<?php
    $con =	mysqli_connect("localhost", "mpampis", "abcd1234", "quiz");


    $firstname = $_POST["firstname"];
    $lastname = $_POST["lastname"];
    $age = $_POST["age"];
    $username = $_POST["username"];
    $password = $_POST["password"];
	$email = $_POST["email"];
    $response = array();
	$response["success"] = "false";

	function username_available(){
		global $con,$username;
		$sqla = "SELECT * FROM users WHERE username = '".$username."';";
		$result = mysqli_query($con, $sqla);
		if(mysqli_num_rows($result) >= 1)
		{
			return false;
		}else{
			return true;
		}
	}

	function email_available(){
		global $con,$email;
		$sqla = "SELECT * FROM users WHERE email = '".$email."';";
		$result = mysqli_query($con, $sqla);
		if(mysqli_num_rows($result) >= 1)
		{
			return false;
		}else{
			return true;
		}

	}

	function all_fields_isFull(){
		global $firstname,$lastname,$age,$username,$password,$email;
		if(empty($firstname) || empty($lastname) || empty($age) || empty($username) || empty($password) || empty($email)){
			return false;
		}
		else{
			return true;
		}
	}

	function register_user(){
		global $con,$firstname,$lastname,$age,$username,$password,$response,$email;
		$statement = mysqli_query($con, "INSERT INTO users (firstname, lastname, age,username , password, email) VALUES ('".$firstname."','". $lastname."','".$age."','". $username."','". $password."','".$email."');");
		$response[success] = "true";
	}

	if (!all_fields_isFull()){
		$response["success"] = "empty_fields";
	}
	else if(!username_available()){
		$response["success"] = "username_exist";
	}
	else if(!email_available()){
		$response["success"] = "email_exist";
	}
	else
	{
		register_user();
	}

    echo json_encode($response);
?>