#!/usr/bin/ucode
// SPDX-License-Identifier: Apache-2.0
'use strict';
import { readfile, writefile, rename, chmod } from 'fs';
import { connect } from 'ubus';
import { netbios_names } from 'luci.client_names';
import { arp_leases, update_history, reverse_names } from 'luci.client_history';

const path = '/tmp/luci-client-history.json';
const boot_id = trim(readfile('/proc/sys/kernel/random/boot_id') || '');
if (!length(boot_id))
	exit(1);
let previous = {};
try { previous = json(readfile(path) || '{}'); } catch (e) {}
const bus = connect();
let current = bus ? bus.call('luci-rpc', 'getDHCPLeases', {}) : null;
current ||= {};
const active = arp_leases(readfile('/proc/net/arp'));
const reverse_dns = reverse_names(previous, current, active, boot_id,
	int(split(readfile('/proc/uptime'), ' ')[0]), function(addrs) {
		let names = bus ? (bus.call('network.rrdns', 'lookup', { addrs, timeout: 1000, limit: 8 }) || {}) : {};
		return { ...names, ...netbios_names(filter(addrs, ip => !names[ip])) };
	});
if (bus)
	bus.disconnect();
// Recheck ownership after the asynchronous DNS query.
const owners = {};
for (let lease in arp_leases(readfile('/proc/net/arp')))
	owners[lease.ipaddr] = lease.macaddr;
current.dhcp_leases = [ ...(current.dhcp_leases || []),
	...filter(active, lease => owners[lease.ipaddr] == lease.macaddr) ];
const result = update_history(previous, current, boot_id);
result.reverse_dns = reverse_dns;
const next = sprintf('%J', result);
if (next != readfile(path)) {
	if (writefile(path + '.new', next) != length(next))
		exit(1);
	chmod(path + '.new', 0600);
	if (!rename(path + '.new', path))
		exit(1);
}