const express = require('express');
const crypto = require('crypto');
const router = express.Router();
const { titleConvo, getCitations, citeText, askBing } = require('../../app/');
const { saveMessage, getConvoTitle, saveConvo } = require('../../models');
const { handleError, sendMessage, createOnProgress } = require('./handlers');
const citationRegex = /\[\^\d+?\^]/g;

router.post('/', async (req, res) => {
  const { model, text, parentMessageId, conversationId: oldConversationId, ...convo } = req.body;
  if (text.length === 0) {
    return handleError(res, { text: 'Prompt empty or too short' });
  }

  const conversationId = oldConversationId || crypto.randomUUID();
  const isNewConversation = !oldConversationId

  const userMessageId = crypto.randomUUID();
  const userParentMessageId = parentMessageId || '00000000-0000-0000-0000-000000000000'
  let userMessage = {
    messageId: userMessageId, 
    sender: 'User', 
    text, 
    parentMessageId: userParentMessageId,
    conversationId, 
    isCreatedByUser: true 
 };

 console.log('ask log', {
    model,
    ...userMessage,
    ...convo
  });

  await saveMessage(userMessage);
  await saveConvo({ ...userMessage, model, ...convo });

  return await ask({
    isNewConversation,
    userMessage, 
    model,
    convo,
    preSendRequest: true,
    req, res 
  });
})

const ask = async ({ 
  isNewConversation,
  overrideParentMessageId = null,
  userMessage, 
  model,
  convo,
  preSendRequest = true,
  req, res 
}) => {
  let { sender, text, parentMessageId: userParentMessageId, conversationId, messageId: userMessageId } = userMessage;

  res.writeHead(200, {
    Connection: 'keep-alive',
    'Content-Type': 'text/event-stream',
    'Cache-Control': 'no-cache, no-transform',
    'Access-Control-Allow-Origin': '*',
    'X-Accel-Buffering': 'no'
  });

  if (preSendRequest)
    sendMessage(res, { message: userMessage, created: true });

  try {
    const progressCallback = createOnProgress();
    let response = await askBing({
      text,
      onProgress: progressCallback.call(null, model, {res, text, parentMessageId: overrideParentMessageId || userMessageId }),
      convo: {
        ...convo,
        parentMessageId: userParentMessageId,
        conversationId,
      },
    });

    console.log('BING RESPONSE', response);
    // console.dir(response, { depth: null });
    const hasCitations = response.response.match(citationRegex)?.length > 0;

    userMessage.conversationSignature =
      convo.conversationSignature || response.conversationSignature;
    userMessage.conversationId = response.conversationId || conversationId;
    userMessage.invocationId = response.invocationId;
    await saveMessage(userMessage);
    
    // Bing API will not use our conversationId at the first time,
    // so change the placeholder conversationId to the real one.
    // Attition: the api will also create new conversationId while using invalid userMessage.parentMessageId,
    // but in this situation, don't change the conversationId, but create new convo.
    if (conversationId != userMessage.conversationId && isNewConversation) 
      await saveConvo({ conversationId: conversationId, newConversationId: userMessage.conversationId });
    conversationId = userMessage.conversationId;

    response.text = response.response;
    delete response.response;
    // response.id = response.details.messageId;
    response.suggestions =
      response.details.suggestedResponses &&
      response.details.suggestedResponses.map((s) => s.text);
    response.sender = model;
    // response.final = true;

    // override the parentMessageId, for the regeneration.
    response.parentMessageId = overrideParentMessageId || response.parentMessageId || userMessageId;

    const links = getCitations(response);
    response.text =
      citeText(response) +
      (links?.length > 0 && hasCitations ? `\n<small>${links}</small>` : '');

    await saveMessage(response);
    await saveConvo({...response, model, ...convo});
    sendMessage(res, {
      title: await getConvoTitle(conversationId),
      final: true, 
      requestMessage: userMessage, 
      responseMessage: response
    });
    res.end();

    if (userParentMessageId == '00000000-0000-0000-0000-000000000000') {
      const title = await titleConvo({
        model,
        message: text,
        response: JSON.stringify(response?.text)
      });

      console.log('CONVERSATION TITLE', title);
      
      await saveConvo({
        conversationId,
        title
      })
    }
  } catch (error) {
    console.log(error);
    // await deleteMessages({ messageId: userMessageId });
    const errorMessage = { 
      messageId: crypto.randomUUID(), sender: model, 
      conversationId, parentMessageId: overrideParentMessageId || userMessageId,
      error: true, text: error.message}
    await saveMessage(errorMessage);
    handleError(res, errorMessage);
  }
};

module.exports = router;