const aiFollowupQuestion = async (req, res) => {
  // curl -X POST http://localhost:3000/your-endpoint-path \
  //   -H "Content-Type: application/json" \
  //   -d '{
  //     "prompt": "Why is the sky blue?",
  //     "sessionId": "",
  //     "model": "gpt-3.5-turbo-16k",
  //     "max_tokens": 200
  //   }'

  // curl -X POST http://localhost:5174/api/aiFollowupQuestion \
  // -H "Content-Type: application/json" \
  // -d '{
  // "prompt": "Why is the sky blue?",
  // "sessionId": "",
  // "model": "gpt-3.5-turbo-16k",
  // "sessionId" : "8c641aca-582d-4ea7-8e56-4f94318efe74",
  // "max_tokens": 200
  // }'

  // {
  //   "success": true,
  //   "data": "The sky looks blue because of how sunlight scatters in the air. Great question! Ask me more!",
  //   "total_tokens": 45,
  //   "sessionId": "2a3b3cc4-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
  // }

  const { MongoClient } = require('mongodb');
  // const fetch = require('node-fetch');
  const { v4: uuidv4 } = require('uuid');
  const url = process.env.MONGODB_URL;
  const dbName = process.env.MONGO_DB_NAME;
  const client = new MongoClient(url);

  await client.connect();
  const database = client.db(dbName);
  const conversationsCollection = database.collection('conversations');

  async function fetchOpenAICompletion(prompt, messages, model = 'gpt-3.5-turbo-16k', max_tokens = 200) {
    const response = await fetch('https://api.openai.com/v1/chat/completions', {
      method: 'POST',
      headers: {
        Authorization: `Bearer ${process.env.OPENAI_KEY}`,
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({
        model: model,
        messages: messages,
        // messages: [
        //     { role: "system", content: "reply must not exceed 20 words" },
        //     { role: "user", content: messages }
        // ],
        max_tokens: max_tokens,
      }),
    });

    const data = await response.json();
    // console.log(process.env.OPENAI_KEY)
    // console.log(data)
    return data;
  }

  try {
    const { prompt, sessionId, model = 'gpt-3.5-turbo-16k', max_tokens = 200 } = req.body;
    if (!conversationsCollection) {
      return res.status(500).json({
        success: false,
        error: 'MongoDB is not connected yet. Please try again later.',
      });
    }
    let conversation;

    if (!sessionId) {
      const newSessionId = uuidv4();

      conversation = {
        sessionId: newSessionId,
        conversationHistory: [
          {
            role: 'system',
            content:
              'Reply to the questions asked by a kindergarten child, Sound excited to answer and encourage the child to ask more questions in 30 words',
          },
          { role: 'user', content: prompt },
        ],
      };
      await conversationsCollection.insertOne(conversation);
    } else {
      conversation = await conversationsCollection.findOne({ sessionId: sessionId });
      if (!conversation) {
        return res.status(400).json({
          success: false,
          error: 'Invalid session ID.',
        });
      }
      conversation.conversationHistory.push({ role: 'user', content: prompt });
    }

    const aiResponse = await fetchOpenAICompletion(prompt, conversation.conversationHistory, model, max_tokens);

    conversation.conversationHistory.push({ role: 'assistant', content: aiResponse.choices[0].message.content });

    await conversationsCollection.updateOne(
      { sessionId: conversation.sessionId },
      { $set: { conversationHistory: conversation.conversationHistory } }
    );

    res.json({
      success: true,
      data: aiResponse.choices[0].message.content,
      total_tokens: aiResponse.usage.total_tokens,
      sessionId: conversation.sessionId,
    });
  } catch (error) {
    console.error('Error generating response:', error.message);
    res.status(500).json({
      success: false,
      error: 'Something went wrong. Please try again later.',
    });
  }
};

module.exports = aiFollowupQuestion;