<?php
// Function to fetch company settings from DB
function get_company_settings() {
    static $settings = null;
    if ($settings === null) {
        try {
            if (function_exists('db')) {
                $pdo = db();
                $stmt = $pdo->query("SELECT * FROM company_settings LIMIT 1");
                $settings = $stmt->fetch(PDO::FETCH_ASSOC);
            }
        } catch (Exception $e) {
            // Log error or ignore if table doesn't exist yet
        }
        
        // Default values if no settings found
        if (!$settings) {
            $settings = [
                'company_name' => 'My Restaurant',
                'address' => '123 Food Street',
                'phone' => '555-0199',
                'email' => 'info@restaurant.com',
                'vat_rate' => 0.00,
                'currency_symbol' => '$',
                'currency_decimals' => 2
            ];
        }
    }
    return $settings;
}

// Function to format currency using settings
function format_currency($amount) {
    $settings = get_company_settings();
    return $settings['currency_symbol'] . number_format((float)$amount, (int)$settings['currency_decimals']);
}

/**
 * Calculate the current price of a product considering promotions.
 * 
 * @param array|object $product The product data from DB.
 * @return float The effective price.
 */
function get_product_price($product) {
    $product = (array)$product;
    $price = (float)$product['price'];
    
    $today = date('Y-m-d');
    $promo_active = !empty($product['promo_discount_percent']) && 
                   !empty($product['promo_date_from']) && 
                   !empty($product['promo_date_to']) && 
                   $today >= $product['promo_date_from'] && 
                   $today <= $product['promo_date_to'];
                   
    if ($promo_active) {
        $discount = (float)$product['promo_discount_percent'];
        $price = $price * (1 - ($discount / 100));
    }
    
    return $price;
}

/**
 * Paginate a query result.
 * 
 * @param PDO $pdo The PDO connection object.
 * @param string $query The base SQL query (without LIMIT/OFFSET).
 * @param array $params Query parameters.
 * @param int $default_limit Default items per page.
 * @return array Pagination result with keys: data, total_rows, total_pages, current_page, limit.
 */
function paginate_query($pdo, $query, $params = [], $default_limit = 20) {
    // Get current page
    $page = isset($_GET['page']) && is_numeric($_GET['page']) ? (int)$_GET['page'] : 1;
    if ($page < 1) $page = 1;

    // Get limit (allow 20, 50, 100, or -1 for all)
    $limit = isset($_GET['limit']) ? (int)$_GET['limit'] : $default_limit;
    // Validate limit, default to 20 if not standard, allow custom if needed but standardizing is safer
    if ($limit != -1 && !in_array($limit, [20, 50, 100])) {
         $limit = $default_limit; 
    }
    
    // If limit is -1, fetch all
    if ($limit == -1) {
         $stmt = $pdo->prepare($query);
         $stmt->execute($params);
         $data = $stmt->fetchAll();
         return [
             'data' => $data,
             'total_rows' => count($data),
             'total_pages' => 1,
             'current_page' => 1,
             'limit' => -1
         ];
    }

    // Count total rows using a subquery to handle complex queries safely
    $count_sql = "SELECT COUNT(*) FROM ($query) as count_table";
    $stmt = $pdo->prepare($count_sql);
    $stmt->execute($params);
    $total_rows = $stmt->fetchColumn();
    
    $total_pages = ceil($total_rows / $limit);
    if ($page > $total_pages && $total_pages > 0) $page = $total_pages;
    
    // Calculate offset
    $offset = ($page - 1) * $limit;
    if ($offset < 0) $offset = 0;
    
    // Add LIMIT and OFFSET
    // Note: PDO parameters for LIMIT/OFFSET can be tricky with some drivers, sticking to direct injection for integers is safe here
    $query_with_limit = $query . " LIMIT " . (int)$limit . " OFFSET " . (int)$offset;
    
    $stmt = $pdo->prepare($query_with_limit);
    $stmt->execute($params);
    $data = $stmt->fetchAll();

    return [
        'data' => $data,
        'total_rows' => $total_rows,
        'total_pages' => $total_pages,
        'current_page' => $page,
        'limit' => $limit
    ];
}

/**
 * Render pagination controls and limit selector.
 * 
 * @param array $pagination The result array from paginate_query.
 * @param array $extra_params Additional GET parameters to preserve.
 */
function render_pagination_controls($pagination, $extra_params = []) {
    $page = $pagination['current_page'];
    $total_pages = $pagination['total_pages'];
    $limit = $pagination['limit'];
    
    // Build query string for limit change
    $params = array_merge($_GET, $extra_params);
    unset($params['page']); // Reset page when limit changes
    
    // Limit Selector
    $limits = [20, 50, 100, -1];
    echo '<div class="d-flex justify-content-between align-items-center mb-0 bg-white p-2 rounded flex-wrap gap-2">';
    
    echo '<div class="d-flex align-items-center flex-wrap gap-3">';
    echo '<form method="GET" class="d-flex align-items-center mb-0">';
    // Preserve other GET params
    foreach ($params as $key => $val) {
        if ($key !== 'limit') echo '<input type="hidden" name="'.htmlspecialchars((string)$key).'" value="'.htmlspecialchars((string)$val).'">';
    }
    echo '<small class="me-2 text-muted fw-bold">SHOW:</small>';
    echo '<select name="limit" class="form-select form-select-sm" style="width: auto;" onchange="this.form.submit()">';
    foreach ($limits as $l) {
        $label = $l == -1 ? 'All' : $l;
        $selected = $limit == $l ? 'selected' : '';
        echo "<option value='$l' $selected>$label</option>";
    }
    echo '</select>';
    echo '</form>';
    
    // Total Count
    echo '<span class="text-muted small border-start ps-3">Total: <strong>' . $pagination['total_rows'] . '</strong> items</span>';
    
    // Optional Total Amount (Sum)
    if (isset($pagination['total_amount_sum'])) {
        echo '<span class="text-success small border-start ps-3">Total Sum: <strong class="fs-5">' . format_currency($pagination['total_amount_sum']) . '</strong></span>';
    }

    if ($total_pages > 0) {
        echo '<span class="text-muted small border-start ps-3">Page <strong>' . $page . '</strong> of <strong>' . $total_pages . '</strong></span>';
    }
    echo '</div>';
    
    // Pagination Links
    if ($total_pages > 1) {
        echo '<nav aria-label="Page navigation">';
        echo '<ul class="pagination pagination-sm mb-0">';
        
        // Previous
        $prev_disabled = $page <= 1 ? 'disabled' : '';
        $prev_page = max(1, $page - 1);
        $url_params = array_merge($params, ['page' => $prev_page, 'limit' => $limit]);
        $prev_url = '?' . http_build_query($url_params);
        echo "<li class='page-item $prev_disabled'><a class='page-link' href='$prev_url' aria-label='Previous'><span aria-hidden='true'>&laquo;</span></a></li>";
        
        // Logic to show limited page numbers with ellipsis
        $shown_pages = [];
        $shown_pages[] = 1;
        $shown_pages[] = $total_pages;
        for ($i = $page - 3; $i <= $page + 3; $i++) {
            if ($i > 1 && $i < $total_pages) {
                $shown_pages[] = $i;
            }
        }
        sort($shown_pages);
        $shown_pages = array_unique($shown_pages);
        
        $prev_p = 0;
        foreach ($shown_pages as $p) {
            if ($prev_p > 0 && $p > $prev_p + 1) {
                echo "<li class='page-item disabled'><span class='page-link'>...</span></li>";
            }
            
            $active = $p == $page ? 'active' : '';
            $url_params = array_merge($params, ['page' => $p, 'limit' => $limit]);
            $url = '?' . http_build_query($url_params);
            echo "<li class='page-item $active'><a class='page-link' href='$url'>$p</a></li>";
            $prev_p = $p;
        }
        
        // Next
        $next_disabled = $page >= $total_pages ? 'disabled' : '';
        $next_page = min($total_pages, $page + 1);
        $url_params = array_merge($params, ['page' => $next_page, 'limit' => $limit]);
        $next_url = '?' . http_build_query($url_params);
        echo "<li class='page-item $next_disabled'><a class='page-link' href='$next_url' aria-label='Next'><span aria-hidden='true'>&raquo;</span></a></li>";
        
        echo '</ul></nav>';
    }
    echo '</div>';
}

/**
 * Auth functions
 */

function init_session() {
    if (session_status() === PHP_SESSION_NONE) {
        session_start();
    }
}

function login_user($username, $password) {
    $pdo = db();
    $stmt = $pdo->prepare("SELECT u.*, g.name as group_name, g.permissions 
                          FROM users u 
                          LEFT JOIN user_groups g ON u.group_id = g.id 
                          WHERE u.username = ? AND u.is_active = 1 
                          LIMIT 1");
    $stmt->execute([username]);
    $user = $stmt->fetch(PDO::FETCH_ASSOC);

    if ($user && password_verify($password, $user['password'])) {
        init_session();
        unset($user['password']); // Don't store hash in session
        $_SESSION['user'] = $user;
        return true;
    }
    return false;
}

function logout_user() {
    init_session();
    unset($_SESSION['user']);
    session_destroy();
}

function get_logged_user() {
    init_session();
    return $_SESSION['user'] ?? null;
}

function require_login() {
    if (!get_logged_user()) {
        header('Location: ' . url('login.php'));
        exit;
    }
}

function has_permission($permission) {
    $user = get_logged_user();
    if (!$user) return false;
    
    $userPermissions = $user['permissions'] ?? '';
    // Global bypass for super admins
    if ($userPermissions === 'all') return true;
    
    $perms = explode(',', $userPermissions);
    return in_array($permission, $perms);
}

function require_permission($permission) {
    require_login();
    if (!has_permission($permission)) {
        http_response_code(403);
        echo "Access Denied: You don't have permission to access this page.";
        exit;
    }
}

/**
 * Get the base path of the application.
 */
function get_base_path() {
    static $base_path = null;
    if ($base_path === null) {
        $script_dir = dirname($_SERVER['SCRIPT_NAME'] ?? '');
        // Replace known subfolders at the end of the path
        $base_path = preg_replace('/(\/admin|\/api|\/includes)$|(\/admin\/.*|\/api\/.*|\/includes\/.*)$/', '', $script_dir);
        if ($base_path === DIRECTORY_SEPARATOR || $base_path === '/') {
            $base_path = '';
        }
    }
    return $base_path;
}

/**
 * Generate a URL relative to the application base.
 */
function url($path = '') {
    $path = ltrim($path, '/');
    return get_base_path() . '/' . $path;
}

/**
 * Get the full base URL including domain and protocol.
 */
function get_base_url() {
    $protocol = (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off' || ($_SERVER['SERVER_PORT'] ?? '') == 443) ? "https://" : "http://";
    $domainName = $_SERVER['HTTP_HOST'] ?? 'localhost';
    
    return $protocol . $domainName . url();
}