package org.apache.maven.surefire.providerapi;
   
   /*
    * 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.
   */
  
  import javax.annotation.Nonnull;
  
  import java.io.IOException;
  import java.util.Collections;
  import java.util.List;
  import java.util.Optional;
  import java.util.Set;
  
  import org.apache.maven.surefire.api.provider.SurefireProvider;
  import org.codehaus.plexus.component.annotations.Component;
  import org.codehaus.plexus.component.annotations.Requirement;
  import org.codehaus.plexus.logging.Logger;
  
  import static java.lang.Thread.currentThread;
  import static java.util.Arrays.stream;
  import static java.util.Collections.emptyList;
  import static java.util.stream.Collectors.toList;
  
  /**
   * @author Kristian Rosenvold
   */
  @Component( role = ProviderDetector.class )
  public final class ProviderDetector
  {
      @Requirement
      private Logger logger;
  
      @Requirement
      private ServiceLoader serviceLoader;
  
      @Nonnull
      public List<ProviderInfo> resolve( ConfigurableProviderInfo dynamicProvider, ProviderInfo... wellKnownProviders )
      {
          Set<String> manuallyConfiguredProviders = getManuallyConfiguredProviders();
  
          List<ProviderInfo> providersToRun = manuallyConfiguredProviders.stream()
              .map( name ->
                  findByName( name, wellKnownProviders )
                      .orElseGet( () -> dynamicProvider.instantiate( name ) ) )
              .collect( toList() );
  
          providersToRun.forEach( p -> logger.info( "Using configured provider " + p.getProviderName() ) );
  
          if ( providersToRun.isEmpty() )
          {
              return autoDetectOneWellKnownProvider( wellKnownProviders )
                  .map( Collections::singletonList )
                  .orElse( emptyList() );
          }
          else
          {
              return Collections.unmodifiableList( providersToRun );
          }
      }
  
      private Optional<ProviderInfo> autoDetectOneWellKnownProvider( ProviderInfo... wellKnownProviders )
      {
          Optional<ProviderInfo> providerInfo = stream( wellKnownProviders )
              .filter( ProviderInfo::isApplicable )
              .findFirst();
  
          providerInfo.ifPresent( p -> logger.info( "Using auto detected provider " + p.getProviderName() ) );
  
          return providerInfo;
      }
  
      private Set<String> getManuallyConfiguredProviders()
      {
          try
          {
              ClassLoader cl = currentThread().getContextClassLoader();
              return serviceLoader.lookup( SurefireProvider.class, cl );
          }
          catch ( IOException e )
          {
              throw new RuntimeException( e );
          }
      }
 
     @Nonnull
     private Optional<ProviderInfo> findByName( String providerClassName, ProviderInfo... wellKnownProviders )
     {
         return stream( wellKnownProviders )
             .filter( p -> p.getProviderName().equals( providerClassName ) )
             .findFirst();
     }
 }