<?php

declare(strict_types=1);

const DASHBOARD_VBB_STOP_ID = '900086103';
const DASHBOARD_VBB_BUS_PRODUCTS = 8;

function dashboard_vbb_datetime(array $departure, bool $realtime = false): ?DateTimeImmutable
{
    $time = trim((string) ($departure[$realtime ? 'rtTime' : 'time'] ?? ''));
    if ($time === '') {
        return null;
    }
    $date = trim((string) ($departure[$realtime ? 'rtDate' : 'date'] ?? $departure['date'] ?? ''));
    $value = DateTimeImmutable::createFromFormat(
        '!Y-m-d H:i:s',
        $date . ' ' . $time,
        new DateTimeZone(DASHBOARD_TIMEZONE)
    );
    return $value ?: null;
}

function dashboard_vbb_normalize_departure(array $departure): ?array
{
    $product = $departure['ProductAtStop'] ?? ($departure['Product'][0] ?? []);
    if (!is_array($product) || stripos((string) ($product['catOut'] ?? $product['catOutL'] ?? ''), 'bus') === false) {
        return null;
    }

    $planned = dashboard_vbb_datetime($departure);
    if (!$planned) {
        return null;
    }
    $actual = dashboard_vbb_datetime($departure, true);
    $status = strtoupper(trim((string) ($departure['JourneyStatus'] ?? '')));
    $cancelled = filter_var($departure['cancelled'] ?? false, FILTER_VALIDATE_BOOLEAN) || $status === 'C';

    $line = trim((string) ($product['displayNumber'] ?? ''));
    $line = $line !== '' ? $line : trim((string) ($product['line'] ?? $product['name'] ?? $departure['name'] ?? 'Bus'));

    return [
        'plannedWhen' => $planned->format(DATE_ATOM),
        'when' => $actual?->format(DATE_ATOM),
        'delay' => $actual ? $actual->getTimestamp() - $planned->getTimestamp() : null,
        'cancelled' => $cancelled,
        'line' => ['name' => $line],
        'direction' => trim((string) ($departure['direction'] ?? '')),
    ];
}

function dashboard_fetch_departures(): array
{
    $directory = __DIR__ . '/../cache';
    if (!is_dir($directory) && !@mkdir($directory, 0775, true) && !is_dir($directory)) {
        throw new RuntimeException('VBB-Cache nicht beschreibbar.');
    }
    $file = fopen($directory . '/vbb-' . DASHBOARD_VBB_STOP_ID . '.json', 'c+');
    if (!$file) {
        throw new RuntimeException('VBB-Cache nicht verfügbar.');
    }

    try {
        if (!flock($file, LOCK_EX)) {
            throw new RuntimeException('VBB-Cache konnte nicht gesperrt werden.');
        }
        $cache = json_decode(stream_get_contents($file), true) ?: [];
        if (microtime(true) >= ($cache['retryAt'] ?? 0)) {
            try {
                $query = http_build_query([
                    'id' => DASHBOARD_VBB_STOP_ID,
                    'duration' => 120,
                    'maxJourneys' => 30,
                    'products' => DASHBOARD_VBB_BUS_PRODUCTS,
                    'type' => 'DEP',
                    'format' => 'json',
                    'lang' => 'de',
                ], '', '&', PHP_QUERY_RFC3986);
                $baseUrl = rtrim(intranet_env('VBB_API_BASE_URL'), '/');
                $data = dashboard_http_json($baseUrl . '/departureBoard?' . $query, [
                    'Authorization: Bearer ' . intranet_env('VBB_ACCESS_ID'),
                ]);
                if (!isset($data['Departure']) || !is_array($data['Departure'])) {
                    throw new RuntimeException('Unerwartete VBB-Antwort.');
                }

                $departures = [];
                foreach ($data['Departure'] as $departure) {
                    if (is_array($departure) && ($normalized = dashboard_vbb_normalize_departure($departure))) {
                        $departures[] = $normalized;
                    }
                }
                $now = microtime(true);
                $cache = [
                    'departures' => array_slice($departures, 0, 30),
                    'updatedAt' => (int) round($now * 1000),
                    'retryAt' => $now + 30,
                    'unavailable' => false,
                ];
            } catch (Throwable $error) {
                // Eine letzte erfolgreiche Antwort behalten und die API nach Fehlern nicht belasten.
                error_log('Dashboard VBB: ' . $error->getMessage());
                $cache['unavailable'] = true;
                $cache['retryAt'] = microtime(true) + 60;
            }

            rewind($file);
            $json = json_encode($cache, JSON_UNESCAPED_UNICODE | JSON_THROW_ON_ERROR);
            if (!ftruncate($file, 0) || fwrite($file, $json) !== strlen($json) || !fflush($file)) {
                throw new RuntimeException('VBB-Cache konnte nicht gespeichert werden.');
            }
        }
        return $cache + ['departures' => [], 'updatedAt' => 0];
    } finally {
        fclose($file);
    }
}