const Challenge = require("../../models/challenge");
const Session = require("../../models/session");
const Participation = require("../../models/participation");
const Group = require("../../models/group");
const User = require('../../models/user');

const Joi = require("joi");
/*POST /api/challenge/getChallenge
{
    challengeName: "challengeName"
}
*/
exports.getChallenge = async (ctx) => {
  try {
    const { challengeName } = ctx.request.body;
    const challenge = await Challenge.findByChallengeName(challengeName).select('-_id');
    if (!challenge) {
      ctx.status = 401;
      return;
    }
    ctx.body = challenge;
  } catch (e) {
    ctx.throw(500, e);
  }
};
/*POST /api/challenge/addChallenge
{
    challengeName: "challengeName",
    startDate: Date Object,
    endDate: Date Object,
    durationPerSession: "2w", // '1d' means one day per session, '2w' means 2 weeks per session, '3m' means 3 months per session.
    goalPerSession: 3,
}
*/
exports.addChallenge = async (ctx) => {
  const schema = Joi.object()
    .keys({
      challengeName: Joi.string(),
      startDate: Joi.date(),
      endDate: Joi.date(),
      durationPerSession: Joi.string(),
      goalPerSession: Joi.number()
    })
    .unknown();
  const result = Joi.validate(ctx.request.body, schema);

  if (result.error) {
    ctx.status = 400;
    ctx.body = result.error;
    return;
  }
  const {
    challengeName,
    startDate,
    endDate,
    durationPerSession,
    goalPerSession,
  } = ctx.request.body;

  try {
    const isChallengeExist = await Challenge.findByChallengeName(challengeName).select('-_id');

    if (isChallengeExist) {
      ctx.status = 409;
      return;
    }
    const challenge = new Challenge({
      challengeName,
      startDate,
      endDate,
      durationPerSession,
      goalPerSession,
    });

    await challenge.save();
    
    const newChallenge=await Challenge.findByChallengeName(challengeName);
    const newChallenge_id=newChallenge._id;
    const timeStep=Number(durationPerSession.slice(0,-1))
    for(let s_date=startDate,e_date=s_date;s_date<endDate;){
      if(durationPerSession[durationPerSession.length-1]==='d'){
        e_date.setDate(s_date.getDate()+timeStep);
      }
      else if(durationPerSession[durationPerSession.length-1]==='w'){
        e_date.setDate(s_date.getDate()+timeStep*7);
      }
      else if(durationPerSession[durationPerSession.length-1]==='m'){
        e_date.setMonth(s_date.getMonth()+timeStep);
      }
      e_date.setMinutes(e_date.getMinutes()-1);
      if(e_date>endDate){
        break;
      }
      let status="";
      if (s_date>new Date()){
        status="enrolled";
      }
      else if (s_date<=new Date() && new Date() <= e_date){
        status="progress";
      }
      else{
        status="end";
      }
      const session=new Session({
        challengeId:newChallenge_id,
        sessionStartDate:s_date,
        sessionEndDate:e_date,
        status:status,
      });
      await session.save();
      s_date=e_date;
      s_date.setMinutes(s_date.getMinutes()+1);
    }
    ctx.body = challenge();
  } catch (e) {
    ctx.throw(500, e);
  }
};


/* GET /api/challenge/list?status
query string status can be in ['all','enrolled','progress','end']
*/
exports.list = async (ctx) => {
  try{
    const status = ctx.qs.status;
    if (status!=='all'){
      const challenges = await Challenge.find({status:status}).select('-_id');
      ctx.body = challenges;
    }
    else {
      const challenges = await Challenge.find({}).select('-_id');
      ctx.body = challenges;
    }
  }
  catch(e){
    ctx.throw(500,e);
  }
};

/* POST /api/challenge/participate
{
  username: 'username',
  challengeName: 'challengename'
}
*/

exports.participate=async (ctx)=>{
  try{
  /*
  TODO: access token validation,
  recommend:get username from access_token
  */
    const {username,challengeName}=ctx.body;
    const challenge=await Challenge.findByChallengeName(challengeName);
    const challenge_id=challenge._id;
    const user=await User.findByUsername(username);
    const user_id=user._id;
    const newGroup=new Group({
      members:[user_id],
    });
    newGroup.save();
  }
  catch(e){
    ctx.throw(500,e);
  }
};