Untitled

/* Login */

<?php
	session_start();

	include './inc/database.php';

	if (!isset($_SESSION)) {
		session_start();
	}

	if (isset($_SESSION['username'])) {
		header('Location: ./index.php');
		exit("Petit problème avec la redirection 'Location'");
	}

	if(isset($_POST['username']) && isset($_POST['password'])){

		$username = mysqli_real_escape_string($con, $_POST['username']);
		$password = mysqli_real_escape_string($con, sha1($_POST['password']));

		$result = mysqli_query($con, "SELECT * FROM `users` WHERE `username` = '$username' && `rank` >= '1'") or die(mysqli_error($con));
		if(mysqli_num_rows($result) < 1){
			exit("Cet utilisateur n'existe pas.");
		}
		while($row = mysqli_fetch_array($result)){
			if($password != $row['password']){
				exit("Mot de passe incorrect");
			}else{
				$_SESSION['id'] = $row['id'];
				$_SESSION['username'] = $username;
				$_SESSION['email'] = $row['email'];
				$_SESSION['rank'] = $row['rank'];
				header("Location: ./index.php");
			}
		}
	}

?>
<!DOCTYPE html>
<html>
	<head>
		<title>Connexion</title>
		<meta charset="utf-8">
		<style type="text/css">
			*{
				margin: 0px;
			}
			body{
				background-color: #3498DB;
			}
			#title{
				font-family: monospace;
				text-decoration: underline;
			}
			#submit_button{
				background-color: #52B3D9;
				border: 1px solid black;
				font-weight: bold;
				font-size: 15px;
				text-decoration: none;
				color: black;
				padding: 4px;
				font-family: monospace;
			}
			#login_form{
				border: 1px solid black;
				padding: 10px;
				padding-top: 0px;
				padding-bottom: 20px;
				width: 20%;
				margin: auto;
				text-align: center
			}
			#account_create_button{
				font-family: monospace;
				text-align: center;
			}
		</style>
	</head>
	<body>
		<form id="login_form" action="login.php" method="POST">
			<br>
			<h1 id="title">Connexion</h1>
			<br>
			<input type="text" id="username" name="username" placeholder="Nom d'utilisateur" required><br><br>
			<input type="password" id="password" name="password" placeholder="Mot de passe" required><br><br>
			<button id="submit_button" type="submit">Se connecter</button>
		</form>
		<div id="account_create_button">
			<a href="./register.php">Pas encore de compte ?</a>
		</div>
	</body>
</html>