package org.apache.maven.plugins.pmd.exec;

/*
 * 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.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Objects;

import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.plugins.pmd.ExcludeDuplicationsFromFile;
import org.apache.maven.reporting.MavenReportException;
import org.codehaus.plexus.util.FileUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import net.sourceforge.pmd.cpd.CPD;
import net.sourceforge.pmd.cpd.CPDConfiguration;
import net.sourceforge.pmd.cpd.CSVRenderer;
import net.sourceforge.pmd.cpd.EcmascriptLanguage;
import net.sourceforge.pmd.cpd.JSPLanguage;
import net.sourceforge.pmd.cpd.JavaLanguage;
import net.sourceforge.pmd.cpd.Language;
import net.sourceforge.pmd.cpd.LanguageFactory;
import net.sourceforge.pmd.cpd.Match;
import net.sourceforge.pmd.cpd.SimpleRenderer;
import net.sourceforge.pmd.cpd.XMLRenderer;
import net.sourceforge.pmd.cpd.renderer.CPDRenderer;

/**
 * Executes CPD with the configuration provided via {@link CpdRequest}.
 */
public class CpdExecutor extends Executor
{
    private static final Logger LOG = LoggerFactory.getLogger( CpdExecutor.class );

    public static CpdResult execute( CpdRequest request ) throws MavenReportException
    {
        if ( request.getJavaExecutable() != null )
        {
            return fork( request );
        }

        ClassLoader origLoader = Thread.currentThread().getContextClassLoader();
        try
        {
            Thread.currentThread().setContextClassLoader( CpdExecutor.class.getClassLoader() );
            CpdExecutor cpdExecutor = new CpdExecutor( request );
            return cpdExecutor.run();
        }
        finally
        {
            Thread.currentThread().setContextClassLoader( origLoader );
        }
    }

    private static CpdResult fork( CpdRequest request )
            throws MavenReportException
    {
        File basePmdDir = new File ( request.getTargetDirectory(), "pmd" );
        basePmdDir.mkdirs();
        File cpdRequestFile = new File( basePmdDir, "cpdrequest.bin" );
        try ( ObjectOutputStream out = new ObjectOutputStream( new FileOutputStream( cpdRequestFile ) ) )
        {
            out.writeObject( request );
        }
        catch ( IOException e )
        {
            throw new MavenReportException( e.getMessage(), e );
        }

        String classpath = buildClasspath();
        ProcessBuilder pb = new ProcessBuilder();
        // note: using env variable instead of -cp cli arg to avoid length limitations under Windows
        pb.environment().put( "CLASSPATH", classpath );
        pb.command().add( request.getJavaExecutable() );
        pb.command().add( CpdExecutor.class.getName() );
        pb.command().add( cpdRequestFile.getAbsolutePath() );

        LOG.debug( "Executing: CLASSPATH={}, command={}", classpath, pb.command() );
        try
        {
            final Process p = pb.start();
            // Note: can't use pb.inheritIO(), since System.out/System.err has been modified after process start
            // and inheritIO would only inherit file handles, not the changed streams.
            ProcessStreamHandler.start( p.getInputStream(), System.out );
            ProcessStreamHandler.start( p.getErrorStream(), System.err );
            int exit = p.waitFor();
            LOG.debug( "CpdExecutor exit code: {}", exit );
            if ( exit != 0 )
            {
                throw new MavenReportException( "CpdExecutor exited with exit code " + exit );
            }
            return new CpdResult( new File( request.getTargetDirectory(), "cpd.xml" ), request.getOutputEncoding() );
        }
        catch ( IOException e )
        {
            throw new MavenReportException( e.getMessage(), e );
        }
        catch ( InterruptedException e )
        {
            Thread.currentThread().interrupt();
            throw new MavenReportException( e.getMessage(), e );
        }
    }

    /**
     * Execute CPD analysis from CLI.
     *
     * <p>
     * Single arg with the filename to the serialized {@link CpdRequest}.
     *
     * <p>
     * Exit-code: 0 = success, 1 = failure in executing
     *
     * @param args
     */
    public static void main( String[] args )
    {
        File requestFile = new File( args[0] );
        try ( ObjectInputStream in = new ObjectInputStream( new FileInputStream( requestFile ) ) )
        {
            CpdRequest request = (CpdRequest) in.readObject();
            CpdExecutor cpdExecutor = new CpdExecutor( request );
            cpdExecutor.setupLogLevel( request.getLogLevel() );
            cpdExecutor.run();
            System.exit( 0 );
        }
        catch ( IOException | ClassNotFoundException | MavenReportException e )
        {
            LOG.error( e.getMessage(), e );
        }
        System.exit( 1 );
    }

    private final CpdRequest request;

    /** Helper to exclude duplications from the result. */
    private final ExcludeDuplicationsFromFile excludeDuplicationsFromFile = new ExcludeDuplicationsFromFile();

    public CpdExecutor( CpdRequest request )
    {
        this.request = Objects.requireNonNull( request );
    }

    private CpdResult run() throws MavenReportException
    {
        setupPmdLogging( request.isShowPmdLog(), request.getLogLevel() );

        try
        {
            excludeDuplicationsFromFile.loadExcludeFromFailuresData( request.getExcludeFromFailureFile() );
        }
        catch ( MojoExecutionException e )
        {
            throw new MavenReportException( "Error loading exclusions", e );
        }

        CPDConfiguration cpdConfiguration = new CPDConfiguration();
        cpdConfiguration.setMinimumTileSize( request.getMinimumTokens() );
        
        Language cpdLanguage;
        if ( "java".equals ( request.getLanguage() ) || null == request.getLanguage() )
        {
            cpdLanguage = new JavaLanguage( request.getLanguageProperties() );
        }
        else if ( "javascript".equals( request.getLanguage() ) )
        {
            cpdLanguage = new EcmascriptLanguage();
        }
        else if ( "jsp".equals( request.getLanguage() ) )
        {
            cpdLanguage = new JSPLanguage();
        }
        else
        {
            cpdLanguage = LanguageFactory.createLanguage( request.getLanguage(), request.getLanguageProperties() );
        }
        
        cpdConfiguration.setLanguage( cpdLanguage );
        cpdConfiguration.setSourceEncoding( request.getSourceEncoding() );

        CPD cpd = new CPD( cpdConfiguration );
        try
        {
            cpd.add( request.getFiles() );
        }
        catch ( IOException e )
        {
            throw new MavenReportException( e.getMessage(), e );
        }

        LOG.debug( "Executing CPD..." );
        cpd.go();
        LOG.debug( "CPD finished." );

        // always create XML format. we need to output it even if the file list is empty or we have no duplications
        // so the "check" goals can check for violations
        writeXmlReport( cpd );

        // html format is handled by maven site report, xml format has already been rendered
        String format = request.getFormat();
        if ( !"html".equals( format ) && !"xml".equals( format ) )
        {
            writeFormattedReport( cpd );
        }

        return new CpdResult( new File( request.getTargetDirectory(), "cpd.xml" ), request.getOutputEncoding() );
    }

    private void writeXmlReport( CPD cpd ) throws MavenReportException
    {
        File targetFile = writeReport( cpd, new XMLRenderer( request.getOutputEncoding() ), "xml" );
        if ( request.isIncludeXmlInSite() )
        {
            File siteDir = new File( request.getReportOutputDirectory() );
            siteDir.mkdirs();
            try
            {
                FileUtils.copyFile( targetFile, new File( siteDir, "cpd.xml" ) );
            }
            catch ( IOException e )
            {
                throw new MavenReportException( e.getMessage(), e );
            }
        }
    }

    private File writeReport( CPD cpd, CPDRenderer r, String extension ) throws MavenReportException
    {
        if ( r == null )
        {
            return null;
        }

        File targetDir = new File( request.getTargetDirectory() );
        targetDir.mkdirs();
        File targetFile = new File( targetDir, "cpd." + extension );
        try ( Writer writer = new OutputStreamWriter( new FileOutputStream( targetFile ),
                request.getOutputEncoding() ) )
        {
            r.render( filterMatches( cpd.getMatches() ), writer );
            writer.flush();
        }
        catch ( IOException ioe )
        {
            throw new MavenReportException( ioe.getMessage(), ioe );
        }
        return targetFile;
    }

    private void writeFormattedReport( CPD cpd )
            throws MavenReportException
        {
            CPDRenderer r = createRenderer( request.getFormat(), request.getOutputEncoding() );
            writeReport( cpd, r, request.getFormat() );

        }

    /**
     * Create and return the correct renderer for the output type.
     *
     * @return the renderer based on the configured output
     * @throws org.apache.maven.reporting.MavenReportException if no renderer found for the output type
     */
    public static CPDRenderer createRenderer( String format, String outputEncoding )
        throws MavenReportException
    {
        CPDRenderer renderer = null;
        if ( "xml".equals( format ) )
        {
            renderer = new XMLRenderer( outputEncoding );
        }
        else if ( "csv".equals( format ) )
        {
            renderer = new CSVRenderer();
        }
        else if ( "txt".equals( format ) )
        {
            renderer = new SimpleRenderer();
        }
        else if ( !"".equals( format ) && !"none".equals( format ) )
        {
            try
            {
                renderer = (CPDRenderer) Class.forName( format ).getConstructor().newInstance();
            }
            catch ( Exception e )
            {
                throw new MavenReportException( "Can't find CPD custom format " + format + ": "
                    + e.getClass().getName(), e );
            }
        }

        return renderer;
    }

    private Iterator<Match> filterMatches( Iterator<Match> matches )
    {
        LOG.debug( "Filtering duplications. Using " + excludeDuplicationsFromFile.countExclusions()
            + " configured exclusions." );

        List<Match> filteredMatches = new ArrayList<>();
        int excludedDuplications = 0;
        while ( matches.hasNext() )
        {
            Match match = matches.next();
            if ( excludeDuplicationsFromFile.isExcludedFromFailure( match ) )
            {
                excludedDuplications++;
            }
            else
            {
                filteredMatches.add( match );
            }
        }

        LOG.debug( "Excluded " + excludedDuplications + " duplications." );
        return filteredMatches.iterator();
    }

}