mediawiki-extensions-RevisionSlider/modules/ext.RevisionSlider.Slider.js

/**
 * @external RevisionList
 * @external SliderView
 */
/**
 * Module handling the slider logic of the RevisionSlider
 *
 * @class Slider
 * @param {RevisionList} revisions
 * @constructor
 */
function Slider( revisions ) {
	this.revisions = revisions;
	this.view = new mw.libs.revisionSlider.SliderView( this );
}

/**
 * @class mw.libs.revisionSlider.Slider
 */
$.extend( Slider.prototype, {
	/**
	 * @type {RevisionList}
	 */
	revisions: null,

	/**
	 * @type {number}
	 */
	oldestVisibleRevisionIndex: 0,

	/**
	 * @type {number}
	 */
	revisionsPerWindow: 0,

	/**
	 * @type {SliderView}
	 */
	view: null,

	/**
	 * @return {RevisionList}
	 */
	getRevisionList: function () {
		return this.revisions;
	},

	/**
	 * @return {SliderView}
	 */
	getView: function () {
		return this.view;
	},

	/**
	 * Sets the number of revisions that are visible at once (depending on browser window size)
	 *
	 * @param {number} n
	 */
	setRevisionsPerWindow: function ( n ) {
		this.revisionsPerWindow = n;
	},

	/**
	 * @return {number}
	 */
	getRevisionsPerWindow: function () {
		return this.revisionsPerWindow;
	},

	/**
	 * Returns the index of the oldest revision that is visible in the current window
	 *
	 * @return {number}
	 */
	getOldestVisibleRevisionIndex: function () {
		return this.oldestVisibleRevisionIndex;
	},

	/**
	 * Returns the index of the newest revision that is visible in the current window
	 *
	 * @return {number}
	 */
	getNewestVisibleRevisionIndex: function () {
		return this.oldestVisibleRevisionIndex + this.revisionsPerWindow - 1;
	},

	/**
	 * @return {boolean}
	 */
	isAtStart: function () {
		return this.getOldestVisibleRevisionIndex() === 0 || this.revisions.getLength() <= this.revisionsPerWindow;
	},

	/**
	 * @return {boolean}
	 */
	isAtEnd: function () {
		return this.getNewestVisibleRevisionIndex() === this.revisions.getLength() - 1 || this.revisions.getLength() <= this.revisionsPerWindow;
	},

	/**
	 * Sets the index of the first revision that is visible in the current window
	 *
	 * @param {number} value
	 */
	setFirstVisibleRevisionIndex: function ( value ) {
		this.oldestVisibleRevisionIndex = value;
	},

	/**
	 * Sets the new oldestVisibleRevisionIndex after sliding in a direction
	 *
	 * @param {number} direction - Either -1, 0 or 1
	 */
	slide: function ( direction ) {
		var highestPossibleFirstRev = this.revisions.getLength() - this.revisionsPerWindow;

		this.oldestVisibleRevisionIndex += direction * this.revisionsPerWindow;
		this.oldestVisibleRevisionIndex = Math.min( this.oldestVisibleRevisionIndex, highestPossibleFirstRev );
		this.oldestVisibleRevisionIndex = Math.max( 0, this.oldestVisibleRevisionIndex );
	}
} );

mw.libs.revisionSlider = mw.libs.revisionSlider || {};
mw.libs.revisionSlider.Slider = Slider;