<?php
require('../config.php');
if(isset($_POST['editr'])){
    $dbc=db_connect();
    $name=check($_POST['name']);
    $id_subject=(int)$_POST['id_subject'];
    if(!empty($_POST['teacher'])){
        $teachers=$_POST['teacher'];
    } else {
        $teachers=array();
    }
    var_dump($teachers);
    $query="SELECT id_teacher FROM yu_teacher_subject WHERE id_subject='$id_subject'";
    $result=mysqli_query($dbc, $query) or die(mysqli_error($dbc));
    $data=array();
    while($row=getRow($result)){
        if(!in_array($row['id_teacher'],$teachers)){
            $query="DELETE FROM yu_teacher_subject WHERE id_subject='$id_subject' AND id_teacher='$row[id_teacher]'";
            $result=mysqli_query($dbc, $query) or die(mysqli_error($dbc));
        }
        $data[]=$row['id_teacher'];
    }
    var_dump($teachers);
    foreach ($teachers as $key => $teacher_id) {
        if(!in_array($teacher_id, $data)){
            $query="INSERT INTO yu_teacher_subject (id_subject, id_teacher) VALUES ('$id_subject', '$teacher_id')";
            $result=mysqli_query($dbc, $query) or die(mysqli_error($dbc));
        }
    }
    $query="SELECT name FROM yu_subject WHERE id_subject='$id_subject'";
    $result=mysqli_query($dbc, $query) or die(mysqli_error($dbc));
    $row=getRow($result);
    if($row['name']!=$name){
        $query="UPDATE yu_subject SET name='$name' WHERE id_subject='$id_subject'";
        $result=mysqli_query($dbc, $query) or die(mysqli_error($dbc));
    }
   // Location('/admin/page/subjects.php');
}
$id_subject=(int)$_GET['id'];
/*Выборка преподавателей*/
    $dbc=db_connect();
    //Выбрали предмет
    $query="SELECT id_subject, name FROM yu_subject WHERE id_subject='$id_subject'";
    $subject=mysqli_query($dbc, $query) or die(mysqli_error($dbc));
    $subject=getRow($subject);
    //если предмет ведут многие преподавателей получим такой список
    $query="SELECT id_teacher FROM yu_teacher_subject WHERE id_subject='$id_subject'";
    $result=mysqli_query($dbc, $query) or die(mysqli_error($dbc));
    while($row=getRow($result)) $teacher_subject[]=$row['id_teacher'];
    if(empty($teacher_subject)){
        $teacher_subject=array();
    }
    //возьмем всех преподавателей
    $query="SELECT id_teacher, name FROM yu_teacher WHERE status=1";
    $teachers=mysqli_query($dbc, $query) or die(mysqli_error($dbc));
require('../view/header.php');
?>
<div class="add">
    <form method="POST" action="<?php echo $_SERVER['PHP_SELF']; ?>">
        <span class="head-subjects">Название предмета:</span>
        <input type="text" name="name" placeholder="Название предмета
        " value="<?php echo $subject['name'];?>" required>
        <span class="head-subjects">Преподаватели:</span>
        <div class="form-subjects">
            <?php
            while($teacher=getRow($teachers)){
                if(in_array($teacher['id_teacher'],$teacher_subject)){
                    echo '<label><input type="checkbox" name="teacher[]" value="'.$teacher['id_teacher'].'" checked>'.$teacher['name'].'</label><br>';
                } else {
                    echo '<label><input type="checkbox" name="teacher[]" value="'.$teacher['id_teacher'].'">'.$teacher['name'].'</label><br>';
                }
            }
             ?>
        </div>
        <input type="hidden" name="id_subject" value="<?php echo $subject['id_subject']; ?>">
        <input type="submit" name="editr" value="Сохранить">
    </form>
</div>
<?php
require('../view/footer.php');
?>