/**

  * Back 2 Browser Bytecode Translator

  * Copyright (C) 2012 Jaroslav Tulach <jaroslav.tulach@apidesign.org>

  *

  * This program is free software: you can redistribute it and/or modify

  * it under the terms of the GNU General Public License as published by

  * the Free Software Foundation, version 2 of the License.

  *

  * This program is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  * GNU General Public License for more details.

  *

  * You should have received a copy of the GNU General Public License

  * along with this program. Look for COPYING file in the top folder.

  * If not, see http://opensource.org/licenses/GPL-2.0.

  */

 package org.apidesign.bck2brwsr.mojo;

 import org.apache.maven.plugin.AbstractMojo;

 import java.io.File;

 import java.io.FileOutputStream;

 import java.io.IOException;

 import java.io.OutputStreamWriter;

 import java.io.Writer;

 import java.net.MalformedURLException;

 import java.net.URL;

 import java.net.URLClassLoader;

 import java.util.ArrayList;

 import java.util.Collection;

 import java.util.List;

 import org.apache.maven.artifact.Artifact;

 import org.apache.maven.plugin.MojoExecutionException;

 import org.apache.maven.plugins.annotations.LifecyclePhase;

 import org.apache.maven.plugins.annotations.Mojo;

 import org.apache.maven.plugins.annotations.Parameter;

 import org.apache.maven.plugins.annotations.ResolutionScope;

 import org.apache.maven.project.MavenProject;

 import org.apidesign.vm4brwsr.Bck2Brwsr;

 import org.apidesign.vm4brwsr.ObfuscationLevel;

 /** Compiles classes into JavaScript. */

 @Mojo(name="j2js", 

     requiresDependencyResolution = ResolutionScope.COMPILE,

     defaultPhase=LifecyclePhase.PROCESS_CLASSES

 )

 public class Java2JavaScript extends AbstractMojo {

     public Java2JavaScript() {

     }

     /** Root of the class files */

     @Parameter(defaultValue="${project.build.directory}/classes")

     private File classes;

     /** JavaScript file to generate */

     @Parameter(defaultValue="${project.build.directory}/bck2brwsr.js")

     private File javascript;

     /** Additional classes that should be pre-compiled into the javascript 

      * file. By default compiles all classes found under <code>classes</code>

      * directory and their transitive closure.

      */

     @Parameter

     private List<String> compileclasses;

     @Parameter(defaultValue="${project}")

     private MavenProject prj;

     /**

      * The obfuscation level for the generated JavaScript file.

      *

      * @since 0.5

      */

     @Parameter(defaultValue="NONE")

     private ObfuscationLevel obfuscation;

     /** Should classes from rt.jar be included? */

     @Parameter(defaultValue = "false")

     private boolean ignoreBootClassPath;

     /**

      * Indicates whether to create an extension library 

      * module instead of a standalone JavaScript VM.

      *

      * @since 0.9

      */

     @Parameter(defaultValue="false")

     private boolean library;

     @Override

     public void execute() throws MojoExecutionException {

         if (!classes.isDirectory()) {

             throw new MojoExecutionException("Can't find " + classes);

         }

         if (javascript == null) {

             throw new MojoExecutionException("Need to define 'javascript' attribute with a path to file to generate");

         }

         List<String> arr = new ArrayList<String>();

         long newest = collectAllClasses("", classes, arr);

         if (compileclasses != null) {

             arr.retainAll(compileclasses);

             arr.addAll(compileclasses);

         }

         if (javascript.lastModified() > newest) {

             return;

         }

         try {

             URLClassLoader url = buildClassLoader(classes, prj.getArtifacts());

             Writer w = new OutputStreamWriter(new FileOutputStream(javascript), "UTF-8");

             Bck2Brwsr c = Bck2Brwsr.newCompiler().

                 obfuscation(obfuscation).

                 resources(url, ignoreBootClassPath).

                 addRootClasses(arr.toArray(new String[0]));

             if (library) {

                 c = c.library();

             }

             c.generate(w);

             w.close();

         } catch (IOException ex) {

             throw new MojoExecutionException("Can't compile", ex);

         }

     }

     private static long collectAllClasses(String prefix, File toCheck, List<String> arr) {

         File[] files = toCheck.listFiles();

         if (files != null) {

             long newest = 0L;

             for (File f : files) {

                 long lastModified = collectAllClasses(prefix + f.getName() + "/", f, arr);

                 if (newest < lastModified) {

                     newest = lastModified;

                 }

             }

             return newest;

         } else if (toCheck.getName().endsWith(".class")) {

             final String cls = prefix.substring(0, prefix.length() - 7);

             if (!cls.endsWith("package-info")) {

                 arr.add(cls);

             }

             return toCheck.lastModified();

         } else {

             return 0L;

         }

     }

     private static URLClassLoader buildClassLoader(File root, Collection<Artifact> deps) throws MalformedURLException {

         List<URL> arr = new ArrayList<URL>();

         arr.add(root.toURI().toURL());

         for (Artifact a : deps) {

             if (a.getFile() != null) {

                 arr.add(a.getFile().toURI().toURL());

             }

         }

         return new URLClassLoader(arr.toArray(new URL[0]), Java2JavaScript.class.getClassLoader());

     }

 }