<?php
/**
 * Holds the auth controllers.
 * @package Sakura
 */

namespace Sakura\Controllers;

use Phroute\Phroute\Exception\HttpMethodNotAllowedException;
use Sakura\ActionCode;
use Sakura\Config;
use Sakura\CurrentSession;
use Sakura\DB;
use Sakura\Net;
use Sakura\User;

/**
 * Authentication controllers.
 * @package Sakura
 * @author Julian van de Groep <me@flash.moe>
 */
class AuthController extends Controller
{
    /**
     * Touch the login rate limit.
     * @param int $user The ID of the user that attempted to log in.
     * @param bool $success Whether the login attempt was successful.
     */
    protected function touchRateLimit(int $user, bool $success = false): void
    {
        DB::table('login_attempts')
            ->insert([
                'attempt_success' => $success ? 1 : 0,
                'attempt_timestamp' => time(),
                'attempt_ip' => Net::pton(Net::ip()),
                'user_id' => $user,
            ]);
    }

    protected function authenticate(User $user): void
    {
        // Generate a session key
        $session = CurrentSession::create(
            $user->id,
            Net::ip(),
            get_country_code(),
            clean_string($_SERVER['HTTP_USER_AGENT'] ?? '')
        );

        $cookiePrefix = config('cookie.prefix');
        setcookie("{$cookiePrefix}id", $user->id, time() + 604800, '/');
        setcookie("{$cookiePrefix}session", $session->key, time() + 604800, '/');

        $this->touchRateLimit($user->id, true);
    }

    /**
     * End the current session.
     * @throws HttpMethodNotAllowedException
     */
    public function logout(): void
    {
        if (!session_check()) {
            throw new HttpMethodNotAllowedException;
        }

        // Destroy the active session
        CurrentSession::stop();
    }

    /**
     * Login page.
     * @return string
     */
    public function login(): string
    {
        if (!session_check()) {
            return $this->json(['error' => 'Your session expired! Please refresh and try again.']);
        }

        // Get request variables
        $username = $_POST['username'] ?? null;
        $password = $_POST['password'] ?? null;

        // Check if we haven't hit the rate limit
        $rates = DB::table('login_attempts')
            ->where('attempt_ip', Net::pton(Net::ip()))
            ->where('attempt_timestamp', '>', time() - 1800)
            ->where('attempt_success', '0')
            ->count();

        if ($rates > 4) {
            return $this->json(['error' => 'Your have hit the login rate limit, try again later.']);
        }

        $user = User::construct(clean_string($username, true, true));

        // Check if the user that's trying to log in actually exists
        if ($user->id === 0) {
            $this->touchRateLimit($user->id);
            return $this->json(['error' => 'The user you tried to log into does not exist.']);
        }

        if ($user->passwordExpired()) {
            return $this->json(['error' => 'Your password expired.']);
        }

        if (!$user->verifyPassword($password)) {
            $this->touchRateLimit($user->id);
            return $this->json(['error' => 'The password you entered was invalid.']);
        }

        // Check if the user has the required privs to log in
        if (!$user->activated) {
            $this->touchRateLimit($user->id);
            return $this->json(['error' => "Your account isn't activated, check your e-mail!"]);
        }

        $this->authenticate($user);

        $msg = ['error' => null];

        if (!$user->lastOnline) {
            $msg['go'] = route('info.welcome');
        }

        return $this->json($msg);
    }

    /**
     * Do a registration attempt.
     * @throws HttpMethodNotAllowedException
     * @return string
     */
    public function register(): string
    {
        if (!session_check()) {
            return view('auth/register', compact('registered_username'));
        }

        // Check if authentication is disallowed
        if (config('user.disable_registration')) {
            return $this->json(['error' => 'Registration is currently disabled.']);
        }

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

        // Attempt to get account data
        $user = User::construct(clean_string($username, true, true));

        // Check if the username already exists
        if ($user && $user->id !== 0) {
            $message = "{$user->username} is already a member here!"
                    . "\r\nIf this is you please use the password reset form instead of making a new account.";
            return $this->json(['error' => $message]);
        }

        // Username too short
        if (strlen($username) < config('user.name_min')) {
            return $this->json(['error' => 'Your name must be at least 3 characters long.']);
        }

        // Username too long
        if (strlen($username) > config('user.name_max')) {
            return $this->json(['error' => "Your name can't be longer than 16 characters."]);
        }

        // Check if the given email address is formatted properly
        if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
            return $this->json(['error' => 'Your e-mail address is formatted incorrectly.']);
        }

        // Check the MX record of the email
        if (!check_mx_record($email)) {
            return $this->json(['error' => 'No valid MX-Record found on the e-mail address you supplied.']);
        }

        // Check if the e-mail has already been used
        $emailCheck = DB::table('users')
            ->where('email', $email)
            ->count();
        if ($emailCheck) {
            return $this->json(['error' => 'Someone already registered using this email!']);
        }

        // Check password entropy
        if (password_entropy($password) < config('user.pass_min_entropy')) {
            return $this->json([
                'error' => 'Your password is considered too weak, try adding some special characters.'
            ]);
        }

        $activation = boolval(config('user.require_activation'));
        $user = User::create($username, $password, $email, !$activation);

        // Check if we require e-mail activation
        if ($activation) {
            $message = 'Almost there, only activation is left! Please check your e-mail for the link.';
            $this->sendActivationMail($user);
        } else {
            $this->authenticate($user);
        }

        return $this->json(['text' => $message ?? null, 'go' => route('main.index')]);
    }

    /**
     * Do a (re)activation attempt.
     * @return string
     */
    public function activate(): string
    {
        // activation link handler
        if (isset($_GET['u'], $_GET['k'])) {
            $user = User::construct($_GET['u'] ?? null);

            if ($user->id === 0
                || $user->activated
                || !ActionCode::validate('ACTIVATE', $_GET['k'] ?? null, $user->id)) {
                return view('auth/activate_failed');
            }

            DB::table('users')
                ->where('user_id', $user->id)
                ->update(['user_activated' => 1]);

            $this->authenticate($user);

            return redirect(route('main.index'));
        }

        // resend handler
        if (session_check() && isset($_POST['username'], $_POST['email'])) {
            $id = DB::table('users')
                ->where('username_clean', clean_string($_POST['username'], true))
                ->where('email', clean_string($_POST['email'], true))
                ->value('user_id');

            if (!$id) {
                return $this->json(['error' => "Couldn't find this username/e-mail combination, double check them!"]);
            }

            $user = User::construct($id);

            if ($user->activated) {
                return $this->json(['error' => 'Your account is already activated! Why are you here?', 'go' => route('main.index')]);
            }

            $this->sendActivationMail($user);

            return $this->json([
                'text' => "The e-mail should be on its way, don't forget to also check your spam folder!",
                'go' => route('main.index')
            ]);
        }

        return view('auth/activate');
    }

    /**
     * Do a password reset attempt.
     * @return string
     */
    public function resetPassword(): string
    {
        if (session_check()) {
            $userId = $_POST['user'] ?? 0;
            $key = $_POST['key'] ?? "";
            $password = $_POST['password'] ?? "";
            $userName = clean_string($_POST['username'] ?? "", true);
            $email = clean_string($_POST['email'] ?? "", true);
            $user = User::construct($userId ? $userId : $userName);

            if ($user->id === 0 || (strlen($email) > 0 ? $email !== $user->email : false)) {
                return $this->json(['error' => "This user does not exist! Contact us if you think this isn't right."]);
            }

            if (!$user->activated) {
                return $this->json([
                    'error' => "Your account isn't activated, go activate it first...",
                    'go' => route('auth.activate'),
                ]);
            }

            if ($key && $password) {
                if (password_entropy($password) < config('user.pass_min_entropy')) {
                    return $this->json(['error' => "Your password doesn't meet the strength requirements!"]);
                }

                $action = ActionCode::validate('LOST_PASS', $key, $user->id);

                if (!$action) {
                    return $this->json(['error' => "Invalid verification code! Contact us if you think this isn't right."]);
                }

                $user->setPassword($password);
                $this->authenticate($user);

                return $this->json([
                    'text' => "Changed your password!",
                    'go' => route('main.index'),
                ]);
            }

            $this->sendPasswordMail($user);

            return $this->json([
                'text' => "The e-mail should be on its way, don't forget to also check your spam folder!",
                'go' => route('main.index'),
            ]);
        }

        return view('auth/resetpassword');
    }

    /**
     * Send the activation e-mail
     * @param User $user
     */
    private function sendActivationMail(User $user): void
    {
        $activate = ActionCode::generate('ACTIVATE', $user->id);
        $siteName = config('general.name');
        $baseUrl = "http://{$_SERVER['HTTP_HOST']}";
        $activateLink = route('auth.activate') . "?u={$user->id}&k={$activate}";
        $signature = config('mail.signature');

        $message = "Hey {$user->username}, welcome to {$siteName}!\r\n\r\n"
            . "Your account is almost ready, the only thing left to do is for you to click the following link:\r\n"
            . "{$baseUrl}{$activateLink}\r\n\r\n"
            . "Hope to see you around,\r\n{$signature}";

        send_mail([$user->email => $user->username], "Welcome to {$siteName}!", $message);
    }

    /**
     * Send the activation e-mail
     * @param User $user
     */
    private function sendPasswordMail(User $user): void
    {
        $verk = ActionCode::generate('LOST_PASS', $user->id);
        $siteName = config('general.name');
        $baseUrl = "http://{$_SERVER['HTTP_HOST']}";
        $pass_confirm = route('auth.resetpassword') . "?u={$user->id}&k={$verk}";
        $signature = config('mail.signature');

        $message = "Hey {$user->username},\r\n\r\n"
            . "You, or someone pretending to be you, requested a password change for your account!\r\n"
            . "Click the following link to confirm the password change:\r\n"
            . "{$baseUrl}{$pass_confirm}\r\n\r\n"
            . "If this wasn't you please just ignore this e-mail, unless this isn't the first"
            . " time this has happened in which case you should contact a staff member.\r\n\r\n"
            . "--\r\n{$signature}";

        send_mail([$user->email => $user->username], "{$siteName} password restoration", $message);
    }
}