/*
    * 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.concurrent;
  
  import javax.inject.Inject;
  import javax.inject.Named;
  import javax.inject.Singleton;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.stream.Collectors;
  import java.util.stream.Stream;
  
  import org.apache.maven.api.Lifecycle;
  import org.apache.maven.execution.ExecutionEvent;
  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.ExecutionEventCatapult;
  import org.apache.maven.lifecycle.internal.GoalTask;
  import org.apache.maven.lifecycle.internal.LifecyclePluginResolver;
  import org.apache.maven.lifecycle.internal.LifecycleStarter;
  import org.apache.maven.lifecycle.internal.LifecycleTask;
  import org.apache.maven.lifecycle.internal.MojoDescriptorCreator;
  import org.apache.maven.lifecycle.internal.PhaseId;
  import org.apache.maven.lifecycle.internal.ReactorBuildStatus;
  import org.apache.maven.lifecycle.internal.ReactorContext;
  import org.apache.maven.lifecycle.internal.TaskSegment;
  import org.apache.maven.plugin.descriptor.MojoDescriptor;
  import org.apache.maven.project.MavenProject;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * Starts the build life cycle
   */
  @Named("concurrent")
  @Singleton
  public class ConcurrentLifecycleStarter implements LifecycleStarter {
      private final Logger logger = LoggerFactory.getLogger(getClass());
  
      private final ExecutionEventCatapult eventCatapult;
      private final DefaultLifecycles defaultLifeCycles;
      private final BuildPlanExecutor executor;
      private final LifecyclePluginResolver lifecyclePluginResolver;
      private final MojoDescriptorCreator mojoDescriptorCreator;
  
      @Inject
      public ConcurrentLifecycleStarter(
              ExecutionEventCatapult eventCatapult,
              DefaultLifecycles defaultLifeCycles,
              BuildPlanExecutor executor,
              LifecyclePluginResolver lifecyclePluginResolver,
              MojoDescriptorCreator mojoDescriptorCreator) {
          this.eventCatapult = eventCatapult;
          this.defaultLifeCycles = defaultLifeCycles;
          this.executor = executor;
          this.lifecyclePluginResolver = lifecyclePluginResolver;
          this.mojoDescriptorCreator = mojoDescriptorCreator;
      }
  
      @Override
      public void execute(MavenSession session) {
          eventCatapult.fire(ExecutionEvent.Type.SessionStarted, session, null);
  
          try {
              if (requiresProject(session) && projectIsNotPresent(session)) {
                  throw new MissingProjectException("The goal you specified requires a project to execute"
                          + " but there is no POM in this directory (" + session.getTopDirectory() + ")."
                          + " Please verify you invoked Maven from the correct directory.");
              }
  
              List<TaskSegment> taskSegments = calculateTaskSegments(session);
              if (taskSegments.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() + ".");
              }
  
             int degreeOfConcurrency = session.getRequest().getDegreeOfConcurrency();
             if (degreeOfConcurrency > 1) {
                 logger.info("");
                 logger.info(String.format(
                         "Using the %s implementation with a thread count of %d",
                         executor.getClass().getSimpleName(), degreeOfConcurrency));
             }
 
             ClassLoader oldContextClassLoader = Thread.currentThread().getContextClassLoader();
             ReactorBuildStatus reactorBuildStatus = new ReactorBuildStatus(session.getProjectDependencyGraph());
             ReactorContext reactorContext =
                     new ReactorContext(session.getResult(), oldContextClassLoader, reactorBuildStatus);
             executor.execute(session, reactorContext, taskSegments);
 
         } catch (Exception e) {
             session.getResult().addException(e);
         } finally {
             eventCatapult.fire(ExecutionEvent.Type.SessionEnded, session, null);
         }
     }
 
     public List<TaskSegment> calculateTaskSegments(MavenSession session) throws Exception {
 
         MavenProject rootProject = session.getTopLevelProject();
 
         List<String> tasks = requireNonNull(session.getGoals()); // session never returns null, but empty list
 
         if (tasks.isEmpty()
                 && (rootProject.getDefaultGoal() != null
                         && !rootProject.getDefaultGoal().isEmpty())) {
             tasks = Stream.of(rootProject.getDefaultGoal().split("\\s+"))
                     .filter(g -> !g.isEmpty())
                     .collect(Collectors.toList());
         }
 
         return calculateTaskSegments(session, tasks);
     }
 
     public List<TaskSegment> calculateTaskSegments(MavenSession session, List<String> tasks) throws Exception {
         List<TaskSegment> taskSegments = new ArrayList<>(tasks.size());
 
         TaskSegment currentSegment = null;
 
         for (String task : tasks) {
             if (isBeforeOrAfterPhase(task)) {
                 String prevTask = task;
                 task = PhaseId.of(task).phase();
                 logger.warn("Illegal call to phase '{}'. The main phase '{}' will be used instead.", prevTask, task);
             }
             if (isGoalSpecification(task)) {
                 // "pluginPrefix[:version]:goal" or "groupId:artifactId[:version]:goal"
 
                 lifecyclePluginResolver.resolveMissingPluginVersions(session.getTopLevelProject(), session);
 
                 MojoDescriptor mojoDescriptor =
                         mojoDescriptorCreator.getMojoDescriptor(task, session, session.getTopLevelProject());
 
                 boolean aggregating = mojoDescriptor.isAggregator() || !mojoDescriptor.isProjectRequired();
 
                 if (currentSegment == null || currentSegment.isAggregating() != aggregating) {
                     currentSegment = new TaskSegment(aggregating);
                     taskSegments.add(currentSegment);
                 }
 
                 currentSegment.getTasks().add(new GoalTask(task));
             } else {
                 // lifecycle phase
 
                 if (currentSegment == null || currentSegment.isAggregating()) {
                     currentSegment = new TaskSegment(false);
                     taskSegments.add(currentSegment);
                 }
 
                 currentSegment.getTasks().add(new LifecycleTask(task));
             }
         }
 
         return taskSegments;
     }
 
     private boolean projectIsNotPresent(MavenSession session) {
         return !session.getRequest().isProjectPresent();
     }
 
     private boolean requiresProject(MavenSession session) {
         List<String> goals = session.getGoals();
         if (goals != null) {
             for (String goal : goals) {
                 if (!isGoalSpecification(goal)) {
                     return true;
                 }
             }
         }
         return false;
     }
 
     private boolean isBeforeOrAfterPhase(String task) {
         return task.startsWith(Lifecycle.BEFORE) || task.startsWith(Lifecycle.AFTER);
     }
 
     private boolean isGoalSpecification(String task) {
         return task.indexOf(':') >= 0;
     }
 }