/**

 * 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.launcher;

import java.io.BufferedReader;

import java.io.File;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.StringWriter;

import java.net.JarURLConnection;

import java.net.URISyntaxException;

import java.net.URL;

import java.util.ArrayList;

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 java.util.zip.ZipEntry;

import org.apidesign.bck2brwsr.launcher.BaseHTTPLauncher.Res;

import org.apidesign.vm4brwsr.Bck2Brwsr;

/**

 *

 * @author Jaroslav Tulach

 */

class CompileCP {

    private static final Logger LOG = Logger.getLogger(CompileCP.class.getName());

    static String compileJAR(final JarFile jar, Set<String> testClasses) 

    throws IOException {

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

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

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

        Set<String> keep = new HashSet<String>(testClasses);

        listJAR(jar, classes, arr, exported, keep);

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

        for (String c : classes) {

            if (keep.contains(c)) {

                root.add(c);

                continue;

            }

            int slash = c.lastIndexOf('/');

            String pkg = c.substring(0, slash + 1);

            if (exported.contains(pkg)) {

                root.add(c);

            }

        }

        StringWriter w = new StringWriter();

        try {

            class JarRes extends EmulationResources implements Bck2Brwsr.Resources {

                @Override

                public InputStream get(String resource) throws IOException {

                    InputStream is = jar.getInputStream(new ZipEntry(resource));

                    return is == null ? super.get(resource) : is;

                }

            }

            Bck2Brwsr.newCompiler()

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

                .addRootClasses(root.toArray(new String[0]))

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

                .library(true)

                .resources(new JarRes())

                .generate(w);

            w.flush();

            return w.toString();

        } catch (IOException ex) {

            throw ex;

        } catch (Throwable ex) {

            throw new IOException("Cannot compile: ", ex);

        } finally {

            w.close();

        }

    }

    static String compileFromClassPath(URL u, final Res r) throws IOException {

        File f;

        try {

            f = new File(u.toURI());

        } catch (URISyntaxException ex) {

            throw new IOException(ex);

        }

        for (String s : System.getProperty("java.class.path").split(File.pathSeparator)) {

            if (!f.getPath().startsWith(s)) {

                continue;

            }

            File root = new File(s);

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

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

            listDir(root, null, classes, arr);

            StringWriter w = new StringWriter();

            try {

                Bck2Brwsr.newCompiler()

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

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

                    .library(true)

                    .resources(new EmulationResources() {

                        @Override

                        public InputStream get(String resource) throws IOException {

                            if (r != null) {

                                final URL url = r.get(resource, 0);

                                return url == null ? null : url.openStream();

                            }

                            return super.get(resource);

                        }

                    })

                    .generate(w);

                w.flush();

                return w.toString();

            } catch (ClassFormatError ex) {

                throw new IOException(ex);

            } finally {

                w.close();

            }

        }

        return null;

    }

    private static void listJAR(

        JarFile j, List<String> classes,

        List<String> resources, Set<String> exported, Set<String> keep

    ) throws IOException {

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

        while (en.hasMoreElements()) {

            JarEntry e = en.nextElement();

            final String n = e.getName();

            if (n.contains("package-info")) {

                continue;

            }

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

                continue;

            }

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

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

            if (skipPkg(pkg)) {

                continue;

            }

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

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

            } else {

                resources.add(n);

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

                    BufferedReader r = new BufferedReader(new InputStreamReader(j.getInputStream(e)));

                    for (;;) {

                        String l = r.readLine();

                        if (l == null) {

                            break;

                        }

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

                            continue;

                        }

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

                    }

                }

            }

        }

        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;

                }

            }

        }

    }

    private static boolean skipPkg(String pkg) {

        return pkg.equals("org/apidesign/bck2brwsr/launcher/");

    }

    private static void listDir(File f, String pref, List<String> classes, List<String> resources) throws IOException {

        File[] arr = f.listFiles();

        if (arr == null) {

            if (f.getName().equals("package-info.class")) {

                return;

            }

            if (f.getName().endsWith(".class")) {

                classes.add(pref + f.getName().substring(0, f.getName().length() - 6));

            } else {

                resources.add(pref + f.getName());

            }

        } else {

            for (File ch : arr) {

                listDir(ch, pref == null ? "" : pref + f.getName() + "/", classes, resources);

            }

        }

    }

    static void compileVM(StringBuilder sb, final Res r) throws IOException {

        URL u = r.get(InterruptedException.class.getName().replace('.', '/') + ".class", 0);

        JarURLConnection juc = (JarURLConnection)u.openConnection();

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

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

        listJAR(juc.getJarFile(), classes, arr, null, null);

        Bck2Brwsr.newCompiler().addRootClasses(classes.toArray(new String[0]))

            .resources(new Bck2Brwsr.Resources() {

                @Override

                public InputStream get(String resource) throws IOException {

                    final URL url = r.get(resource, 0);

                    return url == null ? null : url.openStream();

                }

            }).generate(sb);

    }

    static class EmulationResources implements Bck2Brwsr.Resources {

        @Override

        public InputStream get(String name) throws IOException {

            Enumeration<URL> en = CompileCP.class.getClassLoader().getResources(name);

            URL u = null;

            while (en.hasMoreElements()) {

                u = en.nextElement();

            }

            if (u == null) {

                LOG.log(Level.WARNING, "Cannot find {0}", name);

                return null;

            }

            if (u.toExternalForm().contains("/rt.jar!")) {

                LOG.warning(name + "No bootdelegation for ");

                return null;

            }

            return u.openStream();

        }

    }

}