<?php
$name_from_form=$lastname_from_form=$username_from_form=$password_from_form=$rpassword_from_form=$email_from_form=$am_from_form=$semester_from_form=$telephone_from_form="";

$no_error=true;
Validations();

if($no_error==true){
    $con = mysqli_connect('localhost','root');
    if (!$con) {
    die('Could not connect ERROR: ' . mysqli_error());
    }
else{
        insertStudent();
    }
}



function Validations(){
    nameValid();
    lastnameValid();
    passwordValid();
    rpasswordValid();
    semesterValid();
    amValid();
    telephoneValid();
    emailValid();
}

function test_input($data) {
  $data = trim($data);
  $data = stripslashes($data);
  $data = htmlspecialchars($data);
  return $data;
}

function nameValid(){
    if (empty($_POST["name"])) {
    echo"Name field is empty";echo "<br>";
    $no_error=false;
  } else {
    $name_from_form = test_input($_POST["name"]);
    $name_length=strlen($name_from_form);
    if (!preg_match("/^[a-zA-Z ]*$/",$name_from_form)) {
      echo"Name Error";echo "<br>";
      $no_error=false;
    }
    if($name_length>25 || $name_length<5){
        echo"Name length error";
        $no_error=false;
    }
  }
}
function lastnameValid(){
    if (empty($_POST["lastname"])) {
    echo"Lastname field is empty";echo "<br>";
    $no_error=false;
  } else {
    $lastname_from_form = test_input($_POST["lastname"]);
    $lastname_length=strlen($lastname_from_form);
    if (!preg_match("/^[a-zA-Z ]*$/",$lastname_from_form)) {
      echo"Lastname Error";echo "<br>";
      $no_error=false;
    }
    if($lastname_length>25 || $lastname_length<5){
        echo"Lastname length error";
        $no_error=false;
    }
  }
}
function usernameValid(){
    if (empty($_POST["username"])) {
    echo"Username field is empty";echo "<br>";
    $no_error=false;
  } else {
    $username_from_form = test_input($_POST["username"]);
    $username_length=$strlen($username_from_form);
    if (!preg_match("/^[a-zA-Z ]*$/",$username_from_form)) {
      echo"Username Error";echo "<br>";
      $no_error=false;
    }
    if($username_length>25 || $username_length<8){
        echo"Username length error";
        $no_error=false;
    }
  }
}

function passwordValid(){
    if (empty($_POST["password"])) {
    echo"Password field is empty";echo "<br>";
    $no_error=false;
  } else {
    $password_from_form = test_input($_POST["password"]);
    $pass_length=strlen($password_from_form);
    if ($pass_length>15 || $pass_length<8) {
      echo"Password length error";echo "<br>";
      $no_error=false;
    }
  }
}
function semesterValid(){
    if (empty($_POST["semester"])) {
    echo"Semester field is empty";echo "<br>";
    $no_error=false;
  } else {
    $semester_from_form = test_input($_POST["semester"]);
    $semester_length=strlen($semester_from_form);
    if (!preg_match("/^[0-9]+$/",$semester_from_form)) {
      echo"Semester Error";echo "<br>";
      $no_error=false;
    }
    if ($semester_length>2) {
      echo"Semester length error";echo "<br>";
      $no_error=false;
    }
  }
}
function amValid(){
    if (empty($_POST["am"])) {
    echo"ΑΜ field is empty";echo "<br>";
    $no_error=false;
  } else {
    $am_from_form = test_input($_POST["am"]);
    $am_length=strlen($am_from_form);
    if ($am_length>10) {
      echo"AM length error";echo "<br>";
      $no_error=false;
    }
  }
}
function telephoneValid(){
    if (empty($_POST["telephone"])) {
    echo"Telephone field is empty";echo "<br>";
    $no_error=false;
  } else {
    $telephone_from_form = test_input($_POST["telephone"]);
    $telephone_length=strlen($telephone_from_form);
    if ($telephone_length<10 || $telephone_length>15) {
      echo"Telephone length error";echo "<br>";
      $no_error=false;
    }
  }
}
function rpasswordValid(){
    if (empty($_POST["rpassword"])) {
    echo"Confirm password field is empty";echo "<br>";
    $no_error=false;
  } else {
    $rpassword_from_form = test_input($_POST["rpassword"]);
    $pass=test_input($_POST["password"]);
    if (strcmp($rpassword_from_form,$pass) !=0) {
        echo"Confirm password does not match the password";echo "<br>";
        $no_error=false;
    }
  }
}
function emailValid(){
    if (empty($_POST["email"])) {
    echo"Email field is empty";echo "<br>";
    $no_error=false;
  } else {
    $email_from_form = test_input($_POST["email"]);
    if (!filter_var($email_from_form, FILTER_VALIDATE_EMAIL)) {
      echo"Invalid mail";echo "<br>";
      $no_error=false;
    }
  }
}
function insertStudent(){
        $name_from_form = test_input($_POST["name"]);
        $lastname_from_form = test_input($_POST["lastname"]);
        $username_from_form = test_input($_POST["username"]);
        $password_from_form = test_input($_POST["password"]);
        $semester_from_form = test_input($_POST["semester"]);
        $am_from_form = test_input($_POST["am"]);
        $telephone_from_form = test_input($_POST["telephone"]);
        $email_from_form = test_input($_POST["email"]);
        $shauser = sha1($username_from_form);
        $shapass =  sha1($password_from_form);
        $con = mysqli_connect('localhost','root');
        mysqli_select_db($con,"education");
        $insert_query="INSERT INTO STUDENT (username,password,am,name,surname,semester,telephone,email)VALUES
                  ('$shauser','$shapass','$am_from_form','$name_from_form','$lastname_from_form','$semester_from_form','$telephone_from_form','$email_from_form')";
                    if (mysqli_query($con, $insert_query)) {
        echo "New record created successfully";
}       else {
        echo "Error: " . $insert_query . "<br>" . mysqli_error($con);
}
                    mysqli_close($con);

}

?>