<?php
include 'auth.php'; // Handles session, db, and permissions loading

if ($_SERVER['REQUEST_METHOD'] == 'POST') {
    // Check permissions first
    if (empty($_POST['id'])) {
        require_permission('cars_add');
    } else {
        require_permission('cars_edit');
    }

    // --- Get main car data ---
    $id = !empty($_POST['id']) ? (int)$_POST['id'] : null;
    $name = $_POST['name'];
    $brand = $_POST['brand'];
    $model = $_POST['model'];
    $year = $_POST['year'];
    $category = $_POST['category'];
    $description = $_POST['description'];
    $video_url = $_POST['video_url'] ?? '';

    // Start transaction to ensure atomic saving of car + trims
    $conn->begin_transaction();

    try {
        // --- Database Operation for Cars (Main) ---
        if (empty($id)) {
            // This is an INSERT operation
            $sql = "INSERT INTO cars (name, brand, model, year, category, description, video_url) VALUES (?, ?, ?, ?, ?, ?, ?)";
            $stmt = $conn->prepare($sql);
            $stmt->bind_param("sssisss", $name, $brand, $model, $year, $category, $description, $video_url);
        } else {
            // This is an UPDATE operation
            $sql = "UPDATE cars SET name=?, brand=?, model=?, year=?, category=?, description=?, video_url=? WHERE id=?";
            $stmt = $conn->prepare($sql);
            $stmt->bind_param("sssisssi", $name, $brand, $model, $year, $category, $description, $video_url, $id);
        }

        if (!$stmt->execute()) {
            throw new Exception("Error saving car: " . $stmt->error);
        }

        $car_id = empty($id) ? $conn->insert_id : $id;
        $stmt->close();

        // --- Handle Car Trims ---
        $posted_trim_ids = [];
        $pdf_dir = '../uploads/pdfs/';
        if (!is_dir($pdf_dir)) {
            mkdir($pdf_dir, 0777, true);
        }

        if (isset($_POST['trims']) && is_array($_POST['trims'])) {
            foreach ($_POST['trims'] as $index => $trim_data) {
                $trim_id = !empty($trim_data['id']) ? (int)$trim_data['id'] : null;
                $trim_name = $trim_data['name'];
                $trim_price = $trim_data['price'];
                $fuel_type = $trim_data['fuel_type'];
                $car_condition = $trim_data['car_condition'];
                
                $engine_capacity = $trim_data['engine_capacity'] ?? '';
                $transmission_type = $trim_data['transmission_type'] ?? '';
                $horsepower = !empty($trim_data['horsepower']) ? (int)$trim_data['horsepower'] : 0;
                $torque = $trim_data['torque'] ?? '';
                $acceleration = $trim_data['acceleration'] ?? '';
                $top_speed = $trim_data['top_speed'] ?? '';
                $fuel_consumption = $trim_data['fuel_consumption'] ?? '';
                $drivetrain = $trim_data['drivetrain'] ?? '';
                $seating_capacity = !empty($trim_data['seating_capacity']) ? (int)$trim_data['seating_capacity'] : 0;
                $body_type = $trim_data['body_type'] ?? '';
                $exterior_color = $trim_data['exterior_color'] ?? '';
                $interior_color = $trim_data['interior_color'] ?? '';
                
                // Handle Trim PDF
                $existing_pdf = $trim_data['tech_specs_pdf_existing'] ?? '';
                $pdf_name = $existing_pdf;

                // Check for remove PDF request
                if (isset($trim_data['remove_pdf']) && $trim_data['remove_pdf'] == '1' && !empty($existing_pdf)) {
                    if (file_exists($pdf_dir . $existing_pdf)) {
                        unlink($pdf_dir . $existing_pdf);
                    }
                    $pdf_name = null;
                }

                // Check for new PDF file upload
                $file_input_name = 'tech_specs_pdf_' . $index;
                if (isset($_FILES[$file_input_name]) && $_FILES[$file_input_name]['error'] == 0) {
                    // Delete old PDF if exists
                    if (!empty($existing_pdf) && file_exists($pdf_dir . $existing_pdf)) {
                        unlink($pdf_dir . $existing_pdf);
                    }
                    
                    // Generate unique file name
                    $pdf_name = uniqid() . '-' . basename($_FILES[$file_input_name]['name']);
                    if (!move_uploaded_file($_FILES[$file_input_name]['tmp_name'], $pdf_dir . $pdf_name)) {
                        throw new Exception("Failed to upload PDF for trim: " . $trim_name);
                    }
                }

                if (empty($trim_id)) {
                    // Insert new trim
                    $trim_sql = "INSERT INTO car_trims (
                        car_id, name, price, fuel_type, car_condition, 
                        engine_capacity, transmission_type, horsepower, torque, 
                        acceleration, top_speed, fuel_consumption, drivetrain, 
                        seating_capacity, body_type, exterior_color, interior_color, tech_specs_pdf
                    ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)";
                    
                    $trim_stmt = $conn->prepare($trim_sql);
                    $trim_stmt->bind_param("isdsssssssssisssss", 
                        $car_id, $trim_name, $trim_price, $fuel_type, $car_condition,
                        $engine_capacity, $transmission_type, $horsepower, $torque,
                        $acceleration, $top_speed, $fuel_consumption, $drivetrain,
                        $seating_capacity, $body_type, $exterior_color, $interior_color, $pdf_name
                    );
                } else {
                    // Update existing trim
                    $trim_sql = "UPDATE car_trims SET 
                        name=?, price=?, fuel_type=?, car_condition=?, 
                        engine_capacity=?, transmission_type=?, horsepower=?, torque=?, 
                        acceleration=?, top_speed=?, fuel_consumption=?, drivetrain=?, 
                        seating_capacity=?, body_type=?, exterior_color=?, interior_color=?, tech_specs_pdf=? 
                        WHERE id=? AND car_id=?";
                    
                    $trim_stmt = $conn->prepare($trim_sql);
                    $trim_stmt->bind_param("sdsssssssssisssssii", 
                        $trim_name, $trim_price, $fuel_type, $car_condition,
                        $engine_capacity, $transmission_type, $horsepower, $torque,
                        $acceleration, $top_speed, $fuel_consumption, $drivetrain,
                        $seating_capacity, $body_type, $exterior_color, $interior_color, $pdf_name,
                        $trim_id, $car_id
                    );
                    $posted_trim_ids[] = $trim_id;
                }

                if (!$trim_stmt->execute()) {
                    throw new Exception("Error saving trim: " . $trim_stmt->error);
                }
                
                if (empty($trim_id)) {
                    $posted_trim_ids[] = $trim_stmt->insert_id;
                }
                $trim_stmt->close();
            }
        }

        // --- Delete removed trims from DB ---
        if (!empty($id)) {
            // Fetch all current trims in database
            $db_trims_query = $conn->prepare("SELECT id, tech_specs_pdf FROM car_trims WHERE car_id = ?");
            $db_trims_query->bind_param("i", $id);
            $db_trims_query->execute();
            $db_trims_res = $db_trims_query->get_result();
            
            while ($db_trim = $db_trims_res->fetch_assoc()) {
                if (!in_array($db_trim['id'], $posted_trim_ids)) {
                    // This trim was deleted from UI, remove its PDF first if exists
                    if (!empty($db_trim['tech_specs_pdf']) && file_exists($pdf_dir . $db_trim['tech_specs_pdf'])) {
                        unlink($pdf_dir . $db_trim['tech_specs_pdf']);
                    }
                    
                    // Delete the record
                    $delete_stmt = $conn->prepare("DELETE FROM car_trims WHERE id = ?");
                    $delete_stmt->bind_param("i", $db_trim['id']);
                    $delete_stmt->execute();
                    $delete_stmt->close();
                }
            }
            $db_trims_query->close();
        }

        // --- Handle Multiple Images Upload ---
        if (isset($_FILES['car_images']) && !empty($_FILES['car_images']['name'][0])) {
            $upload_dir = '../uploads/cars/';
            
            $existing_images_count = 0;
            $count_stmt = $conn->prepare("SELECT COUNT(*) as count FROM car_images WHERE car_id = ?");
            $count_stmt->bind_param("i", $car_id);
            $count_stmt->execute();
            $count_result = $count_stmt->get_result();
            $existing_images_count = $count_result->fetch_assoc()['count'];
            $count_stmt->close();
            
            for ($i = 0; $i < count($_FILES['car_images']['name']); $i++) {
                if ($_FILES['car_images']['error'][$i] == 0) {
                    $unique_filename = uniqid() . '-' . basename($_FILES['car_images']['name'][$i]);
                    $target_file = $upload_dir . $unique_filename;
                    
                    if (move_uploaded_file($_FILES['car_images']['tmp_name'][$i], $target_file)) {
                        $is_primary = ($existing_images_count == 0 && $i == 0) ? 1 : 0;
                        $sort_order = $existing_images_count + $i + 1;
                        
                        $img_stmt = $conn->prepare("INSERT INTO car_images (car_id, image_name, is_primary, sort_order) VALUES (?, ?, ?, ?)");
                        $img_stmt->bind_param("isii", $car_id, $unique_filename, $is_primary, $sort_order);
                        $img_stmt->execute();
                        $img_stmt->close();
                    }
                }
            }
        }

        // Commit transaction
        $conn->commit();
        header("Location: cars.php?success=تم حفظ السيارة والفئات بنجاح");

    } catch (Exception $e) {
        // Rollback transaction on error
        $conn->rollback();
        header("Location: cars.php?error=حدث خطأ أثناء حفظ البيانات: " . $e->getMessage());
    }

    $conn->close();

} else {
    header("Location: cars.php");
    exit();
}
?>