terriajs/lib/Models/TimeSeriesStack.js

Geospatial data visualization platform.

"use strict";

/*global require*/

var knockout = require('terriajs-cesium/Source/ThirdParty/knockout');
var defined = require('terriajs-cesium/Source/Core/defined');

/**
 * Manages a stack of all the time series layers currently being shown and makes sure the clock provided is always tracking
 * the highest one. When the top-most layer is disabled, the clock will track the next highest in the stack. Provides access
 * to the current top layer so that can be displayed to the user.
 *
 * @param clock The clock that should track the highest layer.
 * @constructor
 */
var TimeSeriesStack = function(clock) {
    this.clock = clock;

    this._layerStack = [];

    knockout.track(this, ['_layerStack']);

    /**
     * The highest time-series layer, or undefined if there are no time series layers.
     */
    knockout.defineProperty(this, 'topLayer', {
        get: function() {
            if (this._layerStack.length) {
                return this._layerStack[this._layerStack.length - 1];
            }
        }
    });

    knockout.getObservable(this, 'topLayer').subscribe(function(topLayer) {
        if (defined(topLayer)) {
            // If there's a top layer, make the clock track it.
            this.clock.setCatalogItem(this.topLayer);
        } else {
            // If there's no layers, stop the clock from running.
            this.clock.shouldAnimate = false;
        }
    }, this);
};

/**
 * Adds the supplied {@link CatalogItem} to the top of the stack. If the item is already in the stack, it will be moved
 * rather than added twice.
 *
 * @param {CatalogItem} item
 */
TimeSeriesStack.prototype.addLayerToTop = function(item) {
    var currentIndex = this._layerStack.indexOf(item);
    this._layerStack.push(item);
    if (currentIndex > -1) {
        this._layerStack.splice(currentIndex, 1);
    }
};

/**
 * Removes a layer from the stack, no matter what it's location. If the layer is currently at the top, the value of
 * {@link TimeSeriesStack#topLayer} will change.
 *
 * @param {CatalogItem} item;
 */
TimeSeriesStack.prototype.removeLayer = function(item) {
    var index = this._layerStack.indexOf(item);
    this._layerStack.splice(index, 1);
};


/**
 * Promotes the supplied {@link CatalogItem} to the top of the stack if it is already in the stack. If the item is not
 * already in the stack it wont be added.
 *
 * @param {CatalogItem} item
 */
TimeSeriesStack.prototype.promoteLayerToTop = function(item) {
    var currentIndex = this._layerStack.indexOf(item);
    if (currentIndex > -1) {
        this.addLayerToTop(item);
    }
};


module.exports = TimeSeriesStack;