import { NextResponse } from 'next/server';
import Imap from 'imap';
import { simpleParser } from 'mailparser';

// IMAP configuration
const imapConfig = {
  user: 'contact@governance-labs.org',
  password: 'K!376c$6H#kMknM',
  host: 'mail.infomaniak.com',
  port: 993,
  tls: true,
  tlsOptions: { rejectUnauthorized: false }
};

interface ImapMessage {
  header: {
    from?: string[];
    to?: string[];
    subject?: string[];
    date?: string[];
    [key: string]: string[] | undefined;
  };
  body: string;
  attributes: {
    flags: string[];
  };
}

// Helper function to create a promise-based IMAP connection
function createImapConnection() {
  return new Promise((resolve, reject) => {
    const imap = new Imap(imapConfig);
    
    imap.once('ready', () => resolve(imap));
    imap.once('error', (err: Error) => reject(err));
    imap.connect();
  });
}

// Helper function to promisify the message fetching
function fetchMessages(imap: Imap, box: string): Promise<ImapMessage[]> {
  return new Promise((resolve, reject) => {
    imap.openBox(box, false, (err, mailbox) => {
      if (err) {
        reject(err);
        return;
      }

      // Search for all messages
      imap.search(['ALL'], (err, results) => {
        if (err) {
          reject(err);
          return;
        }

        // No messages found
        if (!results || !results.length) {
          resolve([]);
          return;
        }

        const fetch = imap.fetch(results, {
          bodies: ['HEADER.FIELDS (FROM TO SUBJECT DATE)', 'TEXT'],
          struct: true
        });

        const messages: ImapMessage[] = [];

        fetch.on('message', (msg) => {
          const message: Partial<ImapMessage> = {};

          msg.on('body', (stream, info) => {
            let buffer = '';
            stream.on('data', (chunk) => {
              buffer += chunk.toString('utf8');
            });
            stream.once('end', () => {
              if (info.which === 'TEXT') {
                message.body = buffer;
              } else {
                message.header = Imap.parseHeader(buffer);
              }
            });
          });

          msg.once('attributes', (attrs) => {
            message.attributes = attrs;
          });

          msg.once('end', () => {
            messages.push(message as ImapMessage);
          });
        });

        fetch.once('error', (err) => {
          reject(err);
        });

        fetch.once('end', () => {
          resolve(messages);
        });
      });
    });
  });
}

export async function GET(request: Request) {
  try {
    const imap = await createImapConnection() as Imap;
    const messages = await fetchMessages(imap, 'INBOX');
    
    // Process messages into the format expected by the frontend
    const processedMessages = messages.map((msg: ImapMessage, index: number) => ({
      id: index + 1,
      accountId: 1,
      from: msg.header.from?.[0] || '',
      fromName: (msg.header.from?.[0] || '').split('<')[0].trim(),
      to: msg.header.to?.[0] || '',
      subject: msg.header.subject?.[0] || '',
      body: msg.body || '',
      date: msg.header.date?.[0] || new Date().toISOString(),
      read: !(msg.attributes.flags.indexOf('\\Seen') < 0),
      starred: !(msg.attributes.flags.indexOf('\\Flagged') < 0),
      category: 'inbox'
    }));

    imap.end();
    return NextResponse.json({ messages: processedMessages });

  } catch (error) {
    console.error('Error fetching emails:', error);
    return NextResponse.json({ error: 'Failed to fetch emails' }, { status: 500 });
  }
}

// Add endpoint to get mailboxes
export async function POST(request: Request) {
  try {
    const imap = await createImapConnection() as Imap;
    
    const mailboxes = await new Promise((resolve, reject) => {
      imap.getBoxes((err, boxes) => {
        if (err) reject(err);
        resolve(boxes);
      });
    });

    imap.end();
    return NextResponse.json({ mailboxes });

  } catch (error) {
    console.error('Error fetching mailboxes:', error);
    return NextResponse.json({ error: 'Failed to fetch mailboxes' }, { status: 500 });
  }
}