<?php
    $user = $_POST['username'];
    $password = $_POST['password'];
    $assignment = $_POST['assignment'];
    $question = $_POST['question'];

    $assignment_dir = "codes/Assignment-".$assignment;
    $user_dir = $assignment_dir."/".$user;
    $target_dir = $user_dir."/".$question."/";
    $uploadOk = 1;
    $target_file = $target_dir . basename($_FILES["code"]["name"]);
    $imageFileType = strtolower(pathinfo($target_file,PATHINFO_EXTENSION));
    
     $true = chk_user($user, $password);

     if(!$true) {
         die("Login Failed");
     }
	
    if(isset($_POST["submit"])) {

        // Check if assignment directory already exists
        if(!file_exists($assignment_dir)) {
            mkdir($assignment_dir, 0777);
        }

        if(!file_exists($user_dir)) {
            mkdir($user_dir, 0777);
        }

        // Check if target file already exists
        if (!file_exists($target_dir)) {
           mkdir($target_dir, 0777);
        }

        // Allow certain file formats
        if($imageFileType != "java") {
            echo "Sorry, only JAVA files are allowed.";
            $uploadOk = 0;
        }

        // Check if $uploadOk is set to 0 by an error
        if ($uploadOk == 0) {
            echo "Sorry, your file was not uploaded.";
        // if everything is ok, try to upload file
        } else {
            if (move_uploaded_file($_FILES["code"]["tmp_name"], $target_file)) {
                echo "The file ". basename( $_FILES["code"]["name"]). " has been uploaded.";
            } else {
                echo "Sorry, there was an error uploading your file.";
            }
        }
    }
    else {
        echo "POST request required";
    }

    function chk_user( $uid, $pwd ) {
        if ($pwd) {
            $ds = ldap_connect("172.31.1.42");
            ldap_set_option($ds, LDAP_OPT_PROTOCOL_VERSION, 3);
            $a = ldap_search($ds, "dc=iiita,dc=ac,dc=in", "uid=$uid" );
            $b = ldap_get_entries( $ds, $a );
            $dn = $b[0]["dn"];
            $ldapbind=@ldap_bind($ds, $dn, $pwd);
            if ($ldapbind) {
                return 1;
            } else {
                return 0;
            }
            ldap_close($ds);
        } else {
            return 0;
        }
    }    
?>