/**

  * 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 java.io.BufferedReader;

 import java.io.File;

 import java.io.FileWriter;

 import java.io.IOException;

 import java.io.InputStream;

 import java.io.InputStreamReader;

 import java.net.MalformedURLException;

 import java.net.URL;

 import java.net.URLClassLoader;

 import java.util.ArrayList;

 import java.util.Collection;

 import java.util.Enumeration;

 import java.util.HashSet;

 import java.util.List;

 import java.util.Set;

 import java.util.jar.JarEntry;

 import java.util.jar.JarFile;

 import org.apache.maven.artifact.Artifact;

 import org.apache.maven.plugin.AbstractMojo;

 import org.apache.maven.plugin.MojoExecutionException;

 import org.apache.maven.plugin.MojoFailureException;

 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;

 /**

  *

  * @author Jaroslav Tulach

  * @since 0.9

  */

 @Mojo(name = "aot",

     requiresDependencyResolution = ResolutionScope.COMPILE_PLUS_RUNTIME,

     defaultPhase = LifecyclePhase.PACKAGE

 )

 public class AheadOfTime extends AbstractMojo {

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

     private MavenProject prj;

     /**

      * Directory where to generate ahead-of-time JavaScript files for

      * required libraries.

      */

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

     private File aot;

     /** Root JavaScript file to generate */

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

     private File vm;

     /**

      * The obfuscation level for the generated JavaScript file.

      *

      * @since 0.5

      */

     @Parameter(defaultValue = "NONE")

     private ObfuscationLevel obfuscation;

     @Override

     public void execute() throws MojoExecutionException, MojoFailureException {

         try {

             URLClassLoader loader = buildClassLoader(null, prj.getArtifacts());

             for (Artifact a : prj.getArtifacts()) {

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

                     continue;

                 }

                 String n = a.getFile().getName();

                 if (!n.endsWith(".jar")) {

                     continue;

                 }

                 aot.mkdirs();

                 File js = new File(aot, n.substring(0, n.length() - 4) + ".js");

                 aotLibrary(a, js , loader);

             }

             FileWriter w = new FileWriter(vm);

             Bck2Brwsr.newCompiler().

                     obfuscation(obfuscation).

                     standalone(false).

                     resources(new Bck2Brwsr.Resources() {

                 @Override

                 public InputStream get(String resource) throws IOException {

                     return null;

                 }

             }).

                     generate(w);

             w.close();

         } catch (IOException ex) {

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

         }

     }

     private void aotLibrary(Artifact a, File js, URLClassLoader loader) throws IOException {

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

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

         Set<String> exported = new HashSet<String>();

         JarFile jf = new JarFile(a.getFile());

         listJAR(jf, classes , resources, exported);

         FileWriter w = new FileWriter(js);

         Bck2Brwsr.newCompiler().

                 obfuscation(obfuscation).

                 library(true).

                 resources(loader).

                 addResources(resources.toArray(new String[0])).

                 addClasses(classes.toArray(new String[0])).

                 addExported(exported.toArray(new String[0])).

                 generate(w);

         w.close();

     }

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

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

         if (root != null) {

             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());

     }

     private static void listJAR(

             JarFile j, List<String> classes,

             List<String> resources, Set<String> exported

     ) throws IOException {

         Enumeration<JarEntry> en = j.entries();

         while (en.hasMoreElements()) {

             JarEntry e = en.nextElement();

             final String n = e.getName();

             if (n.endsWith("/")) {

                 continue;

             }

             int last = n.lastIndexOf('/');

             String pkg = n.substring(0, last + 1);

             if (n.endsWith(".class")) {

                 classes.add(n.substring(0, n.length() - 6));

             } else {

                 resources.add(n);

                 if (n.startsWith("META-INF/services/") && exported != null) {

                     final InputStream is = j.getInputStream(e);

                     exportedServices(is, exported);

                     is.close();

                 }

             }

         }

         String exp = j.getManifest().getMainAttributes().getValue("Export-Package");

         if (exp != null && exported != null) {

             for (String def : exp.split(",")) {

                 for (String sep : def.split(";")) {

                     exported.add(sep.replace('.', '/') + "/");

                     break;

                 }

             }

         }

     }

     static void exportedServices(final InputStream is, Set<String> exported) throws IOException {

         BufferedReader r = new BufferedReader(new InputStreamReader(is));

         for (;;) {

             String l = r.readLine();

             if (l == null) {

                 break;

             }

             if (l.startsWith("#")) {

                 continue;

             }

             exported.add(l.replace('.', '/'));

         }

     }

 }