import { BaseProvider, ChatOptions, GatewayChatMessage } from "./BaseProvider";

import OpenAI from "openai";
import logManager from "@electron/service/logger"

function _transformChunk(chunk: OpenAI.Chat.Completions.ChatCompletionChunk): UniversalChunk {
  const choice = chunk.choices[0];
  const usage = (chunk as any).usage;
  return {
    isEnd: choice?.finish_reason != null || (chunk.choices.length === 0 && usage != null),
    result: choice?.delta?.content ?? '',
    usage: usage ?? undefined,
  }
}

export class OpenAIProvider extends BaseProvider {
  private client: OpenAI;

  constructor(apiKey: string, baseURL: string, headers?: Record<string, string>) {
    super();
    this.client = new OpenAI({ apiKey, baseURL, defaultHeaders: headers });
  }

  async chat(messages: GatewayChatMessage[], model: string, options?: ChatOptions): Promise<AsyncIterable<UniversalChunk>> {
    const startTime = Date.now();

    const lastMessage = messages[messages.length - 1];

    logManager.logApiRequest('chat.completions.create', {
      model,
      lastMessage: lastMessage?.content?.substring(0, 100) + (lastMessage?.content?.length > 100 ? '...' : ''),
      messageCount: messages.length,
    }, 'POST');

    try {
      const chunks = await this.client.chat.completions.create({
        model,
        messages: messages as any,
        stream: true,
        stream_options: { include_usage: true },
      }, {
        signal: options?.signal,
      });

      return {
        async *[Symbol.asyncIterator]() {
          try {
            for await (const chunk of chunks) {
              if (options?.signal?.aborted) break;
              yield _transformChunk(chunk);
            }
            const responseTime = Date.now() - startTime;
            logManager.logApiResponse('chat.completions.create', { success: true }, 200, responseTime);
          } catch (error) {
            const responseTime = Date.now() - startTime;
            logManager.logApiResponse('chat.completions.create', { error: error instanceof Error ? error.message : String(error) }, 500, responseTime);
            throw error;
          }
        }
      }
    } catch (error) {
      const responseTime = Date.now() - startTime;
      logManager.logApiResponse('chat.completions.create', { error: error instanceof Error ? error.message : String(error) }, 500, responseTime);
      throw error;
    }
  }
}