<?php

declare(strict_types=1);

namespace App\Services;

use App\Enums\GoogleService;
use App\Models\GoogleOAuthConnection;
use Google\Client;

use Illuminate\Support\Facades\Log;

class GoogleOAuthService
{
    private const TOKEN_URI = 'https://oauth2.googleapis.com/token';

    private static function getRedirectUri(): string
    {
        $subfolder = config('app.url');
        return rtrim($subfolder, '/') . '/auth/google/callback';
    }

    public function getAuthorizationUrl(GoogleService $service): string
    {
        $client = $this->createClient($service);
        $client->setRedirectUri(self::getRedirectUri());
        $client->setState($service->value);
        $client->setAccessType('offline');
        $client->setPrompt('consent');
        $client->setIncludeGrantedScopes(true);

        return $client->createAuthUrl();
    }

    public function handleCallback(string $code, GoogleService $service): GoogleOAuthConnection
    {
        $client = $this->createClient($service);
        $client->setRedirectUri(self::getRedirectUri());

        $token = $client->fetchAccessTokenWithAuthCode($code);

        if (isset($token['error'])) {
            throw new \RuntimeException('Google OAuth error: ' . ($token['error_description'] ?? $token['error']));
        }

        if (!isset($token['refresh_token'])) {
            throw new \RuntimeException('No refresh token returned. Ensure access_type=offline and prompt=consent are set.');
        }

        $clientId = $client->getClientId();
        $clientSecret = $client->getClientSecret();

        return GoogleOAuthConnection::updateOrCreate(
            ['service' => $service->value],
            [
                'client_id' => $clientId,
                'client_secret' => $clientSecret,
                'refresh_token' => $token['refresh_token'],
            ]
        );
    }

    public function revoke(GoogleService $service): void
    {
        $connection = $this->getConnection($service);
        if (!$connection) {
            return;
        }

        $client = $this->createClient($service);
        $client->revokeToken();
        $connection->delete();
    }

    public function getAccessToken(GoogleService $service): ?string
    {
        $connection = $this->getConnection($service);
        if (!$connection) {
            return null;
        }

        try {
            $client = $this->createClient($service);
            $client->setAccessToken([
                'access_token' => '',
                'refresh_token' => $connection->refresh_token,
                'client_id' => $connection->client_id,
                'client_secret' => $connection->client_secret,
            ]);

            if ($client->isAccessTokenExpired()) {
                $client->fetchAccessTokenWithRefreshToken($client->getRefreshToken());
                $newToken = $client->getAccessToken();
                if (isset($newToken['refresh_token'])) {
                    $connection->refresh_token = $newToken['refresh_token'];
                    $connection->save();
                }
            }

            $accessToken = $client->getAccessToken();
            return $accessToken['access_token'] ?? null;
        } catch (\Exception $e) {
            Log::error('Google OAuth token refresh failed for ' . $service->value . ': ' . $e->getMessage());
            return null;
        }
    }

    public function isAuthorized(GoogleService $service): bool
    {
        return $this->getConnection($service) !== null;
    }

    public function getConnection(GoogleService $service): ?GoogleOAuthConnection
    {
        return GoogleOAuthConnection::where('service', $service->value)->first();
    }

    public function buildClient(GoogleService $service): Client
    {
        $client = $this->createClient($service);
        $connection = $this->getConnection($service);

        if ($connection) {
            $client->setAccessToken([
                'access_token' => '',
                'refresh_token' => $connection->refresh_token,
                'client_id' => $connection->client_id,
                'client_secret' => $connection->client_secret,
            ]);

            if ($client->isAccessTokenExpired()) {
                $client->fetchAccessTokenWithRefreshToken($client->getRefreshToken());
            }
        }

        return $client;
    }

    private function createClient(GoogleService $service): Client
    {
        $client = new Client();
        $client->setApplicationName(config('app.name'));
        $client->setScopes([$service->scope()]);
        $client->setClientId(config('services.google.client_id'));
        $client->setClientSecret(config('services.google.client_secret'));
        $client->setRedirectUri(self::getRedirectUri());

        return $client;
    }
}