/**

  * 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();

         }

     }

 }