const api        = require('./gitter-api');
const fetch      = require("node-fetch");
const mongoose   = require('mongoose');
const Task       = require('../models/todoListModel');
mongoose.Promise = global.Promise;

const buildMessage = (message) => {
  return {
    messageId: message.id,
    text: message.text,
    html: message.html,
    sent: message.sent,
    userId: message.fromUser.id,
    username: message.fromUser.username,
    displayName: message.fromUser.displayName,
    url: message.fromUser.url,
    avatarUrl: message.fromUser.avatarUrl,
    avatarUrlSmall: message.fromUser.avatarUrlSmall,
    avatarUrlMedium: message.fromUser.avatarUrlMedium,
    v: message.fromUser.v,
    gv: message.fromUser.gv,
    readBy: message.readBy,
    urls: message.urls,
    mentions: message.mentions,
  };
}

const createTaskAndSaveToDb = (messageObj) => {
  let message = buildMessage(messageObj);
  new Task(message).save((err, message) => {
    (err) && console.log(err);

  });
}

const findMessageById = (createTaskAndSaveToDb, messageObj, index, callback) => {
  Task.find({ messageId: messageObj.id }, (err, message) => {
    (err) && console.log(err);
    // console.log(message);
    if(message.length === 0){
      console.log( `${index} it is no message in db ${messageObj.id}`)
      createTaskAndSaveToDb(messageObj, callback);
    } else {
      console.log(`${index} message already exist ${messageObj.id}`)
    }
   }).limit(1);
}

const getData = (response, callback) => {
  let messages = response;
  if(messages.length) {
    messages.forEach((messageObj, index) => {
      findMessageById(createTaskAndSaveToDb, messageObj, index, callback);
    });
  }
}

const promises = [];

const request = (serverResult, callbackGetData, beforeOrAfter, id, doneCb) => {
  let numberOfMessages = 100;
  let url = api.getUrlToMessages(numberOfMessages, beforeOrAfter, id);
  fetch(url)
    .then(res => {
      res.json().then(response => {
        if(response.length == 0){ //corner case: if count of messages is XX00 aka 3500
          console.log(`response retrieve empty array - ${response}\r\n======================finished!========================`);
        }
        else {
          var oldestMessageId = response[0].id;
          Task.find({ messageId: oldestMessageId }, (err, message) => {
            (err) && console.log(err);

            // callbackGetData(response);

            if(message.length === 1){ //if oldest message in response already in db
              callbackGetData(response); //save messages only if it is new and filter old by each "find"
              returnJsonResult (serverResult, beforeOrAfter);
            } else { //if NO message in db

              if(response.length == numberOfMessages) {
                promises.push(Task.insertMany(response)) // insert promise into array and move further
                request(serverResult, callbackGetData, beforeOrAfter, oldestMessageId, doneCb); // fetch again
              }
              else {
                promises.push(Task.insertMany(response))
                Promise.all(promises).then(()=> returnJsonResult(serverResult, beforeOrAfter));
              }
            }
          });
        }
      });
    })
    .catch(error => {
      console.log(error);
  });
}

function returnJsonResult (serverResult, beforeOrAfter) {
  if(serverResult) {
    Task.count({}, function( err, count){
      (err) && serverResult.send(err);
      serverResult.json({type: beforeOrAfter, count: count, status: 'finished!'});
    });
  }
  console.log("======================finished!========================");
}