/**

  * 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.dew;

 import java.io.ByteArrayInputStream;

 import java.io.ByteArrayOutputStream;

 import java.io.IOException;

 import java.io.InputStream;

 import java.io.OutputStream;

 import java.net.URI;

 import java.net.URISyntaxException;

 import java.util.ArrayList;

 import java.util.Arrays;

 import java.util.HashMap;

 import java.util.List;

 import java.util.Map;

 import javax.tools.Diagnostic;

 import javax.tools.DiagnosticListener;

 import javax.tools.FileObject;

 import javax.tools.ForwardingJavaFileManager;

 import javax.tools.JavaFileManager;

 import javax.tools.JavaFileObject;

 import javax.tools.JavaFileObject.Kind;

 import javax.tools.SimpleJavaFileObject;

 import javax.tools.StandardJavaFileManager;

 import javax.tools.StandardLocation;

 import javax.tools.ToolProvider;

 /**

  *

  * @author Jaroslav Tulach <jtulach@netbeans.org>

  */

 final class Compile implements DiagnosticListener<JavaFileObject> {

     private final List<Diagnostic<? extends JavaFileObject>> errors = new ArrayList<>();

     private final Map<String, byte[]> classes;

     private final String pkg;

     private final String cls;

     private final String html;

     private Compile(String html, String code) throws IOException {

         this.pkg = find("package", ';', code);

         this.cls = find("class", ' ', code);

         this.html = html;

         classes = compile(html, code);

     }

     /** Performs compilation of given HTML page and associated Java code

      */

     public static Compile create(String html, String code) throws IOException {

         return new Compile(html, code);

     }

     /** Checks for given class among compiled resources */

     public byte[] get(String res) {

         return classes.get(res);

     }

     /** Obtains errors created during compilation.

      */

     public List<Diagnostic<? extends JavaFileObject>> getErrors() {

         List<Diagnostic<? extends JavaFileObject>> err = new ArrayList<>();

         for (Diagnostic<? extends JavaFileObject> diagnostic : errors) {

             if (diagnostic.getKind() == Diagnostic.Kind.ERROR) {

                 err.add(diagnostic);

             }

         }

         return err;

     }

     private Map<String, byte[]> compile(final String html, final String code) throws IOException {

         StandardJavaFileManager sjfm = ToolProvider.getSystemJavaCompiler().getStandardFileManager(this, null, null);

         final Map<String, ByteArrayOutputStream> class2BAOS = new HashMap<>();

         JavaFileObject file = new SimpleJavaFileObject(URI.create("mem://mem"), Kind.SOURCE) {

             @Override

             public CharSequence getCharContent(boolean ignoreEncodingErrors) throws IOException {

                 return code;

             }

         };

         final JavaFileObject htmlFile = new SimpleJavaFileObject(URI.create("mem://mem2"), Kind.OTHER) {

             @Override

             public CharSequence getCharContent(boolean ignoreEncodingErrors) throws IOException {

                 return html;

             }

             @Override

             public InputStream openInputStream() throws IOException {

                 return new ByteArrayInputStream(html.getBytes());

             }

         };

         final URI scratch;

         try {

             scratch = new URI("mem://mem3");

         } catch (URISyntaxException ex) {

             throw new IOException(ex);

         }

         JavaFileManager jfm = new ForwardingJavaFileManager<JavaFileManager>(sjfm) {

             @Override

             public JavaFileObject getJavaFileForOutput(Location location, String className, Kind kind, FileObject sibling) throws IOException {

                 if (kind  == Kind.CLASS) {

                     final ByteArrayOutputStream buffer = new ByteArrayOutputStream();

                     class2BAOS.put(className.replace('.', '/') + ".class", buffer);

                     return new SimpleJavaFileObject(sibling.toUri(), kind) {

                         @Override

                         public OutputStream openOutputStream() throws IOException {

                             return buffer;

                         }

                     };

                 }

                 if (kind == Kind.SOURCE) {

                     return new SimpleJavaFileObject(scratch/*sibling.toUri()*/, kind) {

                         private final ByteArrayOutputStream data = new ByteArrayOutputStream();

                         @Override

                         public OutputStream openOutputStream() throws IOException {

                             return data;

                         }

                         @Override

                         public CharSequence getCharContent(boolean ignoreEncodingErrors) throws IOException {

                             data.close();

                             return new String(data.toByteArray());

                         }

                     };

                 }

                 throw new IllegalStateException();

             }

             @Override

             public FileObject getFileForInput(Location location, String packageName, String relativeName) throws IOException {

                 if (location == StandardLocation.SOURCE_PATH) {

                     if (packageName.equals(pkg)) {

                         return htmlFile;

                     }

                 }

                 return null;

             }

         };

         ToolProvider.getSystemJavaCompiler().getTask(null, jfm, this, /*XXX:*/Arrays.asList("-source", "1.7", "-target", "1.7"), null, Arrays.asList(file)).call();

         Map<String, byte[]> result = new HashMap<>();

         for (Map.Entry<String, ByteArrayOutputStream> e : class2BAOS.entrySet()) {

             result.put(e.getKey(), e.getValue().toByteArray());

         }

         return result;

     }

     @Override

     public void report(Diagnostic<? extends JavaFileObject> diagnostic) {

         errors.add(diagnostic);

     }

     private static String find(String pref, char term, String java) throws IOException {

         int pkg = java.indexOf(pref);

         if (pkg != -1) {

             pkg += pref.length();

             while (Character.isWhitespace(java.charAt(pkg))) {

                 pkg++;

             }

             int semicolon = java.indexOf(term, pkg);

             if (semicolon != -1) {

                 String pkgName = java.substring(pkg, semicolon).trim();

                 return pkgName;

             }

         }

         throw new IOException("Can't find " + pref + " declaration in the java file");

     }

     String getHtml() {

         String fqn = "'" + pkg + '.' + cls + "'";

         return html.replace("'${fqn}'", fqn);

     }

 }