<?php

namespace App\Http\Controllers;

use App\Models\User;
use App\Models\UserPref;
use Illuminate\Http\Request;
use Illuminate\Validation\Rule;
use LibreNMS\Authentication\TwoFactor;
use LibreNMS\Config;
use LibreNMS\Exceptions\AuthenticationException;
use Session;
use Toastr;

class TwoFactorController extends Controller
{
    public function verifyTwoFactor(Request $request)
    {
        $this->validate($request, [
            'twofactor' => 'required|numeric',
        ]);

        try {
            $this->checkToken($request->user(), $request->input('twofactor'));
        } catch (AuthenticationException $e) {
            return redirect()->route('2fa.form')->withErrors($e->getMessage());
        }

        // token validated
        if (session('twofactorremove')) {
            UserPref::forgetPref(auth()->user(), 'twofactor');
            $request->session()->forget(['twofactor', 'twofactorremove']);

            \Toastr::info(__('TwoFactor auth removed.'));

            return redirect('preferences');
        }

        $request->session()->put('twofactor', true);

        return redirect()->intended();
    }

    public function showTwoFactorForm(Request $request)
    {
        $twoFactorSettings = $this->loadSettings($request->user());

        // don't allow visiting this page if not needed
        if (empty($twoFactorSettings) || !Config::get('twofactor') || session('twofactor')) {
            return redirect()->intended();
        }

        $errors = [];

        // lockout the user if there are too many failures
        if (isset($twoFactorSettings['fails']) && $twoFactorSettings['fails'] >= 3) {
            $lockout_time = Config::get('twofactor_lock', 0);

            if (!$lockout_time) {
                $errors['lockout'] = __('Too many two-factor failures, please contact administrator.');
            } elseif ((time() - $twoFactorSettings['last']) < $lockout_time) {
                $errors['lockout'] = __("Too many two-factor failures, please wait :time seconds", ['time' => $lockout_time]);
            }
        }

        return view('auth.2fa')->with([
            'key' => $twoFactorSettings['key'],
            'uri' => $this->genUri($request->user(), $twoFactorSettings),
        ])->withErrors($errors);
    }

    /**
     * Show the form for creating a new resource.
     *
     * @return \Illuminate\Http\Response
     */
    public function create(Request $request)
    {
        $this->validate($request, [
            'twofactor' => Rule::in('time', 'counter')
        ]);

        $key = \LibreNMS\Authentication\TwoFactor::genKey();

        // assume time based
        $settings = [
            'key' => $key,
            'fails' => 0,
            'last' => 0,
            'counter' => $request->get('twofactor') == 'counter' ? 0 : false,
        ];

        Session::put('twofactoradd', $settings);

        return redirect()->intended();
    }


    /**
     * Remove the specified resource from storage.
     *
     * @param  int  $id
     * @return \Illuminate\Http\Response
     */
    public function destroy(Request $request)
    {
        $request->session()->put('twofactorremove', true);
        $request->session()->forget('twofactor');

        return redirect()->intended();
    }

    /**
     * Remove the specified resource from storage.
     *
     * @param  int  $id
     * @return \Illuminate\Http\Response
     */
    public function cancelAdd(Request $request)
    {
        $request->session()->forget('twofactoradd');

        return redirect()->intended();
    }

    /**
     * @param User $user
     * @param string $token
     * @throws AuthenticationException
     * return true
     */
    private function checkToken($user, $token)
    {
        if (!$token) {
            throw new AuthenticationException(__("No Two-Factor Token entered."));
        }

        // check if this is new
        $twoFactorSettings = $this->loadSettings($user);

        if (empty($twoFactorSettings)) {
            throw new AuthenticationException(__('No Two-Factor settings, how did you get here?'));
        }

        if (($server_count = TwoFactor::verifyHOTP($twoFactorSettings['key'], $token, $twoFactorSettings['counter'])) === false) {
            if (isset($twoFactorSettings['fails'])) {
                $twoFactorSettings['fails']++;
            } else {
                $twoFactorSettings['fails'] = 1;
            }
            $twoFactorSettings['last'] = time();
            UserPref::setPref($user, 'twofactor', $twoFactorSettings);
            throw new AuthenticationException(__("Wrong Two-Factor Token."));
        }

        // update counter
        if ($twoFactorSettings['counter'] !== false) {
            if ($server_count !== true && $server_count !== $twoFactorSettings['counter']) {
                $twoFactorSettings['counter'] = $server_count + 1;
            } else {
                $twoFactorSettings['counter']++;
            }
        }

        // success
        $twoFactorSettings['fails'] = 0;
        UserPref::setPref($user, 'twofactor', $twoFactorSettings);

        // notify if added
        if (Session::has('twofactoradd')) {
            Toastr::success(__('TwoFactor auth added.'));
            Session::forget('twofactoradd');
        }

        return true;
    }

    /**
     * @param $user
     * @return mixed
     */
    private function loadSettings($user)
    {
        if (Session::has('twofactoradd')) {
            return  Session::get('twofactoradd');
        }

        return UserPref::getPref($user, 'twofactor');
    }

    private function genUri($user, $settings)
    {
        $title = urlencode("Librenms:" . $user->username);
        $key = $settings['key'];

        // time based
        if ($settings['counter'] === false) {
            return "otpauth://totp/$title?issuer=LibreNMS&secret=$key";
        }

        // counter based
        return "otpauth://hotp/$title?issuer=LibreNMS&counter=1&secret=$key";
    }
}