<?php
/**
 * API Endpoint: Get Next Start Time
 * Calculates the next available start time based on existing transmissions
 */

require_once __DIR__ . '/../vendor/autoload.php';
require_once __DIR__ . '/../helpers.php';
require_once __DIR__ . '/../auth/auth_functions.php';

use Dotenv\Dotenv;

$dotenv = Dotenv::createImmutable(__DIR__ . '/..');
$dotenv->load();

header('Content-Type: application/json');

if (!isLoggedIn()) {
    http_response_code(401);
    echo json_encode(['success' => false, 'error' => 'Niet geautoriseerd.']);
    exit;
}

try {
    $db = getDbConnection();
    
    $date = $_GET['date'] ?? date('Y-m-d');
    $channel = $_GET['channel'] ?? 'SBS9';
    $requestedTime = $_GET['requested_time'] ?? null;
    
    // Get next start time using helper function
    $nextStartTime = calculateNextStartTime($db, $date, $channel, $requestedTime);
    
    jsonResponse([
        'next_start_time' => $nextStartTime,
        'date' => $date,
        'channel' => $channel
    ]);
    
} catch (Exception $e) {
    jsonResponse([
        'error' => $e->getMessage()
    ], 500);
}