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There is a newer version: 1.4.0
/*jslint node: true */

/*
 * #%L
 * %%
 * Copyright (C) 2011 - 2017 BMW Car IT GmbH
 * %%
 * 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.
 * #L%
 */

/**
 * The ArbitrationStrategyCollection provides three different strategies that can be
 * passed to the Arbitrator to sort the retrieved Capabilities: Nothing, HighestPriority
 * or Keyword
 *
 * @class
 * @name ArbitrationStrategyCollection
 * @see Arbitrator
 * @see DiscoveryQos
 */
var ArbitrationStrategyCollection = {};

/**
 * The ArbitrationStrategyCollection.Nothing just returns the passed array
 * @function ArbitrationStrategyCollection#Nothing
 *
 * @param {Array}
 *            capabilities the array of capability entries
 * @param {DiscoveryEntry}
 *            capabilities.array the array of DiscoveryEntries
 *
 * @returns {Array} an array of capabilities as it came in through the
 *          capabilities parameter
 */
ArbitrationStrategyCollection.Nothing = function(capabilities) {
    return capabilities;
};

/**
 * The ArbitrationStrategyCollection.HighestPriority favors higher priorities
 * @function ArbitrationStrategyCollection#HighestPriority
 *
 * @param {Array}
 *            capabilities the array of capability entries
 * @param {DiscoveryEntry}
 *            capabilities.array the array of capability entries
 *
 * @returns {Array} an array of capabilities sorted by the highest priority
 */
ArbitrationStrategyCollection.HighestPriority = function(capabilities) {
    if (!Array.isArray(capabilities)) {
        throw new Error("provided argument capabilities is not of type Array");
    }

    // sort with descending priority
    return capabilities.sort(function(a, b) {
        return b.qos.priority - a.qos.priority;
    });
};

/**
 * The ArbitrationStrategyCollection.Keyword searches for the given keyword in the
 * "keyword" qos parameter and returns those.
 * NOTE: to use this function, you must bind your keyword as follows:
 * arbitrationStrategy = Keyword.bind(undefined, "myKeyword")
 * @function ArbitrationStrategyCollection#Keyword
 *
 * @param {Array}
 *            capabilities the array of capability entries
 * @param {DiscoveryEntry}
 *            capabilities.array the array of capability entries
 * @param {String}
 *            keyword the keyword to search for
 * @returns {Array} an array of capabilities sorted by the highest priority
 */
ArbitrationStrategyCollection.Keyword = function(keyword, capabilities) {
    var capId,
        qosId,
        qosParam,
        cap,
        keywordCaps = [];

    if (!Array.isArray(capabilities)) {
        throw new Error("provided argument capabilities is not of type Array");
    }

    for (capId in capabilities) {
        if (capabilities.hasOwnProperty(capId)) {
            cap = capabilities[capId];
            if (cap.qos.customParameters && Array.isArray(cap.qos.customParameters)) {
                for (qosId in cap.qos.customParameters) {
                    if (cap.qos.customParameters.hasOwnProperty(qosId)) {
                        qosParam = cap.qos.customParameters[qosId];
                        if (qosParam && qosParam.value && qosParam.value === keyword) {
                            keywordCaps.push(cap);
                        }
                    }
                }
            }
        }
    }
    return keywordCaps;
};

/**
 * The ArbitrationStrategyCollection.LastSeen favors latest lastSeenDateMs
 * @function ArbitrationStrategyCollection#LastSeen
 *
 * @param {Array}
 *            capabilities the array of capability entries
 * @param {DiscoveryEntry}
 *            capabilities.array the array of capability entries
 *
 * @returns {Array} an array of capabilities sorted by the lastSeenDateMs
 */
ArbitrationStrategyCollection.LastSeen = function(capabilities) {
    if (!Array.isArray(capabilities)) {
        throw new Error("provided argument capabilities is not of type Array");
    }

    // sort with descending priority
    return capabilities.sort(function(a, b) {
        return b.lastSeenDateMs - a.lastSeenDateMs;
    });
};

module.exports = ArbitrationStrategyCollection;