import Ember from 'ember';

export default Ember.Service.extend({
  store: Ember.inject.service(),

  setup: function(options) {
    this.setProperties({
      at: options.at,
      trackableType: options.trackableType
    });
    this.set('newTrackings', Ember.A([]));
  },

  existingTrackings: Ember.computed('at', 'trackableType', function() {
    return this.get('store').query('tracking', {
      at: this.get('at'), trackable_type: this.get('trackableType')
    });
  }),

  track: function(trackable, colorId, callback) {
    //save new tracking for trackable and then add it to cache
    //so that user can see it immediately without having to re-query the store
    var tracking = this.get('store').createRecord('tracking', {trackable: trackable, colorId: colorId});
    tracking.save().then( savedTracking => {
      this.get('newTrackings').pushObject(savedTracking);
      if (Ember.isPresent(callback)) {
        callback(savedTracking);
      }
    });
  },

  /* params can be either:
       {tracking: aTracking}
     or:
       {
         trackable: aTrackable,
         trackableType: 'Condition' | 'Symptom' | 'Treatment'
       }
  */
  untrack: function(params, callback) {
    if (Ember.isPresent(params.tracking)) {
      this.destroyTracking(params.tracking, callback);
    } else {
      this.set('trackableType', params.trackableType);
      this.get('existingTrackings').then(trackings => {
        let tracking = trackings.find(record => {
          return this.compare(record, params.trackable);
        });
        if (!Ember.isPresent(tracking)) {
          tracking = this.get('newTrackings').find(record => {
            return this.compare(record, params.trackable);
          });
        }
        if (Ember.isPresent(tracking)) {
          this.destroyTracking(tracking, callback);
        }
      });
    }
  },

  compare: function(tracking, trackable) {
    return Ember.isEqual(tracking.get('trackable.id'), trackable.get('id')) &&
           Ember.isEqual(tracking.get('trackableType').toLowerCase(), trackable.get('constructor.modelName'));
  },

  destroyTracking: function(tracking, callback) {
    tracking.destroyRecord().then(function() {
      if (Ember.isPresent(callback)) {
        callback();
      }
    });
  }

});