import { NextResponse } from 'next/server';
import { getServerSession } from 'next-auth';
import { authOptions } from '@/app/api/auth/[...nextauth]/route';
import { 
  saveUserEmailCredentials, 
  getUserEmailCredentials, 
  testEmailConnection 
} from '@/lib/services/email-service';
import { prefetchUserEmailData } from '@/lib/services/prefetch-service';
import { 
  cacheEmailCredentials, 
  invalidateUserEmailCache,
  getCachedEmailCredentials 
} from '@/lib/redis';
import { prisma } from '@/lib/prisma';

export async function POST(request: Request) {
  try {
    // Authenticate user
    const session = await getServerSession(authOptions);
    if (!session?.user?.id) {
      return NextResponse.json(
        { error: 'Unauthorized' },
        { status: 401 }
      );
    }

    // Get credentials from request
    const { email, password, host, port } = await request.json();

    // Validate required fields
    if (!email || !password || !host || !port) {
      return NextResponse.json(
        { error: 'Missing required fields' },
        { status: 400 }
      );
    }

    // Test connection before saving
    const connectionSuccess = await testEmailConnection({
      email,
      password,
      host,
      port: parseInt(port)
    });

    if (!connectionSuccess) {
      return NextResponse.json(
        { error: 'Failed to connect to email server. Please check your credentials.' },
        { status: 401 }
      );
    }
    
    // Invalidate all cached data for this user as they are changing their credentials
    await invalidateUserEmailCache(session.user.id);

    // Create credentials object with required fields
    const credentials = {
      email,
      password,
      host,
      port: parseInt(port),
      secure: true // Default to secure connection
    };

    // Save credentials in the database and Redis
    // Use email as the accountId since it's unique per user
    await saveUserEmailCredentials(session.user.id, email, credentials);

    // Start prefetching email data in the background
    // We don't await this to avoid blocking the response
    prefetchUserEmailData(session.user.id).catch(err => {
      console.error('Background prefetch error:', err);
    });

    return NextResponse.json({ success: true });
  } catch (error) {
    console.error('Error in login handler:', error);
    return NextResponse.json(
      { error: 'An unexpected error occurred' },
      { status: 500 }
    );
  }
}

export async function GET() {
  try {
    const session = await getServerSession(authOptions);
    if (!session?.user?.id) {
      return NextResponse.json(
        { error: 'Unauthorized' },
        { status: 401 }
      );
    }

    // First try to get from Redis cache
    let credentials = await getCachedEmailCredentials(session.user.id, 'default');
    
    // If not in cache, get from database
    if (!credentials) {
      credentials = await prisma.mailCredentials.findUnique({
        where: {
          userId: session.user.id
        },
        select: {
          email: true,
          host: true,
          port: true
        }
      });
    } else {
      // Remove password from response
      const { password, ...safeCredentials } = credentials;
      credentials = safeCredentials;
    }

    if (!credentials) {
      return NextResponse.json(
        { error: 'No stored credentials found' },
        { status: 404 }
      );
    }

    return NextResponse.json(credentials);
  } catch (error) {
    return NextResponse.json(
      { error: 'Failed to retrieve credentials' },
      { status: 500 }
    );
  }
}