angelovcom.net

revisions.js (33920B)

---

 /**
  * @file Revisions interface functions, Backbone classes and
  * the revisions.php document.ready bootstrap.
  *
  * @output wp-admin/js/revisions.js
  */
 
 /* global isRtl */
 
 window.wp = window.wp || {};
 
 (function($) {
 	var revisions;
 	/**
 	 * Expose the module in window.wp.revisions.
 	 */
 	revisions = wp.revisions = { model: {}, view: {}, controller: {} };
 
 	// Link post revisions data served from the back end.
 	revisions.settings = window._wpRevisionsSettings || {};
 
 	// For debugging.
 	revisions.debug = false;
 
 	/**
 	 * wp.revisions.log
 	 *
 	 * A debugging utility for revisions. Works only when a
 	 * debug flag is on and the browser supports it.
 	 */
 	revisions.log = function() {
 		if ( window.console && revisions.debug ) {
 			window.console.log.apply( window.console, arguments );
 		}
 	};
 
 	// Handy functions to help with positioning.
 	$.fn.allOffsets = function() {
 		var offset = this.offset() || {top: 0, left: 0}, win = $(window);
 		return _.extend( offset, {
 			right:  win.width()  - offset.left - this.outerWidth(),
 			bottom: win.height() - offset.top  - this.outerHeight()
 		});
 	};
 
 	$.fn.allPositions = function() {
 		var position = this.position() || {top: 0, left: 0}, parent = this.parent();
 		return _.extend( position, {
 			right:  parent.outerWidth()  - position.left - this.outerWidth(),
 			bottom: parent.outerHeight() - position.top  - this.outerHeight()
 		});
 	};
 
 	/**
 	 * ========================================================================
 	 * MODELS
 	 * ========================================================================
 	 */
 	revisions.model.Slider = Backbone.Model.extend({
 		defaults: {
 			value: null,
 			values: null,
 			min: 0,
 			max: 1,
 			step: 1,
 			range: false,
 			compareTwoMode: false
 		},
 
 		initialize: function( options ) {
 			this.frame = options.frame;
 			this.revisions = options.revisions;
 
 			// Listen for changes to the revisions or mode from outside.
 			this.listenTo( this.frame, 'update:revisions', this.receiveRevisions );
 			this.listenTo( this.frame, 'change:compareTwoMode', this.updateMode );
 
 			// Listen for internal changes.
 			this.on( 'change:from', this.handleLocalChanges );
 			this.on( 'change:to', this.handleLocalChanges );
 			this.on( 'change:compareTwoMode', this.updateSliderSettings );
 			this.on( 'update:revisions', this.updateSliderSettings );
 
 			// Listen for changes to the hovered revision.
 			this.on( 'change:hoveredRevision', this.hoverRevision );
 
 			this.set({
 				max:   this.revisions.length - 1,
 				compareTwoMode: this.frame.get('compareTwoMode'),
 				from: this.frame.get('from'),
 				to: this.frame.get('to')
 			});
 			this.updateSliderSettings();
 		},
 
 		getSliderValue: function( a, b ) {
 			return isRtl ? this.revisions.length - this.revisions.indexOf( this.get(a) ) - 1 : this.revisions.indexOf( this.get(b) );
 		},
 
 		updateSliderSettings: function() {
 			if ( this.get('compareTwoMode') ) {
 				this.set({
 					values: [
 						this.getSliderValue( 'to', 'from' ),
 						this.getSliderValue( 'from', 'to' )
 					],
 					value: null,
 					range: true // Ensures handles cannot cross.
 				});
 			} else {
 				this.set({
 					value: this.getSliderValue( 'to', 'to' ),
 					values: null,
 					range: false
 				});
 			}
 			this.trigger( 'update:slider' );
 		},
 
 		// Called when a revision is hovered.
 		hoverRevision: function( model, value ) {
 			this.trigger( 'hovered:revision', value );
 		},
 
 		// Called when `compareTwoMode` changes.
 		updateMode: function( model, value ) {
 			this.set({ compareTwoMode: value });
 		},
 
 		// Called when `from` or `to` changes in the local model.
 		handleLocalChanges: function() {
 			this.frame.set({
 				from: this.get('from'),
 				to: this.get('to')
 			});
 		},
 
 		// Receives revisions changes from outside the model.
 		receiveRevisions: function( from, to ) {
 			// Bail if nothing changed.
 			if ( this.get('from') === from && this.get('to') === to ) {
 				return;
 			}
 
 			this.set({ from: from, to: to }, { silent: true });
 			this.trigger( 'update:revisions', from, to );
 		}
 
 	});
 
 	revisions.model.Tooltip = Backbone.Model.extend({
 		defaults: {
 			revision: null,
 			offset: {},
 			hovering: false, // Whether the mouse is hovering.
 			scrubbing: false // Whether the mouse is scrubbing.
 		},
 
 		initialize: function( options ) {
 			this.frame = options.frame;
 			this.revisions = options.revisions;
 			this.slider = options.slider;
 
 			this.listenTo( this.slider, 'hovered:revision', this.updateRevision );
 			this.listenTo( this.slider, 'change:hovering', this.setHovering );
 			this.listenTo( this.slider, 'change:scrubbing', this.setScrubbing );
 		},
 
 
 		updateRevision: function( revision ) {
 			this.set({ revision: revision });
 		},
 
 		setHovering: function( model, value ) {
 			this.set({ hovering: value });
 		},
 
 		setScrubbing: function( model, value ) {
 			this.set({ scrubbing: value });
 		}
 	});
 
 	revisions.model.Revision = Backbone.Model.extend({});
 
 	/**
 	 * wp.revisions.model.Revisions
 	 *
 	 * A collection of post revisions.
 	 */
 	revisions.model.Revisions = Backbone.Collection.extend({
 		model: revisions.model.Revision,
 
 		initialize: function() {
 			_.bindAll( this, 'next', 'prev' );
 		},
 
 		next: function( revision ) {
 			var index = this.indexOf( revision );
 
 			if ( index !== -1 && index !== this.length - 1 ) {
 				return this.at( index + 1 );
 			}
 		},
 
 		prev: function( revision ) {
 			var index = this.indexOf( revision );
 
 			if ( index !== -1 && index !== 0 ) {
 				return this.at( index - 1 );
 			}
 		}
 	});
 
 	revisions.model.Field = Backbone.Model.extend({});
 
 	revisions.model.Fields = Backbone.Collection.extend({
 		model: revisions.model.Field
 	});
 
 	revisions.model.Diff = Backbone.Model.extend({
 		initialize: function() {
 			var fields = this.get('fields');
 			this.unset('fields');
 
 			this.fields = new revisions.model.Fields( fields );
 		}
 	});
 
 	revisions.model.Diffs = Backbone.Collection.extend({
 		initialize: function( models, options ) {
 			_.bindAll( this, 'getClosestUnloaded' );
 			this.loadAll = _.once( this._loadAll );
 			this.revisions = options.revisions;
 			this.postId = options.postId;
 			this.requests  = {};
 		},
 
 		model: revisions.model.Diff,
 
 		ensure: function( id, context ) {
 			var diff     = this.get( id ),
 				request  = this.requests[ id ],
 				deferred = $.Deferred(),
 				ids      = {},
 				from     = id.split(':')[0],
 				to       = id.split(':')[1];
 			ids[id] = true;
 
 			wp.revisions.log( 'ensure', id );
 
 			this.trigger( 'ensure', ids, from, to, deferred.promise() );
 
 			if ( diff ) {
 				deferred.resolveWith( context, [ diff ] );
 			} else {
 				this.trigger( 'ensure:load', ids, from, to, deferred.promise() );
 				_.each( ids, _.bind( function( id ) {
 					// Remove anything that has an ongoing request.
 					if ( this.requests[ id ] ) {
 						delete ids[ id ];
 					}
 					// Remove anything we already have.
 					if ( this.get( id ) ) {
 						delete ids[ id ];
 					}
 				}, this ) );
 				if ( ! request ) {
 					// Always include the ID that started this ensure.
 					ids[ id ] = true;
 					request   = this.load( _.keys( ids ) );
 				}
 
 				request.done( _.bind( function() {
 					deferred.resolveWith( context, [ this.get( id ) ] );
 				}, this ) ).fail( _.bind( function() {
 					deferred.reject();
 				}) );
 			}
 
 			return deferred.promise();
 		},
 
 		// Returns an array of proximal diffs.
 		getClosestUnloaded: function( ids, centerId ) {
 			var self = this;
 			return _.chain([0].concat( ids )).initial().zip( ids ).sortBy( function( pair ) {
 				return Math.abs( centerId - pair[1] );
 			}).map( function( pair ) {
 				return pair.join(':');
 			}).filter( function( diffId ) {
 				return _.isUndefined( self.get( diffId ) ) && ! self.requests[ diffId ];
 			}).value();
 		},
 
 		_loadAll: function( allRevisionIds, centerId, num ) {
 			var self = this, deferred = $.Deferred(),
 				diffs = _.first( this.getClosestUnloaded( allRevisionIds, centerId ), num );
 			if ( _.size( diffs ) > 0 ) {
 				this.load( diffs ).done( function() {
 					self._loadAll( allRevisionIds, centerId, num ).done( function() {
 						deferred.resolve();
 					});
 				}).fail( function() {
 					if ( 1 === num ) { // Already tried 1. This just isn't working. Give up.
 						deferred.reject();
 					} else { // Request fewer diffs this time.
 						self._loadAll( allRevisionIds, centerId, Math.ceil( num / 2 ) ).done( function() {
 							deferred.resolve();
 						});
 					}
 				});
 			} else {
 				deferred.resolve();
 			}
 			return deferred;
 		},
 
 		load: function( comparisons ) {
 			wp.revisions.log( 'load', comparisons );
 			// Our collection should only ever grow, never shrink, so `remove: false`.
 			return this.fetch({ data: { compare: comparisons }, remove: false }).done( function() {
 				wp.revisions.log( 'load:complete', comparisons );
 			});
 		},
 
 		sync: function( method, model, options ) {
 			if ( 'read' === method ) {
 				options = options || {};
 				options.context = this;
 				options.data = _.extend( options.data || {}, {
 					action: 'get-revision-diffs',
 					post_id: this.postId
 				});
 
 				var deferred = wp.ajax.send( options ),
 					requests = this.requests;
 
 				// Record that we're requesting each diff.
 				if ( options.data.compare ) {
 					_.each( options.data.compare, function( id ) {
 						requests[ id ] = deferred;
 					});
 				}
 
 				// When the request completes, clear the stored request.
 				deferred.always( function() {
 					if ( options.data.compare ) {
 						_.each( options.data.compare, function( id ) {
 							delete requests[ id ];
 						});
 					}
 				});
 
 				return deferred;
 
 			// Otherwise, fall back to `Backbone.sync()`.
 			} else {
 				return Backbone.Model.prototype.sync.apply( this, arguments );
 			}
 		}
 	});
 
 
 	/**
 	 * wp.revisions.model.FrameState
 	 *
 	 * The frame state.
 	 *
 	 * @see wp.revisions.view.Frame
 	 *
 	 * @param {object}                    attributes        Model attributes - none are required.
 	 * @param {object}                    options           Options for the model.
 	 * @param {revisions.model.Revisions} options.revisions A collection of revisions.
 	 */
 	revisions.model.FrameState = Backbone.Model.extend({
 		defaults: {
 			loading: false,
 			error: false,
 			compareTwoMode: false
 		},
 
 		initialize: function( attributes, options ) {
 			var state = this.get( 'initialDiffState' );
 			_.bindAll( this, 'receiveDiff' );
 			this._debouncedEnsureDiff = _.debounce( this._ensureDiff, 200 );
 
 			this.revisions = options.revisions;
 
 			this.diffs = new revisions.model.Diffs( [], {
 				revisions: this.revisions,
 				postId: this.get( 'postId' )
 			} );
 
 			// Set the initial diffs collection.
 			this.diffs.set( this.get( 'diffData' ) );
 
 			// Set up internal listeners.
 			this.listenTo( this, 'change:from', this.changeRevisionHandler );
 			this.listenTo( this, 'change:to', this.changeRevisionHandler );
 			this.listenTo( this, 'change:compareTwoMode', this.changeMode );
 			this.listenTo( this, 'update:revisions', this.updatedRevisions );
 			this.listenTo( this.diffs, 'ensure:load', this.updateLoadingStatus );
 			this.listenTo( this, 'update:diff', this.updateLoadingStatus );
 
 			// Set the initial revisions, baseUrl, and mode as provided through attributes.
 
 			this.set( {
 				to : this.revisions.get( state.to ),
 				from : this.revisions.get( state.from ),
 				compareTwoMode : state.compareTwoMode
 			} );
 
 			// Start the router if browser supports History API.
 			if ( window.history && window.history.pushState ) {
 				this.router = new revisions.Router({ model: this });
 				if ( Backbone.History.started ) {
 					Backbone.history.stop();
 				}
 				Backbone.history.start({ pushState: true });
 			}
 		},
 
 		updateLoadingStatus: function() {
 			this.set( 'error', false );
 			this.set( 'loading', ! this.diff() );
 		},
 
 		changeMode: function( model, value ) {
 			var toIndex = this.revisions.indexOf( this.get( 'to' ) );
 
 			// If we were on the first revision before switching to two-handled mode,
 			// bump the 'to' position over one.
 			if ( value && 0 === toIndex ) {
 				this.set({
 					from: this.revisions.at( toIndex ),
 					to:   this.revisions.at( toIndex + 1 )
 				});
 			}
 
 			// When switching back to single-handled mode, reset 'from' model to
 			// one position before the 'to' model.
 			if ( ! value && 0 !== toIndex ) { // '! value' means switching to single-handled mode.
 				this.set({
 					from: this.revisions.at( toIndex - 1 ),
 					to:   this.revisions.at( toIndex )
 				});
 			}
 		},
 
 		updatedRevisions: function( from, to ) {
 			if ( this.get( 'compareTwoMode' ) ) {
 				// @todo Compare-two loading strategy.
 			} else {
 				this.diffs.loadAll( this.revisions.pluck('id'), to.id, 40 );
 			}
 		},
 
 		// Fetch the currently loaded diff.
 		diff: function() {
 			return this.diffs.get( this._diffId );
 		},
 
 		/*
 		 * So long as `from` and `to` are changed at the same time, the diff
 		 * will only be updated once. This is because Backbone updates all of
 		 * the changed attributes in `set`, and then fires the `change` events.
 		 */
 		updateDiff: function( options ) {
 			var from, to, diffId, diff;
 
 			options = options || {};
 			from = this.get('from');
 			to = this.get('to');
 			diffId = ( from ? from.id : 0 ) + ':' + to.id;
 
 			// Check if we're actually changing the diff id.
 			if ( this._diffId === diffId ) {
 				return $.Deferred().reject().promise();
 			}
 
 			this._diffId = diffId;
 			this.trigger( 'update:revisions', from, to );
 
 			diff = this.diffs.get( diffId );
 
 			// If we already have the diff, then immediately trigger the update.
 			if ( diff ) {
 				this.receiveDiff( diff );
 				return $.Deferred().resolve().promise();
 			// Otherwise, fetch the diff.
 			} else {
 				if ( options.immediate ) {
 					return this._ensureDiff();
 				} else {
 					this._debouncedEnsureDiff();
 					return $.Deferred().reject().promise();
 				}
 			}
 		},
 
 		// A simple wrapper around `updateDiff` to prevent the change event's
 		// parameters from being passed through.
 		changeRevisionHandler: function() {
 			this.updateDiff();
 		},
 
 		receiveDiff: function( diff ) {
 			// Did we actually get a diff?
 			if ( _.isUndefined( diff ) || _.isUndefined( diff.id ) ) {
 				this.set({
 					loading: false,
 					error: true
 				});
 			} else if ( this._diffId === diff.id ) { // Make sure the current diff didn't change.
 				this.trigger( 'update:diff', diff );
 			}
 		},
 
 		_ensureDiff: function() {
 			return this.diffs.ensure( this._diffId, this ).always( this.receiveDiff );
 		}
 	});
 
 
 	/**
 	 * ========================================================================
 	 * VIEWS
 	 * ========================================================================
 	 */
 
 	/**
 	 * wp.revisions.view.Frame
 	 *
 	 * Top level frame that orchestrates the revisions experience.
 	 *
 	 * @param {object}                     options       The options hash for the view.
 	 * @param {revisions.model.FrameState} options.model The frame state model.
 	 */
 	revisions.view.Frame = wp.Backbone.View.extend({
 		className: 'revisions',
 		template: wp.template('revisions-frame'),
 
 		initialize: function() {
 			this.listenTo( this.model, 'update:diff', this.renderDiff );
 			this.listenTo( this.model, 'change:compareTwoMode', this.updateCompareTwoMode );
 			this.listenTo( this.model, 'change:loading', this.updateLoadingStatus );
 			this.listenTo( this.model, 'change:error', this.updateErrorStatus );
 
 			this.views.set( '.revisions-control-frame', new revisions.view.Controls({
 				model: this.model
 			}) );
 		},
 
 		render: function() {
 			wp.Backbone.View.prototype.render.apply( this, arguments );
 
 			$('html').css( 'overflow-y', 'scroll' );
 			$('#wpbody-content .wrap').append( this.el );
 			this.updateCompareTwoMode();
 			this.renderDiff( this.model.diff() );
 			this.views.ready();
 
 			return this;
 		},
 
 		renderDiff: function( diff ) {
 			this.views.set( '.revisions-diff-frame', new revisions.view.Diff({
 				model: diff
 			}) );
 		},
 
 		updateLoadingStatus: function() {
 			this.$el.toggleClass( 'loading', this.model.get('loading') );
 		},
 
 		updateErrorStatus: function() {
 			this.$el.toggleClass( 'diff-error', this.model.get('error') );
 		},
 
 		updateCompareTwoMode: function() {
 			this.$el.toggleClass( 'comparing-two-revisions', this.model.get('compareTwoMode') );
 		}
 	});
 
 	/**
 	 * wp.revisions.view.Controls
 	 *
 	 * The controls view.
 	 *
 	 * Contains the revision slider, previous/next buttons, the meta info and the compare checkbox.
 	 */
 	revisions.view.Controls = wp.Backbone.View.extend({
 		className: 'revisions-controls',
 
 		initialize: function() {
 			_.bindAll( this, 'setWidth' );
 
 			// Add the button view.
 			this.views.add( new revisions.view.Buttons({
 				model: this.model
 			}) );
 
 			// Add the checkbox view.
 			this.views.add( new revisions.view.Checkbox({
 				model: this.model
 			}) );
 
 			// Prep the slider model.
 			var slider = new revisions.model.Slider({
 				frame: this.model,
 				revisions: this.model.revisions
 			}),
 
 			// Prep the tooltip model.
 			tooltip = new revisions.model.Tooltip({
 				frame: this.model,
 				revisions: this.model.revisions,
 				slider: slider
 			});
 
 			// Add the tooltip view.
 			this.views.add( new revisions.view.Tooltip({
 				model: tooltip
 			}) );
 
 			// Add the tickmarks view.
 			this.views.add( new revisions.view.Tickmarks({
 				model: tooltip
 			}) );
 
 			// Add the slider view.
 			this.views.add( new revisions.view.Slider({
 				model: slider
 			}) );
 
 			// Add the Metabox view.
 			this.views.add( new revisions.view.Metabox({
 				model: this.model
 			}) );
 		},
 
 		ready: function() {
 			this.top = this.$el.offset().top;
 			this.window = $(window);
 			this.window.on( 'scroll.wp.revisions', {controls: this}, function(e) {
 				var controls  = e.data.controls,
 					container = controls.$el.parent(),
 					scrolled  = controls.window.scrollTop(),
 					frame     = controls.views.parent;
 
 				if ( scrolled >= controls.top ) {
 					if ( ! frame.$el.hasClass('pinned') ) {
 						controls.setWidth();
 						container.css('height', container.height() + 'px' );
 						controls.window.on('resize.wp.revisions.pinning click.wp.revisions.pinning', {controls: controls}, function(e) {
 							e.data.controls.setWidth();
 						});
 					}
 					frame.$el.addClass('pinned');
 				} else if ( frame.$el.hasClass('pinned') ) {
 					controls.window.off('.wp.revisions.pinning');
 					controls.$el.css('width', 'auto');
 					frame.$el.removeClass('pinned');
 					container.css('height', 'auto');
 					controls.top = controls.$el.offset().top;
 				} else {
 					controls.top = controls.$el.offset().top;
 				}
 			});
 		},
 
 		setWidth: function() {
 			this.$el.css('width', this.$el.parent().width() + 'px');
 		}
 	});
 
 	// The tickmarks view.
 	revisions.view.Tickmarks = wp.Backbone.View.extend({
 		className: 'revisions-tickmarks',
 		direction: isRtl ? 'right' : 'left',
 
 		initialize: function() {
 			this.listenTo( this.model, 'change:revision', this.reportTickPosition );
 		},
 
 		reportTickPosition: function( model, revision ) {
 			var offset, thisOffset, parentOffset, tick, index = this.model.revisions.indexOf( revision );
 			thisOffset = this.$el.allOffsets();
 			parentOffset = this.$el.parent().allOffsets();
 			if ( index === this.model.revisions.length - 1 ) {
 				// Last one.
 				offset = {
 					rightPlusWidth: thisOffset.left - parentOffset.left + 1,
 					leftPlusWidth: thisOffset.right - parentOffset.right + 1
 				};
 			} else {
 				// Normal tick.
 				tick = this.$('div:nth-of-type(' + (index + 1) + ')');
 				offset = tick.allPositions();
 				_.extend( offset, {
 					left: offset.left + thisOffset.left - parentOffset.left,
 					right: offset.right + thisOffset.right - parentOffset.right
 				});
 				_.extend( offset, {
 					leftPlusWidth: offset.left + tick.outerWidth(),
 					rightPlusWidth: offset.right + tick.outerWidth()
 				});
 			}
 			this.model.set({ offset: offset });
 		},
 
 		ready: function() {
 			var tickCount, tickWidth;
 			tickCount = this.model.revisions.length - 1;
 			tickWidth = 1 / tickCount;
 			this.$el.css('width', ( this.model.revisions.length * 50 ) + 'px');
 
 			_(tickCount).times( function( index ){
 				this.$el.append( '<div style="' + this.direction + ': ' + ( 100 * tickWidth * index ) + '%"></div>' );
 			}, this );
 		}
 	});
 
 	// The metabox view.
 	revisions.view.Metabox = wp.Backbone.View.extend({
 		className: 'revisions-meta',
 
 		initialize: function() {
 			// Add the 'from' view.
 			this.views.add( new revisions.view.MetaFrom({
 				model: this.model,
 				className: 'diff-meta diff-meta-from'
 			}) );
 
 			// Add the 'to' view.
 			this.views.add( new revisions.view.MetaTo({
 				model: this.model
 			}) );
 		}
 	});
 
 	// The revision meta view (to be extended).
 	revisions.view.Meta = wp.Backbone.View.extend({
 		template: wp.template('revisions-meta'),
 
 		events: {
 			'click .restore-revision': 'restoreRevision'
 		},
 
 		initialize: function() {
 			this.listenTo( this.model, 'update:revisions', this.render );
 		},
 
 		prepare: function() {
 			return _.extend( this.model.toJSON()[this.type] || {}, {
 				type: this.type
 			});
 		},
 
 		restoreRevision: function() {
 			document.location = this.model.get('to').attributes.restoreUrl;
 		}
 	});
 
 	// The revision meta 'from' view.
 	revisions.view.MetaFrom = revisions.view.Meta.extend({
 		className: 'diff-meta diff-meta-from',
 		type: 'from'
 	});
 
 	// The revision meta 'to' view.
 	revisions.view.MetaTo = revisions.view.Meta.extend({
 		className: 'diff-meta diff-meta-to',
 		type: 'to'
 	});
 
 	// The checkbox view.
 	revisions.view.Checkbox = wp.Backbone.View.extend({
 		className: 'revisions-checkbox',
 		template: wp.template('revisions-checkbox'),
 
 		events: {
 			'click .compare-two-revisions': 'compareTwoToggle'
 		},
 
 		initialize: function() {
 			this.listenTo( this.model, 'change:compareTwoMode', this.updateCompareTwoMode );
 		},
 
 		ready: function() {
 			if ( this.model.revisions.length < 3 ) {
 				$('.revision-toggle-compare-mode').hide();
 			}
 		},
 
 		updateCompareTwoMode: function() {
 			this.$('.compare-two-revisions').prop( 'checked', this.model.get('compareTwoMode') );
 		},
 
 		// Toggle the compare two mode feature when the compare two checkbox is checked.
 		compareTwoToggle: function() {
 			// Activate compare two mode?
 			this.model.set({ compareTwoMode: $('.compare-two-revisions').prop('checked') });
 		}
 	});
 
 	// The tooltip view.
 	// Encapsulates the tooltip.
 	revisions.view.Tooltip = wp.Backbone.View.extend({
 		className: 'revisions-tooltip',
 		template: wp.template('revisions-meta'),
 
 		initialize: function() {
 			this.listenTo( this.model, 'change:offset', this.render );
 			this.listenTo( this.model, 'change:hovering', this.toggleVisibility );
 			this.listenTo( this.model, 'change:scrubbing', this.toggleVisibility );
 		},
 
 		prepare: function() {
 			if ( _.isNull( this.model.get('revision') ) ) {
 				return;
 			} else {
 				return _.extend( { type: 'tooltip' }, {
 					attributes: this.model.get('revision').toJSON()
 				});
 			}
 		},
 
 		render: function() {
 			var otherDirection,
 				direction,
 				directionVal,
 				flipped,
 				css      = {},
 				position = this.model.revisions.indexOf( this.model.get('revision') ) + 1;
 
 			flipped = ( position / this.model.revisions.length ) > 0.5;
 			if ( isRtl ) {
 				direction = flipped ? 'left' : 'right';
 				directionVal = flipped ? 'leftPlusWidth' : direction;
 			} else {
 				direction = flipped ? 'right' : 'left';
 				directionVal = flipped ? 'rightPlusWidth' : direction;
 			}
 			otherDirection = 'right' === direction ? 'left': 'right';
 			wp.Backbone.View.prototype.render.apply( this, arguments );
 			css[direction] = this.model.get('offset')[directionVal] + 'px';
 			css[otherDirection] = '';
 			this.$el.toggleClass( 'flipped', flipped ).css( css );
 		},
 
 		visible: function() {
 			return this.model.get( 'scrubbing' ) || this.model.get( 'hovering' );
 		},
 
 		toggleVisibility: function() {
 			if ( this.visible() ) {
 				this.$el.stop().show().fadeTo( 100 - this.el.style.opacity * 100, 1 );
 			} else {
 				this.$el.stop().fadeTo( this.el.style.opacity * 300, 0, function(){ $(this).hide(); } );
 			}
 			return;
 		}
 	});
 
 	// The buttons view.
 	// Encapsulates all of the configuration for the previous/next buttons.
 	revisions.view.Buttons = wp.Backbone.View.extend({
 		className: 'revisions-buttons',
 		template: wp.template('revisions-buttons'),
 
 		events: {
 			'click .revisions-next .button': 'nextRevision',
 			'click .revisions-previous .button': 'previousRevision'
 		},
 
 		initialize: function() {
 			this.listenTo( this.model, 'update:revisions', this.disabledButtonCheck );
 		},
 
 		ready: function() {
 			this.disabledButtonCheck();
 		},
 
 		// Go to a specific model index.
 		gotoModel: function( toIndex ) {
 			var attributes = {
 				to: this.model.revisions.at( toIndex )
 			};
 			// If we're at the first revision, unset 'from'.
 			if ( toIndex ) {
 				attributes.from = this.model.revisions.at( toIndex - 1 );
 			} else {
 				this.model.unset('from', { silent: true });
 			}
 
 			this.model.set( attributes );
 		},
 
 		// Go to the 'next' revision.
 		nextRevision: function() {
 			var toIndex = this.model.revisions.indexOf( this.model.get('to') ) + 1;
 			this.gotoModel( toIndex );
 		},
 
 		// Go to the 'previous' revision.
 		previousRevision: function() {
 			var toIndex = this.model.revisions.indexOf( this.model.get('to') ) - 1;
 			this.gotoModel( toIndex );
 		},
 
 		// Check to see if the Previous or Next buttons need to be disabled or enabled.
 		disabledButtonCheck: function() {
 			var maxVal   = this.model.revisions.length - 1,
 				minVal   = 0,
 				next     = $('.revisions-next .button'),
 				previous = $('.revisions-previous .button'),
 				val      = this.model.revisions.indexOf( this.model.get('to') );
 
 			// Disable "Next" button if you're on the last node.
 			next.prop( 'disabled', ( maxVal === val ) );
 
 			// Disable "Previous" button if you're on the first node.
 			previous.prop( 'disabled', ( minVal === val ) );
 		}
 	});
 
 
 	// The slider view.
 	revisions.view.Slider = wp.Backbone.View.extend({
 		className: 'wp-slider',
 		direction: isRtl ? 'right' : 'left',
 
 		events: {
 			'mousemove' : 'mouseMove'
 		},
 
 		initialize: function() {
 			_.bindAll( this, 'start', 'slide', 'stop', 'mouseMove', 'mouseEnter', 'mouseLeave' );
 			this.listenTo( this.model, 'update:slider', this.applySliderSettings );
 		},
 
 		ready: function() {
 			this.$el.css('width', ( this.model.revisions.length * 50 ) + 'px');
 			this.$el.slider( _.extend( this.model.toJSON(), {
 				start: this.start,
 				slide: this.slide,
 				stop:  this.stop
 			}) );
 
 			this.$el.hoverIntent({
 				over: this.mouseEnter,
 				out: this.mouseLeave,
 				timeout: 800
 			});
 
 			this.applySliderSettings();
 		},
 
 		mouseMove: function( e ) {
 			var zoneCount         = this.model.revisions.length - 1,       // One fewer zone than models.
 				sliderFrom        = this.$el.allOffsets()[this.direction], // "From" edge of slider.
 				sliderWidth       = this.$el.width(),                      // Width of slider.
 				tickWidth         = sliderWidth / zoneCount,               // Calculated width of zone.
 				actualX           = ( isRtl ? $(window).width() - e.pageX : e.pageX ) - sliderFrom, // Flipped for RTL - sliderFrom.
 				currentModelIndex = Math.floor( ( actualX  + ( tickWidth / 2 )  ) / tickWidth );    // Calculate the model index.
 
 			// Ensure sane value for currentModelIndex.
 			if ( currentModelIndex < 0 ) {
 				currentModelIndex = 0;
 			} else if ( currentModelIndex >= this.model.revisions.length ) {
 				currentModelIndex = this.model.revisions.length - 1;
 			}
 
 			// Update the tooltip mode.
 			this.model.set({ hoveredRevision: this.model.revisions.at( currentModelIndex ) });
 		},
 
 		mouseLeave: function() {
 			this.model.set({ hovering: false });
 		},
 
 		mouseEnter: function() {
 			this.model.set({ hovering: true });
 		},
 
 		applySliderSettings: function() {
 			this.$el.slider( _.pick( this.model.toJSON(), 'value', 'values', 'range' ) );
 			var handles = this.$('a.ui-slider-handle');
 
 			if ( this.model.get('compareTwoMode') ) {
 				// In RTL mode the 'left handle' is the second in the slider, 'right' is first.
 				handles.first()
 					.toggleClass( 'to-handle', !! isRtl )
 					.toggleClass( 'from-handle', ! isRtl );
 				handles.last()
 					.toggleClass( 'from-handle', !! isRtl )
 					.toggleClass( 'to-handle', ! isRtl );
 			} else {
 				handles.removeClass('from-handle to-handle');
 			}
 		},
 
 		start: function( event, ui ) {
 			this.model.set({ scrubbing: true });
 
 			// Track the mouse position to enable smooth dragging,
 			// overrides default jQuery UI step behavior.
 			$( window ).on( 'mousemove.wp.revisions', { view: this }, function( e ) {
 				var handles,
 					view              = e.data.view,
 					leftDragBoundary  = view.$el.offset().left,
 					sliderOffset      = leftDragBoundary,
 					sliderRightEdge   = leftDragBoundary + view.$el.width(),
 					rightDragBoundary = sliderRightEdge,
 					leftDragReset     = '0',
 					rightDragReset    = '100%',
 					handle            = $( ui.handle );
 
 				// In two handle mode, ensure handles can't be dragged past each other.
 				// Adjust left/right boundaries and reset points.
 				if ( view.model.get('compareTwoMode') ) {
 					handles = handle.parent().find('.ui-slider-handle');
 					if ( handle.is( handles.first() ) ) {
 						// We're the left handle.
 						rightDragBoundary = handles.last().offset().left;
 						rightDragReset    = rightDragBoundary - sliderOffset;
 					} else {
 						// We're the right handle.
 						leftDragBoundary = handles.first().offset().left + handles.first().width();
 						leftDragReset    = leftDragBoundary - sliderOffset;
 					}
 				}
 
 				// Follow mouse movements, as long as handle remains inside slider.
 				if ( e.pageX < leftDragBoundary ) {
 					handle.css( 'left', leftDragReset ); // Mouse to left of slider.
 				} else if ( e.pageX > rightDragBoundary ) {
 					handle.css( 'left', rightDragReset ); // Mouse to right of slider.
 				} else {
 					handle.css( 'left', e.pageX - sliderOffset ); // Mouse in slider.
 				}
 			} );
 		},
 
 		getPosition: function( position ) {
 			return isRtl ? this.model.revisions.length - position - 1: position;
 		},
 
 		// Responds to slide events.
 		slide: function( event, ui ) {
 			var attributes, movedRevision;
 			// Compare two revisions mode.
 			if ( this.model.get('compareTwoMode') ) {
 				// Prevent sliders from occupying same spot.
 				if ( ui.values[1] === ui.values[0] ) {
 					return false;
 				}
 				if ( isRtl ) {
 					ui.values.reverse();
 				}
 				attributes = {
 					from: this.model.revisions.at( this.getPosition( ui.values[0] ) ),
 					to: this.model.revisions.at( this.getPosition( ui.values[1] ) )
 				};
 			} else {
 				attributes = {
 					to: this.model.revisions.at( this.getPosition( ui.value ) )
 				};
 				// If we're at the first revision, unset 'from'.
 				if ( this.getPosition( ui.value ) > 0 ) {
 					attributes.from = this.model.revisions.at( this.getPosition( ui.value ) - 1 );
 				} else {
 					attributes.from = undefined;
 				}
 			}
 			movedRevision = this.model.revisions.at( this.getPosition( ui.value ) );
 
 			// If we are scrubbing, a scrub to a revision is considered a hover.
 			if ( this.model.get('scrubbing') ) {
 				attributes.hoveredRevision = movedRevision;
 			}
 
 			this.model.set( attributes );
 		},
 
 		stop: function() {
 			$( window ).off('mousemove.wp.revisions');
 			this.model.updateSliderSettings(); // To snap us back to a tick mark.
 			this.model.set({ scrubbing: false });
 		}
 	});
 
 	// The diff view.
 	// This is the view for the current active diff.
 	revisions.view.Diff = wp.Backbone.View.extend({
 		className: 'revisions-diff',
 		template:  wp.template('revisions-diff'),
 
 		// Generate the options to be passed to the template.
 		prepare: function() {
 			return _.extend({ fields: this.model.fields.toJSON() }, this.options );
 		}
 	});
 
 	// The revisions router.
 	// Maintains the URL routes so browser URL matches state.
 	revisions.Router = Backbone.Router.extend({
 		initialize: function( options ) {
 			this.model = options.model;
 
 			// Maintain state and history when navigating.
 			this.listenTo( this.model, 'update:diff', _.debounce( this.updateUrl, 250 ) );
 			this.listenTo( this.model, 'change:compareTwoMode', this.updateUrl );
 		},
 
 		baseUrl: function( url ) {
 			return this.model.get('baseUrl') + url;
 		},
 
 		updateUrl: function() {
 			var from = this.model.has('from') ? this.model.get('from').id : 0,
 				to   = this.model.get('to').id;
 			if ( this.model.get('compareTwoMode' ) ) {
 				this.navigate( this.baseUrl( '?from=' + from + '&to=' + to ), { replace: true } );
 			} else {
 				this.navigate( this.baseUrl( '?revision=' + to ), { replace: true } );
 			}
 		},
 
 		handleRoute: function( a, b ) {
 			var compareTwo = _.isUndefined( b );
 
 			if ( ! compareTwo ) {
 				b = this.model.revisions.get( a );
 				a = this.model.revisions.prev( b );
 				b = b ? b.id : 0;
 				a = a ? a.id : 0;
 			}
 		}
 	});
 
 	/**
 	 * Initialize the revisions UI for revision.php.
 	 */
 	revisions.init = function() {
 		var state;
 
 		// Bail if the current page is not revision.php.
 		if ( ! window.adminpage || 'revision-php' !== window.adminpage ) {
 			return;
 		}
 
 		state = new revisions.model.FrameState({
 			initialDiffState: {
 				// wp_localize_script doesn't stringifies ints, so cast them.
 				to: parseInt( revisions.settings.to, 10 ),
 				from: parseInt( revisions.settings.from, 10 ),
 				// wp_localize_script does not allow for top-level booleans so do a comparator here.
 				compareTwoMode: ( revisions.settings.compareTwoMode === '1' )
 			},
 			diffData: revisions.settings.diffData,
 			baseUrl: revisions.settings.baseUrl,
 			postId: parseInt( revisions.settings.postId, 10 )
 		}, {
 			revisions: new revisions.model.Revisions( revisions.settings.revisionData )
 		});
 
 		revisions.view.frame = new revisions.view.Frame({
 			model: state
 		}).render();
 	};
 
 	$( revisions.init );
 }(jQuery));