<?php
$carName = $_POST['carName'];
$carDesc = $_POST['carDesc'];
/*使用$_FILES方法获取到图片相关的二维数组$_FILES['carPic'] 
 Array ( [name] => x1.jpeg [type] => image/jpeg [tmp_name] => C:\Windows\php79E.tmp [error] => 0 [size] => 8967 ) 错误中有超过文件大小限制，
 在百度搜索可以 解决 php.ini在小皮的设置里可以找到*/
$carPic = $_FILES['carPic'];
$fileName = "";
// print_r($carPic);
//第一步：判断图片上传是否有误
$id = $_POST['id'];
if($carPic['error']>0 && $carPic['error']!=4 ){
    echo "<script>alert('图片上传错误');history.back();</script>";
    exit;
}
//第二步：判断文件格式大小是否正确
//先判断文件大小是否大于2MB size给的是字节
if($carPic['size'] > 2*1024*1024 ) {
    echo "<script>alert('图片大小不能超过2MB');history.back();</script>";
    exit;
}
if (!empty($carPic['name'])) {
    //判断文件类型是否正确
    //使用$_FILES中的type
    $allowType = array('image/gif', 'image/jpeg', 'image/jpg', 'image/pjpeg', 'image/png');
    if (!in_array($carPic['type'], $allowType)) {
        //说明不存在指定类型
        echo "<script>alert('图片类型错误，只能是jpg、png、gif图片。');history.back();</script>";
        exit;
    }
    //使用$_FILES中的name判断
    $allowExt = array('gif', 'jpeg', 'jpg', 'pjpeg', 'png');
    $nameArray = explode('.', $carPic['name']);
    $nameExt = strtolower(end($nameArray));
    if (!in_array($nameExt, $allowExt)) {
        //说明不存在指定类型
        echo "<script>alert('图片类型错误，只能是jpg、png、gif图片。');history.back();</script>";
        exit;
    }
    //采用uniqid函数生成唯一不重复的名称并且和拓展名链接
    $fileName = uniqid() . "." . $nameExt;
    //将缓存区图片移动到指定的文件夹 
    $result = move_uploaded_file($carPic['tmp_name'], "img/" . $fileName);
    if (!$result) {
        //上传不成功
        echo "<script>alert('图片保存失败');history.back();</script>";
        exit;
    }
}

//第三步 写入数据库
include_once 'conn.php';
if($fileName){
    //filename存在，说明上传了图片
    $sql = "UPDATE carinfo set carName = '$carName',carDesc = '$carDesc',carPic ='$fileName' where id = '$id' " ;
}else{
    $sql = "UPDATE carinfo set carName = '$carName',carDesc = '$carDesc' where id = '$id' " ;
}
$result = mysqli_query($conn,$sql);
if($result){
    echo "<script>alert('车辆资料修改成功');location.href='admin.php';</script>";
} else {
    echo "<script>alert('车辆资料修改失败');history.back();</script>";
} 
?>