/**

 * 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.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStreamWriter;

import java.io.Writer;

import java.net.MalformedURLException;

import java.net.URL;

import java.net.URLClassLoader;

import java.nio.file.Files;

import java.util.ArrayList;

import java.util.Collection;

import java.util.List;

import java.util.Map;

import java.util.jar.Attributes;

import java.util.jar.JarFile;

import java.util.jar.Manifest;

import java.util.zip.ZipEntry;

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.bck2brwsr.aot.Bck2BrwsrJars;

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;

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

    private File mainJar;

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

    private File mainJavaScript;

    @Parameter

    private String[] exports;

    /**

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

     * required libraries.

     */

    @Parameter(defaultValue = "lib")

    private String classPathPrefix;

    /** Root JavaScript file to generate */

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

    private File vm;

    @Parameter(defaultValue = "true")

    private boolean generateAotLibraries;

    /**

     * The obfuscation level for the generated JavaScript file.

     *

     * @since 0.5

     */

    @Parameter(defaultValue = "NONE")

    private ObfuscationLevel obfuscation;

    @Override

    public void execute() throws MojoExecutionException, MojoFailureException {

        URLClassLoader loader;

        try {

            loader = buildClassLoader(mainJar, prj.getArtifacts());

        } catch (MalformedURLException ex) {

            throw new MojoFailureException("Can't initialize classloader");

        }

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

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

                continue;

            }

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

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

                continue;

            }

            if ("provided".equals(a.getScope())) {

                continue;

            }

            File aot = new File(prj.getBuild().getDirectory(), classPathPrefix);

            aot.mkdirs();

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

            if (js.exists()) {

                getLog().info("Skipping " + js + " as it already exists.");

                continue;

            }

            try {

                aotLibrary(a, js , loader);

            } catch (IOException ex) {

                throw new MojoFailureException("Can't compile " + a.getFile(), ex);

            }

        }

        try {

            if (mainJavaScript.exists()) {

                getLog().info("Skipping " + mainJavaScript + " as it already exists.");

            } else {

                getLog().info("Generating " + mainJavaScript);

                Bck2Brwsr c = Bck2BrwsrJars.configureFrom(null, mainJar, loader);

                if (exports != null) {

                    for (String e : exports) {

                        c = c.addExported(e.replace('.', '/'));

                    }

                }

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

                c.

                        obfuscation(obfuscation).

                        generate(w);

                w.close();

            }

        } catch (IOException ex) {

            throw new MojoFailureException("Cannot generate script for " + mainJar, ex);

        }

        try {

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

            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, MojoExecutionException {

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

            if ("bck2brwsr".equals(b.getClassifier())) { // NOI18N

                getLog().debug("Inspecting " + b.getFile());

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

                Manifest man = jf.getManifest();

                for (Map.Entry<String, Attributes> entrySet : man.getEntries().entrySet()) {

                    String entryName = entrySet.getKey();

                    Attributes attr = entrySet.getValue();

                    if (

                        a.getArtifactId().equals(attr.getValue("Bck2BrwsrArtifactId")) &&

                        a.getGroupId().equals(attr.getValue("Bck2BrwsrGroupId")) &&

                        a.getVersion().equals(attr.getValue("Bck2BrwsrVersion")) &&

                        (

                            obfuscation == ObfuscationLevel.FULL && "true".equals(attr.getValue("Bck2BrwsrMinified"))

                            ||

                            obfuscation != ObfuscationLevel.FULL && "true".equals(attr.getValue("Bck2BrwsrDebug"))

                        )

                    ) {

                        getLog().info("Extracting " + js + " from " + b.getFile());

                        InputStream is = jf.getInputStream(new ZipEntry(entryName));

                        Files.copy(is, js.toPath());

                        is.close();

                        return;

                    }

                }

            }

        }

        if (!generateAotLibraries) {

            throw new MojoExecutionException("Not generating " + js + " and no precompiled version found!");

        }

        getLog().info("Generating " + js);

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

        Bck2Brwsr c = Bck2BrwsrJars.configureFrom(null, a.getFile(), loader);

        c.

            obfuscation(obfuscation).

            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());

    }

}