import { ImapFlow } from 'imapflow';

export type Account = 'yahoo' | 'fetcherpay';

function getConfig(account: Account = 'yahoo') {
  if (account === 'fetcherpay') {
    return {
      host: process.env['FETCHERPAY_IMAP_HOST'] ?? 'mail.fetcherpay.com',
      port: parseInt(process.env['FETCHERPAY_IMAP_PORT'] ?? '30993'),
      secure: true,
      auth: {
        user: process.env['FETCHERPAY_EMAIL'] as string,
        pass: process.env['FETCHERPAY_PASSWORD'] as string,
      },
      tls: { rejectUnauthorized: false }, // self-signed cert on self-hosted server
    };
  }
  return {
    host: 'imap.mail.yahoo.com',
    port: 993,
    secure: true,
    auth: {
      user: process.env['YAHOO_EMAIL'] as string,
      pass: process.env['YAHOO_APP_PASSWORD'] as string,
    },
  };
}

async function withClient<T>(account: Account, fn: (client: ImapFlow) => Promise<T>): Promise<T> {
  const client = new ImapFlow(getConfig(account));
  await client.connect();
  try {
    return await fn(client);
  } finally {
    await client.logout();
  }
}

export interface MessageSummary {
  uid: number;
  messageId: string;
  subject: string;
  from: string;
  date: string;
  seen: boolean;
  size: number;
}

export interface FullMessage {
  uid: number;
  messageId: string;
  subject: string;
  from: string;
  to: string;
  date: string;
  body: string;
  seen: boolean;
}

export async function searchMessages(query: string, maxResults = 20, account: Account = 'yahoo'): Promise<MessageSummary[]> {
  return withClient(account, async (client) => {
    await client.mailboxOpen('INBOX');

    const criteria = query
      ? { or: [{ subject: query }, { from: query }] }
      : { all: true };

    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    const uids = await client.search(criteria as any, { uid: true });
    const uidList: number[] = Array.isArray(uids) ? uids : [];
    const recentUids = uidList.slice(-maxResults).reverse();

    if (recentUids.length === 0) return [];

    const messages: MessageSummary[] = [];
    for await (const msg of client.fetch(recentUids, {
      envelope: true,
      flags: true,
      size: true,
    }, { uid: true })) {
      const env = msg.envelope;
      messages.push({
        uid: msg.uid,
        messageId: env?.messageId ?? '',
        subject: env?.subject ?? '(no subject)',
        from: env?.from?.[0]
          ? `${env.from[0].name ?? ''} <${env.from[0].address ?? ''}>`.trim()
          : '',
        date: env?.date?.toISOString() ?? '',
        seen: msg.flags?.has('\\Seen') ?? false,
        size: msg.size ?? 0,
      });
    }
    return messages;
  });
}

export async function readMessage(uid: number, account: Account = 'yahoo'): Promise<FullMessage> {
  return withClient(account, async (client) => {
    console.log(`[imap] readMessage uid=${uid} account=${account}`);
    await client.mailboxOpen('INBOX');
    console.log(`[imap] mailbox opened, fetching uid=${uid}`);

    let result: FullMessage | null = null;

    for await (const msg of client.fetch([uid], {
      envelope: true,
      flags: true,
      bodyParts: ['TEXT'],
    }, { uid: true })) {
      const env = msg.envelope;
      console.log(`[imap] got msg uid=${msg.uid} subject="${env?.subject}"`);

      const bpKeys = msg.bodyParts ? [...msg.bodyParts.keys()] : [];
      console.log(`[imap] bodyParts keys:`, JSON.stringify(bpKeys));

      const textBuf =
        msg.bodyParts?.get('text') ??
        msg.bodyParts?.get('TEXT') ??
        msg.bodyParts?.get('1');
      console.log(`[imap] textBuf length=${textBuf ? textBuf.length : 'null'}`);

      const rawBody = textBuf ? textBuf.toString('utf-8') : '';

      const body = rawBody
        .replace(/<style[^>]*>[\s\S]*?<\/style>/gi, '')
        .replace(/<script[^>]*>[\s\S]*?<\/script>/gi, '')
        .replace(/<[^>]+>/g, ' ')
        .replace(/\s+/g, ' ')
        .trim()
        .slice(0, 10000);

      console.log(`[imap] body length after strip=${body.length}`);

      result = {
        uid: msg.uid,
        messageId: env?.messageId ?? '',
        subject: env?.subject ?? '(no subject)',
        from: env?.from?.[0]
          ? `${env.from[0].name ?? ''} <${env.from[0].address ?? ''}>`.trim()
          : '',
        to: env?.to?.[0]?.address ?? '',
        date: env?.date?.toISOString() ?? '',
        body,
        seen: true,
      };
    }

    if (!result) throw new Error(`Message UID ${uid} not found`);

    // Mark as seen AFTER the fetch loop fully completes — calling messageFlagsAdd
    // inside the for-await loop deadlocks because the FETCH command is still active.
    console.log(`[imap] marking uid=${uid} as seen`);
    await client.messageFlagsAdd([uid], ['\\Seen'], { uid: true });

    console.log(`[imap] readMessage done uid=${uid}`);
    return result;
  });
}

export async function getProfile(account: Account = 'yahoo'): Promise<{ email: string; name: string; account: string }> {
  const email = account === 'fetcherpay'
    ? (process.env['FETCHERPAY_EMAIL'] ?? '')
    : (process.env['YAHOO_EMAIL'] ?? '');
  return { email, name: email.split('@')[0], account };
}

export async function listFolders(account: Account = 'yahoo'): Promise<string[]> {
  return withClient(account, async (client) => {
    const mailboxes = await client.list();
    return mailboxes.map((m) => m.path);
  });
}