<?php

namespace App\Support;

use Illuminate\Support\Facades\DB;
use RuntimeException;

/** A command-wide lock also covers direct cron invocations and separate deployments sharing MySQL. */
class SyncCommandLock
{
    public function run(string $command, callable $work): ?int
    {
        $connection = DB::connection();
        $name = 'bot-sync:' . substr(hash('sha256', $connection->getDatabaseName() . ':' . $connection->getTablePrefix() . ':' . $command), 0, 48);
        if (in_array($connection->getDriverName(), ['mysql', 'mariadb'], true)) {
            $acquired = $connection->selectOne('SELECT GET_LOCK(?, 0) AS acquired', [$name], false)->acquired;
            if ($acquired === null) throw new RuntimeException('Unable to acquire synchronization lock');
            if ((int) $acquired !== 1) return null;
            try { return $work(); }
            finally { $connection->selectOne('SELECT RELEASE_LOCK(?) AS released', [$name], false); }
        }

        $handle = fopen(sys_get_temp_dir() . '/' . $name . '.lock', 'c');
        if ($handle === false) throw new RuntimeException('Unable to open synchronization lock');
        try {
            if (!flock($handle, LOCK_EX | LOCK_NB)) return null;
            try { return $work(); }
            finally { flock($handle, LOCK_UN); }
        } finally { fclose($handle); }
    }
}