<?php

/**
 * GET /api/health
 *
 * Verfuegbarkeitspruefung fuer Monitoring und Agenten.
 *
 * Ohne Authentifizierung wird nur der Gesamtzustand gemeldet. Mit gueltigem
 * Token, Shared Key oder angemeldeter Sitzung kommen Schema-Version,
 * ausstehende Migrationen und Kennzahlen dazu.
 */

declare(strict_types=1);

require_once __DIR__ . '/../../src/bootstrap.php';

use Deploymentcenter\Core\ApiAuth;
use Deploymentcenter\Core\Config;
use Deploymentcenter\Core\Db;
use Deploymentcenter\Core\Http;
use Deploymentcenter\Core\Logger;
use Deploymentcenter\Core\Migrator;
use Deploymentcenter\Modules\Bugtracker\BugRepo;

Http::beginJson(['GET', 'OPTIONS'], true);

$checks = [];
$healthy = true;

// --- Datenbank ---
$db = null;
try {
    $started = microtime(true);
    $db = Db::init();
    $db->query('SELECT 1')->fetchColumn();
    $checks['database'] = [
        'ok'         => true,
        'latency_ms' => (int)round((microtime(true) - $started) * 1000),
    ];
} catch (Throwable $e) {
    Logger::error('Health-Check: Datenbank nicht erreichbar', ['error' => $e->getMessage()]);
    $checks['database'] = ['ok' => false, 'error' => 'nicht erreichbar'];
    $healthy = false;
}

// --- Schreibbarkeit des Log-Verzeichnisses ---
$logDir = DC_VAR . '/log';
$checks['log_writable'] = ['ok' => is_dir($logDir) ? is_writable($logDir) : is_writable(DC_ROOT)];

$response = [
    'healthy'   => $healthy,
    'app'       => Config::get('app.name', 'Deploymentcenter'),
    'version'   => Config::get('app.version', 'unknown'),
    'time_utc'  => gmdate('c'),
    'checks'    => $checks,
];

// --- Detailinformationen nur fuer Authentifizierte ---
if ($db !== null && ApiAuth::resolve($db, 'bugtracker:read') !== null) {
    try {
        $status = Migrator::status($db);
        $response['schema'] = [
            'applied_count' => count($status['applied']),
            'pending'       => $status['pending'],
        ];

        if ($status['pending'] !== []) {
            $response['healthy'] = false;
            $response['checks']['migrations'] = [
                'ok'      => false,
                'message' => 'Ausstehende Migrationen: ' . implode(', ', $status['pending']),
            ];
        } else {
            $response['checks']['migrations'] = ['ok' => true];
        }

        $repo = new BugRepo($db);
        $response['bugtracker'] = $repo->getStats();

        $monitors = $db->query('
            SELECT state, COUNT(*) AS total
            FROM watchdog_monitors
            GROUP BY state
        ')->fetchAll() ?: [];

        $byState = [];
        foreach ($monitors as $row) {
            $byState[(string)$row['state']] = (int)$row['total'];
        }
        $response['watchdog'] = ['monitors_by_state' => $byState];

        $lastRun = $db->query("
            SELECT last_run_utc FROM watchdog_cron_jobs WHERE name = 'evaluator'
        ")->fetchColumn();

        $response['watchdog']['evaluator_last_run_utc'] = $lastRun !== false ? $lastRun : null;

        // Laeuft der Evaluator nicht, sind alle Monitor-Zustaende wertlos.
        if ($lastRun === false || $lastRun === null) {
            $response['checks']['evaluator'] = [
                'ok'      => false,
                'message' => 'Der Evaluator lief noch nie. Cron-Job auf /api/watchdog/v1/evaluate einrichten.',
            ];
        } else {
            $age = time() - (int)strtotime((string)$lastRun . ' UTC');
            $response['checks']['evaluator'] = [
                'ok'          => $age < 900,
                'age_seconds' => $age,
                'message'     => $age < 900 ? null : 'Letzter Lauf liegt zu lange zurueck.',
            ];
        }
    } catch (Throwable $e) {
        Logger::warning('Health-Check: Detailabfrage fehlgeschlagen', ['error' => $e->getMessage()]);
        $response['detail_error'] = 'Detailinformationen konnten nicht ermittelt werden.';
    }
}

Http::ok($response, $response['healthy'] ? 200 : 503);