import type { RedisOptions } from 'ioredis';

export function parseRedisOptions(o: (RedisOptions & { url?: string }) | string): RedisOptions {
	const opts = typeof o === 'string' ? { url: o } : o;
	const url = opts.url;
	if (!url) {
		return opts;
	}
	let u = new URL(url);
	let out = {
		...opts,
		host: u.hostname,
		port: Number(u.port),
		password: opts.password || u.password,
		username: opts.password || u.username,
		db: Number(u.pathname.slice(1)) || 0,
	};

	if (u.protocol === 'rediss:') {
		out.tls = { servername: parseServerName(u) };
	}

	return out;
}

function parseServerName(u: URL) {
	let sni = u.searchParams.get('servername') || u.searchParams.get('sni');
	if (sni) {
		switch (sni) {
			case '':
			case '1':
			case 'true':
				return u.hostname;
			case '0':
			case 'false':
				break;
			default:
				return sni;
		}
	} else {
		// if not ipv4 or ipv6, set servername
		if (!/^[0-9.:-]+$/.test(u.hostname)) {
			return u.hostname;
		}
	}
	return undefined;
}

interface ParsedRedisUrl {
	hostname: string;
	port: number;
	password: string;
	username: string;
	db?: number;
	tls?: { servername?: string };
}

function _parseRedisUrl(u: string) {
	let url = new URL(u);
	let out: ParsedRedisUrl = {
		hostname: url.hostname,
		port: Number(url.port),
		password: url.password,
		username: url.username,
	};

	if (url.pathname.length > 1) {
		out.db = Number(url.pathname.split('/')[1]) || 0;
	}

	if (url.protocol === 'rediss:') {
		out.tls = { servername: parseServerName(url) };
	}

	return out;
}