package org.apache.maven.graph;

/*
 * 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 java.io.File;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;

import org.apache.maven.DefaultMaven;
import org.apache.maven.MavenExecutionException;
import org.apache.maven.ProjectCycleException;
import org.apache.maven.artifact.ArtifactUtils;
import org.apache.maven.execution.MavenExecutionRequest;
import org.apache.maven.execution.MavenExecutionResult;
import org.apache.maven.execution.MavenSession;
import org.apache.maven.execution.ProjectDependencyGraph;
import org.apache.maven.model.Plugin;
import org.apache.maven.model.building.DefaultModelProblem;
import org.apache.maven.model.building.ModelProblem;
import org.apache.maven.model.building.ModelProblemUtils;
import org.apache.maven.model.building.ModelSource;
import org.apache.maven.model.building.Result;
import org.apache.maven.model.building.UrlModelSource;
import org.apache.maven.project.MavenProject;
import org.apache.maven.project.ProjectBuilder;
import org.apache.maven.project.ProjectBuildingException;
import org.apache.maven.project.ProjectBuildingRequest;
import org.apache.maven.project.ProjectBuildingResult;
import org.codehaus.plexus.component.annotations.Component;
import org.codehaus.plexus.component.annotations.Requirement;
import org.codehaus.plexus.logging.Logger;
import org.codehaus.plexus.util.StringUtils;
import org.codehaus.plexus.util.dag.CycleDetectedException;

import com.google.common.collect.Lists;

@Component( role = GraphBuilder.class, hint = GraphBuilder.HINT )
public class DefaultGraphBuilder
    implements GraphBuilder
{
    @Requirement
    private Logger logger;

    @Requirement
    protected ProjectBuilder projectBuilder;

    @Override
    public Result<ProjectDependencyGraph> build( MavenSession session )
    {
        if ( session.getProjectDependencyGraph() != null )
        {
            return dependencyGraph( session, session.getProjects(), false );
        }
        
        List<MavenProject> projects = session.getProjects();

        if ( projects == null )
        {
            try
            {
                projects = getProjectsForMavenReactor( session );
            }
            catch ( ProjectBuildingException e )
            {
                return Result.error( Lists.newArrayList( new DefaultModelProblem( null, null, null, null, 0, 0, e ) ) );
            }

            validateProjects( projects );

            return dependencyGraph( session, projects, true );
        }
        else
        {
            return dependencyGraph( session, projects, false );
        }
    }
    
    private Result<ProjectDependencyGraph> dependencyGraph( MavenSession session, List<MavenProject> projects,
                                                            boolean applyMakeBehaviour )
    {
        MavenExecutionRequest request = session.getRequest();

        ProjectDependencyGraph projectDependencyGraph = null;

        try
        {
            projectDependencyGraph = new DefaultProjectDependencyGraph( projects );

            if ( applyMakeBehaviour )
            {
                List<MavenProject> activeProjects = projectDependencyGraph.getSortedProjects();

                activeProjects = trimSelectedProjects( activeProjects, projectDependencyGraph, request );
                activeProjects = trimExcludedProjects( activeProjects, request );
                activeProjects = trimResumedProjects( activeProjects, request );

                if ( activeProjects.size() != projectDependencyGraph.getSortedProjects().size() )
                {
                    projectDependencyGraph =
                        new FilteredProjectDependencyGraph( projectDependencyGraph, activeProjects );
                }
            }
        }
        catch ( CycleDetectedException e )
        {
            String message = "The projects in the reactor contain a cyclic reference: " + e.getMessage();
            ProjectCycleException error = new ProjectCycleException( message, e );
            return Result.error( Lists.newArrayList( new DefaultModelProblem( null, null, null, null, 0, 0, error ) ) );
        }
        catch ( org.apache.maven.project.DuplicateProjectException e )
        {
            return Result.error( Lists.newArrayList( new DefaultModelProblem( null, null, null, null, 0, 0, e ) ) );
        }
        catch ( MavenExecutionException e )
        {
            return Result.error( Lists.newArrayList( new DefaultModelProblem( null, null, null, null, 0, 0, e ) ) );
        }

        session.setProjects( projectDependencyGraph.getSortedProjects() );
        session.setProjectDependencyGraph( projectDependencyGraph );

        return Result.success( projectDependencyGraph );
    }

    private List<MavenProject> trimSelectedProjects( List<MavenProject> projects, ProjectDependencyGraph graph,
                                                     MavenExecutionRequest request )
        throws MavenExecutionException
    {
        List<MavenProject> result = projects;

        if ( !request.getSelectedProjects().isEmpty() )
        {
            File reactorDirectory = null;
            if ( request.getBaseDirectory() != null )
            {
                reactorDirectory = new File( request.getBaseDirectory() );
            }

            Collection<MavenProject> selectedProjects = new LinkedHashSet<MavenProject>( projects.size() );

            for ( String selector : request.getSelectedProjects() )
            {
                MavenProject selectedProject = null;

                for ( MavenProject project : projects )
                {
                    if ( isMatchingProject( project, selector, reactorDirectory ) )
                    {
                        selectedProject = project;
                        break;
                    }
                }

                if ( selectedProject != null )
                {
                    selectedProjects.add( selectedProject );
                }
                else
                {
                    throw new MavenExecutionException( "Could not find the selected project in the reactor: "
                        + selector, request.getPom() );
                }
            }

            boolean makeUpstream = false;
            boolean makeDownstream = false;

            if ( MavenExecutionRequest.REACTOR_MAKE_UPSTREAM.equals( request.getMakeBehavior() ) )
            {
                makeUpstream = true;
            }
            else if ( MavenExecutionRequest.REACTOR_MAKE_DOWNSTREAM.equals( request.getMakeBehavior() ) )
            {
                makeDownstream = true;
            }
            else if ( MavenExecutionRequest.REACTOR_MAKE_BOTH.equals( request.getMakeBehavior() ) )
            {
                makeUpstream = true;
                makeDownstream = true;
            }
            else if ( StringUtils.isNotEmpty( request.getMakeBehavior() ) )
            {
                throw new MavenExecutionException( "Invalid reactor make behavior: " + request.getMakeBehavior(),
                                                   request.getPom() );
            }

            if ( makeUpstream || makeDownstream )
            {
                for ( MavenProject selectedProject : new ArrayList<MavenProject>( selectedProjects ) )
                {
                    if ( makeUpstream )
                    {
                        selectedProjects.addAll( graph.getUpstreamProjects( selectedProject, true ) );
                    }
                    if ( makeDownstream )
                    {
                        selectedProjects.addAll( graph.getDownstreamProjects( selectedProject, true ) );
                    }
                }
            }

            result = new ArrayList<MavenProject>( selectedProjects.size() );

            for ( MavenProject project : projects )
            {
                if ( selectedProjects.contains( project ) )
                {
                    result.add( project );
                }
            }
        }

        return result;
    }

    private List<MavenProject> trimExcludedProjects( List<MavenProject> projects, MavenExecutionRequest request )
        throws MavenExecutionException
    {
        List<MavenProject> result = projects;

        if ( !request.getExcludedProjects().isEmpty() )
        {
            File reactorDirectory = null;

            if ( request.getBaseDirectory() != null )
            {
                reactorDirectory = new File( request.getBaseDirectory() );
            }

            Collection<MavenProject> excludedProjects = new LinkedHashSet<MavenProject>( projects.size() );

            for ( String selector : request.getExcludedProjects() )
            {
                MavenProject excludedProject = null;

                for ( MavenProject project : projects )
                {
                    if ( isMatchingProject( project, selector, reactorDirectory ) )
                    {
                        excludedProject = project;
                        break;
                    }
                }

                if ( excludedProject != null )
                {
                    excludedProjects.add( excludedProject );
                }
                else
                {
                    throw new MavenExecutionException( "Could not find the selected project in the reactor: "
                        + selector, request.getPom() );
                }
            }

            result = new ArrayList<MavenProject>( projects.size() );
            for ( MavenProject project : projects )
            {
                if ( !excludedProjects.contains( project ) )
                {
                    result.add( project );
                }
            }
        }

        return result;
    }

    private List<MavenProject> trimResumedProjects( List<MavenProject> projects, MavenExecutionRequest request )
        throws MavenExecutionException
    {
        List<MavenProject> result = projects;

        if ( StringUtils.isNotEmpty( request.getResumeFrom() ) )
        {
            File reactorDirectory = null;
            if ( request.getBaseDirectory() != null )
            {
                reactorDirectory = new File( request.getBaseDirectory() );
            }

            String selector = request.getResumeFrom();

            result = new ArrayList<MavenProject>( projects.size() );

            boolean resumed = false;

            for ( MavenProject project : projects )
            {
                if ( !resumed && isMatchingProject( project, selector, reactorDirectory ) )
                {
                    resumed = true;
                }

                if ( resumed )
                {
                    result.add( project );
                }
            }

            if ( !resumed )
            {
                throw new MavenExecutionException( "Could not find project to resume reactor build from: " + selector
                    + " vs " + projects, request.getPom() );
            }
        }

        return result;
    }

    private boolean isMatchingProject( MavenProject project, String selector, File reactorDirectory )
    {
        // [groupId]:artifactId
        if ( selector.indexOf( ':' ) >= 0 )
        {
            String id = ':' + project.getArtifactId();

            if ( id.equals( selector ) )
            {
                return true;
            }

            id = project.getGroupId() + id;

            if ( id.equals( selector ) )
            {
                return true;
            }
        }

        // relative path, e.g. "sub", "../sub" or "."
        else if ( reactorDirectory != null )
        {
            File selectedProject = new File( new File( reactorDirectory, selector ).toURI().normalize() );

            if ( selectedProject.isFile() )
            {
                return selectedProject.equals( project.getFile() );
            }
            else if ( selectedProject.isDirectory() )
            {
                return selectedProject.equals( project.getBasedir() );
            }
        }

        return false;
    }

    private MavenExecutionResult addExceptionToResult( MavenExecutionResult result, Throwable e )
    {
        if ( !result.getExceptions().contains( e ) )
        {
            result.addException( e );
        }

        return result;
    }

    // ////////////////////////////////////////////////////////////////////////////////////////////////////////////////
    //
    // Project collection
    //
    // ////////////////////////////////////////////////////////////////////////////////////////////////////////////////

    private List<MavenProject> getProjectsForMavenReactor( MavenSession session )
        throws ProjectBuildingException
    {
        MavenExecutionRequest request = session.getRequest();

        request.getProjectBuildingRequest().setRepositorySession( session.getRepositorySession() );

        List<MavenProject> projects = new ArrayList<MavenProject>();

        // We have no POM file.
        //
        if ( request.getPom() == null )
        {
            ModelSource modelSource = new UrlModelSource( DefaultMaven.class.getResource( "project/standalone.xml" ) );
            MavenProject project = projectBuilder.build( modelSource, request.getProjectBuildingRequest() )
                .getProject();
            project.setExecutionRoot( true );
            projects.add( project );
            request.setProjectPresent( false );
            return projects;
        }

        List<File> files = Arrays.asList( request.getPom().getAbsoluteFile() );
        collectProjects( projects, files, request );
        return projects;
    }

    private void collectProjects( List<MavenProject> projects, List<File> files, MavenExecutionRequest request )
        throws ProjectBuildingException
    {
        ProjectBuildingRequest projectBuildingRequest = request.getProjectBuildingRequest();

        List<ProjectBuildingResult> results = projectBuilder.build( files, request.isRecursive(),
                                                                    projectBuildingRequest );

        boolean problems = false;

        for ( ProjectBuildingResult result : results )
        {
            projects.add( result.getProject() );

            if ( !result.getProblems().isEmpty() && logger.isWarnEnabled() )
            {
                logger.warn( "" );
                logger.warn( "Some problems were encountered while building the effective model for "
                    + result.getProject().getId() );

                for ( ModelProblem problem : result.getProblems() )
                {
                    String loc = ModelProblemUtils.formatLocation( problem, result.getProjectId() );
                    logger.warn( problem.getMessage() + ( StringUtils.isNotEmpty( loc ) ? " @ " + loc : "" ) );
                }

                problems = true;
            }
        }

        if ( problems )
        {
            logger.warn( "" );
            logger.warn( "It is highly recommended to fix these problems"
                + " because they threaten the stability of your build." );
            logger.warn( "" );
            logger.warn( "For this reason, future Maven versions might no"
                + " longer support building such malformed projects." );
            logger.warn( "" );
        }
    }

    private void validateProjects( List<MavenProject> projects )
    {
        Map<String, MavenProject> projectsMap = new HashMap<String, MavenProject>();

        for ( MavenProject p : projects )
        {
            String projectKey = ArtifactUtils.key( p.getGroupId(), p.getArtifactId(), p.getVersion() );

            projectsMap.put( projectKey, p );
        }

        for ( MavenProject project : projects )
        {
            // MNG-1911 / MNG-5572: Building plugins with extensions cannot be part of reactor
            for ( Plugin plugin : project.getBuildPlugins() )
            {
                if ( plugin.isExtensions() )
                {
                    String pluginKey = ArtifactUtils.key( plugin.getGroupId(), plugin.getArtifactId(),
                                                          plugin.getVersion() );

                    if ( projectsMap.containsKey( pluginKey ) )
                    {
                        logger.warn( project.getName() + " uses " + plugin.getKey()
                            + " as extensions, which is not possible within the same reactor build. "
                            + "This plugin was pulled from the local repository!" );
                    }
                }
            }
        }
    }

}