<?php

declare(strict_types=1);

function getLastKmForVehicle(PDO $pdo, int $vehicleId): int
{
    $stmt = $pdo->prepare('
        SELECT COALESCE(
            (SELECT MAX(end_km) FROM trips WHERE vehicle_id = ?),
            (SELECT initial_km FROM vehicles WHERE id = ?),
            0
        ) as last_km
    ');
    $stmt->execute([$vehicleId, $vehicleId]);
    $result = $stmt->fetch();

    return $result ? (int)$result['last_km'] : 0;
}

function formatKm(int $km): string
{
    return number_format($km, 0, ',', ' ') . ' km';
}

// ============================================================================
// GET Handlers
// ============================================================================

/**
 * GET - Current month trips (filtered to current user)
 */
function handleGetCurrent(PDO $pdo, int $userId): void
{
    $month = validateMonth();
    $vehicleId = isset($_GET['vehicle_id']) ? (int)$_GET['vehicle_id'] : null;
    $startDate = "{$month}-01";
    $endDate = date('Y-m-t', strtotime($startDate));

    $sql = "
        SELECT t.id, t.vehicle_id, t.user_id, t.trip_date, t.start_km,
               t.end_km, t.distance, t.route_from, t.route_to,
               t.is_business, t.notes, t.created_at,
               v.spz, v.name as vehicle_name, v.brand, v.model,
               CONCAT(u.first_name, ' ', u.last_name) as driver_name
        FROM trips t
        JOIN vehicles v ON t.vehicle_id = v.id
        JOIN users u ON t.user_id = u.id
        WHERE t.trip_date BETWEEN ? AND ?
        AND t.user_id = ?
    ";
    $params = [$startDate, $endDate, $userId];

    if ($vehicleId) {
        $sql .= ' AND t.vehicle_id = ?';
        $params[] = $vehicleId;
    }

    $sql .= ' ORDER BY t.trip_date DESC, t.start_km DESC';

    $stmt = $pdo->prepare($sql);
    $stmt->execute($params);
    $trips = $stmt->fetchAll();

    // Get active vehicles for selection
    $stmt = $pdo->query('SELECT id, spz, name, brand, model FROM vehicles WHERE is_active = 1 ORDER BY name');
    $vehicles = $stmt->fetchAll();

    // Calculate totals
    $totalDistance = 0;
    $businessDistance = 0;
    $privateDistance = 0;

    foreach ($trips as $trip) {
        $totalDistance += $trip['distance'];
        if ($trip['is_business']) {
            $businessDistance += $trip['distance'];
        } else {
            $privateDistance += $trip['distance'];
        }
    }

    successResponse([
        'trips' => $trips,
        'vehicles' => $vehicles,
        'month' => $month,
        'totals' => [
            'total' => $totalDistance,
            'business' => $businessDistance,
            'private' => $privateDistance,
            'count' => count($trips),
        ],
    ]);
}

/**
 * GET - Trip history with filters (filtered to current user)
 */
function handleGetHistory(PDO $pdo, int $userId): void
{
    $month = validateMonth();
    $vehicleId = isset($_GET['vehicle_id']) ? (int)$_GET['vehicle_id'] : null;

    $startDate = "{$month}-01";
    $endDate = date('Y-m-t', strtotime($startDate));

    $sql = "
        SELECT t.id, t.vehicle_id, t.user_id, t.trip_date, t.start_km,
               t.end_km, t.distance, t.route_from, t.route_to,
               t.is_business, t.notes, t.created_at,
               v.spz, v.name as vehicle_name, v.brand, v.model,
               CONCAT(u.first_name, ' ', u.last_name) as driver_name
        FROM trips t
        JOIN vehicles v ON t.vehicle_id = v.id
        JOIN users u ON t.user_id = u.id
        WHERE t.trip_date BETWEEN ? AND ?
        AND t.user_id = ?
    ";
    $params = [$startDate, $endDate, $userId];

    if ($vehicleId) {
        $sql .= ' AND t.vehicle_id = ?';
        $params[] = $vehicleId;
    }

    $sql .= ' ORDER BY t.trip_date DESC, t.start_km DESC';

    $stmt = $pdo->prepare($sql);
    $stmt->execute($params);
    $trips = $stmt->fetchAll();

    // Get vehicles for filter
    $stmt = $pdo->query('SELECT id, spz, name FROM vehicles WHERE is_active = 1 ORDER BY name');
    $vehicles = $stmt->fetchAll();

    // Calculate totals
    $totalDistance = 0;
    $businessDistance = 0;

    foreach ($trips as $trip) {
        $totalDistance += $trip['distance'];
        if ($trip['is_business']) {
            $businessDistance += $trip['distance'];
        }
    }

    successResponse([
        'trips' => $trips,
        'vehicles' => $vehicles,
        'month' => $month,
        'totals' => [
            'total' => $totalDistance,
            'business' => $businessDistance,
            'count' => count($trips),
        ],
    ]);
}

/**
 * GET - Admin view of all trips
 */
function handleGetAdmin(PDO $pdo): void
{
    $dateFrom = $_GET['date_from'] ?? null;
    $dateTo = $_GET['date_to'] ?? null;
    $vehicleId = isset($_GET['vehicle_id']) ? (int)$_GET['vehicle_id'] : null;
    $filterUserId = isset($_GET['user_id']) ? (int)$_GET['user_id'] : null;

    // Default to current month if no dates provided
    if (!$dateFrom || !$dateTo) {
        $month = date('Y-m');
        $startDate = "{$month}-01";
        $endDate = date('Y-m-t', strtotime($startDate));
    } else {
        if (!preg_match('/^\d{4}-\d{2}-\d{2}$/', $dateFrom) || !preg_match('/^\d{4}-\d{2}-\d{2}$/', $dateTo)) {
            errorResponse('Neplatný formát data (očekáváno YYYY-MM-DD)');
        }
        $startDate = $dateFrom;
        $endDate = $dateTo;
    }

    $sql = "
        SELECT t.id, t.vehicle_id, t.user_id, t.trip_date, t.start_km,
               t.end_km, t.distance, t.route_from, t.route_to,
               t.is_business, t.notes, t.created_at,
               v.spz, v.name as vehicle_name,
               CONCAT(u.first_name, ' ', u.last_name) as driver_name
        FROM trips t
        JOIN vehicles v ON t.vehicle_id = v.id
        JOIN users u ON t.user_id = u.id
        WHERE t.trip_date BETWEEN ? AND ?
    ";
    $params = [$startDate, $endDate];

    if ($vehicleId) {
        $sql .= ' AND t.vehicle_id = ?';
        $params[] = $vehicleId;
    }

    if ($filterUserId) {
        $sql .= ' AND t.user_id = ?';
        $params[] = $filterUserId;
    }

    $sql .= ' ORDER BY t.trip_date DESC, t.start_km DESC';

    $stmt = $pdo->prepare($sql);
    $stmt->execute($params);
    $trips = $stmt->fetchAll();

    // Get vehicles for filter
    $stmt = $pdo->query('SELECT id, spz, name FROM vehicles ORDER BY name');
    $vehicles = $stmt->fetchAll();

    // Get users for filter
    $stmt = $pdo->query(
        "SELECT id, CONCAT(first_name, ' ', last_name) as name FROM users WHERE is_active = 1 ORDER BY last_name"
    );
    $users = $stmt->fetchAll();

    // Calculate totals
    $totalDistance = 0;
    $businessDistance = 0;

    foreach ($trips as $trip) {
        $totalDistance += $trip['distance'];
        if ($trip['is_business']) {
            $businessDistance += $trip['distance'];
        }
    }

    successResponse([
        'trips' => $trips,
        'vehicles' => $vehicles,
        'users' => $users,
        'date_from' => $startDate,
        'date_to' => $endDate,
        'totals' => [
            'total' => $totalDistance,
            'business' => $businessDistance,
            'count' => count($trips),
        ],
    ]);
}

/**
 * GET - All vehicles (admin)
 */
function handleGetVehicles(PDO $pdo): void
{
    $stmt = $pdo->query('
        SELECT v.id, v.spz, v.name, v.brand, v.model,
               v.initial_km, v.actual_km, v.is_active,
               v.created_at, v.updated_at,
               COUNT(t.id) as trip_count,
               COALESCE(MAX(t.end_km), v.initial_km) as current_km
        FROM vehicles v
        LEFT JOIN trips t ON t.vehicle_id = v.id
        GROUP BY v.id
        ORDER BY v.is_active DESC, v.name
    ');
    $vehicles = $stmt->fetchAll();

    successResponse(['vehicles' => $vehicles]);
}

/**
 * GET - Active vehicles for selection
 */
function handleGetActiveVehicles(PDO $pdo): void
{
    $stmt = $pdo->query('
        SELECT v.id, v.spz, v.name, v.brand, v.model,
               COALESCE(MAX(t.end_km), v.initial_km) as current_km
        FROM vehicles v
        LEFT JOIN trips t ON t.vehicle_id = v.id
        WHERE v.is_active = 1
        GROUP BY v.id
        ORDER BY v.name
    ');
    $vehicles = $stmt->fetchAll();

    successResponse(['vehicles' => $vehicles]);
}

/**
 * GET - Last km for vehicle
 */
function handleGetLastKm(PDO $pdo): void
{
    $vehicleId = (int)($_GET['vehicle_id'] ?? 0);
    if (!$vehicleId) {
        errorResponse('Vehicle ID je povinné');
    }

    $lastKm = getLastKmForVehicle($pdo, $vehicleId);
    successResponse(['last_km' => $lastKm]);
}

// ============================================================================
// POST Handlers
// ============================================================================

/**
 * POST - Create trip
 */
function handleCreateTrip(PDO $pdo, int $userId): void
{
    $input = getJsonInput();

    $vehicleId = (int)($input['vehicle_id'] ?? 0);
    $tripDate = $input['trip_date'] ?? '';
    $startKm = (int)($input['start_km'] ?? 0);
    $endKm = (int)($input['end_km'] ?? 0);
    $routeFrom = trim($input['route_from'] ?? '');
    $routeTo = trim($input['route_to'] ?? '');
    $isBusiness = (int)($input['is_business'] ?? 1);
    $notes = trim($input['notes'] ?? '');

    // Validation
    if (!$vehicleId) {
        errorResponse('Vyberte vozidlo');
    }
    if (!$tripDate) {
        errorResponse('Datum jízdy je povinné');
    }
    if (!$startKm) {
        errorResponse('Počáteční stav km je povinný');
    }
    if (!$endKm) {
        errorResponse('Konečný stav km je povinný');
    }
    if (!$routeFrom) {
        errorResponse('Místo odjezdu je povinné');
    }
    if (!$routeTo) {
        errorResponse('Místo příjezdu je povinné');
    }
    if ($endKm <= $startKm) {
        errorResponse('Konečný stav km musí být větší než počáteční');
    }

    // Check vehicle exists
    $stmt = $pdo->prepare('SELECT id FROM vehicles WHERE id = ? AND is_active = 1');
    $stmt->execute([$vehicleId]);
    if (!$stmt->fetch()) {
        errorResponse('Vozidlo neexistuje nebo není aktivní');
    }

    $stmt = $pdo->prepare('
        INSERT INTO trips (vehicle_id, user_id, trip_date, start_km, end_km, route_from, route_to, is_business, notes)
        VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)
    ');
    $stmt->execute([
        $vehicleId, $userId, $tripDate, $startKm, $endKm,
        $routeFrom, $routeTo, $isBusiness, $notes ?: null,
    ]);

    $newId = (int)$pdo->lastInsertId();
    AuditLog::logCreate('trips', $newId, $input, 'Vytvořen záznam jízdy');

    successResponse(['id' => $newId], 'Jízda byla zaznamenána');
}

/**
 * POST - Create/update vehicle (admin)
 */
function handleVehicle(PDO $pdo): void
{
    $input = getJsonInput();

    $id = (int)($input['id'] ?? 0);
    $spz = strtoupper(trim($input['spz'] ?? ''));
    $name = trim($input['name'] ?? '');
    $brand = trim($input['brand'] ?? '');
    $model = trim($input['model'] ?? '');
    $initialKm = (int)($input['initial_km'] ?? 0);
    $isActive = isset($input['is_active']) ? (int)$input['is_active'] : 1;

    if (!$spz) {
        errorResponse('SPZ je povinná');
    }
    if (!$name) {
        errorResponse('Název je povinný');
    }

    if ($id) {
        // Update
        $stmt = $pdo->prepare('
            UPDATE vehicles
            SET spz = ?, name = ?, brand = ?, model = ?, initial_km = ?, is_active = ?
            WHERE id = ?
        ');
        $stmt->execute([$spz, $name, $brand ?: null, $model ?: null, $initialKm, $isActive, $id]);

        AuditLog::logUpdate('vehicles', $id, [], $input, 'Upraveno vozidlo');
        successResponse(null, 'Vozidlo bylo aktualizováno');
    } else {
        // Create
        $stmt = $pdo->prepare('
            INSERT INTO vehicles (spz, name, brand, model, initial_km, is_active)
            VALUES (?, ?, ?, ?, ?, ?)
        ');

        try {
            $stmt->execute([$spz, $name, $brand ?: null, $model ?: null, $initialKm, $isActive]);
            $newId = (int)$pdo->lastInsertId();

            AuditLog::logCreate('vehicles', $newId, $input, 'Vytvořeno vozidlo');
            successResponse(['id' => $newId], 'Vozidlo bylo vytvořeno');
        } catch (PDOException $e) {
            if ($e->getCode() == 23000) {
                errorResponse('Vozidlo s touto SPZ již existuje');
            }
            throw $e;
        }
    }
}

// ============================================================================
// PUT Handler
// ============================================================================

/**
 * PUT - Update trip
 *
 * @param array<string, mixed> $authData
 */
function handleUpdateTrip(PDO $pdo, int $id, int $userId, array $authData): void
{
    $stmt = $pdo->prepare(
        'SELECT id, vehicle_id, user_id, trip_date, start_km, end_km,
                route_from, route_to, is_business, notes
        FROM trips WHERE id = ?'
    );
    $stmt->execute([$id]);
    $trip = $stmt->fetch();

    if (!$trip) {
        errorResponse('Záznam nebyl nalezen', 404);
    }

    // Check permission - own trips or trips.admin
    if ($trip['user_id'] !== $userId && !hasPermission($authData, 'trips.admin')) {
        errorResponse('Nemáte oprávnění upravit tento záznam', 403);
    }

    $input = getJsonInput();

    $vehicleId = (int)($input['vehicle_id'] ?? $trip['vehicle_id']);
    $tripDate = $input['trip_date'] ?? $trip['trip_date'];
    $startKm = (int)($input['start_km'] ?? $trip['start_km']);
    $endKm = (int)($input['end_km'] ?? $trip['end_km']);
    $routeFrom = trim($input['route_from'] ?? $trip['route_from']);
    $routeTo = trim($input['route_to'] ?? $trip['route_to']);
    $isBusiness = isset($input['is_business']) ? (int)$input['is_business'] : $trip['is_business'];
    $notes = trim($input['notes'] ?? $trip['notes'] ?? '');

    if ($endKm <= $startKm) {
        errorResponse('Konečný stav km musí být větší než počáteční');
    }

    $stmt = $pdo->prepare('
        UPDATE trips
        SET vehicle_id = ?, trip_date = ?, start_km = ?, end_km = ?,
            route_from = ?, route_to = ?, is_business = ?, notes = ?
        WHERE id = ?
    ');
    $stmt->execute([$vehicleId, $tripDate, $startKm, $endKm, $routeFrom, $routeTo, $isBusiness, $notes ?: null, $id]);

    AuditLog::logUpdate('trips', $id, $trip, $input, 'Upraven záznam jízdy');

    successResponse(null, 'Záznam byl aktualizován');
}

// ============================================================================
// DELETE Handlers
// ============================================================================

/**
 * DELETE - Delete trip
 *
 * @param array<string, mixed> $authData
 */
function handleDeleteTrip(PDO $pdo, int $id, int $userId, array $authData): void
{
    $stmt = $pdo->prepare(
        'SELECT id, vehicle_id, user_id, trip_date, start_km, end_km,
                route_from, route_to, is_business, notes
        FROM trips WHERE id = ?'
    );
    $stmt->execute([$id]);
    $trip = $stmt->fetch();

    if (!$trip) {
        errorResponse('Záznam nebyl nalezen', 404);
    }

    // Check permission - own trips or trips.admin
    if ($trip['user_id'] !== $userId && !hasPermission($authData, 'trips.admin')) {
        errorResponse('Nemáte oprávnění smazat tento záznam', 403);
    }

    $stmt = $pdo->prepare('DELETE FROM trips WHERE id = ?');
    $stmt->execute([$id]);

    AuditLog::logDelete('trips', $id, $trip, 'Smazán záznam jízdy');

    successResponse(null, 'Záznam byl smazán');
}

/**
 * DELETE - Delete vehicle (admin)
 */
function handleDeleteVehicle(PDO $pdo, int $id): void
{
    if (!$id) {
        errorResponse('ID je povinné');
    }

    $stmt = $pdo->prepare(
        'SELECT id, spz, name, brand, model, is_active FROM vehicles WHERE id = ?'
    );
    $stmt->execute([$id]);
    $vehicle = $stmt->fetch();

    if (!$vehicle) {
        errorResponse('Vozidlo nebylo nalezeno', 404);
    }

    // Check if vehicle has trips
    $stmt = $pdo->prepare('SELECT COUNT(*) FROM trips WHERE vehicle_id = ?');
    $stmt->execute([$id]);
    $tripCount = $stmt->fetchColumn();

    if ($tripCount > 0) {
        errorResponse(
            "Nelze smazat vozidlo s {$tripCount} záznamy jízd. Nejprve smažte záznamy jízd nebo deaktivujte vozidlo."
        );
    }

    $stmt = $pdo->prepare('DELETE FROM vehicles WHERE id = ?');
    $stmt->execute([$id]);

    AuditLog::logDelete('vehicles', $id, $vehicle, 'Smazáno vozidlo');

    successResponse(null, 'Vozidlo bylo smazáno');
}

// ============================================================================
// Print Handler
// ============================================================================

/**
 * Format date range for display
 */
function formatPeriodName(string $startDate, string $endDate): string
{
    $start = new DateTime($startDate);
    $end = new DateTime($endDate);

    // If same month
    if ($start->format('Y-m') === $end->format('Y-m')) {
        return getCzechMonthName((int)$start->format('n')) . ' ' . $start->format('Y');
    }

    // If same year
    if ($start->format('Y') === $end->format('Y')) {
        return $start->format('j.n.') . ' - ' . $end->format('j.n.Y');
    }

    // Different years
    return $start->format('j.n.Y') . ' - ' . $end->format('j.n.Y');
}

/**
 * GET - Print data for trips (admin)
 */
function handleGetPrint(PDO $pdo): void
{
    $dateFrom = $_GET['date_from'] ?? null;
    $dateTo = $_GET['date_to'] ?? null;
    $vehicleId = isset($_GET['vehicle_id']) && $_GET['vehicle_id'] !== '' ? (int)$_GET['vehicle_id'] : null;
    $filterUserId = isset($_GET['user_id']) && $_GET['user_id'] !== '' ? (int)$_GET['user_id'] : null;

    // Default to current month if no dates provided
    if (!$dateFrom || !$dateTo) {
        $startDate = date('Y-m-01');
        $endDate = date('Y-m-t');
    } else {
        if (!preg_match('/^\d{4}-\d{2}-\d{2}$/', $dateFrom) || !preg_match('/^\d{4}-\d{2}-\d{2}$/', $dateTo)) {
            errorResponse('Neplatný formát data (očekáváno YYYY-MM-DD)');
        }
        $startDate = $dateFrom;
        $endDate = $dateTo;
    }

    $sql = "
        SELECT t.id, t.vehicle_id, t.user_id, t.trip_date, t.start_km,
               t.end_km, t.distance, t.route_from, t.route_to,
               t.is_business, t.notes, t.created_at,
               v.spz, v.name as vehicle_name, v.brand, v.model,
               CONCAT(u.first_name, ' ', u.last_name) as driver_name
        FROM trips t
        JOIN vehicles v ON t.vehicle_id = v.id
        JOIN users u ON t.user_id = u.id
        WHERE t.trip_date BETWEEN ? AND ?
    ";
    $params = [$startDate, $endDate];

    if ($vehicleId) {
        $sql .= ' AND t.vehicle_id = ?';
        $params[] = $vehicleId;
    }

    if ($filterUserId) {
        $sql .= ' AND t.user_id = ?';
        $params[] = $filterUserId;
    }

    $sql .= ' ORDER BY t.trip_date ASC, t.start_km ASC';

    $stmt = $pdo->prepare($sql);
    $stmt->execute($params);
    $trips = $stmt->fetchAll();

    // Get vehicles for filter
    $stmt = $pdo->query('SELECT id, spz, name FROM vehicles ORDER BY name');
    $vehicles = $stmt->fetchAll();

    // Get users for filter
    $stmt = $pdo->query(
        "SELECT id, CONCAT(first_name, ' ', last_name) as name FROM users WHERE is_active = 1 ORDER BY last_name"
    );
    $users = $stmt->fetchAll();

    // Calculate totals
    $totalDistance = 0;
    $businessDistance = 0;
    $privateDistance = 0;

    foreach ($trips as $trip) {
        $totalDistance += $trip['distance'];
        if ($trip['is_business']) {
            $businessDistance += $trip['distance'];
        } else {
            $privateDistance += $trip['distance'];
        }
    }

    // Get selected vehicle/user names for header
    $selectedVehicleName = '';
    if ($vehicleId) {
        $stmt = $pdo->prepare("SELECT CONCAT(spz, ' - ', name) as name FROM vehicles WHERE id = ?");
        $stmt->execute([$vehicleId]);
        $v = $stmt->fetch();
        $selectedVehicleName = $v ? $v['name'] : '';
    }

    $selectedUserName = '';
    if ($filterUserId) {
        $stmt = $pdo->prepare("SELECT CONCAT(first_name, ' ', last_name) as name FROM users WHERE id = ?");
        $stmt->execute([$filterUserId]);
        $u = $stmt->fetch();
        $selectedUserName = $u ? $u['name'] : '';
    }

    successResponse([
        'trips' => $trips,
        'vehicles' => $vehicles,
        'users' => $users,
        'date_from' => $startDate,
        'date_to' => $endDate,
        'period_name' => formatPeriodName($startDate, $endDate),
        'selected_vehicle' => $vehicleId,
        'selected_vehicle_name' => $selectedVehicleName,
        'selected_user' => $filterUserId,
        'selected_user_name' => $selectedUserName,
        'totals' => [
            'total' => $totalDistance,
            'business' => $businessDistance,
            'private' => $privateDistance,
            'count' => count($trips),
        ],
    ]);
}