/*****************************************************************************
 * Open MCT, Copyright (c) 2014-2022, United States Government
 * as represented by the Administrator of the National Aeronautics and Space
 * Administration. All rights reserved.
 *
 * Open MCT is licensed under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0.
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 * Open MCT includes source code licensed under additional open source
 * licenses. See the Open Source Licenses file (LICENSES.md) included with
 * this source code distribution or the Licensing information page available
 * at runtime from the About dialog for additional information.
 *****************************************************************************/

export default class LocalStorageObjectProvider {
    constructor(spaceKey = 'mct') {
        this.localStorage = window.localStorage;
        this.spaceKey = spaceKey;
        this.initializeSpace(spaceKey);
    }

    get(identifier) {
        if (this.getSpaceAsObject()[identifier.key] !== undefined) {
            const persistedModel = this.getSpaceAsObject()[identifier.key];
            const domainObject = {
                identifier,
                ...persistedModel
            };

            return Promise.resolve(domainObject);
        } else {
            return Promise.resolve(undefined);
        }
    }

    create(object) {
        return this.persistObject(object);
    }

    update(object) {
        return this.persistObject(object);
    }

    /**
     * @private
     */
    persistObject(domainObject) {
        let space = this.getSpaceAsObject();
        space[domainObject.identifier.key] = domainObject;

        this.persistSpace(space);

        return Promise.resolve(true);
    }

    /**
     * @private
     */
    persistSpace(space) {
        this.localStorage[this.spaceKey] = JSON.stringify(space);
    }

    /**
     * @private
     */
    getSpace() {
        return this.localStorage[this.spaceKey];
    }

    /**
     * @private
     */
    getSpaceAsObject() {
        return JSON.parse(this.getSpace());
    }

    /**
     * @private
     */
    initializeSpace() {
        if (this.isEmpty()) {
            this.localStorage[this.spaceKey] = JSON.stringify({});
        }
    }

    /**
     * @private
     */
    isEmpty() {
        return this.getSpace() === undefined;
    }
}