/*
 * 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 javax.inject.Named;
import javax.inject.Singleton;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import org.apache.maven.execution.MavenSession;
import org.apache.maven.lifecycle.internal.builder.BuilderCommon;
import org.apache.maven.project.MavenProject;

/**
 * <strong>NOTE:</strong> This class is not part of any public api and can be changed or deleted without prior notice.
 *
 * @since 3.0
 */
@Named
@Singleton
public class BuildListCalculator {
    public ProjectBuildList calculateProjectBuilds(MavenSession session, List<TaskSegment> taskSegments) {
        List<ProjectSegment> projectBuilds = new ArrayList<>();

        MavenProject rootProject = session.getTopLevelProject();

        for (TaskSegment taskSegment : taskSegments) {
            List<MavenProject> projects;

            if (taskSegment.isAggregating()) {
                projects = Collections.singletonList(rootProject);
            } else {
                projects = session.getProjects();
            }
            for (MavenProject project : projects) {
                ClassLoader tccl = Thread.currentThread().getContextClassLoader();
                MavenProject currentProject = session.getCurrentProject();
                try {
                    BuilderCommon.attachToThread(project); // Not totally sure if this is needed for anything
                    session.setCurrentProject(project);
                    projectBuilds.add(new ProjectSegment(project, taskSegment, session));
                } finally {
                    session.setCurrentProject(currentProject);
                    Thread.currentThread().setContextClassLoader(tccl);
                }
            }
        }
        return new ProjectBuildList(projectBuilds);
    }
}
