/**

 * 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.ClassData;

import org.apidesign.vm4brwsr.ByteCodeParser.FieldData;

import org.apidesign.vm4brwsr.ByteCodeParser.MethodData;

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

final class ClassDataCache {

    private static final Object MISSING_CLASS = new Object();

    private final Bck2Brwsr.Resources resources;

    private final Map<String, Object> classDataMap;

    ClassDataCache(final Bck2Brwsr.Resources resources) {

        this.resources = resources;

        classDataMap = new HashMap<String, Object>();

    }

    ClassData getClassData(String className) throws IOException {

        if (className.startsWith("[")) {

            // required for accessVirtualMethod, shouldn't be problematic for

            // calls from other sources

            className = "java/lang/Object";

        }

        Object cacheEntry = classDataMap.get(className);

        if (cacheEntry == null) {

            final InputStream is = loadClass(resources, className);

            cacheEntry = (is != null) ? new ClassData(is) : MISSING_CLASS;

            classDataMap.put(className, cacheEntry);

        }

        return (cacheEntry != MISSING_CLASS) ? (ClassData) cacheEntry : null;

    }

    MethodData findMethod(final String startingClass,

                          final String name,

                          final String signature) throws IOException {

        return findMethod(getClassData(startingClass), name, signature);

    }

    FieldData findField(final String startingClass,

                        final String name,

                        final String signature) throws IOException {

        return findField(getClassData(startingClass), name, signature);

    }

    MethodData findMethod(ClassData currentClass,

                          final String name,

                          final String signature) throws IOException {

        while (currentClass != null) {

            final MethodData methodData =

                    currentClass.findMethod(name, signature);

            if (methodData != null) {

                return methodData;

            }

            final String superClassName = currentClass.getSuperClassName();

            if (superClassName == null) {

                break;

            }

            currentClass = getClassData(superClassName);

        }

        return null;

    }

    FieldData findField(ClassData currentClass,

                        final String name,

                        final String signature) throws IOException {

        while (currentClass != null) {

            final FieldData fieldData =

                    currentClass.findField(name, signature);

            if (fieldData != null) {

                return fieldData;

            }

            final String superClassName = currentClass.getSuperClassName();

            if (superClassName == null) {

                break;

            }

            currentClass = getClassData(superClassName);

        }

        return null;

    }

    private static InputStream loadClass(Bck2Brwsr.Resources l, String name)

            throws IOException {

        return l.get(name + ".class"); // NOI18N

    }

}