<?php

namespace App\Http\Controllers\Auth;

use App\Http\Controllers\Controller;
use App\Models\User;
use Illuminate\Http\RedirectResponse;
use Illuminate\Http\Request;
use Illuminate\Http\Response;
use Illuminate\Support\Facades\Auth;
use Illuminate\Support\Facades\Http;
use Illuminate\Support\Str;

/**
 * "Sign in with Ladill" — Authorization Code + PKCE against auth.ladill.com.
 * Establishes a local session + thin user mirror keyed by the OIDC `sub`.
 */
class SsoLoginController extends Controller
{
    public function connect(Request $request): RedirectResponse
    {
        $intended = (string) $request->query('redirect', route('servers.dashboard'));

        if (Auth::check()) {
            return $this->safeRedirect($intended, route('servers.dashboard'));
        }

        $verifier = Str::random(64);
        $state = Str::random(40);
        $request->session()->put('sso.verifier', $verifier);
        $request->session()->put('sso.state', $state);
        $request->session()->put('sso.intended', $intended);

        $challenge = rtrim(strtr(base64_encode(hash('sha256', $verifier, true)), '+/', '-_'), '=');

        $query = [
            'response_type' => 'code',
            'client_id' => (string) config('services.ladill_sso.client_id'),
            'redirect_uri' => (string) config('services.ladill_sso.redirect'),
            'scope' => 'openid profile email',
            'state' => $state,
            'code_challenge' => $challenge,
            'code_challenge_method' => 'S256',
        ];

        if (! $request->boolean('interactive')) {
            $query['prompt'] = 'none';
        }

        return redirect()->away(rtrim((string) config('services.ladill_sso.issuer'), '/').'/oauth/authorize?'.http_build_query($query));
    }

    public function callback(Request $request): RedirectResponse
    {
        $intended = (string) $request->session()->get('sso.intended', route('servers.dashboard'));

        if ($request->filled('error')) {
            if (in_array($request->query('error'), ['login_required', 'interaction_required', 'consent_required'], true)
                && ! $request->boolean('interactive')) {
                return redirect()->route('sso.connect', [
                    'redirect' => $intended,
                    'interactive' => 1,
                ]);
            }

            return redirect()->route('sso.connect', [
                'redirect' => $intended,
                'interactive' => 1,
            ]);
        }

        if (! $request->filled('code')
            || $request->query('state') !== $request->session()->pull('sso.state')) {
            return redirect()->route('sso.connect', [
                'redirect' => $intended,
                'interactive' => 1,
            ]);
        }

        $issuer = rtrim((string) config('services.ladill_sso.issuer'), '/');

        $tokenRes = Http::asForm()->post($issuer.'/oauth/token', [
            'grant_type' => 'authorization_code',
            'client_id' => (string) config('services.ladill_sso.client_id'),
            'client_secret' => (string) config('services.ladill_sso.client_secret'),
            'redirect_uri' => (string) config('services.ladill_sso.redirect'),
            'code' => (string) $request->query('code'),
            'code_verifier' => (string) $request->session()->pull('sso.verifier'),
        ]);
        if ($tokenRes->failed()) {
            return redirect()->route('sso.connect', [
                'redirect' => $intended,
                'interactive' => 1,
            ]);
        }

        $claims = Http::withToken((string) $tokenRes->json('access_token'))->acceptJson()->get($issuer.'/oauth/userinfo');
        if ($claims->failed() || ! $claims->json('sub')) {
            return redirect()->route('sso.connect', [
                'redirect' => $intended,
                'interactive' => 1,
            ]);
        }

        $user = User::updateOrCreate(
            ['public_id' => (string) $claims->json('sub')],
            [
                'name' => $claims->json('name'),
                'email' => $claims->json('email') ?: (string) $claims->json('sub').'@users.ladill.com',
                'avatar_url' => $claims->json('picture'),
            ],
        );

        \App\Models\HostingTeamMember::linkPendingInvitesFor($user);

        Auth::login($user, remember: true);
        $request->session()->regenerate();
        $request->session()->forget('mailbox_link_banner_dismissed');

        return $this->safeRedirect($intended, route('servers.dashboard'));
    }

    public function logout(Request $request): RedirectResponse
    {
        Auth::logout();
        $request->session()->invalidate();
        $request->session()->regenerateToken();

        $home = 'https://'.config('app.platform_domain');
        $endSession = 'https://'.config('app.auth_domain').'/logout/sso?redirect='.urlencode($home);

        return redirect()->away($endSession);
    }

    public function frontchannelLogout(Request $request): Response|RedirectResponse
    {
        if ($this->shouldLogoutForMailbox($request)) {
            Auth::logout();
            $request->session()->invalidate();
            $request->session()->regenerateToken();
        }

        $return = (string) $request->query('return', '');
        $root = (string) config('app.platform_domain', 'ladill.com');
        $host = parse_url($return, PHP_URL_HOST);
        if (str_starts_with($return, 'https://') && is_string($host) && ($host === $root || str_ends_with($host, '.'.$root))) {
            return redirect()->away($return);
        }

        return response('', 204);
    }

    private function shouldLogoutForMailbox(Request $request): bool
    {
        $mailbox = strtolower(trim((string) $request->query('mailbox', '')));
        if ($mailbox === '' || ! str_contains($mailbox, '@')) {
            return true;
        }

        $user = Auth::user();
        if (! $user) {
            return false;
        }

        return strtolower((string) $user->email) !== $mailbox;
    }

    private function safeRedirect(string $url, string $fallback): RedirectResponse
    {
        $host = parse_url($url, PHP_URL_HOST);
        $root = (string) config('app.platform_domain', 'ladill.com');

        if (is_string($host) && str_starts_with($url, 'https://')
            && ($host === $root || str_ends_with($host, '.'.$root))) {
            return redirect()->away($url);
        }

        return redirect()->away($fallback);
    }
}