paginator.js

import Ember from 'ember';

export default Ember.Object.extend({
  store: null,
  model: null,

  currPage: 1,
  pageSize: 30,
  cacheSize: 5,

  params: null,
  request: null,
  cache: null,
  meta: null,

  pageRecords: null,

  countFiltered: Ember.computed.alias('meta.count_filtered'),
  countTotal: Ember.computed.alias('meta.count_total'),

  initialize: function() {
    Ember.assert('Erorr: Pager must have a store!', !Ember.isNone(this.get('store')));
    Ember.assert('Erorr: Pager must have a model!', !Ember.isNone(this.get('model')));

    this.set('pageRecords', []);
  }.on('init'),

  isLoading: Ember.computed.equal('request.isPending', true),
  metaIsEmpty: Ember.computed.empty('meta'),
  isRefreshing: Ember.computed.and('isLoading', 'metaIsEmpty'),

  prevButtonIsDisabled: Ember.computed.or('isLoading', 'isFirstPage'),
  nextButtonIsDisabled: Ember.computed.or('isLoading', 'isLastPage'),

  load: function(params) {
    this.setProperties({
      params: params,
      request: null,
      cache: [],
      meta: null,
      currPage: 1
    });

    this.updatePageRecords();
  },

  updatePageRecords: function() {
    var currPage = this.get('currPage');
    var pageSize = this.get('pageSize');
    var cacheSize = this.get('cacheSize');
    var cache = this.get('cache');
    var start = (currPage - 1) * pageSize;
    var pageRecords = this.get('pageRecords');
    var cacheRecords = cache.slice(start, start + pageSize);

    pageRecords.setObjects(cacheRecords);

    if (Ember.isEmpty(pageRecords)) {
      var self = this;
      var store = this.get('store');
      var model = this.get('model');
      var params = this.get('params');
      var data = {
        filter: params.filter,
        orderColumn: params.orderColumn,
        orderDirection: params.orderDirection,
        offset: start,
        limit: pageSize * cacheSize
      };

      var request = store.find(model, data);
      this.set('request', request);

      request.then(function(data) {
        if (request === self.get('request')) {
          var meta = data.get('meta');
          self.set('meta', meta);

          var records = data.get('content');
          cache.pushObjects(records);

          var cacheRecords = cache.slice(start, start + pageSize);
          pageRecords.setObjects(cacheRecords);
        }
      });
    }
  }.observes('currPage'),

  maxPage: function() {
    var countFiltered = this.get('countFiltered');
    var pageSize = this.get('pageSize');
    var page = Math.ceil(countFiltered / pageSize);

    return (page === 0) ? 1 : page;
  }.property('meta.count_filtered', 'pageSize'),

  currPageStart: function() {
    var currPage = this.get('currPage');
    var pageSize = this.get('pageSize');
    var index = (currPage - 1) * pageSize + 1;

    return index;
  }.property('currPage', 'pageSize', 'countFiltered'),

  currPageStop: function() {
    var maxPage = this.get('maxPage');
    var currPage = this.get('currPage');
    var pageSize = this.get('pageSize');
    var countFiltered = this.get('countFiltered');
    var index = null;

    if (currPage < maxPage) {
      index = currPage * pageSize;
    } else {
      index = countFiltered;
    }

    return index;
  }.property('currPage', 'pageSize', 'countFiltered'),

  gotoPrevPage: function() {
    if (!this.get('isFirstPage')) {
      this.decrementProperty('currPage');
    }
  },

  gotoNextPage: function() {
    if (!this.get('isLastPage')) {
      this.incrementProperty('currPage');
    }
  },

  isFirstPage: function() {
    return this.get('currPage') === 1;
  }.property('currPage'),

  isLastPage: function() {
    var currPage = this.get('currPage');
    var maxPage = this.get('maxPage');

    return currPage === maxPage;
  }.property('currPage', 'maxPage')
});