import { NextResponse } from 'next/server';
import { getServerSession } from 'next-auth';
import { authOptions } from "@/app/api/auth/options";
import { getImapConnection } from '@/lib/services/email-service';
import { simpleParser } from 'mailparser';

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

  try {
    const { searchParams } = new URL(request.url);
    const emailId = searchParams.get('id');
    const folder = searchParams.get('folder') || 'INBOX';

    if (!emailId) {
      return NextResponse.json({ error: 'Email ID is required' }, { status: 400 });
    }

    // Connect to IMAP
    const client = await getImapConnection(session.user.id);
    
    try {
      await client.mailboxOpen(folder);
      
      // Fetch raw email
      const message = await client.fetchOne(emailId, {
        source: true,
        envelope: true,
        flags: true
      });
      
      if (!message) {
        return NextResponse.json({ error: 'Email not found' }, { status: 404 });
      }
      
      // Get raw source content
      const { source, envelope } = message;
      const rawSource = source.toString();
      
      // Parse the email with multiple options to debug
      const parsedEmail = await simpleParser(rawSource, {
        skipHtmlToText: true,
        keepCidLinks: true
      });
      
      // Extract all available data
      return NextResponse.json({
        id: emailId,
        folder,
        date: envelope.date,
        subject: envelope.subject,
        from: envelope.from,
        to: envelope.to,
        // Raw content (truncated to prevent massive responses)
        sourcePreview: rawSource.substring(0, 1000) + (rawSource.length > 1000 ? '...' : ''),
        sourceLength: rawSource.length,
        // Parsed content
        htmlPreview: parsedEmail.html ? parsedEmail.html.substring(0, 1000) + (parsedEmail.html.length > 1000 ? '...' : '') : null,
        htmlLength: parsedEmail.html ? parsedEmail.html.length : 0,
        textPreview: parsedEmail.text ? parsedEmail.text.substring(0, 1000) + (parsedEmail.text.length > 1000 ? '...' : '') : null,
        textLength: parsedEmail.text ? parsedEmail.text.length : 0,
        // Detect if there's HTML and what type of content it contains
        hasHtml: !!parsedEmail.html,
        hasStyleTags: typeof parsedEmail.html === 'string' && parsedEmail.html.includes('<style'),
        hasCss: typeof parsedEmail.html === 'string' && parsedEmail.html.includes('style='),
        // Headers that might be relevant
        contentType: parsedEmail.headers.get('content-type'),
        // Attachment count
        attachmentCount: parsedEmail.attachments.length
      });
    } finally {
      try {
        await client.logout();
      } catch (error) {
        console.error('Error logging out:', error);
      }
    }
  } catch (error) {
    console.error('Error in debug-email route:', error);
    return NextResponse.json(
      { error: 'Server error', message: error instanceof Error ? error.message : String(error) },
      { status: 500 }
    );
  }
}