/*

 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.nashorn.internal.objects;

import static jdk.nashorn.internal.runtime.ECMAErrors.typeError;

import java.nio.ByteBuffer;

import jdk.nashorn.internal.objects.annotations.Attribute;

import jdk.nashorn.internal.objects.annotations.Constructor;

import jdk.nashorn.internal.objects.annotations.Function;

import jdk.nashorn.internal.objects.annotations.Getter;

import jdk.nashorn.internal.objects.annotations.ScriptClass;

import jdk.nashorn.internal.objects.annotations.SpecializedFunction;

import jdk.nashorn.internal.objects.annotations.Where;

import jdk.nashorn.internal.runtime.JSType;

import jdk.nashorn.internal.runtime.PropertyMap;

import jdk.nashorn.internal.runtime.ScriptObject;

import jdk.nashorn.internal.runtime.ScriptRuntime;

/**

 * NativeArrayBuffer - ArrayBuffer as described in the JS typed

 * array spec

 */

@ScriptClass("ArrayBuffer")

public final class NativeArrayBuffer extends ScriptObject {

    private final ByteBuffer nb;

    // initialized by nasgen

    private static PropertyMap $nasgenmap$;

    /**

     * Constructor

     * @param nb native byte buffer to wrap

     * @param global global instance

     */

    protected NativeArrayBuffer(final ByteBuffer nb, final Global global) {

        super(global.getArrayBufferPrototype(), $nasgenmap$);

        this.nb = nb;

    }

    /**

     * Constructor

     * @param nb native byte buffer to wrap

     */

    protected NativeArrayBuffer(final ByteBuffer nb) {

        this(nb, Global.instance());

    }

    /**

     * Constructor

     * @param byteLength byteLength for buffer

     */

    protected NativeArrayBuffer(final int byteLength) {

        this(ByteBuffer.allocateDirect(byteLength));

    }

    /**

     * Clone constructor

     * Used only for slice

     * @param other original buffer

     * @param begin begin byte index

     * @param end   end byte index

     */

    protected NativeArrayBuffer(final NativeArrayBuffer other, final int begin, final int end) {

        this(cloneBuffer(other.getNioBuffer(), begin, end));

    }

    /**

     * Constructor

     * @param newObj is this invoked with new

     * @param self   self reference

     * @param args   arguments to constructor

     * @return new NativeArrayBuffer

     */

    @Constructor(arity = 1)

    public static NativeArrayBuffer constructor(final boolean newObj, final Object self, final Object... args) {

        if (!newObj) {

            throw typeError("constructor.requires.new", "ArrayBuffer");

        }

        if (args.length == 0) {

            return new NativeArrayBuffer(0);

        }

        return new NativeArrayBuffer(JSType.toInt32(args[0]));

    }

    private static ByteBuffer cloneBuffer(final ByteBuffer original, final int begin, final int end) {

        final ByteBuffer clone = ByteBuffer.allocateDirect(original.capacity());

        original.rewind();//copy from the beginning

        clone.put(original);

        original.rewind();

        clone.flip();

        clone.position(begin);

        clone.limit(end);

        return clone.slice();

    }

    ByteBuffer getNioBuffer() {

        return nb;

    }

    @Override

    public String getClassName() {

        return "ArrayBuffer";

    }

    /**

     * Byte length for native array buffer

     * @param self native array buffer

     * @return byte length

     */

    @Getter(attributes = Attribute.NOT_ENUMERABLE | Attribute.NOT_WRITABLE | Attribute.NOT_CONFIGURABLE)

    public static int byteLength(final Object self) {

        return ((NativeArrayBuffer)self).getByteLength();

    }

    /**

     * Returns true if an object is an ArrayBufferView

     *

     * @param self self

     * @param obj  object to check

     *

     * @return true if obj is an ArrayBufferView

     */

    @Function(attributes = Attribute.NOT_ENUMERABLE, where = Where.CONSTRUCTOR)

    public static boolean isView(final Object self, final Object obj) {

        return obj instanceof ArrayBufferView;

    }

    /**

     * Slice function

     * @param self   native array buffer

     * @param begin0 start byte index

     * @param end0   end byte index

     * @return new array buffer, sliced

     */

    @Function(attributes = Attribute.NOT_ENUMERABLE)

    public static NativeArrayBuffer slice(final Object self, final Object begin0, final Object end0) {

        final NativeArrayBuffer arrayBuffer = (NativeArrayBuffer)self;

        final int               byteLength  = arrayBuffer.getByteLength();

        final int               begin       = adjustIndex(JSType.toInt32(begin0), byteLength);

        final int               end         = adjustIndex(end0 != ScriptRuntime.UNDEFINED ? JSType.toInt32(end0) : byteLength, byteLength);

        return new NativeArrayBuffer(arrayBuffer, begin, Math.max(end, begin));

    }

    /**

     * Specialized slice function

     * @param self   native array buffer

     * @param begin  start byte index

     * @param end    end byte index

     * @return new array buffer, sliced

     */

    @SpecializedFunction

    public static Object slice(final Object self, final int begin, final int end) {

        final NativeArrayBuffer arrayBuffer = (NativeArrayBuffer)self;

        final int byteLength  = arrayBuffer.getByteLength();

        return new NativeArrayBuffer(arrayBuffer, adjustIndex(begin, byteLength), Math.max(adjustIndex(end, byteLength), begin));

    }

    /**

     * Specialized slice function

     * @param self   native array buffer

     * @param begin  start byte index

     * @return new array buffer, sliced

     */

    @SpecializedFunction

    public static Object slice(final Object self, final int begin) {

        return slice(self, begin, ((NativeArrayBuffer)self).getByteLength());

    }

    /**

     * If index is negative, it refers to an index from the end of the array, as

     * opposed to from the beginning. The index is clamped to the valid index

     * range for the array.

     *

     * @param index  The index.

     * @param length The length of the array.

     * @return valid index index in the range [0, length).

     */

    static int adjustIndex(final int index, final int length) {

        return index < 0 ? clamp(index + length, length) : clamp(index, length);

    }

    /**

     * Clamp index into the range [0, length).

     */

    private static int clamp(final int index, final int length) {

        if (index < 0) {

            return 0;

        } else if (index > length) {

            return length;

        }

        return index;

    }

    int getByteLength() {

        return nb.limit();

    }

    ByteBuffer getBuffer() {

       return nb;

    }

    ByteBuffer getBuffer(final int offset) {

    }

    ByteBuffer getBuffer(final int offset, final int length) {

    }

}