/**

 * 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.vm4brwsr;

import com.google.javascript.jscomp.CommandLineRunner;

import com.google.javascript.jscomp.SourceFile;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.io.PrintStream;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collection;

import java.util.Collections;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import org.apidesign.bck2brwsr.core.ExtraJavaScript;

import org.apidesign.vm4brwsr.ByteCodeParser.AnnotationParser;

import org.apidesign.vm4brwsr.ByteCodeParser.ClassData;

import org.apidesign.vm4brwsr.ByteCodeParser.FieldData;

import org.apidesign.vm4brwsr.ByteCodeParser.MethodData;

/**

 *

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

 */

@ExtraJavaScript(processByteCode = false, resource="")

final class ClosureWrapper extends CommandLineRunner {

    private static final String[] ARGS = { "--compilation_level", "SIMPLE_OPTIMIZATIONS", "--js", "bck2brwsr-raw.js" /*, "--debug", "--formatting", "PRETTY_PRINT" */ };

    private final ClosuresObfuscationDelegate obfuscationDelegate;

    private final Bck2Brwsr.Resources res;

    private final StringArray classes;

    private String compiledCode;

    private String externsCode;

    private ClosureWrapper(Appendable out, 

                           String compilationLevel,

                           ClosuresObfuscationDelegate obfuscationDelegate,

                           Bck2Brwsr.Resources res, StringArray classes) {

        super(

            generateArguments(compilationLevel),

            new PrintStream(new APS(out)), System.err

        );

        this.obfuscationDelegate = obfuscationDelegate;

        this.res = res;

        this.classes = classes;

    }

    @Override

    protected List<SourceFile> createInputs(List<String> files, boolean allowStdIn) throws FlagUsageException, IOException {

        if (files.size() != 1 || !"bck2brwsr-raw.js".equals(files.get(0))) {

            throw new IOException("Unexpected files: " + files);

        }

        return Collections.nCopies(

                   1,

                   SourceFile.fromGenerator(

                       "bck2brwsr-raw.js",

                       new SourceFile.Generator() {

                           @Override

                           public String getCode() {

                               return getCompiledCode();

                           }

                       }));

    }

    @Override

    protected List<SourceFile> createExterns()

            throws FlagUsageException, IOException {

        final List<SourceFile> externsFiles =

                new ArrayList<SourceFile>(super.createExterns());

        externsFiles.add(

                SourceFile.fromGenerator(

                        "bck2brwsr_externs.js",

                        new SourceFile.Generator() {

                            @Override

                            public String getCode() {

                                return getExternsCode();

                            }

                        }));

        return externsFiles;

    }

    private String getCompiledCode() {

        if (compiledCode == null) {

            StringBuilder sb = new StringBuilder();

            try {

                VM.compile(res, sb, classes, obfuscationDelegate);

                compiledCode = sb.toString();

            } catch (IOException ex) {

                compiledCode = ex.getMessage();

            }

        }

        return compiledCode;

    }

    private String getExternsCode() {

        if (externsCode == null) {

            // need compiled code at this point

            getCompiledCode();

            final StringBuilder sb = new StringBuilder("function RAW() {};\n");

            for (final String extern: obfuscationDelegate.getExterns()) {

                sb.append("RAW.prototype.").append(extern).append(";\n");

            }

            externsCode = sb.toString();

        }

        return externsCode;

    }

    private static final class APS extends OutputStream {

        private final Appendable out;

        public APS(Appendable out) {

            this.out = out;

        }

        @Override

        public void write(int b) throws IOException {

            out.append((char)b);

        }

    }

    private static String[] generateArguments(String compilationLevel) {

        String[] finalArgs = ARGS.clone();

        finalArgs[1] = compilationLevel;

        return finalArgs;

    }

    static int produceTo(Appendable w, ObfuscationLevel obfuscationLevel, Bck2Brwsr.Resources resources, StringArray arr) throws IOException {

        ClosureWrapper cw = create(w, obfuscationLevel, resources, arr);

        try {

            return cw.doRun();

        } catch (FlagUsageException ex) {

            throw new IOException(ex);

        }

    }

    private static ClosureWrapper create(Appendable w,

                                         ObfuscationLevel obfuscationLevel,

                                         Bck2Brwsr.Resources resources,

                                         StringArray arr) {

        switch (obfuscationLevel) {

            case MINIMAL:

                return new ClosureWrapper(w, "SIMPLE_OPTIMIZATIONS",

                                          new SimpleObfuscationDelegate(),

                                          resources, arr);

/*                

            case MEDIUM:

                return new ClosureWrapper(w, "ADVANCED_OPTIMIZATIONS",

                                          new MediumObfuscationDelegate(

                                                  resources),

                                          resources, arr);

*/

            case FULL:

                return new ClosureWrapper(w, "ADVANCED_OPTIMIZATIONS",

                                          new FullObfuscationDelegate(

                                                  resources),

                                          resources, arr);

            default:

                throw new IllegalArgumentException(

                        "Unsupported level: " + obfuscationLevel);

        }

    }

    private static abstract class ClosuresObfuscationDelegate

            extends ObfuscationDelegate {

        public abstract Collection<String> getExterns();

    }

    private static final class SimpleObfuscationDelegate

            extends ClosuresObfuscationDelegate {

        @Override

        public void exportJSProperty(Appendable out,

                                     String destObject,

                                     String propertyName) throws IOException {

        }

        @Override

        public void exportClass(Appendable out,

                                String destObject,

                                String mangledName,

                                ClassData classData) throws IOException {

        }

        @Override

        public void exportMethod(Appendable out,

                                 String destObject,

                                 String mangledName,

                                 MethodData methodData) throws IOException {

        }

        @Override

        public void exportField(Appendable out,

                                String destObject,

                                String mangledName,

                                FieldData fieldData) throws IOException {

        }

        @Override

        public Collection<String> getExterns() {

            return Collections.EMPTY_LIST;

        }

    }

    private static abstract class AdvancedObfuscationDelegate

            extends ClosuresObfuscationDelegate {

        private static final String[] INITIAL_EXTERNS = {

            "bck2brwsr",

            "$class",

            "anno",

            "array",

            "access",

            "cls",

            "vm",

            "loadClass",

            "loadBytes",

            "jvmName",

            "primitive",

            "superclass",

            "cnstr",

            "add32",

            "sub32",

            "mul32",

            "neg32",

            "toInt8",

            "toInt16",

            "next32",

            "high32",

            "toInt32",

            "toFP",

            "toLong",

            "toExactString",

            "add64",

            "sub64",

            "mul64",

            "and64",

            "or64",

            "xor64",

            "shl64",

            "shr64",

            "ushr64",

            "compare64",

            "neg64",

            "div32",

            "mod32",

            "div64",

            "mod64",

            "at",

            "getClass__Ljava_lang_Class_2",

            "clone__Ljava_lang_Object_2"

        };

        private final Bck2Brwsr.Resources resources;

        private final Collection<String> externs;

        private final Map<Object, Boolean> isMarkedAsExportedCache;

        protected AdvancedObfuscationDelegate(Bck2Brwsr.Resources resources) {

            this.resources = resources;

            externs = new ArrayList<String>(Arrays.asList(INITIAL_EXTERNS));

            isMarkedAsExportedCache = new HashMap<Object, Boolean>();

        }

        @Override

        public void exportClass(Appendable out,

                                String destObject,

                                String mangledName,

                                ClassData classData) throws IOException {

            if (isExportedClass(classData)) {

                exportJSProperty(out, destObject, mangledName);

            }

        }

        @Override

        public void exportMethod(Appendable out,

                                 String destObject,

                                 String mangledName,

                                 MethodData methodData) throws IOException {

            if (isAccessible(methodData.access)

                        && isExportedClass(methodData.cls)

                    || isMarkedAsExported(methodData)) {

                exportJSProperty(out, destObject, mangledName);

            }

        }

        @Override

        public void exportField(Appendable out,

                                String destObject,

                                String mangledName,

                                FieldData fieldData) throws IOException {

            if (isAccessible(fieldData.access)

                        && isExportedClass(fieldData.cls)

                    || isMarkedAsExported(fieldData)) {

                exportJSProperty(out, destObject, mangledName);

            }

        }

        @Override

        public Collection<String> getExterns() {

            return externs;

        }

        protected void addExtern(String extern) {

            externs.add(extern);

        }

        private boolean isExportedClass(ClassData classData)

                throws IOException {

            return classData.isPublic() && isMarkedAsExportedPackage(

                                               classData.getPkgName())

                       || isMarkedAsExported(classData);

        }

        private boolean isMarkedAsExportedPackage(String pkgName) {

            if (pkgName == null) {

                return false;

            }

            final Boolean cachedValue = isMarkedAsExportedCache.get(pkgName);

            if (cachedValue != null) {

                return cachedValue;

            }

            final boolean newValue = resolveIsMarkedAsExportedPackage(pkgName);

            isMarkedAsExportedCache.put(pkgName, newValue);

            return newValue;

        }

        private boolean isMarkedAsExported(ClassData classData)

                throws IOException {

            final Boolean cachedValue = isMarkedAsExportedCache.get(classData);

            if (cachedValue != null) {

                return cachedValue;

            }

            final boolean newValue =

                    isMarkedAsExported(classData.findAnnotationData(true),

                                       classData);

            isMarkedAsExportedCache.put(classData, newValue);

            return newValue;

        }

        private boolean isMarkedAsExported(MethodData methodData)

                throws IOException {

            return isMarkedAsExported(methodData.findAnnotationData(true),

                                      methodData.cls);

        }

        private boolean isMarkedAsExported(FieldData fieldData)

                throws IOException {

            return isMarkedAsExported(fieldData.findAnnotationData(true),

                                      fieldData.cls);

        }

        private boolean resolveIsMarkedAsExportedPackage(String pkgName) {

            try {

                final InputStream is =

                        resources.get(pkgName + "/package-info.class");

                try {

                    final ClassData pkgInfoClass = new ClassData(is);

                    return isMarkedAsExported(

                                   pkgInfoClass.findAnnotationData(true),

                                   pkgInfoClass);

                } finally {

                    is.close();

                }

            } catch (final IOException e) {

                return false;

            }

        }

        private boolean isMarkedAsExported(byte[] arrData, ClassData cd)

                throws IOException {

            if (arrData == null) {

                return false;

            }

            final boolean[] found = { false };

            final AnnotationParser annotationParser =

                    new AnnotationParser(false, false) {

                        @Override

                        protected void visitAnnotationStart(

                                String type,

                                boolean top) {

                            if (top && type.equals("Lorg/apidesign/bck2brwsr"

                                                       + "/core/Exported;")) {

                                found[0] = true;

                            }

                        }

                    };

            annotationParser.parse(arrData, cd);

            return found[0];

        }

        private static boolean isAccessible(int access) {

            return (access & (ByteCodeParser.ACC_PUBLIC

                                  | ByteCodeParser.ACC_PROTECTED)) != 0;

        }

    }

    private static final class MediumObfuscationDelegate

            extends AdvancedObfuscationDelegate {

        public MediumObfuscationDelegate(Bck2Brwsr.Resources resources) {

            super(resources);

        }

        @Override

        public void exportJSProperty(Appendable out,

                                     String destObject,

                                     String propertyName) {

            addExtern(propertyName);

        }

    }

    private static final class FullObfuscationDelegate

            extends AdvancedObfuscationDelegate {

        public FullObfuscationDelegate(Bck2Brwsr.Resources resources) {

            super(resources);

        }

        @Override

        public void exportJSProperty(Appendable out,

                                     String destObject,

                                     String propertyName) throws IOException {

            out.append("\n").append(destObject).append("['")

                                               .append(propertyName)

                                               .append("'] = ")

                            .append(destObject).append(".").append(propertyName)

               .append(";\n");

        }

    }

}