/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 *
 */

package org.apache.skywalking.oap.server.storage.plugin.elasticsearch.query;

import com.google.common.base.Strings;
import com.google.gson.Gson;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import org.apache.commons.lang3.StringUtils;
import org.apache.skywalking.library.elasticsearch.requests.search.BoolQueryBuilder;
import org.apache.skywalking.library.elasticsearch.requests.search.Query;
import org.apache.skywalking.library.elasticsearch.requests.search.RangeQueryBuilder;
import org.apache.skywalking.library.elasticsearch.requests.search.Search;
import org.apache.skywalking.library.elasticsearch.requests.search.SearchBuilder;
import org.apache.skywalking.library.elasticsearch.response.search.SearchHit;
import org.apache.skywalking.library.elasticsearch.response.search.SearchResponse;
import org.apache.skywalking.oap.server.core.analysis.IDManager;
import org.apache.skywalking.oap.server.core.analysis.Layer;
import org.apache.skywalking.oap.server.core.analysis.TimeBucket;
import org.apache.skywalking.oap.server.core.analysis.manual.endpoint.EndpointTraffic;
import org.apache.skywalking.oap.server.core.analysis.manual.instance.InstanceTraffic;
import org.apache.skywalking.oap.server.core.analysis.manual.process.ProcessDetectType;
import org.apache.skywalking.oap.server.core.analysis.manual.process.ProcessTraffic;
import org.apache.skywalking.oap.server.core.analysis.manual.service.ServiceTraffic;
import org.apache.skywalking.oap.server.core.query.enumeration.Language;
import org.apache.skywalking.oap.server.core.query.enumeration.ProfilingSupportStatus;
import org.apache.skywalking.oap.server.core.query.input.Duration;
import org.apache.skywalking.oap.server.core.query.type.Attribute;
import org.apache.skywalking.oap.server.core.query.type.Endpoint;
import org.apache.skywalking.oap.server.core.query.type.Process;
import org.apache.skywalking.oap.server.core.query.type.Service;
import org.apache.skywalking.oap.server.core.query.type.ServiceInstance;
import org.apache.skywalking.oap.server.core.storage.query.IMetadataQueryDAO;
import org.apache.skywalking.oap.server.library.client.elasticsearch.ElasticSearchClient;
import org.apache.skywalking.oap.server.library.client.elasticsearch.ElasticSearchScroller;
import org.apache.skywalking.oap.server.library.util.StringUtil;
import org.apache.skywalking.oap.server.storage.plugin.elasticsearch.StorageModuleElasticsearchConfig;
import org.apache.skywalking.oap.server.storage.plugin.elasticsearch.base.ElasticSearchConverter;
import org.apache.skywalking.oap.server.storage.plugin.elasticsearch.base.EsDAO;
import org.apache.skywalking.oap.server.storage.plugin.elasticsearch.base.IndexController;
import org.apache.skywalking.oap.server.storage.plugin.elasticsearch.base.MatchCNameBuilder;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.function.Function;
import java.util.stream.Collectors;

import static org.apache.skywalking.oap.server.core.analysis.manual.instance.InstanceTraffic.PropertyUtil.LANGUAGE;

public class MetadataQueryEsDAO extends EsDAO implements IMetadataQueryDAO {
    private static final Gson GSON = new Gson();

    private final int queryMaxSize;
    private final int scrollingBatchSize;
    private String endpointTrafficNameAlias;
    private boolean aliasNameInit = false;
    private final int layerSize;

    protected final Function<SearchHit, Service> searchHitServiceFunction = hit -> {
        final var sourceAsMap = hit.getSource();
        final var builder = new ServiceTraffic.Builder();
        final var serviceTraffic = builder.storage2Entity(new ElasticSearchConverter.ToEntity(ServiceTraffic.INDEX_NAME, sourceAsMap));
        final var serviceName = serviceTraffic.getName();
        final var service = new Service();
        service.setId(serviceTraffic.getServiceId());
        service.setName(serviceName);
        service.setShortName(serviceTraffic.getShortName());
        service.setGroup(serviceTraffic.getGroup());
        service.getLayers().add(serviceTraffic.getLayer().name());
        return service;
    };

    protected final Function<SearchHit, ServiceInstance> searchHitServiceInstanceFunction = hit -> {
        final var sourceAsMap = hit.getSource();

        final var instanceTraffic =
            new InstanceTraffic.Builder().storage2Entity(new ElasticSearchConverter.ToEntity(InstanceTraffic.INDEX_NAME, sourceAsMap));

        final var serviceInstance = new ServiceInstance();
        serviceInstance.setId(instanceTraffic.id().build());
        serviceInstance.setName(instanceTraffic.getName());
        serviceInstance.setInstanceUUID(serviceInstance.getId());

        final var properties = instanceTraffic.getProperties();
        if (properties != null) {
            for (final var property : properties.entrySet()) {
                final var key = property.getKey();
                final var value = property.getValue().getAsString();
                if (key.equals(LANGUAGE)) {
                    serviceInstance.setLanguage(Language.value(value));
                } else {
                    serviceInstance.getAttributes().add(new Attribute(key, value));
                }
            }
        } else {
            serviceInstance.setLanguage(Language.UNKNOWN);
        }
        return serviceInstance;
    };

    public MetadataQueryEsDAO(
        ElasticSearchClient client,
        StorageModuleElasticsearchConfig config) {
        super(client);
        this.queryMaxSize = config.getMetadataQueryMaxSize();
        this.scrollingBatchSize = config.getScrollingBatchSize();
        this.layerSize = Layer.values().length;
    }

    @Override
    public List<Service> listServices() {
        final String index =
            IndexController.LogicIndicesRegister.getPhysicalTableName(ServiceTraffic.INDEX_NAME);

        final int batchSize = Math.min(queryMaxSize, scrollingBatchSize);
        final BoolQueryBuilder query = Query.bool();
        final SearchBuilder search = Search.builder().query(query).size(batchSize);
        if (IndexController.LogicIndicesRegister.isMergedTable(ServiceTraffic.INDEX_NAME)) {
            query.must(Query.term(IndexController.LogicIndicesRegister.METRIC_TABLE_NAME, ServiceTraffic.INDEX_NAME));
        }

        final var scroller = ElasticSearchScroller
            .<Service>builder()
            .client(getClient())
            .search(search.build())
            .index(index)
            .queryMaxSize(queryMaxSize)
            .resultConverter(searchHitServiceFunction)
            .build();
        return scroller.scroll();
    }

    @Override
    public List<ServiceInstance> listInstances(Duration duration,
                                               String serviceId) {
        final String index =
            IndexController.LogicIndicesRegister.getPhysicalTableName(InstanceTraffic.INDEX_NAME);

        final long minuteTimeBucket = TimeBucket.getMinuteTimeBucket(duration.getStartTimestamp());
        final BoolQueryBuilder query =
            Query.bool()
                 .must(Query.range(InstanceTraffic.LAST_PING_TIME_BUCKET).gte(minuteTimeBucket))
                 .must(Query.term(InstanceTraffic.SERVICE_ID, serviceId));
        if (IndexController.LogicIndicesRegister.isMergedTable(InstanceTraffic.INDEX_NAME)) {
            query.must(Query.term(IndexController.LogicIndicesRegister.METRIC_TABLE_NAME, InstanceTraffic.INDEX_NAME));
        }
        final int batchSize = Math.min(queryMaxSize, scrollingBatchSize);
        final SearchBuilder search = Search.builder().query(query).size(batchSize);

        final var scroller = ElasticSearchScroller
            .<ServiceInstance>builder()
            .client(getClient())
            .search(search.build())
            .index(index)
            .queryMaxSize(queryMaxSize)
            .resultConverter(searchHitServiceInstanceFunction)
            .build();
        return scroller.scroll();
    }

    @Override
    public ServiceInstance getInstance(final String instanceId) {
        final String index =
            IndexController.LogicIndicesRegister.getPhysicalTableName(InstanceTraffic.INDEX_NAME);
        String id = instanceId;
        if (IndexController.LogicIndicesRegister.isMergedTable(InstanceTraffic.INDEX_NAME)) {
            id = IndexController.INSTANCE.generateDocId(InstanceTraffic.INDEX_NAME, instanceId);
        }
        final BoolQueryBuilder query =
            Query.bool()
                 .must(Query.term("_id", id));
        final SearchBuilder search = Search.builder().query(query).size(1);

        final SearchResponse response = getClient().search(index, search.build());
        final List<ServiceInstance> instances = buildInstances(response);
        return instances.size() > 0 ? instances.get(0) : null;
    }

    @Override
    public List<ServiceInstance> getInstances(List<String> instanceIds) {
        final String index =
            IndexController.LogicIndicesRegister.getPhysicalTableName(InstanceTraffic.INDEX_NAME);
        final BoolQueryBuilder query = Query.bool();
        if (IndexController.LogicIndicesRegister.isMergedTable(InstanceTraffic.INDEX_NAME)) {
            query.must(Query.term(IndexController.LogicIndicesRegister.METRIC_TABLE_NAME, InstanceTraffic.INDEX_NAME));
            instanceIds = instanceIds.stream()
                .map(s -> IndexController.INSTANCE.generateDocId(InstanceTraffic.INDEX_NAME, s)).collect(Collectors.toList());
        }
        query.must(Query.terms("_id", instanceIds));
        final SearchBuilder search = Search.builder().query(query).size(instanceIds.size());

        final SearchResponse response = getClient().search(index, search.build());
        return buildInstances(response);
    }

    @Override
    public List<Endpoint> findEndpoint(String keyword, String serviceId, int limit) {
        initColumnName();
        final String index = IndexController.LogicIndicesRegister.getPhysicalTableName(
            EndpointTraffic.INDEX_NAME);

        final BoolQueryBuilder query =
            Query.bool()
                 .must(Query.term(EndpointTraffic.SERVICE_ID, serviceId));

        if (!Strings.isNullOrEmpty(keyword)) {
            String matchCName = MatchCNameBuilder.INSTANCE.build(endpointTrafficNameAlias);
            query.must(Query.match(matchCName, keyword));
        }

        if (IndexController.LogicIndicesRegister.isMergedTable(EndpointTraffic.INDEX_NAME)) {
            query.must(Query.term(IndexController.LogicIndicesRegister.METRIC_TABLE_NAME, EndpointTraffic.INDEX_NAME));
        }

        final var search = Search.builder().query(query).size(limit);

        final var scroller = ElasticSearchScroller
            .<Endpoint>builder()
            .client(getClient())
            .search(search.build())
            .index(index)
            .queryMaxSize(queryMaxSize)
            .resultConverter(searchHit -> {
                final var sourceAsMap = searchHit.getSource();

                final var endpointTraffic =
                    new EndpointTraffic.Builder().storage2Entity(new ElasticSearchConverter.ToEntity(EndpointTraffic.INDEX_NAME, sourceAsMap));

                final var endpoint = new Endpoint();
                endpoint.setId(endpointTraffic.id().build());
                endpoint.setName(endpointTraffic.getName());
                return endpoint;
            })
            .build();

        return scroller.scroll();
    }

    @Override
    public List<Process> listProcesses(String serviceId, ProfilingSupportStatus supportStatus, long lastPingStartTimeBucket, long lastPingEndTimeBucket) {
        final String index =
            IndexController.LogicIndicesRegister.getPhysicalTableName(ProcessTraffic.INDEX_NAME);

        final BoolQueryBuilder query = Query.bool();
        if (IndexController.LogicIndicesRegister.isMergedTable(ProcessTraffic.INDEX_NAME)) {
            query.must(Query.term(IndexController.LogicIndicesRegister.METRIC_TABLE_NAME, ProcessTraffic.INDEX_NAME));
        }
        final SearchBuilder search = Search.builder().query(query).size(queryMaxSize);
        appendProcessWhereQuery(query, serviceId, null, null, supportStatus, lastPingStartTimeBucket, lastPingEndTimeBucket, false);

        final var scroller = ElasticSearchScroller
            .<Process>builder()
            .client(getClient())
            .search(search.build())
            .index(index)
            .queryMaxSize(queryMaxSize)
            .resultConverter(this::buildProcess)
            .build();
        return scroller.scroll();
    }

    @Override
    public List<Process> listProcesses(String serviceInstanceId, Duration duration, boolean includeVirtual) {
        long lastPingStartTimeBucket = duration.getStartTimeBucket();
        long lastPingEndTimeBucket = duration.getEndTimeBucket();
        final String index =
            IndexController.LogicIndicesRegister.getPhysicalTableName(ProcessTraffic.INDEX_NAME);

        final BoolQueryBuilder query = Query.bool();
        if (IndexController.LogicIndicesRegister.isMergedTable(ProcessTraffic.INDEX_NAME)) {
            query.must(Query.term(IndexController.LogicIndicesRegister.METRIC_TABLE_NAME, ProcessTraffic.INDEX_NAME));
        }
        final SearchBuilder search = Search.builder().query(query).size(queryMaxSize);
        appendProcessWhereQuery(query, null, serviceInstanceId, null, null, lastPingStartTimeBucket, lastPingEndTimeBucket, includeVirtual);

        final var scroller = ElasticSearchScroller
            .<Process>builder()
            .client(getClient())
            .search(search.build())
            .index(index)
            .queryMaxSize(queryMaxSize)
            .resultConverter(this::buildProcess)
            .build();
        return scroller.scroll();
    }

    @Override
    public List<Process> listProcesses(String agentId) {
        final String index =
            IndexController.LogicIndicesRegister.getPhysicalTableName(ProcessTraffic.INDEX_NAME);

        final BoolQueryBuilder query = Query.bool();
        if (IndexController.LogicIndicesRegister.isMergedTable(ProcessTraffic.INDEX_NAME)) {
            query.must(Query.term(IndexController.LogicIndicesRegister.METRIC_TABLE_NAME, ProcessTraffic.INDEX_NAME));
        }
        final SearchBuilder search = Search.builder().query(query).size(queryMaxSize);
        appendProcessWhereQuery(query, null, null, agentId, null, 0, 0, false);

        final var scroller = ElasticSearchScroller
            .<Process>builder()
            .client(getClient())
            .search(search.build())
            .index(index)
            .queryMaxSize(queryMaxSize)
            .resultConverter(this::buildProcess)
            .build();
        return scroller.scroll();
    }

    @Override
    public long getProcessCount(String serviceId, ProfilingSupportStatus profilingSupportStatus, long lastPingStartTimeBucket, long lastPingEndTimeBucket) {
        final String index =
            IndexController.LogicIndicesRegister.getPhysicalTableName(ProcessTraffic.INDEX_NAME);

        final BoolQueryBuilder query = Query.bool();
        if (IndexController.LogicIndicesRegister.isMergedTable(ProcessTraffic.INDEX_NAME)) {
            query.must(Query.term(IndexController.LogicIndicesRegister.METRIC_TABLE_NAME, ProcessTraffic.INDEX_NAME));
        }
        final SearchBuilder search = Search.builder().query(query).size(0);
        appendProcessWhereQuery(query, serviceId, null, null, profilingSupportStatus,
            lastPingStartTimeBucket, lastPingEndTimeBucket, false);
        final SearchResponse results = getClient().search(index, search.build());

        return results.getHits().getTotal();
    }

    @Override
    public long getProcessCount(String instanceId) {
        final String index =
            IndexController.LogicIndicesRegister.getPhysicalTableName(ProcessTraffic.INDEX_NAME);

        final BoolQueryBuilder query = Query.bool();
        if (IndexController.LogicIndicesRegister.isMergedTable(ProcessTraffic.INDEX_NAME)) {
            query.must(Query.term(IndexController.LogicIndicesRegister.METRIC_TABLE_NAME, ProcessTraffic.INDEX_NAME));
        }
        final SearchBuilder search = Search.builder().query(query).size(0);
        appendProcessWhereQuery(query, null, instanceId, null, null, 0, 0, false);
        final SearchResponse results = getClient().search(index, search.build());

        return results.getHits().getTotal();
    }

    private void appendProcessWhereQuery(BoolQueryBuilder query, String serviceId, String instanceId, String agentId,
                                         final ProfilingSupportStatus profilingSupportStatus,
                                         final long lastPingStartTimeBucket, final long lastPingEndTimeBucket,
                                         boolean includeVirtual) {
        if (StringUtil.isNotEmpty(serviceId)) {
            query.must(Query.term(ProcessTraffic.SERVICE_ID, serviceId));
        }
        if (StringUtil.isNotEmpty(instanceId)) {
            query.must(Query.term(ProcessTraffic.INSTANCE_ID, instanceId));
        }
        if (StringUtil.isNotEmpty(agentId)) {
            query.must(Query.term(ProcessTraffic.AGENT_ID, agentId));
        }
        if (profilingSupportStatus != null) {
            query.must(Query.term(ProcessTraffic.PROFILING_SUPPORT_STATUS, profilingSupportStatus.value()));
        }
        if (lastPingStartTimeBucket > 0) {
            final RangeQueryBuilder rangeQuery = Query.range(ProcessTraffic.LAST_PING_TIME_BUCKET);
            rangeQuery.gte(lastPingStartTimeBucket);
            query.must(rangeQuery);
        }
        if (!includeVirtual) {
            query.mustNot(Query.term(ProcessTraffic.DETECT_TYPE, ProcessDetectType.VIRTUAL.value()));
        }
    }

    @Override
    public Process getProcess(String processId) {
        final String index =
            IndexController.LogicIndicesRegister.getPhysicalTableName(ProcessTraffic.INDEX_NAME);
        final BoolQueryBuilder query = Query.bool()
                                            .must(Query.term("_id", processId));
        if (IndexController.LogicIndicesRegister.isMergedTable(ProcessTraffic.INDEX_NAME)) {
            query.must(Query.term(IndexController.LogicIndicesRegister.METRIC_TABLE_NAME, ProcessTraffic.INDEX_NAME));
        }
        final SearchBuilder search = Search.builder().query(query).size(queryMaxSize);

        final var response = getClient().search(index, search.build());
        final var iterator = response.getHits().iterator();
        if (iterator.hasNext()) {
            return buildProcess(iterator.next());
        }
        return null;
    }

    private List<Service> buildServices(SearchResponse response) {
        List<Service> services = new ArrayList<>();
        for (SearchHit hit : response.getHits()) {
            services.add(searchHitServiceFunction.apply(hit));
        }
        return services;
    }

    private List<ServiceInstance> buildInstances(SearchResponse response) {
        List<ServiceInstance> serviceInstances = new ArrayList<>();
        for (SearchHit searchHit : response.getHits()) {
            serviceInstances.add(searchHitServiceInstanceFunction.apply(searchHit));
        }
        return serviceInstances;
    }

    private Process buildProcess(final SearchHit searchHit) {
        Map<String, Object> sourceAsMap = searchHit.getSource();

        final ProcessTraffic processTraffic =
            new ProcessTraffic.Builder().storage2Entity(new ElasticSearchConverter.ToEntity(ProcessTraffic.INDEX_NAME, sourceAsMap));

        Process process = new Process();
        process.setId(processTraffic.id().build());
        process.setName(processTraffic.getName());
        final String serviceId = processTraffic.getServiceId();
        process.setServiceId(serviceId);
        process.setServiceName(IDManager.ServiceID.analysisId(serviceId).getName());
        final String instanceId = processTraffic.getInstanceId();
        process.setInstanceId(instanceId);
        process.setInstanceName(IDManager.ServiceInstanceID.analysisId(instanceId).getName());
        process.setAgentId(processTraffic.getAgentId());
        process.setDetectType(ProcessDetectType.valueOf(processTraffic.getDetectType()).name());
        process.setProfilingSupportStatus(ProfilingSupportStatus.valueOf(processTraffic.getProfilingSupportStatus())
                                                                .name());

        JsonObject properties = processTraffic.getProperties();
        if (properties != null) {
            for (Map.Entry<String, JsonElement> property : properties.entrySet()) {
                String key = property.getKey();
                String value = property.getValue().getAsString();
                process.getAttributes().add(new Attribute(key, value));
            }
        }
        final String labelsJson = processTraffic.getLabelsJson();
        if (StringUtils.isNotEmpty(labelsJson)) {
            final List<String> labels = GSON.<List<String>>fromJson(labelsJson, ArrayList.class);
            process.getLabels().addAll(labels);
        }
        return process;
    }

    /**
     * When the index column use an alias, we should get it's real physical column name for query.
     */
    private void initColumnName() {
        if (!aliasNameInit) {
            this.endpointTrafficNameAlias = IndexController.LogicIndicesRegister.getPhysicalColumnName(EndpointTraffic.INDEX_NAME, EndpointTraffic.NAME);
            aliasNameInit = true;
        }
    }
}
