<?php
require_once 'include/db_connect.inc.php';

function isUserCorrect($conn, $username, $password){

	try{

		// Check if user exists in DB
		$sql = "
		SELECT 
			`unique_id`, `password`
		FROM user
		WHERE 
			username = ?
		LIMIT 1";

		$stmt = $conn->prepare($sql);
		$stmt->bind_param('s', $username);

		$stmt->execute();

		$user = array();
		if ($result = $stmt->get_result()){
			while ($obj = $result->fetch_assoc()){
				$user = [
					'password' => $obj['password'],
					'unique_id' => $obj['unique_id'],
				];
			}
		}

		if ($user and password_verify($password, $user['password'])){
			return $user['unique_id'];
		}

		return false;

	} catch(Throwable $t) {
		# Could be Error/Exception classes, that are both Throwable
		$errorMessage = "Throwable: ".$t->getCode().": ".$t->getMessage()."\n".
			"Line number ".$t->getLine()." in file ".$t->getFile()."\n".
			"Stack Trace: ". $t->getTrace()."\n".
			date('Y-m-d h:i:s A');

		error_log($errorMessage, 0);
		# Email to the admin
		return NULL;
	}

}

function registerUser($conn, $username, $password, $password_repeat){

	// Both passwords must match
	if ($password !== $password_repeat){
		return false;
	}

	// First check if the username is taken.
	$sql = "SELECT 1 FROM user WHERE username = ?";
	$stmt = $conn->prepare($sql);
	$stmt->bind_param('s', $username);
	$stmt->execute();
	$stmt->store_result();
	if($stmt->num_rows > 0){ return false; }

	// Hash and Secure password with a salt.
	// https://www.php.net/manual/en/function.password-hash.php
	$password = password_hash($password, PASSWORD_BCRYPT, ['cost' => 10]);

	// needs a unique id also for cookies, uniqID, with a hash appended
	$uniqueId = generateUniqueId();

	// Now add the user details to the DB
	$sql = "INSERT INTO user (username, password, unique_id) VALUES (?, ?, ?)";
	
	$stmt = $conn->prepare($sql);
	$stmt->bind_param('sss', $username, $password, $uniqueId);

	if ($stmt->execute()){
		return $uniqueId;
	}

	return false;

}

function generateUniqueId(){
	return uniqid() . '_' . md5(mt_rand());
}