/*
    * Copyright 2019 LINE Corporation
    *
    * LINE Corporation 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:
    *
    *   https://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.linecorp.centraldogma.client.armeria;
  
  import java.net.UnknownHostException;
  import java.util.concurrent.ScheduledExecutorService;
  
  import com.linecorp.armeria.client.ClientBuilder;
  import com.linecorp.armeria.client.ClientRequestContext;
  import com.linecorp.armeria.client.WebClient;
  import com.linecorp.armeria.client.encoding.DecodingClient;
  import com.linecorp.armeria.client.endpoint.EndpointGroup;
  import com.linecorp.centraldogma.client.CentralDogma;
  import com.linecorp.centraldogma.internal.client.ReplicationLagTolerantCentralDogma;
  
  /**
   * Builds a {@link CentralDogma} client based on an <a href="https://line.github.io/armeria/">Armeria</a>
   * HTTP client.
   */
  public final class ArmeriaCentralDogmaBuilder
          extends AbstractArmeriaCentralDogmaBuilder<ArmeriaCentralDogmaBuilder> {
      /**
       * Returns a newly-created {@link CentralDogma} instance.
       *
       * @throws UnknownHostException if failed to resolve the host names from the DNS servers
       */
      public CentralDogma build() throws UnknownHostException {
          final EndpointGroup endpointGroup = endpointGroup();
          final String scheme = "none+" + (isUseTls() ? "https" : "http");
          final ClientBuilder builder =
                  newClientBuilder(scheme, endpointGroup, cb -> cb.decorator(DecodingClient.newDecorator()), "/");
          final int maxRetriesOnReplicationLag = maxNumRetriesOnReplicationLag();
  
          // TODO(ikhoon): Apply ExecutorServiceMetrics for the 'blockingTaskExecutor' once
          //               https://github.com/line/centraldogma/pull/542 is merged.
          final ScheduledExecutorService blockingTaskExecutor = blockingTaskExecutor();
  
          final CentralDogma dogma = new ArmeriaCentralDogma(blockingTaskExecutor,
                                                             builder.build(WebClient.class),
                                                             accessToken());
          if (maxRetriesOnReplicationLag <= 0) {
              return dogma;
          } else {
              return new ReplicationLagTolerantCentralDogma(
                      blockingTaskExecutor, dogma, maxRetriesOnReplicationLag,
                      retryIntervalOnReplicationLagMillis(),
                      () -> {
                          // FIXME(trustin): Note that this will always return `null` due to a known limitation
                          //                 in Armeria: https://github.com/line/armeria/issues/760
                          final ClientRequestContext ctx = ClientRequestContext.currentOrNull();
                          return ctx != null ? ctx.remoteAddress() : null;
                      });
          }
      }
  }