#!/usr/bin/env node
import { ImapFlow } from 'imapflow';
import { readFileSync } from 'fs';
import { execFileSync } from 'child_process';

const CONFIG_PATH = process.env.MAIL_BUDDY_CONFIG ?? '/home/devilholk/.config/claude-mail-buddy/config.json';

function load_config() {
	try {
		return JSON.parse(readFileSync(CONFIG_PATH, 'utf8'));
	} catch (err) {
		console.error(`Failed to load config from ${CONFIG_PATH}: ${err.message}`);
		process.exit(1);
	}
}

function make_prompt(message) {
	const from = message.envelope.from?.[0]?.address ?? 'unknown';
	const subject = message.envelope.subject ?? '(no subject)';
	const body = message.text ?? '(no body)';

	return [
		`[mail-buddy] New email from ${from}`,
		`Subject: ${subject}`,
		``,
		body.trim(),
		``,
		`Please reply to this email using the send-email CCC action, addressed to ${from} with an appropriate subject.`,
	].join('\n');
}

function send_to_claude(text, config) {
	const window_id = String(config.claude_window_id);
	execFileSync('node', [config.claude_remote_path, '--window-id', window_id], {
		input: text,
		encoding: 'utf8',
		stdio: ['pipe', 'inherit', 'inherit'],
	});
}

async function handle_message(client, uid, config) {
	const msg = await client.fetchOne(uid, { envelope: true, bodyStructure: true, source: true });
	if (!msg) {
		return;
	}

	// Fetch plain text part
	let text = '';
	for await (const part of client.fetch(uid, { bodyParts: ['text/plain'] })) {
		text = part.bodyParts?.get('text/plain')?.toString('utf8') ?? '';
	}
	msg.text = text;

	const sender = msg.envelope.from?.[0]?.address ?? '';
	if (!sender.toLowerCase().includes(config.allowed_sender.toLowerCase())) {
		console.log(`Ignoring message from ${sender}`);
		return;
	}

	console.log(`Dispatching message from ${sender}: ${msg.envelope.subject}`);
	const prompt = make_prompt(msg);
	send_to_claude(prompt, config);
}

async function main() {
	const config = load_config();

	const client = new ImapFlow({
		host: config.imap.host,
		port: config.imap.port ?? 993,
		secure: config.imap.secure ?? true,
		auth: {
			user: config.imap.user,
			pass: config.imap.pass,
		},
		logger: false,
	});

	await client.connect();
	console.log(`Connected to ${config.imap.host}`);

	const lock = await client.getMailboxLock(config.imap.mailbox ?? 'INBOX');

	try {
		// Process any unseen messages already waiting
		const unseen = await client.search({ unseen: true });
		for (const uid of unseen) {
			await handle_message(client, uid, config);
		}

		console.log('Waiting for new mail (IDLE)...');

		// IDLE loop — re-enters IDLE after each notification
		while (true) {
			await client.idle();

			const new_msgs = await client.search({ unseen: true });
			for (const uid of new_msgs) {
				await handle_message(client, uid, config);
				await client.messageFlagsAdd(uid, ['\\Seen']);
			}
		}
	} finally {
		lock.release();
		await client.logout();
	}
}

main().catch(err => {
	console.error(err);
	process.exit(1);
});