/**

 * 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.OutputStream;

import java.io.PrintStream;

import java.util.ArrayList;

import java.util.Collections;

import java.util.List;

import org.apidesign.bck2brwsr.core.ExtraJavaScript;

/**

 *

 * @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 Bck2Brwsr.Resources res;

    private final StringArray classes;

    private String compiledCode;

    private String externsCode;

    private ClosureWrapper(Appendable out, 

                           String compilationLevel,

                           Bck2Brwsr.Resources res, StringArray classes) {

        super(

            generateArguments(compilationLevel),

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

        );

        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.compileStandalone(res, sb, classes);

                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: FIXED_EXTERNS) {

                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",

                                          resources, arr);

            case FULL:

                return new ClosureWrapper(w, "ADVANCED_OPTIMIZATIONS",

                                          resources, arr);

            default:

                throw new IllegalArgumentException(

                        "Unsupported level: " + obfuscationLevel);

        }

    }

    private static final String[] FIXED_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"

    };

}