define(["underscore", "gettext", "js/views/baseview"], function(_, gettext, BaseView) {

    var PagingHeader = BaseView.extend({
        events : {
            "click .next-page-link": "nextPage",
            "click .previous-page-link": "previousPage"
        },

        initialize: function(options) {
            var view = options.view,
                collection = view.collection;
            this.view = view;
            this.template = this.loadTemplate('paging-header');
            collection.bind('add', _.bind(this.render, this));
            collection.bind('remove', _.bind(this.render, this));
            collection.bind('reset', _.bind(this.render, this));
        },

        render: function() {
            var view = this.view,
                collection = view.collection,
                currentPage = collection.currentPage,
                lastPage = collection.totalPages - 1,
                messageHtml = this.messageHtml();
            this.$el.html(this.template({
                messageHtml: messageHtml
            }));
            this.$(".previous-page-link").toggleClass("is-disabled", currentPage === 0).attr('aria-disabled', currentPage === 0);
            this.$(".next-page-link").toggleClass("is-disabled", currentPage === lastPage).attr('aria-disabled', currentPage === lastPage);
            return this;
        },

        messageHtml: function() {
            var message = '';
            var asset_type = false;
            if (this.view.collection.assetType) {
                if (this.view.collection.sortDirection === 'asc') {
                    // Translators: sample result:
                    // "Showing 0-9 out of 25 total, filtered by Images, sorted by Date Added ascending"
                    message = gettext('Showing %(current_item_range)s out of %(total_items_count)s, ' +
                        'filtered by %(asset_type)s, sorted by %(sort_name)s ascending');
                } else {
                    // Translators: sample result:
                    // "Showing 0-9 out of 25 total, filtered by Images, sorted by Date Added descending"
                    message = gettext('Showing %(current_item_range)s out of %(total_items_count)s, ' +
                        'filtered by %(asset_type)s, sorted by %(sort_name)s descending');
                }
                asset_type = this.filterNameLabel();
            }
            else {
                if (this.view.collection.sortDirection === 'asc') {
                    // Translators: sample result:
                    // "Showing 0-9 out of 25 total, sorted by Date Added ascending"
                    message = gettext('Showing %(current_item_range)s out of %(total_items_count)s, ' +
                        'sorted by %(sort_name)s ascending');
                } else {
                    // Translators: sample result:
                    // "Showing 0-9 out of 25 total, sorted by Date Added descending"
                    message = gettext('Showing %(current_item_range)s out of %(total_items_count)s, ' +
                        'sorted by %(sort_name)s descending');
                }
            }

            return '<p>' + interpolate(message, {
                current_item_range: this.currentItemRangeLabel(),
                total_items_count: this.totalItemsCountLabel(),
                asset_type: asset_type,
                sort_name: this.sortNameLabel()
            }, true) + "</p>";
        },

        currentItemRangeLabel: function() {
            var view = this.view,
                collection = view.collection,
                start = collection.start,
                count = collection.size(),
                end = start + count;
            return interpolate('<span class="count-current-shown">%(start)s-%(end)s</span>', {
                start: Math.min(start + 1, end),
                end: end
            }, true);
        },

        totalItemsCountLabel: function() {
            var totalItemsLabel;
            // Translators: turns into "25 total" to be used in other sentences, e.g. "Showing 0-9 out of 25 total".
            totalItemsLabel = interpolate(gettext('%(total_items)s total'), {
                total_items: this.view.collection.totalCount
            }, true);
            return interpolate('<span class="count-total">%(total_items_label)s</span>', {
                total_items_label: totalItemsLabel
            }, true);
        },

        sortNameLabel: function() {
            return interpolate('<span class="sort-order">%(sort_name)s</span>', {
                sort_name: this.view.sortDisplayName()
            }, true);
        },

        filterNameLabel: function() {
            return interpolate('<span class="filter-column">%(filter_name)s</span>', {
                filter_name: this.view.filterDisplayName()
            }, true);
        },

        nextPage: function() {
            this.view.nextPage();
        },

        previousPage: function() {
            this.view.previousPage();
        }
    });

    return PagingHeader;
}); // end define();