import { NextRequest, NextResponse } from 'next/server';
import { logger } from '@/lib/logger';
import { getStalwartCredentials } from '@/lib/stalwart/credentials';
import { JmapRedirectError, fetchJmapSession, postJmap, rebaseApiUrl } from '@/lib/stalwart/jmap-api';

/**
 * POST /api/account/stalwart/jmap
 *
 * Passthrough to Stalwart's JMAP endpoint using the stored basic-auth
 * context so the browser does not need access to the user's credentials.
 *
 * Body: standard JMAP request `{ using: string[], methodCalls: [...] }`
 *
 * In Stalwart 0.16 all management operations (password change, app
 * passwords, API keys, account settings, etc.) are exposed as JMAP
 * methods under the `x:` namespace on the same endpoint.
 */
export async function POST(request: NextRequest) {
  try {
    const creds = await getStalwartCredentials(request);
    if (!creds) {
      return NextResponse.json({ error: 'Not authenticated' }, { status: 401 });
    }

    const body = await request.text();

    const directUrl = `${creds.serverUrl}/jmap/`;
    let response = await postJmap(directUrl, creds.authHeader, body);

    if (response.status === 404) {
      // `${serverUrl}/jmap/` is not the API endpoint on this deployment
      // (path prefix, non-Stalwart URL layout). Resolve the session's
      // advertised apiUrl on the same host and retry once.
      const session = await fetchJmapSession(creds.serverUrl, creds.authHeader);
      const apiUrl = rebaseApiUrl(session, creds.serverUrl);
      if (apiUrl && apiUrl !== directUrl) {
        response = await postJmap(apiUrl, creds.authHeader, body);
      }
    }

    if (!response.ok) {
      logger.warn('Stalwart JMAP passthrough upstream error', {
        status: response.status,
        serverUrl: creds.serverUrl,
      });
    }

    const responseText = await response.text();
    return new NextResponse(responseText, {
      status: response.status,
      headers: { 'Content-Type': response.headers.get('Content-Type') || 'application/json' },
    });
  } catch (error) {
    if (error instanceof JmapRedirectError) {
      logger.error('Stalwart JMAP passthrough redirect error', { error: error.message });
      return NextResponse.json({ error: error.message }, { status: 502 });
    }
    logger.error('Stalwart JMAP passthrough error', {
      error: error instanceof Error ? error.message : 'Unknown',
    });
    return NextResponse.json({ error: 'Internal server error' }, { status: 500 });
  }
}