<?php
session_start();
require_once 'db/config.php';

header('Content-Type: application/json');

$response = ['success' => false, 'message' => 'Invalid username or password.'];

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

    if (empty($username) || empty($password)) {
        $response['message'] = 'Username and password are required.';
        echo json_encode($response);
        exit;
    }

    try {
        $pdo = db();

        $stmt = $pdo->prepare("SELECT id, username, password 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'];
            $response['success'] = true;
            $response['message'] = 'Login successful.';
        } else {
            $response['message'] = 'Invalid username or password.';
        }
    } catch (PDOException $e) {
        $response['message'] = 'Database error: ' . $e->getMessage();
    }

    echo json_encode($response);
}
?>