<?php

declare(strict_types=1);

class Int_VGT extends IPSModule
{
    public function Create()
    {
        parent::Create();

        // Properties
        $this->RegisterPropertyInteger("MQTTServer", 0);
        $this->RegisterPropertyString("DeviceID", "");

        // Create script handler only once
        if (!@$this->GetIDForIdent("ReceiveScript")) {
            $scriptID = IPS_CreateScript(0);
            IPS_SetName($scriptID, "INTVGT_ReceiveHandler");
            IPS_SetIdent($scriptID, "ReceiveScript");
            IPS_SetParent($scriptID, $this->InstanceID);

            IPS_SetScriptContent($scriptID, $this->GenerateReceiveScript());
        }
    }

    public function ApplyChanges()
    {
        parent::ApplyChanges();

        $mqttServer = $this->ReadPropertyInteger("MQTTServer");
        $deviceId = $this->ReadPropertyString("DeviceID");

        if ($mqttServer == 0 || $deviceId == "") {
            $this->SetStatus(104); // missing config
            return;
        }

        // Create MQTT Server Devices
        $this->RegisterMQTTDevice("FeedbackRequest", "feedback-request/" . $deviceId);
        $this->RegisterMQTTDevice("RemoteControlResponse", "remote-control-response/" . $deviceId);

        $this->SetStatus(102);
    }

    private function RegisterMQTTDevice(string $ident, string $topic)
    {
        $instanceID = @$this->GetIDForIdent($ident);

        if ($instanceID === false) {
            $instanceID = IPS_CreateInstance("{058A5647-0C2F-4D7D-9F4B-50A28C7D83BA}"); // MQTT Server Device
            IPS_SetParent($instanceID, $this->InstanceID);
            IPS_SetIdent($instanceID, $ident);
            IPS_SetName($instanceID, "MQTT Device: " . $ident);
        }

        IPS_SetProperty($instanceID, "Topic", $topic);
        IPS_SetProperty($instanceID, "Server", $this->ReadPropertyInteger("MQTTServer"));
        IPS_SetProperty($instanceID, "Script", $this->GetIDForIdent("ReceiveScript"));
        IPS_ApplyChanges($instanceID);

        return $instanceID;
    }

    /** Script to be executed when MQTT message is received */
    private function GenerateReceiveScript(): string
    {
        return <<<SCR
<?php

\$parent = IPS_GetParent(\$_IPS['SELF']);
IPS_RequestAction(\$parent, "OnReceive", json_encode([
    "Topic" => \$_IPS['Topic'],
    "Value" => \$_IPS['VALUE']
]));

SCR;
    }

    /** Called by ReceiveScript */
    public function RequestAction($ident, $value)
    {
        if ($ident == "OnReceive") {
            $data = json_decode($value, true);
            $this->OnReceiveMQTT($data["Topic"], $data["Value"]);
        }
    }

    /** THIS IS YOUR CALLBACK FOR INCOMING MQTT MESSAGES */
    private function OnReceiveMQTT(string $topic, string $value)
    {
        IPS_LogMessage("Int_VGT", "Received on $topic: $value");

        // Here you implement later your handling logic
        // Example: respond to feedback-request
        $mqttServer = $this->ReadPropertyInteger("MQTTServer");

        if (str_contains($topic, "feedback-request")) {
            $response = json_encode([
                "status" => "ok",
                "timestamp" => time()
            ]);
            MQTT_Publish($mqttServer, str_replace("request", "response", $topic), $response, 0, false);
        }

        if (str_contains($topic, "remote-control-response")) {
            // Echo back the same payload
            MQTT_Publish($mqttServer, str_replace("response", "feedback", $topic), $value, 0, false);
        }
    }
}

?>