content: /*
   * Copyright 1999-2018 Alibaba Group Holding Ltd.
   *
   * 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.
   */
  
  package com.alibaba.nacos.istio.xds;
  
  import com.alibaba.nacos.istio.api.ApiGenerator;
  import com.alibaba.nacos.istio.misc.IstioConfig;
  import com.alibaba.nacos.istio.model.IstioService;
  import com.alibaba.nacos.istio.model.PushRequest;
  import com.alibaba.nacos.istio.model.ServiceEntryWrapper;
  import com.google.protobuf.Any;
  import istio.mcp.v1alpha1.MetadataOuterClass.Metadata;
  import istio.mcp.v1alpha1.ResourceOuterClass.Resource;
  import istio.networking.v1alpha3.ServiceEntryOuterClass;
  import istio.networking.v1alpha3.ServiceEntryOuterClass.ServiceEntry;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  
  import static com.alibaba.nacos.istio.api.ApiConstants.*;
  import static com.alibaba.nacos.istio.util.IstioCrdUtil.buildServiceEntry;
  import static com.alibaba.nacos.istio.util.IstioCrdUtil.parseServiceEntryNameToServiceName;
  
  /**
   * @author special.fy
   */
  public final class ServiceEntryXdsGenerator implements ApiGenerator<Any> {
  
      private static volatile ServiceEntryXdsGenerator singleton = null;
      
      private List<ServiceEntryWrapper> serviceEntries;
  
      public static ServiceEntryXdsGenerator getInstance() {
          if (singleton == null) {
              synchronized (ServiceEntryXdsGenerator.class) {
                  if (singleton == null) {
                      singleton = new ServiceEntryXdsGenerator();
                  }
              }
          }
          return singleton;
      }
  
      @Override
      public List<Any> generate(PushRequest pushRequest) {
          List<Resource> resources = new ArrayList<>();
          serviceEntries = new ArrayList<>(16);
          IstioConfig istioConfig = pushRequest.getResourceSnapshot().getIstioConfig();
          Map<String, IstioService> serviceInfoMap = pushRequest.getResourceSnapshot().getIstioResources().getIstioServiceMap();
      
          for (Map.Entry<String, IstioService> entry : serviceInfoMap.entrySet()) {
              String serviceName = entry.getKey();
              
              ServiceEntryWrapper serviceEntryWrapper = buildServiceEntry(serviceName, serviceName + istioConfig.getDomainSuffix(), serviceInfoMap.get(serviceName));
              if (serviceEntryWrapper != null) {
                  serviceEntries.add(serviceEntryWrapper);
              }
          }
          for (ServiceEntryWrapper serviceEntryWrapper : serviceEntries) {
              Metadata metadata = serviceEntryWrapper.getMetadata();
              ServiceEntry serviceEntry = serviceEntryWrapper.getServiceEntry();
  
              Any any = Any.newBuilder().setValue(serviceEntry.toByteString()).setTypeUrl(SERVICE_ENTRY_PROTO).build();
  
              resources.add(Resource.newBuilder().setBody(any).setMetadata(metadata).build());
          }
  
          List<Any> result = new ArrayList<>();
          for (Resource resource : resources) {
              result.add(Any.newBuilder().setValue(resource.toByteString()).setTypeUrl(MCP_RESOURCE_PROTO).build());
          }
      
          return result;
      }
      
      @Override
      public List<io.envoyproxy.envoy.service.discovery.v3.Resource> deltaGenerate(PushRequest pushRequest) {
          if (pushRequest.isFull()) {
              return null;
          }
          
          List<io.envoyproxy.envoy.service.discovery.v3.Resource> result = new ArrayList<>();
          serviceEntries = new ArrayList<>();
          Set<String> reason = pushRequest.getReason();
          IstioConfig istioConfig = pushRequest.getResourceSnapshot().getIstioConfig();
          Map<String, IstioService> istioServiceMap = pushRequest.getResourceSnapshot().getIstioResources().getIstioServiceMap();
          
          if (pushRequest.getSubscribe().size() != 0) {
              for (String subscribe : pushRequest.getSubscribe()) {
                  String serviceName = parseServiceEntryNameToServiceName(subscribe, istioConfig.getDomainSuffix());
                  if (reason.contains(serviceName)) {
                      if (istioServiceMap.containsKey(serviceName)) {
                          ServiceEntryWrapper serviceEntryWrapper = buildServiceEntry(serviceName, subscribe, istioServiceMap.get(serviceName));
                          if (serviceEntryWrapper != null) {
                              serviceEntries.add(serviceEntryWrapper);
                          } else {
                              pushRequest.addRemoved(subscribe);
                          }
                      } else {
                          pushRequest.addRemoved(subscribe);
                      }
                  }
              }
          } else {
              for (Map.Entry<String, IstioService> entry : istioServiceMap.entrySet()) {
                  String hostName = entry.getKey() + "." + istioConfig.getDomainSuffix();
                  ServiceEntryWrapper serviceEntryWrapper = buildServiceEntry(entry.getKey(), hostName, entry.getValue());
                  if (serviceEntryWrapper != null) {
                      serviceEntries.add(serviceEntryWrapper);
                  } else {
                      pushRequest.addRemoved(hostName);
                  }
              }
          }
          
          
          for (ServiceEntryWrapper serviceEntryWrapper : serviceEntries) {
              ServiceEntryOuterClass.ServiceEntry serviceEntry = serviceEntryWrapper.getServiceEntry();
  
              Any any = Any.newBuilder().setValue(serviceEntry.toByteString()).setTypeUrl(SERVICE_ENTRY_PROTO).build();
  
              result.add(io.envoyproxy.envoy.service.discovery.v3.Resource.newBuilder().setResource(any).setVersion(
                      pushRequest.getResourceSnapshot().getVersion()).build());
          }
          
          return result;
      }
  }
  