package org.apache.maven.plugins.assembly.utils;

/*
 * 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 org.apache.maven.artifact.Artifact;
import org.apache.maven.project.MavenProject;
import org.codehaus.plexus.logging.Logger;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import java.io.File;
import java.io.IOException;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;

/**
 * @version $Id$
 */
public final class ProjectUtils
{

    private ProjectUtils()
    {
    }

    @Nullable
    public static String getClassifier( @Nonnull Artifact artifact )
    {
        String classifier = artifact.getClassifier();
        if ( classifier != null && classifier.length() == 0 )
        {
            classifier = null;
        }
        return classifier;
    }

    @Nonnull
    public static Set<MavenProject> getProjectModules( @Nonnull final MavenProject project,
                                                       @Nonnull final List<MavenProject> reactorProjects,
                                                       final boolean includeSubModules, @Nonnull final Logger logger )
        throws IOException
    {
        final Set<MavenProject> singleParentSet = Collections.singleton( project );

        final Set<MavenProject> moduleCandidates = new LinkedHashSet<MavenProject>( reactorProjects );

        final Set<MavenProject> modules = new LinkedHashSet<MavenProject>();

        // we temporarily add the master project to the modules set, since this
        // set is pulling double duty as a set of
        // potential module parents in the tree rooted at the master
        // project...this allows us to use the same looping
        // algorithm below to discover both direct modules of the master project
        // AND modules of those direct modules.
        modules.add( project );

        int changed;

        do
        {
            changed = 0;

            for ( final Iterator<MavenProject> candidateIterator = moduleCandidates.iterator();
                  candidateIterator.hasNext(); )
            {
                final MavenProject moduleCandidate = candidateIterator.next();

                if ( moduleCandidate.getFile() == null )
                {
                    logger.warn(
                        "Cannot compute whether " + moduleCandidate.getId() + " is a module of: " + project.getId()
                            + "; it does not have an associated POM file on the local filesystem." );
                    continue;
                }

                Set<MavenProject> currentPotentialParents;
                if ( includeSubModules )
                {
                    currentPotentialParents = new LinkedHashSet<MavenProject>( modules );
                }
                else
                {
                    currentPotentialParents = singleParentSet;
                }

                for ( final MavenProject potentialParent : currentPotentialParents )
                {
                    if ( potentialParent.getFile() == null )
                    {
                        logger.warn( "Cannot use: " + moduleCandidate.getId()
                                         + " as a potential module-parent while computing the module set for: "
                                         + project.getId()
                                         + "; it does not have an associated POM file on the local filesystem." );
                        continue;
                    }

                    // if this parent has an entry for the module candidate in
                    // the path adjustments map, it's a direct
                    // module of that parent.
                    if ( projectContainsModule( potentialParent, moduleCandidate ) )
                    {
                        // add the candidate to the list of modules (and
                        // potential parents)
                        modules.add( moduleCandidate );

                        // remove the candidate from the candidate pool, because
                        // it's been verified.
                        candidateIterator.remove();

                        // increment the change counter, to show that we
                        // verified a new module on this pass.
                        changed++;
                        
                        // We need to move on to the next candidate since this one was just verified
                        break;
                    }
                }
            }
        }
        while ( changed != 0 );

        // remove the master project from the modules set, now that we're done
        // using it as a set of potential module
        // parents...
        modules.remove( project );

        return modules;
    }

    private static boolean projectContainsModule( @Nonnull final MavenProject mainProject,
                                                  @Nonnull final MavenProject moduleProject )
        throws IOException
    {
        final List<String> modules = mainProject.getModules();
        final File basedir = mainProject.getBasedir();

        final File moduleFile = moduleProject.getFile().getCanonicalFile();

        File moduleBasedir = moduleProject.getBasedir();

        if ( moduleBasedir == null )
        {
            moduleBasedir = moduleFile.getParentFile();

            if ( moduleBasedir == null )
            {
                moduleBasedir = new File( "." );
            }
        }

        moduleBasedir = moduleBasedir.getCanonicalFile();

        for ( final String moduleSubpath : modules )
        {
            final File moduleDir = new File( basedir, moduleSubpath ).getCanonicalFile();

            if ( moduleDir.equals( moduleFile ) || moduleDir.equals( moduleBasedir ) )
            {
                return true;
            }
        }

        return false;
    }

}