import { cookies } from 'next/headers';
import type { NextRequest } from 'next/server';
import { NextResponse } from 'next/server';

import { exampleModelsResponse, HttpHeaderJson, HttpMethod, HttpStatus } from '@/utils/constants';
import { env } from '@/utils/env';
import { getApiKey } from '@/utils/getApiKey';

export const config = {
  runtime: 'edge',
};

/**
 * 获取可用的 models
 */
export async function GET(req: NextRequest) {
  // 测试环境返回 example
  if (env.NODE_ENV === 'development') {
    return NextResponse.json(exampleModelsResponse, { status: HttpStatus.OK });
  }

  // 正式环境透传即可
  const apiKey = getApiKey(cookies().get('apiKey')?.value);

  const fetchResult = await fetch(`https://${env.CHATGPT_NEXT_API_HOST}/v1/models`, {
    method: HttpMethod.GET,
    headers: {
      ...HttpHeaderJson,
      Authorization: `Bearer ${apiKey}`,
    },
  });

  // https://stackoverflow.com/a/29082416/2777142
  // 当状态码为 401 且响应头包含 Www-Authenticate 时，浏览器会弹一个框要求输入用户名和密码，故这里需要过滤此 header
  if (fetchResult.status === HttpStatus.Unauthorized && fetchResult.headers.get('Www-Authenticate')) {
    const wwwAuthenticateValue = fetchResult.headers.get('Www-Authenticate') ?? '';
    fetchResult.headers.delete('Www-Authenticate');
    fetchResult.headers.set('X-Www-Authenticate', wwwAuthenticateValue);
  }

  return fetchResult;
}