import { NextRequest } from 'next/server';
import { createLogger } from '@/lib/logger';
import { apiError, apiSuccess } from '@/lib/server/api-response';
import { resolvePDFApiKey, resolvePDFBaseUrl } from '@/lib/server/provider-config';
import { validateUrlForSSRF } from '@/lib/server/ssrf-guard';

const log = createLogger('Verify PDF Provider');

export async function POST(req: NextRequest) {
  let providerId: string | undefined;
  try {
    const body = await req.json();
    providerId = body.providerId;
    const { apiKey, baseUrl } = body;

    if (!providerId) {
      return apiError('MISSING_REQUIRED_FIELD', 400, 'Provider ID is required');
    }

    const clientBaseUrl = (baseUrl as string | undefined) || undefined;
    if (clientBaseUrl && process.env.NODE_ENV === 'production') {
      const ssrfError = await validateUrlForSSRF(clientBaseUrl);
      if (ssrfError) {
        return apiError('INVALID_URL', 403, ssrfError);
      }
    }

    const resolvedBaseUrl = clientBaseUrl ? clientBaseUrl : resolvePDFBaseUrl(providerId, baseUrl);
    if (!resolvedBaseUrl) {
      return apiError('MISSING_REQUIRED_FIELD', 400, 'Base URL is required');
    }

    const resolvedApiKey = clientBaseUrl
      ? (apiKey as string | undefined) || ''
      : resolvePDFApiKey(providerId, apiKey);

    const headers: Record<string, string> = {};
    if (resolvedApiKey) {
      headers['Authorization'] = `Bearer ${resolvedApiKey}`;
    }

    const response = await fetch(resolvedBaseUrl, {
      headers,
      signal: AbortSignal.timeout(10000),
      redirect: 'manual',
    });

    if (response.status >= 300 && response.status < 400) {
      return apiError('REDIRECT_NOT_ALLOWED', 403, 'Redirects are not allowed');
    }

    // MinerU's FastAPI root returns 404 (no root route), but the server is reachable.
    // Any HTTP response (including 404) means the server is up.
    return apiSuccess({
      message: 'Connection successful',
      status: response.status,
    });
  } catch (error) {
    log.error(`PDF provider verification failed [provider=${providerId ?? 'unknown'}]:`, error);

    let errorMessage = 'Connection failed';
    if (error instanceof Error) {
      if (error.message.includes('ECONNREFUSED')) {
        errorMessage = 'Cannot connect to server, please check the Base URL';
      } else if (error.message.includes('ENOTFOUND')) {
        errorMessage = 'Server not found, please check the Base URL';
      } else if (error.message.includes('timeout') || error.name === 'TimeoutError') {
        errorMessage = 'Connection timed out';
      } else {
        errorMessage = error.message;
      }
    }

    return apiError('INTERNAL_ERROR', 500, errorMessage);
  }
}