import { NextResponse } from 'next/server';
import Imap from 'imap';
import nodemailer from 'nodemailer';
import { parseEmailHeaders, decodeEmailBody } from '@/lib/email-parser';
import { cookies } from 'next/headers';

interface StoredCredentials {
  email: string;
  password: string;
  host: string;
  port: number;
}

interface Email {
  id: string;
  from: string;
  subject: string;
  date: Date;
  read: boolean;
  starred: boolean;
  body: string;
  to?: string;
}

interface ImapBox {
  messages: {
    total: number;
  };
}

interface ImapMessage {
  on: (event: string, callback: (data: any) => void) => void;
  once: (event: string, callback: (data: any) => void) => void;
  attributes: {
    uid: number;
    flags: string[];
    size: number;
  };
  body: {
    [key: string]: {
      on: (event: string, callback: (data: any) => void) => void;
    };
  };
}

interface ImapConfig {
  user: string;
  password: string;
  host: string;
  port: number;
  tls: boolean;
  authTimeout: number;
  connTimeout: number;
  debug?: (info: string) => void;
}

function getStoredCredentials(): StoredCredentials | null {
  const cookieStore = cookies();
  
  const credentialsCookie = cookieStore.get('imap_credentials');
  console.log('Retrieved credentials cookie:', credentialsCookie ? 'Found' : 'Not found');

  if (!credentialsCookie?.value) {
    console.log('No credentials cookie found');
    return null;
  }

  try {
    const credentials = JSON.parse(credentialsCookie.value);
    console.log('Parsed credentials:', {
      ...credentials,
      password: '***'
    });

    // Validate required fields
    if (!credentials.email || !credentials.password || !credentials.host || !credentials.port) {
      console.error('Missing required credentials fields');
      return null;
    }

    return {
      email: credentials.email,
      password: credentials.password,
      host: credentials.host,
      port: credentials.port
    };
  } catch (error) {
    console.error('Error parsing credentials cookie:', error);
    return null;
  }
}

export async function GET() {
  try {
    console.log('GET /api/mail called');
    const credentials = getStoredCredentials();
    if (!credentials) {
      console.log('No credentials found in cookies');
      return NextResponse.json(
        { error: 'No stored credentials found' },
        { status: 401 }
      );
    }

    console.log('Using credentials:', {
      ...credentials,
      password: '***'
    });

    const imap = new Imap({
      user: credentials.email,
      password: credentials.password,
      host: credentials.host,
      port: credentials.port,
      tls: true,
      tlsOptions: { rejectUnauthorized: false },
      authTimeout: 30000,
      connTimeout: 30000
    });

    return new Promise((resolve) => {
      const emails: Email[] = [];

      imap.once('ready', () => {
        imap.openBox('INBOX', false, (err, box) => {
          if (err) {
            console.error('Error opening inbox:', err);
            imap.end();
            resolve(NextResponse.json({ emails: [], error: 'Failed to open inbox' }));
            return;
          }

          console.log('Inbox opened, total messages:', box.messages.total);

          if (box.messages.total === 0) {
            imap.end();
            resolve(NextResponse.json({ 
              emails: [],
              mailUrl: process.env.NEXTCLOUD_URL ? `${process.env.NEXTCLOUD_URL}/apps/mail/` : null
            }));
            return;
          }

          const start = Math.max(1, box.messages.total - 19); // Get last 20 emails
          const f = imap.seq.fetch(`${start}:${box.messages.total}`, {
            bodies: ['HEADER.FIELDS (FROM TO SUBJECT DATE)', 'TEXT'],
            struct: true
          });

          f.on('message', (msg) => {
            const email: any = {
              id: '',
              from: '',
              subject: '',
              date: new Date(),
              read: true,
              starred: false,
              body: '',
              to: ''
            };

            msg.on('body', (stream, info) => {
              let buffer = '';
              stream.on('data', (chunk) => {
                buffer += chunk.toString('utf8');
              });
              stream.on('end', () => {
                if (info.which === 'HEADER.FIELDS (FROM TO SUBJECT DATE)') {
                  const headers = Imap.parseHeader(buffer);
                  email.from = headers.from?.[0] || '';
                  email.to = headers.to?.[0] || '';
                  email.subject = headers.subject?.[0] || '(No subject)';
                  email.date = headers.date?.[0] || new Date().toISOString();
                } else {
                  email.body = buffer;
                }
              });
            });

            msg.once('attributes', (attrs) => {
              email.id = attrs.uid;
              email.read = attrs.flags?.includes('\\Seen') || false;
              email.starred = attrs.flags?.includes('\\Flagged') || false;
            });

            msg.once('end', () => {
              emails.push(email);
            });
          });

          f.once('error', (err) => {
            console.error('Fetch error:', err);
            imap.end();
            resolve(NextResponse.json({ 
              emails: [],
              error: 'Failed to fetch emails'
            }));
          });

          f.once('end', () => {
            console.log('Emails before sending:', emails);
            const response = {
              emails: emails,
              mailUrl: process.env.NEXTCLOUD_URL ? `${process.env.NEXTCLOUD_URL}/apps/mail/` : null
            };
            console.log('Final response:', response);
            imap.end();
            resolve(NextResponse.json(response));
          });
        });
      });

      imap.once('error', (err) => {
        console.error('IMAP error:', err);
        resolve(NextResponse.json({ 
          emails: [],
          error: 'IMAP connection error'
        }));
      });

      imap.connect();
    });
  } catch (error) {
    console.error('Error in mail API:', error);
    return NextResponse.json({ 
      emails: [],
      error: error instanceof Error ? error.message : 'Unknown error'
    });
  }
}

export async function POST(request: Request) {
  try {
    const credentials = getStoredCredentials();
    if (!credentials) {
      return NextResponse.json(
        { error: 'No stored credentials found' },
        { status: 401 }
      );
    }

    let body;
    try {
      body = await request.json();
    } catch (error) {
      return NextResponse.json(
        { error: 'Invalid JSON in request body' },
        { status: 400 }
      );
    }

    const { to, subject, body: emailBody, attachments } = body;

    if (!to || !subject || !emailBody) {
      return NextResponse.json(
        { error: 'Missing required fields: to, subject, or body' },
        { status: 400 }
      );
    }

    const transporter = nodemailer.createTransport({
      host: credentials.host,
      port: credentials.port,
      secure: true,
      auth: {
        user: credentials.email,
        pass: credentials.password,
      },
    });

    const mailOptions = {
      from: credentials.email,
      to,
      subject,
      text: emailBody,
      attachments: attachments || [],
    };

    const info = await transporter.sendMail(mailOptions);
    console.log('Email sent:', info.messageId);

    return NextResponse.json({ 
      success: true, 
      messageId: info.messageId,
      message: 'Email sent successfully'
    });
  } catch (error) {
    console.error('Error sending email:', error);
    return NextResponse.json(
      { 
        error: error instanceof Error ? error.message : 'Failed to send email',
        details: error instanceof Error ? error.stack : undefined
      },
      { status: 500 }
    );
  }
}