Minta Bantuannya Mas Gan..(fungsi Delete dan Unlink)

// File Add_produk.php
<?php
include 'koneksi.php';
if(cek_login($mysqli) == false){ // Jika user tidak login
    header('location: login.php'); // Alihkan ke halaman login (index.php)
    exit();
}

$stmt = $mysqli->prepare("SELECT username FROM user WHERE id = ?");
$stmt->bind_param('i', $_SESSION['id']);
$stmt->execute();
$stmt->store_result();
$stmt->bind_result($username);
$stmt->fetch();
?>
<?php
                                if (isset($_POST["simpan"])){
                                $dir = "upload/";
                                $lok_file = $_FILES['foto']['tmp_name'];
                                $nama_file = $_FILES['foto']['name'];
                                $ekstensi = pathinfo( $nama_file, PATHINFO_EXTENSION );

                                $accept = array('jpg','jpeg','png');

                                if ( in_array( $ekstensi, $accept ) ) {
                                $nama_file_modif = "foto-". date('d-m-Y') ."-" . time() . "." . $ekstensi;
                                $dir_up = $dir .$nama_file_modif;

                                move_uploaded_file($lok_file, $dir_up);
                                $mysqli->query("INSERT INTO produk VALUES('','$_POST[kode_produk]','$_POST[namabarang]','$_POST[harga]','$_POST[deskripsi]','$nama_file_modif','$time()')");
                                            echo '<div class="alert alert-success">Produk telah di postingkan.</div>';
                                            echo "<script>setTimeout(\"location.href='home_admin.php';\",1000);</script>";

                                            } else {
                                            echo "<p class='alert-error'><b>Gagal...!</b> Pastikan file yang anda upload bertipe jpg/jpeg atau png.</p>
                                            <script>setTimeout(\"self.history.back();\",3000);</script>";
                                            }
                                    }
                                ?>
<div class="row">
    <div class="col-md- column">
                <form method="post" class="form-horizontal" action='' enctype="multipart/form-data">
                                <fieldset>

                                <!-- Form Name -->

                                <!-- Text input-->
                                <div class="form-group">
                                  <label class="col-md-3 control-label" for="Kode Produk">Kode Barang</label>
                                  <div class="col-md-8">
                                  <input id="Kode Produk" name="kode_produk" placeholder="Kode Produk" class="form-control input-md" type="text">

                                  </div>
                                </div>

                                <!-- Text input-->
                                <div class="form-group">
                                  <label class="col-md-3 control-label" for="namabarang">Nama Produk</label>
                                  <div class="col-md-8">
                                  <input id="namabarang" name="namabarang" placeholder="Nama Produk" class="form-control input-md" type="text">

                                  </div>
                                </div>

                                <!-- Prepended text-->
                                <div class="form-group">
                                  <label class="col-md-3 control-label" for="harga">Harga</label>
                                  <div class="col-md-8">
                                    <div class="input-group">
                                      <span class="input-group-addon">Rp.</span>
                                      <input id="harga" name="harga" class="form-control" placeholder="" type="text">
                                    </div>

                                  </div>
                                </div>

                                <!-- Textarea -->
                                <div class="form-group">
                                  <label class="col-md-3 control-label" for="deskripsi">Deskirpsi</label>
                                  <div class="col-md-8">
                                    <script type="text/javascript" src="tinymce/tinymce.min.js"></script>
                                    <script type="text/javascript">
                                        tinymce.init({
                                        selector: "textarea"
                                        });
                                    </script>
                                    <textarea class="form-control" id="deskripsi" name="deskripsi"></textarea>
                                  </div>
                                </div>

                                <!-- File Button -->
                                <div class="form-group">
                                  <label class="col-md-3 control-label" for="gambar">Pilih Gambar</label>
                                  <div class="col-md-8">
                                    <script type="text/javascript" src="js/bootstrap-filestyle.js"></script>
                                    <input type="file" name="foto" class="filestyle" data-buttonName="btn-danger">
                                    <script type="text/javascript" charset="utf-8">
                                          $(":file").filestyle({buttonName: "btn-danger"});
                                      </script>

                                  </div>
                                </div>

                                <!-- Button (Double) -->
                                <div class="form-group">
                                  <label class="col-md-4 control-label" for="simpan"></label>
                                  <div class="col-md-4">
                                    <button id="simpan" type="submit"name="simpan" class="btn btn-primary">Posting</button>
                                    <button id="Batal" name="Batal" class="btn btn-danger">Cancel</button>
                                  </div>
                                </div>
                                </fieldset>
                                </form>

            </div>
</div>

// sintak Delete.php

<?php
include 'koneksi.php';
    $del = $mysqli->query("DELETE FROM produk where id='$_GET[id]'");

    if(isset($_GET['foto'])){
    $idfoto=$_GET['foto'];
    $file="upload/".$idfoto;
    unlink("$idfoto");
    header( 'Location:home_admin.php' ) ;

    }

?>