// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
/**
* Javascript to manage the paging dropdown control.
*
* @module core/paged_content_paging_dropdown
* @copyright 2018 Ryan Wyllie <ryan@moodle.com>
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
define(
[
'jquery',
'core/custom_interaction_events',
'core/paged_content_events',
'core/pubsub'
],
function(
$,
CustomEvents,
PagedContentEvents,
PubSub
) {
var SELECTORS = {
ROOT: '[data-region="paging-dropdown-container"]',
DROPDOWN_ITEM: '[data-region="dropdown-item"]',
DROPDOWN_TOGGLE: '[data-region="dropdown-toggle"]',
ACTIVE_DROPDOWN_ITEM: '[data-region="dropdown-item"].active',
CARET: '[data-region="caret"]'
};
/**
* Get the page number.
*
* @param {jquery} item The dropdown item.
* @returns {Number}
*/
var getPageNumber = function(item) {
return parseInt(item.attr('data-page-number'), 10);
};
/**
* Get all paging dropdown items.
*
* @param {jquery} root The root element.
* @returns {jquery} A jquery object with all items.
*/
var getAllItems = function(root) {
return root.find(SELECTORS.DROPDOWN_ITEM);
};
/**
* Get all paging dropdown items with lower page numbers than the given
* dropdown item.
*
* @param {jquery} root The root element.
* @param {jquery} item The dropdown item.
* @returns {jquery} A jquery object with all items.
*/
var getPreviousItems = function(root, item) {
var pageNumber = getPageNumber(item);
return getAllItems(root).filter(function(index, element) {
return getPageNumber($(element)) < pageNumber;
});
};
/**
* Get the number of items to be loaded for the dropdown item.
*
* @param {jquery} item The dropdown item.
* @returns {Number}
*/
var getLimit = function(item) {
return parseInt(item.attr('data-item-count'), 10);
};
/**
* Get the offset of items from the start of the itemset for the given
* dropdown item.
*
* @param {jquery} root The root element.
* @param {jquery} item The dropdown item.
* @returns {Number}
*/
var getOffset = function(root, item) {
if (item.attr('data-offset') != undefined) {
return parseInt(item.attr('data-offset'), 10);
}
var offset = 0;
getPreviousItems(root, item).each(function(index, prevItem) {
prevItem = $(prevItem);
offset += getLimit(prevItem);
});
item.attr('data-offset', offset);
return offset;
};
/**
* Get the active dropdown item.
*
* @param {jquery} root The root element.
* @returns {jquery} The active dropdown item.
*/
var getActiveItem = function(root) {
return root.find(SELECTORS.ACTIVE_DROPDOWN_ITEM);
};
/**
* Create the event payload for the list of dropdown items. The event payload
* is an array of objects with one object per dropdown item.
*
* Each payload object contains the page number, limit, and offset for the
* corresponding dropdown item.
*
* For example: If we had 3 dropdown items with incrementing page numbers loading
* 25 items per page then the generated payload would look like:
* [
* {
* pageNumber: 1,
* limit: 25,
* offset: 0
* },
* {
* pageNumber: 2,
* limit: 25,
* offset: 25
* },
* {
* pageNumber: 3,
* limit: 25,
* offset: 50
* }
* ]
*
* @param {jquery} root The root element.
* @param {jquery} items The dropdown items.
* @returns {object[]} The payload for the event.
*/
var generateEventPayload = function(root, items) {
return items.map(function(index, item) {
item = $(item);
return {
pageNumber: getPageNumber(item),
limit: getLimit(item),
offset: getOffset(root, item),
};
}).get();
};
/**
* Add page number attributes to each of the given items. The page numbers
* start at 1 and increment by 1 for each item, e.g. 1, 2, 3 etc.
*
* @param {jquery} items The dropdown items.
*/
var generatePageNumbers = function(items) {
items.each(function(index, item) {
item = $(item);
item.attr('data-page-number', index + 1);
});
};
/**
* Make the given item active by setting the active class on it and firing
* the SHOW_PAGES event for the paged content to show the appropriate
* pages.
*
* @param {jquery} root The root element.
* @param {jquery} item The dropdown item.
* @param {string} id A unique id for this instance.
*/
var setActiveItem = function(root, item, id) {
var prevItems = getPreviousItems(root, item);
var allItems = prevItems.add(item);
var eventPayload = generateEventPayload(root, allItems);
var toggle = root.find(SELECTORS.DROPDOWN_TOGGLE);
var caret = toggle.find(SELECTORS.CARET);
getActiveItem(root).removeClass('active');
item.addClass('active');
// Update the dropdown toggle to show which item is selected.
toggle.html(item.text());
// Bootstrap 2 compatibility.
toggle.append(caret);
// Fire the event to tell the content to update.
PubSub.publish(id + PagedContentEvents.SHOW_PAGES, eventPayload);
};
/**
* Initialise the module by firing the SHOW_PAGES event for an existing
* active page found and setting up the event listener for the user to select
* new pages.
*
* @param {object} root The root element.
* @param {string} id A unique id for this instance.
*/
var init = function(root, id) {
root = $(root);
var items = getAllItems(root);
generatePageNumbers(items);
var activeItem = getActiveItem(root);
if (activeItem.length) {
// Fire the first event for the content to make sure it's visible.
setActiveItem(root, activeItem, id);
}
CustomEvents.define(root, [
CustomEvents.events.activate
]);
root.on(CustomEvents.events.activate, SELECTORS.DROPDOWN_ITEM, function(e, data) {
var item = $(e.target).closest(SELECTORS.DROPDOWN_ITEM);
setActiveItem(root, item, id);
data.originalEvent.preventDefault();
});
};
return {
init: init,
rootSelector: SELECTORS.ROOT,
};
});