T[], meta: PaginationMeta }（docs/api/conventions.md §3），meta 需要原样保留 */
function unwrapListEnvelope<T, M>(response: AxiosResponse): { data: T[]; meta: M } {
    const body = response.data as { data?: unknown; meta?: unknown } | undefined;
    return {
        data: Array.isArray(body?.data) ? (body.data as T[]) : [],
        meta: (body?.meta ?? {}) as M,
    };
}

export const api = {
    get: <T = unknown>(url: string, config?: AxiosRequestConfig) =>
        apiClient.get<T>(url, config).then((res) => unwrapEnvelope<T>(res)),

    getList: <T = unknown, M = unknown>(url: string, config?: AxiosRequestConfig) =>
        apiClient.get(url, config).then((res) => unwrapListEnvelope<T, M>(res)),

    post: <T = unknown>(url: string, data?: unknown, config?: AxiosRequestConfig) =>
        apiClient.post<T>(url, data, config).then((res) => unwrapEnvelope<T>(res)),

    put: <T = unknown>(url: string, data?: unknown, config?: AxiosRequestConfig) =>
        apiClient.put<T>(url, data, config).then((res) => unwrapEnvelope<T>(res)),

    patch: <T = unknown>(url: string, data?: unknown, config?: AxiosRequestConfig) =>
        apiClient.patch<T>(url, data, config).then((res) => unwrapEnvelope<T>(res)),

    delete: <T = unknown>(url: string, config?: AxiosRequestConfig) =>
        apiClient.delete<T>(url, config).then((res) => unwrapEnvelope<T>(res)),
};

/** 统一错误格式为 { error: { code, message, request_id } }（docs/api/conventions.md），提取可展示信息 */
export function apiErrorMessage(error: unknown): string {
    if (axios.isAxiosError(error)) {
        const data = error.response?.data as
            { error?: { message?: unknown }; message?: unknown } | undefined;
        if (data?.error?.message) return String(data.error.message);
        if (data?.message) return String(data.message);
        if (error.response) return `请求失败（HTTP ${error.response.status}）`;
        return '网络连接失败，请稍后重试';
    }
    return error instanceof Error ? error.message : String(error);
}

/** 提取业务错误码（如 VERSION_CONFLICT、DEFAULT_STORE_REPLACEMENT_REQUIRED），无则返回 null */
export function apiErrorCode(error: unknown): string | null {
    if (!axios.isAxiosError(error)) return null;
    const code = (error.response?.data as { error?: { code?: unknown } } | undefined)?.error?.code;
    return typeof code === 'string' ? code : null;
}

export interface ApiErrorDetail {
    field: string;
    code: string;
    message: string;
}

/** 提取错误信封中的字段级明细 details: [{ field, code, message }]（docs/api/conventions.md §4） */
export function apiErrorDetails(error: unknown): ApiErrorDetail[] {
    if (!axios.isAxiosError(error)) return [];
    const details = (error.response?.data as { error?: { details?: unknown } } | undefined)?.error
        ?.details;
    if (!Array.isArray(details)) return [];
    return details.filter(
        (item): item is ApiErrorDetail =>
            !!item &&
            typeof item === 'object' &&
            typeof (item as ApiErrorDetail).field === 'string' &&
            typeof (item as ApiErrorDetail).message === 'string'
    );
}

export default apiClient;