terriajs/lib/ReactViewModels/DisclaimerHandler.js

Geospatial data visualization platform.

'use strict';

import defined from 'terriajs-cesium/Source/Core/defined';
import combine from 'terriajs-cesium/Source/Core/combine';

/**
 * Shows disclaimers for {@link CatalogItem}s that are dispatched through {@link Terria#disclaimerEvent} - ensures that
 * disclaimers that share the same key (as specified in {@link CatalogItem#initialMessage#key}) are only ever displayed
 * once per key - if a single disclaimer is triggered 3 different times, for instance, one disclaimer popup will be
 * displayed, and then once that disclaimer is accepted, the callbacks for all three {@Terria#disclaimerEvent} will be
 * executed. This response will be persisted in localStorage so that subsequent calls to {@Terria#disclaimerEvent} do
 * not display any disclaimer and have their successCallback executed immediately.
 *
 * Also accepts disclaimers with no key, which will always be displayed, and disclaimers with no need for confirmation
 * (as specified by {@link CatalogItem#initialMessage#confirmation}), which will have their successCallback executed
 * immediately as the message is shown.
 *
 * Note that this is not for displaying a general disclaimer on startup.
 *
 * @param terria The {@link Terria} instance to use.
 * @param viewState the viewstate to manipulate in order to display notifications.
 * @constructor
 */
export default class DisclaimerHandler {
    constructor(terria, viewState) {
        this.terria = terria;
        this.viewState = viewState;
        this._pending = {};

        this.terria.disclaimerListener = this._handleInitialMessage.bind(this);
    }

    dispose() {
        this.terria.disclaimerListener = undefined;
    }

    /**
     * Handles the {@Terria#disclaimerEvent} being raised. Only one disclaimer will be shown for each catalogItem with the
     * same {@link CatalogItem#initialMessage#key}, but all calls will have their successCallback executed when it's
     * accepted.
     *
     * @param catalogItem The catalog item to display a disclaimer for.
     * @param successCallback A callback to execute once the disclaimer is accepted.
     * @private
     */
    _handleInitialMessage(catalogItem, successCallback) {
        var keySpecified = defined(catalogItem.initialMessage.key);
        if (keySpecified && this.terria.getLocalProperty(catalogItem.initialMessage.key)) {
            successCallback();
            return;
        }

        if (catalogItem.initialMessage.confirmation) {
            if (keySpecified) {
                var key = catalogItem.initialMessage.key;

                if (defined(this._pending[key])) {
                    this._pending[key].push(successCallback);
                } else {
                    this._pending[key] = [successCallback];
                    this._openConfirmationModal(catalogItem, this._executeCallbacksForKey.bind(this, key));
                }
            } else {
                this._openConfirmationModal(catalogItem, successCallback);
            }
        } else {
            if (keySpecified) {
                this.terria.setLocalProperty(catalogItem.initialMessage.key, true);
            }
            this._openNotificationModel(catalogItem);
            successCallback();
        }
    }

    /**
     * Opens a confirmation modal for the specified {@link CatalogItem}.
     *
     * @param catalogItem The catalog item to get disclaimer details from.
     * @param callback The callback to execute when the modal is dismissed.
     * @private
     */
    _openConfirmationModal(catalogItem, callback) {
        this.viewState.notifications.push(combine({
            confirmAction: callback
        }, DisclaimerHandler._generateOptions(catalogItem)));
    }

    _openNotificationModel(catalogItem) {
        this.viewState.notifications.push(DisclaimerHandler._generateOptions(catalogItem));
    }

    /**
     * Executes all the callbacks stored in {@link DisclaimerHandler#pending} for the specified key, and clears that key
     * in pending.
     *
     * @param key The key to get callbacks from.
     * @private
     */
    _executeCallbacksForKey(key) {
        (this._pending[key] || []).forEach(function(cb) {cb();});
        this._pending[key] = undefined;
        this.terria.setLocalProperty(key, true);
    }

    /**
     * Generates options for {@link PopupMessageConfirmationViewModel} and {@link PopupMessageViewModel} for a
     * {@link CatalogItem}
     * @returns {{title: string, message: string, width: number, height: number, confirmText: string}}
     * @private
     */
    static _generateOptions(catalogItem) {
        return {
            title: catalogItem.initialMessage.title,
            message: catalogItem.initialMessage.content,
            confirmText: catalogItem.initialMessage.confirmText,
            width: catalogItem.initialMessage.width,
            height: catalogItem.initialMessage.height
        };
    }
}