import { IrcMessage } from './types';

/**
 * Parse IRC message.
 *
 * @since 0.1.0
 */
export function parseIrc(raw: string): IrcMessage {
	const msg: IrcMessage = {
		raw,
		tags: null,
		prefix: null,
		cmd: null,
		args: [],
	};
	let s = raw.replace(/\r?\n$/, '');
	if (!s) return msg;

	if (s[0] === '@') {
		const sp = s.indexOf(' ');
		msg.tags = s.slice(1, sp);
		s = s.slice(sp + 1);
	}

	if (s[0] === ':') {
		const i = s.indexOf(' ');
		msg.prefix = s.slice(1, i);
		s = s.slice(i + 1);
	}

	const sp = s.indexOf(' ');
	if (sp === -1) {
		msg.cmd = s;
		return msg;
	}

	msg.cmd = s.slice(0, sp);
	s = s.slice(sp + 1);
	const trailIdx = s.indexOf(' :');
	if (trailIdx !== -1) {
		const pre = s.slice(0, trailIdx).split(' ').filter(Boolean);
		msg.args = pre.concat([s.slice(trailIdx + 2)]);
	} else {
		msg.args = s.split(' ').filter(Boolean);
	}
	return msg;
}