/*
    * 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.maven.cling;
  
  import java.io.IOException;
  
  import org.apache.maven.api.cli.Invoker;
  import org.apache.maven.api.cli.InvokerException;
  import org.apache.maven.api.cli.InvokerRequest;
  import org.apache.maven.api.cli.Options;
  import org.apache.maven.api.cli.ParserException;
  import org.codehaus.plexus.classworlds.ClassWorld;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * The CLI "new-gen".
   *
   * @param <O> the options type
   * @param <R> the request type
   */
  public abstract class ClingSupport<O extends Options, R extends InvokerRequest<O>> {
      static final String CORE_CLASS_REALM_ID = "plexus.core";
  
      protected final ClassWorld classWorld;
      protected final boolean classWorldManaged;
  
      /**
       * Ctor that creates "managed" ClassWorld. This constructor is not used in "normal" circumstances.
       */
      public ClingSupport() {
          this(new ClassWorld(CORE_CLASS_REALM_ID, Thread.currentThread().getContextClassLoader()), true);
      }
  
      /**
       * Ctor to be used when running in ClassWorlds Launcher.
       */
      public ClingSupport(ClassWorld classWorld) {
          this(classWorld, false);
      }
  
      private ClingSupport(ClassWorld classWorld, boolean classWorldManaged) {
          this.classWorld = requireNonNull(classWorld);
          this.classWorldManaged = classWorldManaged;
      }
  
      /**
       * The main entry point.
       */
      public int run(String[] args) throws IOException {
          try (Invoker<R> invoker = createInvoker()) {
              return invoker.invoke(parseArguments(args));
          } catch (ParserException e) {
              System.err.println(e.getMessage());
              return 1;
          } catch (InvokerException e) {
              return 1;
          } finally {
              if (classWorldManaged) {
                  classWorld.close();
              }
          }
      }
  
      protected abstract Invoker<R> createInvoker();
  
      protected abstract R parseArguments(String[] args) throws ParserException, IOException;
  }