import { ServiceError, LLMConfig, DocumentMetadata } from '../types';
const { store } = require('../store');
import OpenAI from 'openai';
import { OpenRouter } from 'openrouter-client';
import { ollamaService } from './ollamaService';

type Message = { role: 'system' | 'user' | 'assistant'; content: string };

interface OpenAIClient {
  chat: {
    completions: {
      create: Function;
    };
  };
}

interface OpenRouterStreamResponse {
  success: boolean;
  data?: {
    choices: Array<{ delta?: { content?: string }; message?: { content: string } }>;
  };
  errorCode?: number;
  errorMessage?: string;
}

type OpenRouterConfig = {
  temperature?: number;
  model?: string;
  stream?: boolean;
};

interface OpenRouterClient {
  chat: (messages: Message[], config?: OpenRouterConfig) => Promise<OpenRouterStreamResponse>;
}


export class LLMService {
  #config: LLMConfig;
  #openaiClient: OpenAIClient | null;
  #openrouterClient: OpenRouterClient | null;

  constructor() {
    const storedConfig = store.get('llm_config');
    
    this.#config = storedConfig || {
      provider: 'ollama',
      model: 'jimscard/blackhat-hacker:v2',
      baseUrl: 'http://localhost:11434',
      temperature: 0.7,
      apiKey: null
    };
    
    // Ensure config is saved with defaults
    store.set('llm_config', this.#config);
    this.#openaiClient = null;
    this.#openrouterClient = null;
    this.#initializeClient();
  }

  /**
   * @private
   */
  #initializeClient() {
    switch (this.#config?.provider) {
      case 'openai':
        if (!this.#config.apiKey) {
          throw new ServiceError('OpenAI API key is required');
        }
        this.#openaiClient = new OpenAI({
          apiKey: this.#config.apiKey,
          baseURL: this.#config.baseUrl,
        });
        break;
      case 'openrouter':
        if (!this.#config.apiKey) {
          throw new ServiceError('OpenRouter API key is required');
        }
        this.#openrouterClient = new OpenRouter(this.#config.apiKey);
        break;
      case 'ollama':
        if (this.#config.baseUrl) {
          ollamaService.updateBaseUrl(this.#config.baseUrl);
        }
        break;
    }
  }

  async query(
    question: string,
    onChunk?: (chunk: string) => void
  ): Promise<{ answer: string, sources: DocumentMetadata[] }> {
    if (!this.#config?.provider) {
      throw new ServiceError('LLM provider not configured');
    }

    try {
      let response;

      switch (this.#config.provider) {
        case 'openai':
          if (!this.#openaiClient) {
            throw new ServiceError('OpenAI client not initialized');
          }
          const openaiResponse = await this.#openaiClient.chat.completions.create({
            model: this.#config.model || 'gpt-3.5-turbo',
            messages: [{ role: 'user', content: question }],
            temperature: this.#config.temperature || 0.7,
            stream: true,
          });

          let openaiText = '';
          for await (const chunk of openaiResponse) {
            const content = chunk.choices[0]?.delta?.content || '';
            if (content) {
              openaiText += content;
              onChunk?.(content);
            }
          }
          response = openaiText;
          break;

        case 'openrouter':
          if (!this.#openrouterClient) {
            throw new ServiceError('OpenRouter client not initialized');
          }
          const openrouterResponse = await this.#openrouterClient.chat(
            [{ role: 'user', content: question }],
            {
              model: this.#config.model || 'openai/gpt-3.5-turbo',
              temperature: this.#config.temperature || 0.7,
              stream: true,
            }
          );
          if (!openrouterResponse.success) {
            throw new ServiceError(openrouterResponse.errorMessage || 'OpenRouter request failed');
          }

          let routerText = '';
          for await (const chunk of openrouterResponse.data?.choices || []) {
            const content = chunk.delta?.content || chunk.message?.content || '';
            if (content) {
              routerText += content;
              onChunk?.(content);
            }
          }
          response = routerText;
          break;

        case 'ollama':
          const ollamaResponse = await ollamaService.chat({
            model: this.#config.model || 'phi4:latest',
            messages: [{ role: 'user', content: question }],
            temperature: this.#config.temperature,
            onChunk,
          });
          response = ollamaResponse.message.content;
          break;

        default:
          throw new ServiceError(`Unsupported provider: ${this.#config.provider}`);
      }

      /** @type {DocumentMetadata[]} */
      const sources = []; // TODO: Implement source retrieval from vector store

      return {
        answer: response,
        sources,
      };
    } catch (error) {
      console.error('Error querying LLM:', error);
      throw new ServiceError(
        error instanceof Error ? error.message : 'Unknown error occurred'
      );
    }
  }

  /**
   * @returns {LLMConfig}
   */
  getConfig() {
    return this.#config;
  }

  /**
   * @param {LLMConfig} newConfig - The new LLM configuration
   */
  async updateConfig(newConfig) {
    // Validate required fields from schema
    if (!newConfig.provider) {
      throw new ServiceError('Provider is required');
    }

    // Clean config to only include allowed properties from schema
    const cleanConfig = {
      provider: newConfig.provider,
      apiKey: newConfig.apiKey ?? null,
      model: newConfig.model ?? (newConfig.provider === 'ollama' ? 'phi4' : null),
      baseUrl: newConfig.provider === 'ollama' ? (newConfig.baseUrl ?? 'http://localhost:11434') : (newConfig.baseUrl ?? null),
      temperature: typeof newConfig.temperature === 'number' ? newConfig.temperature : 0.7
    };

    // Validate provider-specific requirements
    if (cleanConfig.provider !== 'ollama' && !cleanConfig.apiKey) {
      throw new ServiceError(`${cleanConfig.provider} requires an API key`);
    }

    try {
      store.set('llm_config', cleanConfig);
      this.#config = cleanConfig;
      this.#initializeClient();
    } catch (error) {
      throw new ServiceError(
        error instanceof Error ? error.message : 'Failed to update config'
      );
    }
  }

  /**
   * Get available models from Ollama server
   * @returns {Promise<string[]>} List of model names
   */
  async getOllamaModels() {
    try {
      return await ollamaService.getModels();
    } catch (error) {
      console.error('Error fetching Ollama models:', error);
      throw new ServiceError(
        error instanceof Error ? error.message : 'Failed to fetch Ollama models'
      );
    }
  }
}

const llmService = new LLMService();
export { llmService };