<?php

namespace App\Services;

use App\Models\User;
use PDO;

class AuthService
{
    private PDO $pdo;
    private ?array $user = null;

    public function __construct(PDO $pdo)
    {
        $this->pdo = $pdo;
        $this->checkSession();
    }

    public function checkSession(): void
    {
        if (isset($_SESSION['user_id'])) {
            $user = User::findByUsername($this->pdo, $_SESSION['username']);

            if (!$user || !$user['is_active']) {
                $this->logout();
            } else {
                $this->user = $user;
            }
        }
    }

    public function login(string $username, string $password, string $ip = null): bool
    {
        $user = User::findByUsername($this->pdo, $username);

        if (!$user || !$user['is_active']) {
            return false;
        }

        // Verify password directly using the hash from database
        if (!password_verify($password, $user['password'])) {
            return false;
        }

        // Set session
        $_SESSION['user_id'] = $user['id'];
        $_SESSION['username'] = $user['username'];
        $_SESSION['role'] = $user['role'];

        // Update last login
        $this->updateUserLastLogin($user['id'], $ip);

        $this->user = $user;
        return true;
    }

    public function logout(): void
    {
        unset($_SESSION['user_id']);
        unset($_SESSION['username']);
        unset($_SESSION['role']);
        $this->user = null;
    }

    public function getCurrentUser(): ?array
    {
        return $this->user;
    }

    public function isLoggedIn(): bool
    {
        return $this->user !== null;
    }

    public function isAdmin(): bool
    {
        return $this->isLoggedIn() && $this->user['role'] === 'admin';
    }

    public function requireLogin(): void
    {
        if (!$this->isLoggedIn()) {
            header('Location: /login');
            exit;
        }
    }

    public function requireAdmin(): void
    {
        $this->requireLogin();

        if (!$this->isAdmin()) {
            http_response_code(403);
            echo 'Access denied. Admin privileges required.';
            exit;
        }
    }

    public function generateCSRFToken(): string
    {
        if (!isset($_SESSION['csrf_token'])) {
            $_SESSION['csrf_token'] = bin2hex(random_bytes(32));
        }
        return $_SESSION['csrf_token'];
    }

    public function verifyCSRFToken(string $token): bool
    {
        return isset($_SESSION['csrf_token']) && $_SESSION['csrf_token'] === $token;
    }

    private function updateUserLastLogin(int $userId, string $ip = null): void
    {
        $stmt = $this->pdo->prepare("UPDATE users SET last_login_at = :last_login_at, login_ip = :login_ip WHERE id = :id");
        $stmt->execute([
            'id' => $userId,
            'last_login_at' => date('Y-m-d H:i:s'),
            'login_ip' => $ip
        ]);
    }
}