/*
    * ====================================================================
    * 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.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   */
  package org.apache.hc.client5.http.impl.cache;
  
  import java.io.File;
  import java.util.concurrent.ScheduledExecutorService;
  import java.util.concurrent.ScheduledThreadPoolExecutor;
  
  import org.apache.hc.client5.http.cache.HttpCacheInvalidator;
  import org.apache.hc.client5.http.cache.HttpCacheStorage;
  import org.apache.hc.client5.http.cache.ResourceFactory;
  import org.apache.hc.client5.http.classic.ExecChainHandler;
  import org.apache.hc.client5.http.impl.ChainElement;
  import org.apache.hc.client5.http.impl.classic.HttpClientBuilder;
  import org.apache.hc.client5.http.impl.schedule.ImmediateSchedulingStrategy;
  import org.apache.hc.client5.http.schedule.SchedulingStrategy;
  import org.apache.hc.core5.http.config.NamedElementChain;
  
  /**
   * Builder for {@link org.apache.hc.client5.http.impl.classic.CloseableHttpClient}
   * instances capable of client-side caching.
   *
   * @since 4.3
   */
  public class CachingHttpClientBuilder extends HttpClientBuilder {
  
      private ResourceFactory resourceFactory;
      private HttpCacheStorage storage;
      private File cacheDir;
      private SchedulingStrategy schedulingStrategy;
      private CacheConfig cacheConfig;
      private HttpCacheInvalidator httpCacheInvalidator;
      private boolean deleteCache;
  
      public static CachingHttpClientBuilder create() {
          return new CachingHttpClientBuilder();
      }
  
      protected CachingHttpClientBuilder() {
          super();
          this.deleteCache = true;
      }
  
      public final CachingHttpClientBuilder setResourceFactory(
              final ResourceFactory resourceFactory) {
          this.resourceFactory = resourceFactory;
          return this;
      }
  
      public final CachingHttpClientBuilder setHttpCacheStorage(final HttpCacheStorage storage) {
          this.storage = storage;
          return this;
      }
  
      public final CachingHttpClientBuilder setCacheDir(final File cacheDir) {
          this.cacheDir = cacheDir;
          return this;
      }
  
      public final CachingHttpClientBuilder setSchedulingStrategy(final SchedulingStrategy schedulingStrategy) {
          this.schedulingStrategy = schedulingStrategy;
          return this;
      }
  
      public final CachingHttpClientBuilder setCacheConfig(final CacheConfig cacheConfig) {
          this.cacheConfig = cacheConfig;
          return this;
      }
  
      public final CachingHttpClientBuilder setHttpCacheInvalidator(final HttpCacheInvalidator cacheInvalidator) {
          this.httpCacheInvalidator = cacheInvalidator;
          return this;
      }
  
      public final CachingHttpClientBuilder setDeleteCache(final boolean deleteCache) {
         this.deleteCache = deleteCache;
         return this;
     }
 
     @Override
     protected void customizeExecChain(final NamedElementChain<ExecChainHandler> execChainDefinition) {
         final CacheConfig config = this.cacheConfig != null ? this.cacheConfig : CacheConfig.DEFAULT;
         // We copy the instance fields to avoid changing them, and rename to avoid accidental use of the wrong version
         ResourceFactory resourceFactoryCopy = this.resourceFactory;
         if (resourceFactoryCopy == null) {
             if (this.cacheDir == null) {
                 resourceFactoryCopy = new HeapResourceFactory();
             } else {
                 resourceFactoryCopy = new FileResourceFactory(cacheDir);
             }
         }
         HttpCacheStorage storageCopy = this.storage;
         if (storageCopy == null) {
             if (this.cacheDir == null) {
                 storageCopy = new BasicHttpCacheStorage(config);
             } else {
                 final ManagedHttpCacheStorage managedStorage = new ManagedHttpCacheStorage(config);
                 if (this.deleteCache) {
                     addCloseable(managedStorage::shutdown);
                 } else {
                     addCloseable(managedStorage);
                 }
                 storageCopy = managedStorage;
             }
         }
         final HttpCache httpCache = new BasicHttpCache(
                 resourceFactoryCopy,
                 storageCopy,
                 CacheKeyGenerator.INSTANCE,
                 this.httpCacheInvalidator != null ? this.httpCacheInvalidator : new DefaultCacheInvalidator());
 
         DefaultCacheRevalidator cacheRevalidator = null;
         if (config.getAsynchronousWorkers() > 0) {
             final ScheduledExecutorService executorService = new ScheduledThreadPoolExecutor(config.getAsynchronousWorkers());
             addCloseable(executorService::shutdownNow);
             cacheRevalidator = new DefaultCacheRevalidator(
                     executorService,
                     this.schedulingStrategy != null ? this.schedulingStrategy : ImmediateSchedulingStrategy.INSTANCE);
         }
         final CachingExec cachingExec = new CachingExec(
                 httpCache,
                 cacheRevalidator,
                 config);
         execChainDefinition.addBefore(ChainElement.PROTOCOL.name(), cachingExec, ChainElement.CACHING.name());
     }
 
 }