content: /*
   * 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.kafka.clients.admin.internals;
  
  import org.apache.kafka.common.errors.GroupAuthorizationException;
  import org.apache.kafka.common.errors.InvalidGroupIdException;
  import org.apache.kafka.common.errors.TransactionalIdAuthorizationException;
  import org.apache.kafka.common.message.FindCoordinatorRequestData;
  import org.apache.kafka.common.message.FindCoordinatorResponseData.Coordinator;
  import org.apache.kafka.common.protocol.Errors;
  import org.apache.kafka.common.requests.AbstractResponse;
  import org.apache.kafka.common.requests.FindCoordinatorRequest;
  import org.apache.kafka.common.requests.FindCoordinatorRequest.CoordinatorType;
  import org.apache.kafka.common.requests.FindCoordinatorResponse;
  import org.apache.kafka.common.utils.LogContext;
  
  import org.slf4j.Logger;
  
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Objects;
  import java.util.Set;
  import java.util.stream.Collectors;
  
  public class CoordinatorStrategy implements AdminApiLookupStrategy<CoordinatorKey> {
  
      private static final ApiRequestScope BATCH_REQUEST_SCOPE = new ApiRequestScope() { };
  
      private final Logger log;
      private final FindCoordinatorRequest.CoordinatorType type;
      private Set<CoordinatorKey> unrepresentableKeys = Collections.emptySet();
  
      boolean batch = true;
  
      public CoordinatorStrategy(
          FindCoordinatorRequest.CoordinatorType type,
          LogContext logContext
      ) {
          this.type = type;
          this.log = logContext.logger(CoordinatorStrategy.class);
      }
  
      @Override
      public ApiRequestScope lookupScope(CoordinatorKey key) {
          if (batch) {
              return BATCH_REQUEST_SCOPE;
          } else {
              // If the `FindCoordinator` API does not support batched lookups, we use a
              // separate lookup context for each coordinator key we need to lookup
              return new LookupRequestScope(key);
          }
      }
  
      @Override
      public FindCoordinatorRequest.Builder buildRequest(Set<CoordinatorKey> keys) {
          unrepresentableKeys = keys.stream().filter(k -> k == null || !isRepresentableKey(k.idValue)).collect(Collectors.toSet());
          Set<CoordinatorKey> representableKeys = keys.stream().filter(k -> k != null && isRepresentableKey(k.idValue)).collect(Collectors.toSet());
          if (batch) {
              ensureSameType(representableKeys);
              FindCoordinatorRequestData data = new FindCoordinatorRequestData()
                      .setKeyType(type.id())
                      .setCoordinatorKeys(representableKeys.stream().map(k -> k.idValue).collect(Collectors.toList()));
              return new FindCoordinatorRequest.Builder(data);
          } else {
              CoordinatorKey key = requireSingletonAndType(representableKeys);
              return new FindCoordinatorRequest.Builder(
                  new FindCoordinatorRequestData()
                      .setKey(key.idValue)
                      .setKeyType(key.type.id())
              );
          }
      }
  
      @Override
      public LookupResult<CoordinatorKey> handleResponse(
          Set<CoordinatorKey> keys,
          AbstractResponse abstractResponse
      ) {
          Map<CoordinatorKey, Integer> mappedKeys = new HashMap<>();
          Map<CoordinatorKey, Throwable> failedKeys = new HashMap<>();
  
          for (CoordinatorKey key : unrepresentableKeys) {
              failedKeys.put(key, new InvalidGroupIdException("The given group id '" +
                  key.idValue + "' cannot be represented in a request."));
          }
  
          for (Coordinator coordinator : ((FindCoordinatorResponse) abstractResponse).coordinators()) {
              CoordinatorKey key;
              if (coordinator.key() == null) // old version without batching
                  key = requireSingletonAndType(keys);
              else {
                  key = (type == CoordinatorType.GROUP)
                          ? CoordinatorKey.byGroupId(coordinator.key())
                          : CoordinatorKey.byTransactionalId(coordinator.key());
              }
              handleError(Errors.forCode(coordinator.errorCode()),
                          key,
                          coordinator.nodeId(),
                          mappedKeys,
                          failedKeys);
          }
          return new LookupResult<>(failedKeys, mappedKeys);
      }
  
      public void disableBatch() {
          batch = false;
      }
  
      public boolean batch() {
          return batch;
      }
  
      private CoordinatorKey requireSingletonAndType(Set<CoordinatorKey> keys) {
          if (keys.size() != 1) {
              throw new IllegalArgumentException("Unexpected size of key set: expected 1, but got " + keys.size());
          }
          CoordinatorKey key = keys.iterator().next();
          if (key.type != type) {
              throw new IllegalArgumentException("Unexpected key type: expected key to be of type " + type + ", but got " + key.type);
          }
          return key;
      }
  
      private void ensureSameType(Set<CoordinatorKey> keys) {
          if (keys.isEmpty()) {
              throw new IllegalArgumentException("Unexpected size of key set: expected >= 1, but got 0");
          }
          if (keys.stream().filter(k -> k.type == type).collect(Collectors.toSet()).size() != keys.size()) {
              throw new IllegalArgumentException("Unexpected key set: expected all key to be of type " + type + ", but some key were not");
          }
      }
  
      private static boolean isRepresentableKey(String groupId) {
          return groupId != null;
      }
  
      private void handleError(Errors error, CoordinatorKey key, int nodeId, Map<CoordinatorKey, Integer> mappedKeys, Map<CoordinatorKey, Throwable> failedKeys) {
          switch (error) {
              case NONE:
                  mappedKeys.put(key, nodeId);
                  break;
              case COORDINATOR_NOT_AVAILABLE:
              case COORDINATOR_LOAD_IN_PROGRESS:
                  log.debug("FindCoordinator request for key {} returned topic-level error {}. Will retry",
                      key, error);
                  break;
              case GROUP_AUTHORIZATION_FAILED:
                  failedKeys.put(key, new GroupAuthorizationException("FindCoordinator request for groupId " +
                      "`" + key + "` failed due to authorization failure", key.idValue));
                  break;
              case TRANSACTIONAL_ID_AUTHORIZATION_FAILED:
                  failedKeys.put(key, new TransactionalIdAuthorizationException("FindCoordinator request for " +
                      "transactionalId `" + key + "` failed due to authorization failure"));
                  break;
              default:
                  failedKeys.put(key, error.exception("FindCoordinator request for key " +
                      "`" + key + "` failed due to an unexpected error"));
          }
      }
  
      private static class LookupRequestScope implements ApiRequestScope {
          final CoordinatorKey key;
  
          private LookupRequestScope(CoordinatorKey key) {
              this.key = key;
          }
  
          @Override
          public boolean equals(Object o) {
              if (this == o) return true;
              if (o == null || getClass() != o.getClass()) return false;
              LookupRequestScope that = (LookupRequestScope) o;
              return Objects.equals(key, that.key);
          }
  
          @Override
          public int hashCode() {
              return Objects.hash(key);
          }
      }
  }
  