/**

 * 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 java.io.IOException;

import java.io.InputStream;

import java.util.HashMap;

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;

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

final class ExportedSymbols {

    private final Bck2Brwsr.Resources resources;

    private final StringArray exported;

    private final Map<Object, Boolean> isMarkedAsExportedCache;

    ExportedSymbols(final Bck2Brwsr.Resources resources, StringArray explicitlyExported) {

        this.resources = resources;

        this.exported = explicitlyExported;

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

    }

    boolean isExported(ClassData classData) throws IOException {

        if (exported.contains(classData.getClassName())) {

            return true;

        }

        return classData.isPublic() && isMarkedAsExportedPackage(

                                           classData.getPkgName())

                   || isMarkedAsExported(classData);

    }

    boolean isExported(MethodData methodData) throws IOException {

        return isAccessible(methodData.access) && isExported(methodData.cls)

                   || isMarkedAsExported(methodData);

    }

    boolean isExported(FieldData fieldData) throws IOException {

        if (

            isAccessible(fieldData.access) && 

            isExported(fieldData.cls) || isMarkedAsExported(fieldData)

        ) {

            return true;

        }

        if (

            fieldData.isStatic() && fieldData.getName().equals("$VALUES") &&

            "java/lang/Enum".equals(fieldData.cls.getSuperClassName())

        ) {

            // enum values need to be exported

            return true;

        }

        return false;

    }

    private boolean isMarkedAsExportedPackage(String pkgName) {

        if (pkgName == null) {

            return false;

        }

        if (pkgName.startsWith("java/")) {

            return true;

        }

        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) {

        if (exported.contains(pkgName + '/')) {

            return true;

        }

        try {

            final InputStream is =

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

            if (is == null) {

                return false;

            }

            try {

                final ClassData pkgInfoClass = new ClassData(is);

                return isMarkedAsExported(

                               pkgInfoClass.findAnnotationData(true),

                               pkgInfoClass);

            } finally {

                is.close();

            }

        } catch (final IOException e) {

            return false;

        }

    }

    static 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;

    }

}