/**

 * 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 java.util.logging.Level;

import java.util.logging.Logger;

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 {

        URLClassLoader loader;

        try {

            loader = buildClassLoader(null, 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;

            }

            aot.mkdirs();

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

            try {

                aotLibrary(a, js , loader);

            } catch (IOException ex) {

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

            }

        }

        try {

            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('.', '/'));

        }

    }

}