/*******************************************************************************
 *  ============LICENSE_START=======================================================
 *  slice-analysis-ms
 *  ================================================================================
 *   Copyright (C) 2020-2022 Wipro Limited.
 *   ==============================================================================
 *     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.
 *     ============LICENSE_END=========================================================
 *
 *******************************************************************************/

package org.onap.slice.analysis.ms.service;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Objects;

import javax.annotation.PostConstruct;

import org.onap.slice.analysis.ms.aai.AaiInterface;
import org.onap.slice.analysis.ms.configdb.IConfigDbService;
import org.onap.slice.analysis.ms.cps.CpsInterface;
import org.onap.slice.analysis.ms.models.Configuration;
import org.onap.slice.analysis.ms.models.MeasurementObject;
import org.onap.slice.analysis.ms.models.SubCounter;
import org.onap.slice.analysis.ms.models.policy.AdditionalProperties;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;

/**
 * This class process the measurement data of an S-NSSAI
 */
@Component
@Scope("prototype")
public class SnssaiSamplesProcessor {
    private static Logger log = LoggerFactory.getLogger(SnssaiSamplesProcessor.class);

    @Autowired
    private PolicyService policyService;

    @Autowired
    private IConfigDbService configDbService;

    @Autowired
    private PmDataQueue pmDataQueue;

    @Autowired
    private AverageCalculator averageCalculator;

    @Autowired
    private AaiInterface aaiInterface;

    @Autowired
    private CpsInterface cpsInterface;

    private List<MeasurementObject> snssaiMeasurementList = new ArrayList<>();
    private Map<String, List<String>> ricToCellMapping = new HashMap<>();
    private Map<String, Map<String, Integer>> ricToPrbsMapping = new HashMap<>();
    private Map<String, Map<String, Integer>> ricToThroughputMapping = new HashMap<>();
    private int noOfSamples;
    private List<String> pmsToCompute;
    private Map<String, String> prbThroughputMapping = new HashMap<>();
    private int minPercentageChange;

    @PostConstruct
    public void init() {
        Configuration configuration = Configuration.getInstance();
        noOfSamples = configuration.getSamples();
        pmsToCompute = new ArrayList<>();
        pmsToCompute.add("PrbUsedDl");
        pmsToCompute.add("PrbUsedUl");
        prbThroughputMapping = new HashMap<>();
        prbThroughputMapping.put("PrbUsedDl", "dLThptPerSlice");
        prbThroughputMapping.put("PrbUsedUl", "uLThptPerSlice");
        minPercentageChange = configuration.getMinPercentageChange();
    }

    /**
     * process the measurement data of an S-NSSAI
     */
    public boolean processSamplesOfSnnsai(String snssai, List<String> networkFunctions) {
        Boolean isConfigDbEnabled = (Objects.isNull(Configuration.getInstance().getConfigDbEnabled())) ? true
                : Configuration.getInstance().getConfigDbEnabled();
        List<MeasurementObject> sample = null;
        List<List<MeasurementObject>> samples = null;
        Map<String, String> serviceDetails = null;
        log.info("Network Functions {} of snssai {}", networkFunctions, snssai);
        for (String nf : networkFunctions) {
            log.debug("Average of samples for {}:", snssai);
            samples = pmDataQueue.getSamplesFromQueue(new SubCounter(nf, snssai), noOfSamples);
            if (samples != null) {
                sample = averageCalculator.findAverageOfSamples(samples);
                addToMeasurementList(sample);
            } else {
                log.info("Not enough samples present for nf {}", nf);
                return false;
            }
        }
        log.info("snssai measurement list {}", snssaiMeasurementList);
        Map<String, Map<String, Object>> ricConfiguration;
        Map<String, Integer> sliceConfiguration;
        if (isConfigDbEnabled) {
            ricToCellMapping = configDbService.fetchRICsOfSnssai(snssai);
            ricConfiguration = configDbService.fetchCurrentConfigurationOfRIC(snssai);
            sliceConfiguration = configDbService.fetchCurrentConfigurationOfSlice(snssai);
            serviceDetails = configDbService.fetchServiceDetails(snssai);
        } else {
            ricToCellMapping = cpsInterface.fetchRICsOfSnssai(snssai);
            ricConfiguration = cpsInterface.fetchCurrentConfigurationOfRIC(snssai);
            serviceDetails = aaiInterface.fetchServiceDetails(snssai);
            sliceConfiguration = aaiInterface.fetchCurrentConfigurationOfSlice(snssai);
        }
        log.info("RIC to Cell Mapping for {} S-NSSAI: {}", snssai, ricToCellMapping);
        log.info("RIC Configuration {} and Slice Configuration {}", ricConfiguration, sliceConfiguration);
        pmsToCompute.forEach(pm -> {
            log.debug("processing for pm {}", pm);
            sumOfPrbsAcrossCells(pm);
            int sum = computeSum(pm);
            computeThroughput(sliceConfiguration, sum, pm);
            calculatePercentageChange(ricConfiguration, prbThroughputMapping.get(pm));
        });
        updateConfiguration();
        if (ricToThroughputMapping.size() > 0) {
            AdditionalProperties<Map<String, List<Map<String, Integer>>>> addProps = new AdditionalProperties<>();
            addProps.setResourceConfig(getChangedRIConfigFormat(ricToThroughputMapping));
            policyService.sendOnsetMessageToPolicy(snssai, addProps, serviceDetails);
        }
        return true;
    }

    /**
     * change the RICConfig data format to be compatible with SDN-R
     */
    protected Map<String, List<Map<String, Integer>>> getChangedRIConfigFormat(
            Map<String, Map<String, Integer>> ricToThroughputMapping) {
        Iterator<Map.Entry<String, Map<String, Integer>>> it = ricToThroughputMapping.entrySet().iterator();
        Map.Entry<String, Map<String, Integer>> entry = null;
        List<Map<String, Integer>> ricConfigList = new ArrayList<>();
        Map<String, List<Map<String, Integer>>> ricConfigData = new HashMap<>();
        while (it.hasNext()) {
            Map<String, Integer> newConfigMap = new HashMap<>();
            entry = it.next();
            newConfigMap = entry.getValue();
            newConfigMap.put("nearRTRICId", Integer.parseInt(entry.getKey()));
            ricConfigList.add(newConfigMap);
        }
        ricConfigData.put("data", ricConfigList);
        return ricConfigData;
    }

    /**
     * process the measurement data of an S-NSSAI
     */
    protected void updateConfiguration() {
        Iterator<Map.Entry<String, Map<String, Integer>>> it = ricToThroughputMapping.entrySet().iterator();
        Map.Entry<String, Map<String, Integer>> entry = null;
        while (it.hasNext()) {
            entry = it.next();
            if (entry.getValue().size() == 0) {
                it.remove();
            }
        }
    }

    private void addToMeasurementList(List<MeasurementObject> sample) {
        snssaiMeasurementList.addAll(sample);
    }

    /**
     * Calculate the change in the configuration value and keep the configuration
     * only if it is greater than a specific limit
     */
    protected void calculatePercentageChange(Map<String, Map<String, Object>> ricConfiguration, String pm) {
        Iterator<Map.Entry<String, Map<String, Integer>>> it = ricToThroughputMapping.entrySet().iterator();
        Map.Entry<String, Map<String, Integer>> entry = null;
        float existing = 0;
        float change = 0;
        while (it.hasNext()) {
            entry = it.next();
            existing = (float) ((int) ricConfiguration.get(entry.getKey()).get(pm));
            change = ((Math.abs(entry.getValue().get(pm) - existing)) / existing) * 100;
            if (change <= minPercentageChange) {
                ricToThroughputMapping.get(entry.getKey()).remove(pm);
                log.info("Removing pm data {} for RIC {}", pm, entry.getKey());
            }
        }
    }

    protected void sumOfPrbsAcrossCells(String pmName) {
        ricToCellMapping.forEach((ric, cells) -> {
            int sumOfPrbs = 0;
            for (String cell : cells) {
                int index = MeasurementObject.findIndex(cell, snssaiMeasurementList);
                sumOfPrbs += snssaiMeasurementList.get(index).getPmData().get(pmName);
            }
            if (ricToPrbsMapping.containsKey(ric)) {
                ricToPrbsMapping.get(ric).put(pmName, sumOfPrbs);
            } else {
                Map<String, Integer> pmToPrbMapping = new HashMap<>();
                pmToPrbMapping.put(pmName, sumOfPrbs);
                ricToPrbsMapping.put(ric, pmToPrbMapping);
            }
        });
        log.info("PRBs sum computed for RIC {}", ricToPrbsMapping);
    }

    protected Integer computeSum(String pm) {
        return ricToPrbsMapping.entrySet().stream().map(x -> x.getValue().get(pm)).reduce(0, Integer::sum);
    }

    protected void computeThroughput(Map<String, Integer> sliceConfiguration, int sum, String pm) {
        Iterator<Map.Entry<String, Map<String, Integer>>> it = ricToPrbsMapping.entrySet().iterator();
        Map.Entry<String, Map<String, Integer>> entry = null;
        Map<String, Integer> throughtputMap = null;
        String ric = "";
        int value = 0;
        while (it.hasNext()) {
            entry = it.next();
            ric = entry.getKey();
            value = Math.round(((float) entry.getValue().get(pm) / sum)
                    * (float) sliceConfiguration.get(prbThroughputMapping.get(pm)));
            if (ricToThroughputMapping.containsKey(ric)) {
                ricToThroughputMapping.get(ric).put(prbThroughputMapping.get(pm), value);
            } else {
                throughtputMap = new HashMap<>();
                throughtputMap.put(prbThroughputMapping.get(pm), value);
                ricToThroughputMapping.put(ric, throughtputMap);
            }
        }
        log.info("Throughput computed for RIC {}", ricToThroughputMapping);
    }

}