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

if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
    header('Location: login.php');
    exit;
}

$username = $_POST['username'] ?? '';
$password = $_POST['password'] ?? '';

if (empty($username) || empty($password)) {
    $_SESSION['error'] = 'Por favor, complete todos los campos.';
    header('Location: login.php');
    exit;
}

try {
    $pdo = db();
    $stmt = $pdo->prepare("SELECT * FROM users WHERE username = :username");
    $stmt->bindParam(':username', $username);
    $stmt->execute();
    $user = $stmt->fetch(PDO::FETCH_ASSOC);

    if ($user && password_verify($password, $user['password'])) {
        // Regenerate session ID to prevent session fixation
        session_regenerate_id(true);

        // Store user data in session
        $_SESSION['user_id'] = $user['id'];
        $_SESSION['username'] = $user['username'];
        $_SESSION['role'] = $user['role'];

        // Redirect based on role
        if ($user['role'] === 'admin') {
            header('Location: dashboard.php');
        } else {
            // Redirect to a general user page or index if not admin
            header('Location: index.php');
        }
        exit;
    } else {
        $_SESSION['error'] = 'Usuario o contraseña incorrectos.';
        header('Location: login.php');
        exit;
    }
} catch (PDOException $e) {
    // In a real app, log this error instead of showing it to the user
    $_SESSION['error'] = 'Error de base de datos. Intente de nuevo más tarde.';
    // error_log($e->getMessage());
    header('Location: login.php');
    exit;
}