import { NextResponse } from 'next/server';
import { getServerSession } from 'next-auth';
import { authOptions } from '@/app/api/auth/[...nextauth]/route';
import { DOMParser } from '@xmldom/xmldom';

async function establishNextcloudSession(nextcloudUrl: string, keycloakToken: string) {
  // First, try to establish a session with Nextcloud using the Keycloak token
  const sessionResponse = await fetch(`${nextcloudUrl}/index.php/apps/oauth2/api/v1/token`, {
    method: 'POST',
    headers: {
      'Content-Type': 'application/x-www-form-urlencoded',
      'Authorization': `Bearer ${keycloakToken}`,
    },
    body: new URLSearchParams({
      grant_type: 'urn:ietf:params:oauth:grant-type:token-exchange',
      subject_token: keycloakToken,
      subject_token_type: 'urn:ietf:params:oauth:token-type:access_token',
      client_id: process.env.NEXTCLOUD_CLIENT_ID || '',
      client_secret: process.env.NEXTCLOUD_CLIENT_SECRET || '',
    }).toString(),
  });

  if (!sessionResponse.ok) {
    const errorText = await sessionResponse.text();
    console.error('Failed to establish Nextcloud session:', errorText);
    throw new Error('Failed to establish Nextcloud session');
  }

  const sessionData = await sessionResponse.json();
  return sessionData.access_token;
}

export async function GET() {
  try {
    const session = await getServerSession(authOptions);

    if (!session?.user?.email || !session?.accessToken) {
      return NextResponse.json(
        { error: 'Unauthorized' },
        { status: 401 }
      );
    }

    const nextcloudUrl = process.env.NEXTCLOUD_URL;
    if (!nextcloudUrl) {
      console.error('Missing Nextcloud configuration');
      return NextResponse.json(
        { error: 'Nextcloud configuration is missing' },
        { status: 500 }
      );
    }

    // Test Nextcloud connectivity
    const testResponse = await fetch(`${nextcloudUrl}/status.php`);
    if (!testResponse.ok) {
      console.error('Nextcloud is not accessible:', await testResponse.text());
      return NextResponse.json(
        { error: "Nextcloud n'est pas accessible" },
        { status: 503 }
      );
    }

    try {
      // Establish Nextcloud session
      const nextcloudToken = await establishNextcloudSession(nextcloudUrl, session.accessToken);
      
      // Get user's folders using WebDAV with Nextcloud token
      const webdavUrl = `${nextcloudUrl}/remote.php/dav/files/${encodeURIComponent(session.user.email)}/`;
      console.log('Requesting WebDAV URL:', webdavUrl);

      const foldersResponse = await fetch(webdavUrl, {
        headers: {
          'Authorization': `Bearer ${nextcloudToken}`,
          'Depth': '1',
          'Content-Type': 'application/xml',
        },
      });

      if (!foldersResponse.ok) {
        const errorText = await foldersResponse.text();
        console.error('Failed to fetch folders. Status:', foldersResponse.status);
        console.error('Response:', errorText);
        console.error('Response headers:', Object.fromEntries(foldersResponse.headers.entries()));
        throw new Error(`Failed to fetch folders: ${errorText}`);
      }

      const folderData = await foldersResponse.text();
      console.log('Folder data:', folderData);

      // Parse the XML response to get folder names and filter only directories
      const parser = new DOMParser();
      const xmlDoc = parser.parseFromString(folderData, 'text/xml');
      const responses = Array.from(xmlDoc.getElementsByTagName('d:response'));
      
      const folders: string[] = [];
      for (const response of responses) {
        const resourceType = response.getElementsByTagName('d:resourcetype')[0];
        const isCollection = resourceType?.getElementsByTagName('d:collection').length > 0;
        
        if (isCollection) {
          const displayName = response.getElementsByTagName('d:displayname')[0]?.textContent;
          if (displayName && displayName !== session.user.email) {
            folders.push(displayName);
          }
        }
      }

      console.log('Parsed folders:', folders);

      return NextResponse.json({
        isConnected: true,
        folders
      });
    } catch (error: any) {
      console.error('Error accessing Nextcloud WebDAV:', error);
      return NextResponse.json(
        { error: "Erreur d'accès aux dossiers Nextcloud", details: error?.message || String(error) },
        { status: 503 }
      );
    }
  } catch (error: any) {
    console.error('Error checking Nextcloud status:', error);
    return NextResponse.json(
      { error: 'Failed to check Nextcloud status', details: error?.message || String(error) },
      { status: 500 }
    );
  }
}