<?php
	//session_start allows us to access the session array
	session_start();

	//inluding connection.php connects us to the database
	require_once('connection.php');

	//store success messages, error messages in data array
	$data = NULL;

	//redirect user to a page and pass data via session
	function redirect($session_data, $url)
	{
		$_SESSION = $session_data;
		header('location:'.$url);
	}

	//if re_password fied isset process registration else login
	if(isset($_POST['re_password']))
	{
		//validate email and password, set validation errors
		if(filter_var($_POST['email'], FILTER_VALIDATE_EMAIL) === FALSE)

		$data['errors'][] = "Invalid email";
		if($_POST['password'] != $_POST['re_password'] OR $_POST['password'] == NULL)
			$data['errors'][] = "Passwords do not match";

		//if no errors and email is not in use then add user
		if($data['errors'] == NULL)
		{
			$check_user = $connection->query("SELECT * FROM users WHERE users.email = '".$_POST['email']."' ")->fetch_assoc();

			if($check_user == NULL)
			{
				$new_user = $connection->query("INSERT INTO users (username, first_name, last_name, email, password) ('','".$_POST['username']."','".$_POST['first_name']."', '".$_POST['last_name']."', '".$_POST['email']."', '".md5($_POST['password'])."')");

				if($new_user === TRUE)
				{
					$data['registered'] = $_POST['email'];
					redirect($data, 'login.php');
				}
			}
			else
			{
				$data['errors'][] = "Email already in use";
				redirect($data, 'register.php');
			}
		}
		else
		{
			$date['success'] = "You are now Registered... Please Login";
			redirect($data, 'register.php');
		}
	}
	else
	{
		//check if user exist in database with given email and password
		$check_user = $connection->query("SELECT * FROM users WHERE users.email = '".$_POST['email']."' AND users.password = '".md5($_POST['password'])."' ")->fetch_assoc();
		//if user exist set session variables and redirect user to profile page
		if($check_user != NULL)
		{
			$_SESSION['id'] = $check_user['id'];
			$_SESSION['email'] = $check_user['email'];
			$_SESSION['login'] = TRUE;

			if($_SESSION['login'] === TRUE)
				header('location: user_profile.php?id='.$check_user['id']);
		}
		else
		{
			$data['errors'][] = "Invalid email or password";
				redirect($data, 'login.php');
		}
	}
?>