module.exports = function() {
  const Workout = require('../../app/models/workout');
  const fs = require('fs');

  require('../../app/models/level');
  require('../../app/models/topic');
  require('../../app/models/subtopic');

  const getWorkoutTitle = function(workout) {
    return workout.title || workout.topic.name + ' ' + workout.subtopic.name + ' ' + workout.level.label;
  }

  const encodeWorkoutsIds = function(workout) {
    return workout.insights.map(i => i.toString()).join('+');
  }

  const workoutsList = {};
  const query = {
      hardcoded: true,
      done: true,
      userRating: { $exists: true },
      topic: { $exists: true },
      subtopic: { $exists: true },
      level: { $exists: true },
  };

  let counter = 0;

  Workout.count(query).then(totalWorkoutsCount => {
    const workoutStream = Workout.find(query, {
      title: 1,
      insights: 1,
      userRating: 1,
      topic: 1,
      subtopic: 1,
      level: 1
    }).populate('topic','name').populate('subtopic','name').populate('level', 'label')
      .limit(30).lean().stream();

    workoutStream.on('data', workout => {
      workoutStream.pause();

      const encoded = encodeWorkoutsIds(workout);
      if(!workoutsList[encoded]) {
        workoutsList[encoded] = {
          title: getWorkoutTitle(workout),
          insights: workout.insights.map(i => i.toString()),
          avg: workout.userRating,
          count: 1,
          sum: workout.userRating,
          topic: workout.topic.name,
          subtopics: workout.subtopic.name,
          level: workout.level.label,
        }
      } else {
        workoutsList[encoded].count += 1;
        workoutsList[encoded].sum += workout.userRating;
        workoutsList[encoded].avg = workoutsList[encoded].sum /
          workoutsList[encoded].count;
      }

      counter += 1;
      console.log(counter + '/' + totalWorkoutsCount);
      workoutStream.resume();
    });


    workoutStream.on('end', () => {
      console.log('done');
      // console.log(workoutsList);
      fs.writeFile('output.txt', JSON.stringify(workoutsList, null, 2), err => {
        if (err) console.log('something wrong happened', err);
        console.log('done writing to file');
        process.exit(0);
      })
    });

    workoutStream.on('error', err =>{
      console.log(err);
      process.exit(1);
    });

  });
};