<?php
session_start();
header('Content-Type: application/json');

$response = ['success' => false, 'message' => 'Wystąpił nieoczekiwany błąd.'];

if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
    http_response_code(405);
    $response['message'] = 'Invalid request method.';
    echo json_encode($response);
    exit;
}

require_once 'WorkflowEngine.php';

if (!isset($_POST['instanceId']) || !isset($_POST['transitionId'])) {
    http_response_code(400);
    $response['message'] = 'Błąd: Brak wymaganych parametrów.';
    echo json_encode($response);
    exit;
}

$instanceId = (int)$_POST['instanceId'];
$transitionId = $_POST['transitionId'];
$userId = $_SESSION['user_id'] ?? null;
$payload = $_POST['payload'] ?? [];

if (!$userId) {
    http_response_code(401);
    $response['message'] = 'Błąd: Sesja wygasła.';
    echo json_encode($response);
    exit;
}

try {
    $engine = new WorkflowEngine();
    $success = false;

    if ($transitionId === 'note') {
        // Special case: Just add a note, don't change state.
        $message = $payload['message'] ?? '';
        if (!empty($message)) {
            $success = $engine->addNote($instanceId, $message, $userId);
            if ($success) {
                $response['message'] = 'Notatka została dodana.';
            }
        }
    } else {
        // Standard transition logic
        $success = $engine->applyTransition($instanceId, $transitionId, $payload, $userId);
        if ($success) {
            $response['message'] = 'Akcja została wykonana pomyślnie.';
        }
    }

    if ($success) {
        $response['success'] = true;
    }

} catch (Exception $e) {
    error_log("Error applying transition: " . $e->getMessage());
    http_response_code(500);
    $response['message'] = 'Wystąpił krytyczny błąd: ' . $e->getMessage();
}

echo json_encode($response);
exit;