import { mkdir, writeFile } from 'node:fs/promises';
import path from 'node:path';
import { randomUUID } from 'node:crypto';
import nodemailer from 'nodemailer';
import { getMailConfig, getServerPaths } from './config.js';

export type MailMessage = {
	to: string;
	subject: string;
	text: string;
};

export async function sendMail(message: MailMessage): Promise<'local' | 'smtp'> {
	const config = getMailConfig();
	if (config.transport === 'local') {
		const outbox = getServerPaths().mailOutbox;
		await mkdir(outbox, { recursive: true, mode: 0o700 });
		const filename = `${new Date().toISOString().replaceAll(':', '-')}-${randomUUID()}.json`;
		await writeFile(
			path.join(outbox, filename),
			JSON.stringify({ from: config.from, ...message }, null, 2),
			{ encoding: 'utf8', mode: 0o600 }
		);
		return 'local';
	}

	if (
		!config.host ||
		!config.from ||
		!Number.isInteger(config.port) ||
		config.port < 1 ||
		config.port > 65_535 ||
		Boolean(config.user) !== Boolean(config.password)
	) {
		throw new Error('Die SMTP-Konfiguration ist unvollständig.');
	}
	const transporter = nodemailer.createTransport({
		host: config.host,
		port: config.port,
		secure: config.secure,
		requireTLS: !config.secure,
		connectionTimeout: 10_000,
		greetingTimeout: 10_000,
		socketTimeout: 20_000,
		auth: config.user ? { user: config.user, pass: config.password } : undefined
	});
	await transporter.sendMail({ from: config.from, ...message });
	return 'smtp';
}