<?php

class ConnectionRegistry
{
    public static function empty(): array
    {
        return [
            'connections' => [],
            'lastSeen' => []
        ];
    }

    public static function fromJson(string $json): array
    {
        $data = json_decode($json, true);
        if (!is_array($data)) {
            return self::empty();
        }
        return array_replace(self::empty(), $data);
    }

    public static function toJson(array $state): string
    {
        return json_encode(array_replace(self::empty(), $state));
    }

    public static function touch(array $state, string $chargePointId, string $remote = ''): array
    {
        $state = array_replace(self::empty(), $state);
        $state['connections'][$chargePointId] = [
            'chargePointId' => $chargePointId,
            'remote' => $remote,
            'timestamp' => time()
        ];
        $state['lastSeen'][$chargePointId] = time();
        return $state;
    }
}

?>