const express = require('express');
const fetch = require('node-fetch');
const crypto = require('crypto');

const app = express();
const port = 8000;

// 这里粘贴您提供的所有常量和函数定义
const NOTDIAMOND_URL = 'https://chat.notdiamond.ai/mini-chat';
const NOTDIAMOND_HEADERS = {
  'Content-Type': 'application/json',
  'next-action': '8189eb37107121e024940f588629a394a594e6a4'
};
const AUTH_KEY = process.env.AUTH_KEY;

const MODEL_LIST = [
  {"provider":"openai","model":"gpt-4-turbo-2024-04-09"},{"provider":"google","model":"gemini-1.5-pro-exp-0801"},{"provider":"togetherai","model":"Meta-Llama-3.1-70B-Instruct-Turbo"},{"provider":"togetherai","model":"Meta-Llama-3.1-405B-Instruct-Turbo"},{"provider":"perplexity","model":"llama-3.1-sonar-large-128k-online"},{"provider":"google","model":"gemini-1.5-pro-latest"},{"provider":"anthropic","model":"claude-3-5-sonnet-20240620"},{"provider":"anthropic","model":"claude-3-haiku-20240307"},{"provider":"openai","model":"gpt-4o-mini"},{"provider":"openai","model":"gpt-4o"},{"provider":"mistral","model":"mistral-large-2407"}
];

// 这里粘贴所有的函数定义（getNotdiamondModel, createOpenAIChunk, streamNotdiamondResponse）

app.use(express.json());

app.post('/ai/v1/chat/completions', async (req, res) => {
  const authHeader = req.headers['authorization'];
  if (!authHeader || !authHeader.startsWith('Bearer ') || authHeader.slice(7) !== AUTH_KEY) {
    return res.status(401).json({ error: 'Unauthorized' });
  }

  try {
    let requestData = req.body;

    let messages = requestData.messages;
    let model = requestData.model || '';
    const stream = requestData.stream || false;

    if (!messages || !Array.isArray(messages)) {
      return res.status(400).json({ 
        error: 'Invalid request body', 
        details: 'messages should be an array of message objects',
        receivedBody: req.body
      });
    }

    try {
      const { model: resolvedModel } = await getNotdiamondModel(messages, model);
      if (resolvedModel) {
        model = resolvedModel;
      } else {
        throw new Error("Failed to get model from NotDiamond");
      }
    } catch (error) {
      return res.status(400).json({ error: error.message });
    }

    const payload = {
      messages: messages,
      model: model,
      stream: stream,
      frequency_penalty: requestData.frequency_penalty || 0,
      presence_penalty: requestData.presence_penalty || 0,
      temperature: requestData.temperature || 0.6,
      top_p: requestData.top_p || 1
    };

    const headers = {
      'Content-Type': 'application/json',
      'next-action': '4e63dabc37fef18cae74cbfd41d1bace49acf47e'
    };

    const response = await fetch(NOTDIAMOND_URL, {
      method: 'POST',
      headers: headers,
      body: JSON.stringify([payload])
    });

    const generator = streamNotdiamondResponse(response, model);
    
    if (stream) {
      res.writeHead(200, { 
        'Content-Type': 'text/event-stream',
        'Cache-Control': 'no-cache',
        'Connection': 'keep-alive'
      });

      for await (const chunk of generator) {
        res.write(`data: ${JSON.stringify(chunk)}\n\n`);
      }
      res.write("data: [DONE]\n\n");
      res.end();
    } else {
      let fullContent = "";
      for await (const chunk of generator) {
        if (chunk.choices[0].delta.content) {
          fullContent += chunk.choices[0].delta.content;
        }
      }

      res.json({
        id: `chatcmpl-${crypto.randomUUID()}`,
        object: "chat.completion",
        created: Math.floor(Date.now() / 1000),
        model: model,
        system_fingerprint: "fp_4e2b2da518",
        choices: [
          {
            index: 0,
            message: {
              role: "assistant",
              content: fullContent
            },
            finish_reason: "stop"
          }
        ],
        usage: {
          prompt_tokens: Math.floor(fullContent.length / 4),
          completion_tokens: Math.floor(fullContent.length / 4),
          total_tokens: Math.floor(fullContent.length / 2)
        }
      });
    } 
  } catch (error) {
    res.status(500).json({ 
      error: 'Internal Server Error', 
      details: error.message
    });
  }
});

app.listen(port, () => {
  console.log(`Server running on port ${port}`);
});