import { NextResponse } from 'next/server';
import { getServerSession } from 'next-auth';
import { authOptions } from '@/app/api/auth/[...nextauth]/route';
import { prisma } from '@/lib/prisma';
import { ImapFlow } from 'imapflow';

export async function POST(request: Request) {
  let client: ImapFlow | null = null;
  try {
    // Get the session and validate it
    const session = await getServerSession(authOptions);
    console.log('Session:', session);
    
    if (!session?.user?.id) {
      console.error('No session or user ID found');
      return NextResponse.json(
        { error: 'Unauthorized' },
        { status: 401 }
      );
    }

    // Get the request body
    const { emailId, isRead } = await request.json();
    console.log('Request body:', { emailId, isRead });
    
    if (!emailId || typeof isRead !== 'boolean') {
      console.error('Invalid request parameters:', { emailId, isRead });
      return NextResponse.json(
        { error: 'Invalid request parameters' },
        { status: 400 }
      );
    }

    // Get the current folder from the request URL
    const url = new URL(request.url);
    const folder = url.searchParams.get('folder') || 'INBOX';
    console.log('Folder:', folder);

    // Get credentials directly from database
    const credentials = await prisma.mailCredentials.findUnique({
      where: {
        userId: session.user.id
      }
    });

    if (!credentials) {
      return NextResponse.json(
        { error: 'No mail credentials found. Please configure your email account.' },
        { status: 401 }
      );
    }

    // Create IMAP client
    client = new ImapFlow({
      host: credentials.host,
      port: credentials.port,
      secure: true,
      auth: {
        user: credentials.email,
        pass: credentials.password,
      },
      logger: false,
      emitLogs: false,
      tls: {
        rejectUnauthorized: false
      },
      disableAutoIdle: true
    });

    try {
      await client.connect();
      
      // Open the mailbox
      const mailbox = await client.mailboxOpen(folder);
      console.log(`Mailbox opened: ${folder}, total messages: ${mailbox.exists}`);
      
      // Scan through messages in chunks to find the one with the right UID
      let foundMessage = false;
      const chunkSize = 10;
      
      for (let i = 1; i <= mailbox.exists; i += chunkSize) {
        const endIdx = Math.min(i + chunkSize - 1, mailbox.exists);
        const range = `${i}:${endIdx}`;
        
        console.log(`Scanning messages ${range} to find UID ${emailId}`);
        
        // Fetch messages in chunks with UID
        const messages = client.fetch(range, {
          uid: true,
          flags: true
        });
        
        for await (const message of messages) {
          if (message.uid.toString() === emailId) {
            console.log(`Found matching message with UID ${emailId}`);
            
            // Get the sequence number (i is the start of the range)
            const seqNum = i + message.seq - 1;
            console.log(`Message sequence number: ${seqNum}`);
            
            // Update the flags based on the isRead parameter
            if (isRead && !message.flags.has('\\Seen')) {
              console.log(`Marking message ${emailId} as read`);
              await client.messageFlagsAdd(seqNum.toString(), ['\\Seen']);
            } else if (!isRead && message.flags.has('\\Seen')) {
              console.log(`Marking message ${emailId} as unread`);
              await client.messageFlagsRemove(seqNum.toString(), ['\\Seen']);
            } else {
              console.log(`Message ${emailId} already has the correct read status`);
            }
            
            foundMessage = true;
            break;
          }
        }
        
        if (foundMessage) {
          break;
        }
      }

      if (!foundMessage) {
        console.error(`Email with UID ${emailId} not found`);
        return NextResponse.json(
          { error: 'Email not found' },
          { status: 404 }
        );
      }

      return NextResponse.json({ success: true });
    } finally {
      if (client) {
        try {
          await client.logout();
        } catch (e) {
          console.error('Error during logout:', e);
        }
      }
    }
  } catch (error) {
    console.error('Error marking email as read:', error);
    return NextResponse.json(
      { error: 'Failed to mark email as read' },
      { status: 500 }
    );
  }
}