<?php
session_start();

require_once("inc/config.inc.php");
require_once("inc/functions.inc.php");

$user = check_user();
if (!is_admin_user()) {
    http_response_code(403);
    die("Keine Berechtigung.");
}

if ($_SERVER["REQUEST_METHOD"] !== "POST") {
    die("Ungueltige Anfrage.");
}

$employeeId = isset($_POST['employee_id']) ? (int)$_POST['employee_id'] : 0;
$hoursRaw = isset($_POST['hours_to_close']) ? str_replace(',', '.', trim((string)$_POST['hours_to_close'])) : '';
$hoursToClose = is_numeric($hoursRaw) ? (float)$hoursRaw : 0.0;

if ($employeeId <= 0) {
    $_SESSION['time_error_close_result'] = [
        'type' => 'danger',
        'message' => 'Es wurde kein gueltiger Mitarbeiter uebergeben.',
    ];
    header("Location: allefehlbuchungen.php");
    exit;
}

if ($hoursToClose <= 0) {
    $_SESSION['time_error_close_result'] = [
        'type' => 'danger',
        'message' => 'Bitte eine gueltige Stundenanzahl groesser als 0 angeben.',
    ];
    header("Location: allefehlbuchungen.php");
    exit;
}

try {
    $stmt = $pdo->prepare("SELECT id, vorname, nachname FROM users WHERE id = :employee_id LIMIT 1");
    $stmt->bindValue(':employee_id', $employeeId, PDO::PARAM_INT);
    $stmt->execute();
    $employee = $stmt->fetch(PDO::FETCH_ASSOC);

    if (!$employee) {
        throw new RuntimeException('Mitarbeiter wurde nicht gefunden.');
    }

    $stmt = $pdo->prepare(
        "SELECT
            DATE(timestamp_datetime) AS datum,
            GROUP_CONCAT(timestamp_type ORDER BY timestamp_datetime) AS day_sequence
         FROM timestamps
         WHERE employee_id = :employee_id
         GROUP BY DATE(timestamp_datetime)
         ORDER BY datum ASC"
    );
    $stmt->bindValue(':employee_id', $employeeId, PDO::PARAM_INT);
    $stmt->execute();
    $days = $stmt->fetchAll(PDO::FETCH_ASSOC);

    $invalidDates = [];
    foreach ($days as $day) {
        if (!isValidSequence((string)$day['day_sequence'])) {
            $invalidDates[] = (string)$day['datum'];
        }
    }

    if (empty($invalidDates)) {
        $_SESSION['time_error_close_result'] = [
            'type' => 'info',
            'message' => 'Es wurden keine offenen Fehlbuchungen fuer den Mitarbeiter gefunden.',
        ];
        header("Location: allefehlbuchungen.php");
        exit;
    }

    $pdo->beginTransaction();

    $insertedDates = [];
    $skippedDates = [];
    $secondsToClose = (int)round($hoursToClose * 3600);

    $lastEntryStmt = $pdo->prepare(
        "SELECT timestamp_type, timestamp_datetime
         FROM timestamps
         WHERE employee_id = :employee_id
           AND DATE(timestamp_datetime) = :datum
         ORDER BY timestamp_datetime DESC, timestamp_id DESC
         LIMIT 1"
    );

    $insertStmt = $pdo->prepare(
        "INSERT INTO timestamps (employee_id, timestamp_type, timestamp_datetime, timestamp_endpoint)
         VALUES (:employee_id, 'GEHEN', :timestamp_datetime, 0)"
    );

    foreach ($invalidDates as $invalidDate) {
        $lastEntryStmt->bindValue(':employee_id', $employeeId, PDO::PARAM_INT);
        $lastEntryStmt->bindValue(':datum', $invalidDate);
        $lastEntryStmt->execute();
        $lastEntry = $lastEntryStmt->fetch(PDO::FETCH_ASSOC);

        if (!$lastEntry || (string)$lastEntry['timestamp_type'] !== 'KOMMEN') {
            $skippedDates[] = $invalidDate;
            continue;
        }

        $closeTimestamp = (new DateTimeImmutable((string)$lastEntry['timestamp_datetime']))
            ->modify('+' . $secondsToClose . ' seconds')
            ->format('Y-m-d H:i:s');

        $insertStmt->bindValue(':employee_id', $employeeId, PDO::PARAM_INT);
        $insertStmt->bindValue(':timestamp_datetime', $closeTimestamp);
        $insertStmt->execute();

        $insertedDates[] = $invalidDate;
    }

    $pdo->commit();

    $message = count($insertedDates) . ' Fehlbuchungstage fuer '
        . $employee['vorname'] . ' ' . $employee['nachname']
        . ' wurden mit ' . rtrim(rtrim(number_format($hoursToClose, 2, '.', ''), '0'), '.')
        . ' Stunden geschlossen.';

    if (!empty($skippedDates)) {
        $message .= ' ' . count($skippedDates) . ' Tage konnten nicht automatisch geschlossen werden.';
    }

    $_SESSION['time_error_close_result'] = [
        'type' => !empty($insertedDates) ? 'success' : 'warning',
        'message' => $message,
    ];
} catch (Throwable $e) {
    if ($pdo->inTransaction()) {
        $pdo->rollBack();
    }

    $_SESSION['time_error_close_result'] = [
        'type' => 'danger',
        'message' => 'Automatisches Schliessen fehlgeschlagen: ' . $e->getMessage(),
    ];
}

header("Location: allefehlbuchungen.php");
exit;