/**
 * RAG Chat 服务端 API 模块
 *
 * 提供 Node.js 服务端调用 FastAPI 后端的基础功能。
 * 现已改为走自有 RAG 接口：
 * Remix Server -> FastAPI /api/v3/rag/*
 *
 * @module api/dify-chat/client.server
 */

import { API_BASE_URL } from '~/config/api-config';

const RAG_API_ROOT = `${API_BASE_URL}/v3/rag`;

export interface DifyFetchOptions extends RequestInit {
    appId?: string;
}

function buildHeaders(fetchOptions: RequestInit, jwt?: string): HeadersInit {
    const headers: HeadersInit = {
        'Content-Type': 'application/json',
        ...fetchOptions.headers,
    };

    if (jwt) {
        (headers as Record<string, string>).Authorization = `Bearer ${jwt}`;
    } else {
        console.warn('[RAG Chat] 没有提供 JWT，FastAPI 请求可能失败');
    }

    return headers;
}

export async function difyFetch(
    endpoint: string,
    options: DifyFetchOptions = {},
    jwt?: string
): Promise<Response> {
    const { appId, ...fetchOptions } = options;
    const cleanEndpoint = endpoint.replace(/^\//, '');
    let url = `${RAG_API_ROOT}/${cleanEndpoint}`;

    if (appId) {
        const separator = url.includes('?') ? '&' : '?';
        url = `${url}${separator}appId=${encodeURIComponent(appId)}`;
    }

    const response = await fetch(url, {
        ...fetchOptions,
        headers: buildHeaders(fetchOptions, jwt),
    });

    if (!response.ok) {
        const errorText = await response.text();
        console.error('[RAG Chat] API 转发错误:', {
            status: response.status,
            statusText: response.statusText,
            error: errorText,
        });

        if (response.status === 401) {
            throw new Error('JWT认证失败，请重新登录');
        }

        throw new Error(`RAG API Error: ${response.status} ${response.statusText}`);
    }

    return response;
}

export { difyClient } from './chat';