Lidarr/UI/Shared/Grid/Pager.js

'use strict';
define([
    'app',
    'backgrid',
    'backgrid.paginator'
], function () {

    NzbDrone.Shared.Grid.Pager = Backgrid.Extension.Paginator.extend({

        template: 'Shared/Grid/PagerTemplate',

        events: {
            'click .pager-btn': 'changePage'
        },

        windowSize: 1,

        fastForwardHandleLabels: {
            first: 'icon-fast-backward',
            prev : 'icon-backward',
            next : 'icon-forward',
            last : 'icon-fast-forward'
        },

        changePage: function (e) {
            e.preventDefault();

            var target = $(e.target);

            if (target.closest('li').hasClass('disabled')) {
                return;
            }

            var label = target.attr('data-action');
            var ffLabels = this.fastForwardHandleLabels;

            var collection = this.collection;

            if (ffLabels) {
                switch (label) {
                    case 'first':
                        collection.getFirstPage();
                        return;
                    case 'prev':
                        if (collection.hasPrevious()) {
                            collection.getPreviousPage();
                        }
                        return;
                    case 'next':
                        if (collection.hasNext()) {
                            collection.getNextPage();
                        }
                        return;
                    case 'last':
                        collection.getLastPage();
                        return;
                }
            }

            var state = collection.state;
            var pageIndex = $(e.target).text() * 1;
            collection.getPage(state.firstPage === 0 ? pageIndex - 1 :pageIndex);
        },

        makeHandles: function () {

            var handles = [];
            var collection = this.collection;
            var state = collection.state;

            // convert all indices to 0-based here
            var firstPage = state.firstPage;
            var lastPage = +state.lastPage;
            lastPage = Math.max(0, firstPage ? lastPage - 1 :lastPage);
            var currentPage = Math.max(state.currentPage, state.firstPage);
            currentPage = firstPage ? currentPage - 1 :currentPage;
            var windowStart = Math.floor(currentPage / this.windowSize) * this.windowSize;
            var windowEnd = Math.min(lastPage + 1, windowStart + this.windowSize);

            if (collection.mode !== 'infinite') {
                for (var i = windowStart; i < windowEnd; i++) {
                    handles.push({
                        label     : i + 1,
                        title     : 'No. ' + (i + 1),
                        className : currentPage === i ? 'active' :undefined,
                        pageNumber: i + 1
                    });
                }
            }

            var ffLabels = this.fastForwardHandleLabels;
            if (ffLabels) {

                if (ffLabels.prev) {
                    handles.unshift({
                        label    : ffLabels.prev,
                        className: collection.hasPrevious() ? void 0 :'disabled',
                        action   : 'prev'
                    });
                }

                if (ffLabels.first) {
                    handles.unshift({
                        label    : ffLabels.first,
                        className: collection.hasPrevious() ? void 0 :'disabled',
                        action   : 'first'
                    });
                }

                if (ffLabels.next) {
                    handles.push({
                        label    : ffLabels.next,
                        className: collection.hasNext() ? void 0 :'disabled',
                        action   : 'next'
                    });
                }

                if (ffLabels.last) {
                    handles.push({
                        label    : ffLabels.last,
                        className: collection.hasNext() ? void 0 :'disabled',
                        action   : 'last'
                    });
                }
            }

            return handles;
        },

        render: function () {
            this.$el.empty();

            var templateFunction = Marionette.TemplateCache.get(this.template);

            this.$el.html(templateFunction({
                handles: this.makeHandles()
            }));

            this.delegateEvents();

            return this;
        }
    });

    return NzbDrone.Shared.Grid.Pager;
});