Integrating Local and Cloud LLMs into the WordPress Admin Panel

<?php
declare(strict_types=1);

/**
* Author: Artur Yusupov (Fullstack Agentic Lab)
* Package: @agentic-lab/ai-gateway
* Module: LlmGatewayController
* Standard: WordPress 6.8+ / PHP 8.4 Strict / REST API v2
*/

namespace AgenticLab\Ai\Gateway;

use WP_REST_Controller;
use WP_REST_Server;
use WP_REST_Request;
use WP_REST_Response;
use WP_Error;

final class LlmGatewayController extends WP_REST_Controller
{
  protected $namespace = 'agentic-lab/v1';
  protected $rest_base = 'ai';

  private string $ollamaEndpoint;
  private string $cloudApiKey;

  public function __construct()
  {
      $this->ollamaEndpoint = (string) (getenv('OLLAMA_HOST') ?: 'http://127.0.0.1:11434');
      $this->cloudApiKey    = (string) (getenv('OPENAI_API_KEY') ?: '');
  }

  public function register_routes(): void
  {
      register_rest_route($this->namespace, '/' . $this->rest_base . '/generate', [
          [
              'methods'             => WP_REST_Server::CREATABLE,
              'callback'            => [$this, 'handleGenerateRequest'],
              'permission_callback' => [$this, 'checkPermissions'],
              'args'                => [
                  'prompt' => [
                      'required'          => true,
                      'type'              => 'string',
                      'sanitize_callback' => 'sanitize_textarea_field',
                  ],
                  'mode' => [
                      'required' => false,
                      'type'     => 'string',
                      'enum'     => ['local', 'cloud', 'auto'],
                      'default'  => 'auto',
                  ],
              ],
          ],
      ]);
  }

  public function checkPermissions(WP_REST_Request $request): bool|WP_Error
  {
      if (!current_user_can('edit_posts')) {
          return new WP_Error('rest_forbidden', __('Недостаточно прав для генерации контента.', 'agentic-lab'), ['status' => 403]);
      }
      return true;
  }

  public function handleGenerateRequest(WP_REST_Request $request): WP_REST_Response|WP_Error
  {
      $prompt = (string) $request->get_param('prompt');
      $mode   = (string) $request->get_param('mode');
      $userId = get_current_user_id();

      // 1. Проверка Rate Limit: не более 10 запросов в минуту на пользователя
      $rateLimitKey = "agentic_ai_ratelimit_{$userId}";
      $currentHits  = (int) get_transient($rateLimitKey);

      if ($currentHits >= 10) {
          return new WP_Error('rate_limit_exceeded', __('Превышен лимит запросов к ИИ. Попробуйте через минуту.', 'agentic-lab'), ['status' => 429]);
      }
      set_transient($rateLimitKey, $currentHits + 1, 60);

      // 2. Выбор провайдера инференса
      $result = null;
      if ($mode === 'local' || $mode === 'auto') {
          $result = $this->callOllamaLocal($prompt);
      }

      // 3. Fallback на Cloud, если локальный сервер недоступен
      if ($result === null && ($mode === 'cloud' || $mode === 'auto')) {
          $result = $this->callCloudProvider($prompt);
      }

      if ($result === null) {
          return new WP_Error('ai_service_unavailable', __('Сервисы генерации временно недоступны.', 'agentic-lab'), ['status' => 503]);
      }

      return new WP_REST_Response([
          'success'   => true,
          'content'   => $result['text'],
          'provider'  => $result['provider'],
          'tokens'    => $result['tokens'] ?? 0,
      ], 200);
  }

  /**
   * Вызов локального инференса через Ollama API.
   *
   * @return array{text: string, provider: string}|null
   */
  private function callOllamaLocal(string $prompt): ?array
  {
      $response = wp_remote_post("{$this->ollamaEndpoint}/api/generate", [
          'timeout' => 15,
          'headers' => ['Content-Type' => 'application/json'],
          'body'    => wp_json_encode([
              'model'  => 'llama3.3:latest',
              'prompt' => $prompt,
              'stream' => false,
          ]),
      ]);

      if (is_wp_error($response) || wp_remote_retrieve_response_code($response) !== 200) {
          return null; // Fallback триггер
      }

      $data = json_decode(wp_remote_retrieve_body($response), true);
      if (!isset($data['response'])) {
          return null;
      }

      return [
          'text'     => trim((string) $data['response']),
          'provider' => 'local_ollama',
      ];
  }

  /**
   * Вызов облачного шлюза OpenAI в качестве резервного провайдера.
   *
   * @return array{text: string, provider: string}|null
   */
  private function callCloudProvider(string $prompt): ?array
  {
      if ($this->cloudApiKey === '') {
          return null;
      }

      $response = wp_remote_post('https://api.openai.com/v1/chat/completions', [
          'timeout' => 20,
          'headers' => [
              'Authorization' => 'Bearer ' . $this->cloudApiKey,
              'Content-Type'  => 'application/json',
          ],
          'body' => wp_json_encode([
              'model'       => 'gpt-4o-mini',
              'messages'    => [
                  ['role' => 'system', 'content' => 'You are an enterprise WordPress editorial assistant. Output clear text.'],
                  ['role' => 'user', 'content' => $prompt],
              ],
              'temperature' => 0.3,
          ]),
      ]);

      if (is_wp_error($response) || wp_remote_retrieve_response_code($response) !== 200) {
          return null;
      }

      $data = json_decode(wp_remote_retrieve_body($response), true);
      $text = $data['choices'][0]['message']['content'] ?? null;

      if ($text === null) {
          return null;
      }

      return [
          'text'     => trim((string) $text),
          'provider' => 'cloud_openai',
      ];
  }
}