<?php
declare(strict_types=1);

namespace App\Framework\Router\Result;

/**
 * Repräsentiert ein einzelnes Server-Sent Event
 */
final readonly class SseEvent
{
    /**
     * @param string $data Der Dateninhalt des Events
     * @param string|null $event Der Event-Typ (optional)
     * @param string|null $id Die Event-ID (optional)
     * @param int|null $retry Retry-Intervall in Millisekunden (optional)
     */
    public function __construct(
        public string $data,
        public ?string $event = null,
        public ?string $id = null,
        public ?int $retry = null
    ) {}

    /**
     * Formatiert das Event in das SSE-Protokollformat
     */
    public function format(): string
    {
        $formatted = [];

        if ($this->id !== null) {
            $formatted[] = "id: {$this->id}";
        }

        if ($this->event !== null) {
            $formatted[] = "event: {$this->event}";
        }

        if ($this->retry !== null) {
            $formatted[] = "retry: {$this->retry}";
        }

        // Mehrzeilige Daten unterstützen
        foreach (explode("\n", $this->data) as $line) {
            $formatted[] = "data: {$line}";
        }

        $formatted[] = ''; // Leere Zeile am Ende

        return implode("\n", $formatted);
    }
}