<?php
session_start();
require 'db.php';

if ($_SERVER['REQUEST_METHOD'] == 'POST') {
    $username = htmlspecialchars($_POST['username']);
    $password = $_POST['password'];

    $stmt = $pdo->prepare("SELECT * FROM users WHERE username = ?");
    $stmt->execute([$username]);
    $user = $stmt->fetch();

    if ($user && password_verify($password, $user['password'])) {
        $_SESSION['user_id'] = $user['id'];
        $_SESSION['username'] = $user['username'];
        echo 'success';
    } else {
        echo 'Invalid login credentials';
    }
}
?>