const axios = require('axios');

exports.handler = function(context, event, callback) {
  /* Assemble vars */
  const { Body } = event;
  const summonerName = Body;
  const championPoolUrl = context.Riot_Champion_Pool_Url;
  const summonerGetUrl = context.Riot_Base_Url + '/lol/summoner/v4/summoners/by-name/' + summonerName + "?api_key=" + context.Riot_Api_Key;

  /* Set up inital axios HTTP promises */
  // Retrieves static champion information from Data Dragon
  let championsPromise = 
    axios
      .get(championPoolUrl)
      .catch((error) => logErrorAndReturn(error, callback));

  // Retrieves summoner information
  let summonerPromise = 
    axios
      .get(summonerGetUrl)
      .catch((error) => {
        if(error.response.status == 404)
          handleSummonerNotFound(summonerName, callback)
        else
          logErrorAndReturn(error, callback)
      });

  /* Promise Logic */
  Promise
    .all([championsPromise, summonerPromise])
    .then((responses) => {
      /* Parse out responses */
      let championsResponse = responses[0];
      let summonerResponse = responses[1];
      let champions = championsResponse.data.data;

      /* Successful summoner lookup */
      if (summonerResponse.status == 200)
      {
        handleSummonerFound(summonerName, summonerResponse.data.summonerLevel, summonerResponse.data.id, champions, context, callback);
      }
      /* Other status code */
      else
      {
        logErrorAndReturn("Whoops! Looks like an issue communicating with Riot! Please try again later.", callback);
      }
    })
};

/* Matches champion Id from the Masteries information to the static information from DataDragon to get the champion name */
function getTopChampionName(champions, topChampionId) {
  for(const prop in champions)
  {
    if(champions[prop] != null && 
      champions[prop] !== 'undefined' && 
      champions[prop].key.toString() == topChampionId.toString())
    {
      return champions[prop].id;
    }
  }
}

/* Assembles the text response with releveant summoner and champion mastery information */
function handleSummonerFound(summonerName, summonerLevel, summonerId, champions, context, callback){
  /* Variable Set Up */
  const masteriesBaseUrl = context.Riot_Base_Url + '/lol/champion-mastery/v4/champion-masteries/by-summoner/' + summonerId + '?api_key=' + context.Riot_Api_Key;
  let message = "Summoner " + summonerName + " found. " + summonerName + " is level " + summonerLevel + ". ";
  let twiml = new Twilio.twiml.MessagingResponse()

  console.log("Summoner found!");

  axios
    .get(masteriesBaseUrl)
    .then((masteryResponse) => {
      let topChampionId = masteryResponse.data[0].championId;
      let topChampionPoints = masteryResponse.data[0].championPoints;
      let topChampion = getTopChampionName(champions, topChampionId);
      message += summonerName + "'s champion with the highest points is " + topChampion + ", at " + topChampionPoints + " points!";
      twiml.message(message);
      completeCallback(twiml, callback);
    })
    .catch((error) => {
      logErrorAndReturn(error, callback);
    })
}

/* Handles no summoner found cleanly */
function handleSummonerNotFound(summonerName, callback) {
  let twiml = new Twilio.twiml.MessagingResponse()
  twiml.message("Summoner " + summonerName + " was not found.")
  console.log("Summoner not found.");
  completeCallback(twiml, callback);
}

/* Generic error and log catching function */
function logErrorAndReturn(error, callback) {
  console.log(error);
  callback(error, null);
}

/* Generic callback completion function */
function completeCallback(twiml, callback){
  callback(null, twiml)
}