// Copyright 2022 Jo-Philipp Wich <jo@mein.io>
// Licensed to the public under the Apache License 2.0.

'use strict';

import { access, open, popen } from 'fs';
import { connect } from 'ubus';
import { cursor } from 'uci';

// Establish ubus connection persistently outside of the call handler scope to
// prevent premature GC'ing. Can be moved into `get_status` callback once
// https://github.com/jow-/ucode/commit/a58fe4709f661b5f28e26701ea8638efccf5aeb6
// is merged.
const ubus = connect();

const methods = {
	get_status: {
		call: function(req) {
			const uci = cursor();

			const rules = [];
			const leases = [];

			const leasefile = open(uci.get('upnpd', 'config', 'upnp_lease_file'), 'r');

			if (leasefile) {
				for (let line = leasefile.read('line'); length(line); line = leasefile.read('line')) {
					const record = split(line, ':', 6);

					if (length(record) == 6) {
						push(leases, {
							proto: uc(record[0]),
							extport: +record[1],
							intaddr: arrtoip(iptoarr(record[2])),
							intport: +record[3],
							expiry: +record[4],
							description: trim(record[5])
						});
					}
				}

				leasefile.close();
			}

			const ipt = popen('iptables --line-numbers -t nat -xnvL MINIUPNPD 2>/dev/null');

			if (ipt) {
				for (let line = ipt.read('line'); length(line); line = ipt.read('line')) {
					let m = match(line, /^([0-9]+)\s+([a-z]+).+dpt:([0-9]+) to:(\S+):([0-9]+)/);

					if (m) {
						push(rules, {
							num: m[1],
							proto: uc(m[2]),
							extport: +m[3],
							intaddr: arrtoip(iptoarr(m[4])),
							intport: +m[5],
							descr: ''
						});
					}
				}

				ipt.close();
			}

			const nft = popen('nft --handle list chain inet fw4 upnp_prerouting 2>/dev/null');

			if (nft) {
				for (let line = nft.read('line'), num = 1; length(line); line = nft.read('line')) {
					let m = match(line, /^\t\tiif ".+" @nh,72,8 (0x6|0x11) th dport ([0-9]+) dnat ip to ([0-9.]+):([0-9]+)/);

					if (m) {
						push(rules, {
							num: `${num}`,
							proto: (m[1] == '0x6') ? 'TCP' : 'UDP',
							extport: +m[2],
							intaddr: arrtoip(iptoarr(m[3])),
							intport: +m[4],
							descr: ''
						});

						num++;
					}
				}

				nft.close();
			}

			return ubus.defer('luci-rpc', 'getHostHints', {}, function(rc, host_hints) {
				for (let rule in rules) {
					for (let lease in leases) {
						if (lease.proto == rule.proto &&
						    lease.intaddr == rule.intaddr &&
						    lease.intport == rule.intport &&
						    lease.extport == rule.extport)
						{
							rule.descr = lease.description;
							break;
						}
					}

					for (let mac, hint in host_hints) {
						if (rule.intaddr in hint.ipaddrs) {
							rule.host_hint = hint.name;
							break;
						}
					}
				}

				req.reply({ rules });
			});
		}
	},

	delete_rule: {
		args: { token: 'token' },
		call: function(req) {
			const idx = +req.args?.token;

			if (idx > 0) {
				const uci = cursor();
				const leasefile = uci.get('upnpd', 'config', 'upnp_lease_file');

				if (access(leasefile)) {
					system(['sed', '-i', '-e', `${idx}d`, leasefile]);
					system(['/etc/init.d/miniupnpd', 'restart']);
				}

				return { result: 'OK' };
			}

			return { result: 'Bad request' };
		}
	}
};

return { 'luci.upnp': methods };