/*

  * 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.shared.test.plugin;

 import java.io.File;

 import java.io.FileWriter;

 import java.io.IOException;

 import java.util.List;

 import java.util.Properties;

 import org.apache.maven.shared.invoker.DefaultInvocationRequest;

 import org.apache.maven.shared.invoker.DefaultInvoker;

 import org.apache.maven.shared.invoker.InvocationOutputHandler;

 import org.apache.maven.shared.invoker.InvocationRequest;

 import org.apache.maven.shared.invoker.InvocationResult;

 import org.apache.maven.shared.invoker.Invoker;

 import org.apache.maven.shared.invoker.MavenInvocationException;

 import org.codehaus.plexus.personality.plexus.lifecycle.phase.Disposable;

 import org.codehaus.plexus.personality.plexus.lifecycle.phase.Initializable;

 import org.codehaus.plexus.personality.plexus.lifecycle.phase.InitializationException;

 import org.codehaus.plexus.util.IOUtil;

 import org.codehaus.plexus.util.cli.CommandLineUtils;

 /**

  * Test-tool used to execute Maven builds in order to test plugin functionality.

  * 

  * @plexus.component role="org.apache.maven.shared.test.plugin.BuildTool" role-hint="default"

  * @author jdcasey

  *

  */

 public class BuildTool

     implements Initializable, Disposable

 {

     public static final String ROLE = BuildTool.class.getName();

     private Invoker mavenInvoker;

     /**

      * Build a standard InvocationRequest using the specified test-build POM, command-line properties,

      * goals, and output logfile. Then, execute Maven using this standard request. Return the result

      * of the invocation.

      * 

      * @param pom The test-build POM

      * @param properties command-line properties to fine-tune the test build, or test parameter 

      *   extraction from CLI properties 

      * @param goals The list of goals and/or lifecycle phases to execute during this build

      * @param buildLogFile The logfile used to capture build output

      * @return The result of the Maven invocation, including exit value and any execution exceptions

      *   resulting from the Maven invocation.

      */

     public InvocationResult executeMaven( File pom, Properties properties, List goals, File buildLogFile )

         throws TestToolsException

     {

         InvocationRequest request = createBasicInvocationRequest( pom, properties, goals, buildLogFile );

         return executeMaven( request );

     }

     /**

      * Execute a test build using a customized InvocationRequest. Normally, this request would be 

      * created using the <code>createBasicInvocationRequest</code> method in this class.

      * 

      * @param request The customized InvocationRequest containing the configuration used to execute

      *   the current test build

      * @return The result of the Maven invocation, containing exit value, along with any execution

      *   exceptions resulting from the [attempted] Maven invocation.

      */

     public InvocationResult executeMaven( InvocationRequest request )

         throws TestToolsException

     {

         try

         {

             return mavenInvoker.execute( request );

         }

         catch ( MavenInvocationException e )

         {

             throw new TestToolsException( "Error executing maven.", e );

         }

         finally

         {

             closeHandlers( request );

         }

     }

     /**

      * Detect the location of the local Maven installation, and start up the MavenInvoker using that

      * path. Detection uses the system property <code>maven.home</code>, and falls back to the shell

      * environment variable <code>M2_HOME</code>.

      * 

      * @throws IOException in case the shell environment variables cannot be read

      */

     private void startInvoker()

         throws IOException

     {

         if ( mavenInvoker == null )

         {

             mavenInvoker = new DefaultInvoker();

             if ( System.getProperty( "maven.home" ) == null )

             {

                 Properties envars = CommandLineUtils.getSystemEnvVars();

                 String mavenHome = envars.getProperty( "M2_HOME" );

                 if ( mavenHome != null )

                 {

                     mavenInvoker.setMavenHome( new File( mavenHome ) );

                 }

             }

         }

     }

     /**

      * If we're logging output to a logfile using standard output handlers, make sure these are

      * closed.

      * 

      * @param request

      */

     private void closeHandlers( InvocationRequest request )

     {

         InvocationOutputHandler outHandler = request.getOutputHandler( null );

         if ( outHandler != null && ( outHandler instanceof LoggerHandler ) )

         {

             ( (LoggerHandler) outHandler ).close();

         }

         InvocationOutputHandler errHandler = request.getErrorHandler( null );

         if ( errHandler != null && ( outHandler == null || errHandler != outHandler )

             && ( errHandler instanceof LoggerHandler ) )

         {

             ( (LoggerHandler) errHandler ).close();

         }

     }

     /**

      * Construct a standardized InvocationRequest given the test-build POM, a set of CLI properties,

      * a list of goals to execute, and the location of a log file to which build output should be

      * directed. The resulting InvocationRequest can then be customized by the test class before

      * being used to execute a test build. Both standard-out and standard-error will be directed

      * to the specified log file.

      * 

      * @param pom The POM for the test build

      * @param properties The command-line properties for use in this test build

      * @param goals The goals and/or lifecycle phases to execute during the test build

      * @param buildLogFile Location to which build output should be logged

      * @return The standardized InvocationRequest for the test build, ready for any necessary 

      *   customizations.

      */

     public InvocationRequest createBasicInvocationRequest( File pom, Properties properties, List goals,

                                                            File buildLogFile )

     {

         InvocationRequest request = new DefaultInvocationRequest();

         request.setPomFile( pom );

         request.setGoals( goals );

         request.setProperties( properties );

         LoggerHandler handler = new LoggerHandler( buildLogFile );

         request.setOutputHandler( handler );

         request.setErrorHandler( handler );

         return request;

     }

     private static final class LoggerHandler

         implements InvocationOutputHandler

     {

         private static final String LS = System.getProperty( "line.separator" );

         private final File output;

         private FileWriter writer;

         LoggerHandler( File logFile )

         {

             output = logFile;

         }

         public void consumeLine( String line )

         {

             if ( writer == null )

             {

                 try

                 {

                     writer = new FileWriter( output );

                 }

                 catch ( IOException e )

                 {

                     throw new IllegalStateException( "Failed to open build log: " + output + "\n\nError: "

                         + e.getMessage() );

                 }

             }

             try

             {

                 writer.write( line + LS );

                 writer.flush();

             }

             catch ( IOException e )

             {

                 throw new IllegalStateException( "Failed to write to build log: " + output + " output:\n\n\'" + line

                     + "\'\n\nError: " + e.getMessage() );

             }

         }

         void close()

         {

             IOUtil.close( writer );

         }

     }

     /**

      * Initialize this tool once it's been instantiated and composed, in order to start up the

      * MavenInvoker instance.

      */

     public void initialize()

         throws InitializationException

     {

         try

         {

             startInvoker();

         }

         catch ( IOException e )

         {

             throw new InitializationException( "Error detecting maven home.", e );

         }

     }

     /**

      * Not currently used; when this API switches to use the Maven Embedder, it will be used to 

      * shutdown the embedder and its associated container, to free up JVM memory.

      */

     public void dispose()

     {

         // TODO: When we switch to the embedder, use this to deallocate the MavenEmbedder, along 

         // with the PlexusContainer and ClassRealm that it wraps.

     }

 }