/*
 This file is part of GNUnet.
 Copyright (C) 2011, 2012 Christian Grothoff (and other contributing authors)

 GNUnet 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; either version 3, or (at your
 option) any later version.

 GNUnet 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 GNUnet; see the file COPYING.  If not, write to the
 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 Boston, MA 02110-1301, USA.
 */

package org.gnunet.construct.parsers;

import org.gnunet.construct.Message;
import org.gnunet.construct.ReflectUtil;

import java.lang.reflect.Array;
import java.lang.reflect.Field;
import java.nio.ByteBuffer;
import java.util.List;

public class IntegerFillParser implements Parser {
    private final Field targetField;
    private final boolean signed;
    private final int byteSize;

    public IntegerFillParser(Field targetField,
                             boolean signed, int byteSize) {

        this.targetField = targetField;
        this.signed = signed;
        this.byteSize = byteSize;
    }


    @Override
    public int getSize(Message srcObj) {
        final Object arr = ReflectUtil.justGet(srcObj, targetField);

        if (arr == null) {
            throw new RuntimeException("array not initialized");
        }

        return byteSize * Array.getLength(arr);
    }

    @Override
    public int parse(ByteBuffer srcBuf, int frameStart, Message frameObj, Message dstObj, List<Field> frameSizePath) {
        if (frameSizePath == null) {
            throw new AssertionError("IntegerFillParser expects a non-null frameSizePath. Did you specify a @FrameSize field?");
        }
        final int frameSize = ReflectUtil.justGetInt(frameObj, frameSizePath);
        int remaining = frameStart + frameSize - srcBuf.position();

        int elemNumber = remaining / byteSize;

        @SuppressWarnings("unchecked")
        final Class<Message> arrayElementType = (Class<Message>) targetField.getType().getComponentType();

        if (!arrayElementType.isPrimitive()) {
            throw new AssertionError("IntegerFillParser is expected to be of primitive type, not " + arrayElementType);
        }

        final Object arr = Array.newInstance(arrayElementType, elemNumber);
        ReflectUtil.justSet(dstObj, targetField, arr);


        for (int i = 0; i < elemNumber; ++i) {
            long v = IntegerUtil.readLong(srcBuf, signed, byteSize);
            ReflectUtil.justSetArray(arr, i, v);
        }

        return remaining;
    }

    @Override
    public int write(ByteBuffer dstBuf, Message srcObj) {
        final Object arr = ReflectUtil.justGet(srcObj, targetField);

        if (arr == null) {
            throw new RuntimeException("array not initialized");
        }

        for (int i = 0; i < Array.getLength(arr); ++i) {
            IntegerUtil.writeLong(Array.getLong(arr, i), dstBuf, signed, byteSize);
        }

        return getSize(srcObj);
    }

    @Override
    public void patch(Message m, int frameSize, List<Field> frameSizePath, Message frameObj) {
        if (frameSizePath == null) {
            throw new AssertionError("IntegerFillParser expects a non-null frameSizePath. Did you specify a @FrameSize field?");
        }
        ReflectUtil.justSetInt(frameObj, frameSizePath, frameSize);
    }

    @Override
    public int getStaticSize() {
        // not known
        return 0;
    }
}