<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use Illuminate\Support\Facades\Auth;
use Illuminate\Http\Response;

class AuthController extends Controller
{
    private int $loginDecaySeconds = 60;
    private int $maxLoginAttempts = 10;

    public function index(){
        $captcha = $this->generateCaptchaCode(6);
        session(['login_captcha' => $captcha]);
        $data = [
            'title' => 'Login Admin | Order Gizi',
        ];
        return view('auth.index', $data);
    }

    public function authanticate(Request $request){
            $validated = $request->validate([
                'username' => 'required',
                'password' => 'required',
                'captcha' => 'required',
                'website' => 'nullable',
            ]);

            if (trim((string) $request->input('website', '')) !== '') {
            return back()->withInput($request->only('username'))
                    ->with(['alertError' => 'Gagal Login!']);
            }

            $now = time();
            $rateKey = 'login:' . $request->ip() . ':' . strtolower((string) $request->input('username'));
            $windowSeconds = 60;
            $maxAttempts = 10;
            $attempts = (array) $request->session()->get($rateKey, []);
            $attempts = array_values(array_filter($attempts, fn($ts) => is_int($ts) && $ts > ($now - $windowSeconds)));
            if(count($attempts) >= $maxAttempts){
                return back()->withInput($request->only('username'))
                ->with(['alertError' => 'rate']);
            }

            $backoffKey = $rateKey . ':backoff_until';
            $until = (int) $request->session()->get($backoffKey, 0);
            if($until > $now){
                return back()->withInput($request->only('username'))
                ->with(['alertError' => 'backoff']);
            }

            $expectedCaptcha = (string) session('login_captcha', '');
            $givenCaptcha = strtoupper(preg_replace('/\s+/', '', (string) $request->input('captcha', '')));
            if($expectedCaptcha === '' || !hash_equals(strtoupper($expectedCaptcha), (string) $givenCaptcha)){
                 return back()->withInput($request->only('username'))
                ->with(['alertError' => 'captcha']);
            }
            $request->session()->forget('login_captcha');


            // IMPORTANT: only pass auth credentials to Auth::attempt
            // (do not include captcha / honeypot fields, otherwise Laravel will query non-existent columns)
            $credentials = [
                'username' => (string) ($validated['username'] ?? ''),
                'password' => (string) ($validated['password'] ?? ''),
            ];

            if(Auth::attempt($credentials)){
                $request->session()->regenerate();
                $request->session()->forget($rateKey);
                $request->session()->forget($backoffKey);
                return redirect()->intended('/dashboard');
            }
            // record failed attempt
            $attempts[] = $now;
            $request->session()->put($rateKey, $attempts);

            // set exponential backoff (1,2,4,8,16,30 seconds max) based on failures in window
            $failCount = count($attempts);
            $delay = min(30, (int) pow(2, max(0, $failCount - 1)));
            $request->session()->put($backoffKey, $now + $delay);
            return back()->with(['alertError' => 'Gagal Login!']);
    }

    public function logout()
    {
        Auth::logout();
        request()->session()->invalidate();
        request()->session()->regenerateToken();
        return redirect('/login');
    }

    public function captcha(){
        $captcha = (string) session('login_captcha', '');
        if($captcha === ''){
            $captcha = $this->generateCaptchaCode(6);
            session(['login_captcha' => $captcha]);
        }
        if(!function_exists('imagecreatetruecolor')){
            return response('GD extension is not available', Response::HTTP_INTERNAL_SERVER_ERROR)->header('Content-Type', 'text/plain');
        }

        $width=140;
        $height=44;
        $img = imagecreatetruecolor($width, $height);
        $bg = imagecolorallocate($img, 245, 247, 250);
        $fg = imagecolorallocate($img, 35, 45, 70);
        $noise = imagecolorallocate($img, 120, 130, 150);

        imagefilledrectangle($img, 0, 0, $width, $height, $bg);

        for($i = 0; $i < 6; $i++){
            imageline(
                $img,
                random_int(0, $width),
                random_int(0, $height),
                random_int(0, $width),
                random_int(0, $height),
                $noise
            );
        }

        for($i = 0; $i < 180; $i++){
            imagesetpixel($img, random_int(0, $width - 1), random_int(0, $height - 1), $noise);
        }

        $font = 5;
        $textWidth = imagefontwidth($font) * strlen($captcha);
        $textHeight = imagefontwidth($font);
        $x = (int) (($width - $textWidth) / 2);
        $y = (int) (($height - $textHeight) / 2);
        imagestring($img, $font, $x, $y, $captcha, $fg);

        ob_start();
        imagepng($img);
        $png = ob_get_clean();
        imagedestroy($img);
        return response($png, 200)->header('Content-Type', 'image/png')->header('Cache-Control', 'no-store, no-cache, must-revalidate, max-age=0');
    }

    public function generateCaptchaCode(int $length = 6): string
    {
        $chars = '23456789ABCDEFGHJKLMNPQRSTUVWXYZ';
        $out = '';
        $max = strlen($chars) - 1;
        for ($i = 0; $i < $length; $i++){
            $out .= $chars[random_int(0, $max)];
        }
        return $out;
    }
}