upload library

<?php

     // Validate uploaded image
        if ($gambar['error'] !== UPLOAD_ERR_OK) {
            echo "Error uploading image. Please try again.";
        } else {
            $file_name = $gambar['name'];
            $file_size = $gambar['size'];
            $file_tmp = $gambar['tmp_name'];
            $file_type = $gambar['type'];
    
            $allowed_extensions = array("image/jpeg", "image/jpg", "image/png", "image/gif");
            $max_file_size = 5 * 1024 * 1024; // 5MB
    
            if (!in_array($file_type, $allowed_extensions)) {
                echo "Invalid file type. Allowed types are JPG, JPEG, PNG, and GIF.";
            } elseif ($file_size > $max_file_size) {
                echo "File size is too large. Maximum file size is 5MB.";
            } else {
                // Generate a unique random file name
                $unique_filename = uniqid() . '_' . $file_name;
    
                // Move the uploaded image to a designated folder with the unique file name
                $upload_path = "img/";
                $destination = $upload_path . $unique_filename;
    
                if (move_uploaded_file($file_tmp, $destination)) {
                    // Insert the data into the database
                    $query = "INSERT INTO books (judul, gambar, kategori, isi) VALUES ('$judul', '$destination', '$kategori', '$isi')";
                    mysqli_query($conn, $query);
    
                    if (mysqli_affected_rows($conn) > 0) {
                        header("Location: index.php");
                    } else {
                        echo "Error inserting data into the database.";
                    }
                } else {
                    echo "Error moving the uploaded image.";
                }
            }
        }