/*
    * 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.lifecycle.internal;
  
  import java.util.List;
  import java.util.Map;
  
  import org.apache.maven.execution.ExecutionEvent;
  import org.apache.maven.execution.MavenExecutionResult;
  import org.apache.maven.execution.MavenSession;
  import org.apache.maven.lifecycle.DefaultLifecycles;
  import org.apache.maven.lifecycle.MissingProjectException;
  import org.apache.maven.lifecycle.NoGoalSpecifiedException;
  import org.apache.maven.lifecycle.internal.builder.Builder;
  import org.apache.maven.lifecycle.internal.builder.BuilderNotFoundException;
  import org.apache.maven.session.scope.internal.SessionScope;
  import org.codehaus.plexus.component.annotations.Component;
  import org.codehaus.plexus.component.annotations.Requirement;
  import org.codehaus.plexus.logging.Logger;
  
  /**
   * Starts the build life cycle
   *
   * @author Jason van Zyl
   * @author Benjamin Bentmann
   * @author Kristian Rosenvold
   */
  @Component(role = LifecycleStarter.class)
  public class LifecycleStarter {
      @Requirement
      private ExecutionEventCatapult eventCatapult;
  
      @Requirement
      private DefaultLifecycles defaultLifeCycles;
  
      @Requirement
      private Logger logger;
  
      @Requirement
      private BuildListCalculator buildListCalculator;
  
      @Requirement
      private LifecycleDebugLogger lifecycleDebugLogger;
  
      @Requirement
      private LifecycleTaskSegmentCalculator lifecycleTaskSegmentCalculator;
  
      @Requirement
      private Map<String, Builder> builders;
  
      @Requirement
      private SessionScope sessionScope;
  
      public void execute(MavenSession session) {
          eventCatapult.fire(ExecutionEvent.Type.SessionStarted, session, null);
  
          ReactorContext reactorContext = null;
          ProjectBuildList projectBuilds = null;
          MavenExecutionResult result = session.getResult();
  
          try {
              if (buildExecutionRequiresProject(session) && projectIsNotPresent(session)) {
                  throw new MissingProjectException("The goal you specified requires a project to execute"
                          + " but there is no POM in this directory (" + session.getExecutionRootDirectory() + ")."
                          + " Please verify you invoked Maven from the correct directory.");
              }
  
              List<TaskSegment> taskSegments = lifecycleTaskSegmentCalculator.calculateTaskSegments(session);
              projectBuilds = buildListCalculator.calculateProjectBuilds(session, taskSegments);
  
              if (projectBuilds.isEmpty()) {
                  throw new NoGoalSpecifiedException("No goals have been specified for this build."
                          + " You must specify a valid lifecycle phase or a goal in the format <plugin-prefix>:<goal> or"
                          + " <plugin-group-id>:<plugin-artifact-id>[:<plugin-version>]:<goal>."
                          + " Available lifecycle phases are: " + defaultLifeCycles.getLifecyclePhaseList() + ".");
              }
  
              ProjectIndex projectIndex = new ProjectIndex(session.getProjects());
  
              if (logger.isDebugEnabled()) {
                  lifecycleDebugLogger.debugReactorPlan(projectBuilds);
              }
  
             ClassLoader oldContextClassLoader = Thread.currentThread().getContextClassLoader();
             ReactorBuildStatus reactorBuildStatus = new ReactorBuildStatus(session.getProjectDependencyGraph());
             reactorContext = new ReactorContext(result, projectIndex, oldContextClassLoader, reactorBuildStatus);
 
             String builderId = session.getRequest().getBuilderId();
             Builder builder = builders.get(builderId);
             if (builder == null) {
                 throw new BuilderNotFoundException(
                         String.format("The builder requested using id = %s cannot be" + " found", builderId));
             }
 
             int degreeOfConcurrency = session.getRequest().getDegreeOfConcurrency();
             if (degreeOfConcurrency > 1) {
                 logger.info("");
                 logger.info(String.format(
                         "Using the %s implementation with a thread count of %d",
                         builder.getClass().getSimpleName(), degreeOfConcurrency));
             }
             builder.build(session, reactorContext, projectBuilds, taskSegments, reactorBuildStatus);
 
         } catch (Exception e) {
             result.addException(e);
         } finally {
             eventCatapult.fire(ExecutionEvent.Type.SessionEnded, session, null);
         }
     }
 
     private boolean buildExecutionRequiresProject(MavenSession session) {
         return lifecycleTaskSegmentCalculator.requiresProject(session);
     }
 
     private boolean projectIsNotPresent(MavenSession session) {
         return !session.getRequest().isProjectPresent();
     }
 }