module.exports = Marionette.Behavior.extend( {
	oldValues: [],

	listenerAttached: false,

	initialize: function() {
		this.lazySaveTextHistory = _.debounce( _.bind( this.saveTextHistory, this ), 800 );
	},

	// use beforeRender that runs after the settingsModel is exist
	onBeforeRender: function() {
		if ( ! this.listenerAttached ) {
			this.listenTo( this.view.getEditModel().get( 'settings' ), 'change', this.saveHistory );
			this.listenerAttached = true;
		}
	},

	saveTextHistory: function( model, changed, control ) {
		var changedAttributes = {},
			currentValue = model.get( control.name ),
			newValue;

		if ( currentValue instanceof Backbone.Collection ) {
			// Deep clone.
			newValue = currentValue.toJSON();
		} else {
			newValue = currentValue;
		}

		changedAttributes[ control.name ] = {
			old: this.oldValues[ control.name ],
			'new': newValue
		};

		var historyItem = {
			type: 'change',
			elementType: 'control',
			title: qazana.history.history.getModelLabel( model ),
			subTitle: model.controls[ changed[0] ].label,
			history: {
				behavior: this,
				changed: changedAttributes,
				model: this.view.getEditModel().toJSON()
			}
		};

		qazana.history.history.addItem( historyItem );

		delete this.oldValues[ control.name ];
	},

	saveHistory: function( model ) {
		if ( ! qazana.history.history.getActive() ) {
			return;
		}

		var self = this,
			changed = Object.keys( model.changed );

		if ( ! changed.length || ! model.controls[ changed[0] ] ) {
			return;
		}

		if ( 1 === changed.length ) {
			var control = model.controls[ changed[0] ];

			if ( _.isUndefined( self.oldValues[ control.name ] ) ) {
				self.oldValues[ control.name ] = model.previous( control.name );
			}

			if ( qazana.history.history.isItemStarted() ) {
				// Do not delay the execution
				self.saveTextHistory( model, changed, control );
			} else {
				self.lazySaveTextHistory( model, changed, control );
			}

			return;
		}

		var changedAttributes = {};

		_.each( changed, function( controlName ) {
			changedAttributes[ controlName ] = {
				old: model.previous( controlName ),
				'new': model.get( controlName )
			};
		} );

		var historyItem = {
			type: 'change',
			elementType: 'control',
			title: qazana.history.history.getModelLabel( model ),
			history: {
				behavior: this,
				changed: changedAttributes,
				model: this.view.getEditModel().toJSON()
			}
		};

		if ( 1 === changed.length ) {
			historyItem.subTitle = model.controls[ changed[0] ].label;
		}

		qazana.history.history.addItem( historyItem );
	},

	restore: function( historyItem, isRedo ) {
		var	history = historyItem.get( 'history' ),
			modelID = history.model.id,
			view = qazana.history.history.findView( modelID );

		if ( ! view ) {
			return;
		}

		var model = view.getEditModel ? view.getEditModel() : view.model,
			settings = model.get( 'settings' ),
			behavior = view.getBehavior( 'ElementHistory' );

		// Stop listen to restore actions
		behavior.stopListening( settings, 'change', this.saveHistory );

		var restoredValues = {};
		_.each( history.changed, function( values, key ) {
			if ( isRedo ) {
				restoredValues[ key ] = values['new'];
			} else {
				restoredValues[ key ] = values.old;
			}
		} );

		// Set at once.
		settings.set( restoredValues );

		// Trigger each field for `baseControl.onSettingsExternalChange`
		_.each( history.changed, function( values, key ) {
			settings.trigger( 'change:external:' + key );
		} );

		historyItem.set( 'status', isRedo ? 'not_applied' : 'applied' );

		// Listen again
		behavior.listenTo( settings, 'change', this.saveHistory );
	}
} );
