/*

 * 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

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 */

package jdk.nashorn.internal.runtime.arrays;

import static jdk.nashorn.internal.codegen.CompilerConstants.specialCall;

import java.lang.invoke.MethodHandle;

import java.lang.invoke.MethodHandles;

import java.util.Arrays;

import jdk.nashorn.internal.runtime.JSType;

import jdk.nashorn.internal.runtime.ScriptRuntime;

/**

 * Implementation of {@link ArrayData} as soon as an Object has been

 * written to the array

 */

final class ObjectArrayData extends ContinuousArrayData implements AnyElements {

    /**

     * The wrapped array

     */

    private Object[] array;

    /**

     * Constructor

     * @param array an int array

     * @param length a length, not necessarily array.length

     */

    ObjectArrayData(final Object[] array, final int length) {

        super(length);

        assert array.length >= length;

        this.array  = array;

    }

    @Override

    public final Class<?> getElementType() {

        return Object.class;

    }

    @Override

    public final Class<?> getBoxedElementType() {

        return getElementType();

    }

    @Override

    public final int getElementWeight() {

        return 4;

    }

    @Override

    public final ContinuousArrayData widest(final ContinuousArrayData otherData) {

        return otherData instanceof NumericElements ? this : otherData;

    }

    @Override

    public ObjectArrayData copy() {

        return new ObjectArrayData(array.clone(), (int)length());

    }

    @Override

    public Object[] asObjectArray() {

        return array.length == length() ? array.clone() : asObjectArrayCopy();

    }

    private Object[] asObjectArrayCopy() {

        final long len = length();

        assert len <= Integer.MAX_VALUE;

        final Object[] copy = new Object[(int)len];

        System.arraycopy(array, 0, copy, 0, (int)len);

        return copy;

    }

    @Override

    public ObjectArrayData convert(final Class<?> type) {

        return this;

    }

    @Override

    public ArrayData shiftLeft(final int by) {

        if (by >= length()) {

            shrink(0);

        } else {

            System.arraycopy(array, by, array, 0, array.length - by);

        }

        setLength(Math.max(0, length() - by));

        return this;

    }

    @Override

    public ArrayData shiftRight(final int by) {

        final ArrayData newData = ensure(by + length() - 1);

        if (newData != this) {

            newData.shiftRight(by);

            return newData;

        }

        System.arraycopy(array, 0, array, by, array.length - by);

        return this;

    }

    @Override

    public ArrayData ensure(final long safeIndex) {

        if (safeIndex >= SparseArrayData.MAX_DENSE_LENGTH) {

            return new SparseArrayData(this, safeIndex + 1);

        }

        final int alen = array.length;

        if (safeIndex >= alen) {

            final int newLength = ArrayData.nextSize((int)safeIndex);

            array = Arrays.copyOf(array, newLength); //fill with undefined or OK? TODO

        }

        if (safeIndex >= length()) {

            setLength(safeIndex + 1);

        }

        return this;

    }

    @Override

    public ArrayData shrink(final long newLength) {

        Arrays.fill(array, (int) newLength, array.length, ScriptRuntime.UNDEFINED);

        return this;

    }

    @Override

    public ArrayData set(final int index, final Object value, final boolean strict) {

        array[index] = value;

        setLength(Math.max(index + 1, length()));

        return this;

    }

    @Override

    public ArrayData set(final int index, final int value, final boolean strict) {

        array[index] = value;

        setLength(Math.max(index + 1, length()));

        return this;

    }

    @Override

    public ArrayData set(final int index, final double value, final boolean strict) {

        array[index] = value;

        setLength(Math.max(index + 1, length()));

        return this;

    }

    @Override

    public ArrayData setEmpty(final int index) {

        array[index] = ScriptRuntime.EMPTY;

        return this;

    }

    @Override

    public ArrayData setEmpty(final long lo, final long hi) {

        // hi parameter is inclusive, but Arrays.fill toIndex parameter is exclusive

        Arrays.fill(array, (int)Math.max(lo, 0L), (int)Math.min(hi + 1, Integer.MAX_VALUE), ScriptRuntime.EMPTY);

        return this;

    }

    private static final MethodHandle HAS_GET_ELEM = specialCall(MethodHandles.lookup(), ObjectArrayData.class, "getElem", Object.class, int.class).methodHandle();

    private static final MethodHandle SET_ELEM     = specialCall(MethodHandles.lookup(), ObjectArrayData.class, "setElem", void.class, int.class, Object.class).methodHandle();

    @SuppressWarnings("unused")

    private Object getElem(final int index) {

        if (has(index)) {

            return array[index];

        }

        throw new ClassCastException();

    }

    @SuppressWarnings("unused")

    private void setElem(final int index, final Object elem) {

        if (hasRoomFor(index)) {

            array[index] = elem;

            return;

        }

        throw new ClassCastException();

    }

    @Override

    public MethodHandle getElementGetter(final Class<?> returnType, final int programPoint) {

        if (returnType.isPrimitive()) {

            return null;

        }

        return getContinuousElementGetter(HAS_GET_ELEM, returnType, programPoint);

    }

    @Override

    public MethodHandle getElementSetter(final Class<?> elementType) {

        return getContinuousElementSetter(SET_ELEM, Object.class);

    }

    @Override

    public int getInt(final int index) {

        return JSType.toInt32(array[index]);

    }

    @Override

    public double getDouble(final int index) {

        return JSType.toNumber(array[index]);

    }

    @Override

    public Object getObject(final int index) {

        return array[index];

    }

    @Override

    public boolean has(final int index) {

        return 0 <= index && index < length();

    }

    @Override

    public ArrayData delete(final int index) {

        setEmpty(index);

        return new DeletedRangeArrayFilter(this, index, index);

    }

    @Override

    public ArrayData delete(final long fromIndex, final long toIndex) {

        setEmpty(fromIndex, toIndex);

        return new DeletedRangeArrayFilter(this, fromIndex, toIndex);

    }

    @Override

    public double fastPush(final int arg) {

        return fastPush((Object)arg);

    }

    @Override

    public double fastPush(final long arg) {

        return fastPush((Object)arg);

    }

    @Override

    public double fastPush(final double arg) {

        return fastPush((Object)arg);

    }

    @Override

    public double fastPush(final Object arg) {

        final int len = (int)length();

        if (len == array.length) {

            array = Arrays.copyOf(array, nextSize(len));

        }

        array[len] = arg;

        return increaseLength();

    }

    @Override

    public Object fastPopObject() {

        if (length() == 0) {

            return ScriptRuntime.UNDEFINED;

        }

        final int newLength = (int)decreaseLength();

        final Object elem = array[newLength];

        array[newLength] = ScriptRuntime.EMPTY;

        return elem;

    }

    @Override

    public Object pop() {

        if (length() == 0) {

            return ScriptRuntime.UNDEFINED;

        }

        final int newLength = (int)length() - 1;

        final Object elem = array[newLength];

        setEmpty(newLength);

        setLength(newLength);

        return elem;

    }

    @Override

    public ArrayData slice(final long from, final long to) {

        final long start     = from < 0 ? from + length() : from;

        final long newLength = to - start;

        return new ObjectArrayData(Arrays.copyOfRange(array, (int)from, (int)to), (int)newLength);

    }

    @Override

    public ArrayData push(final boolean strict, final Object item) {

        final long      len     = length();

        final ArrayData newData = ensure(len);

        if (newData == this) {

            array[(int)len] = item;

            return this;

        }

        return newData.set((int)len, item, strict);

    }

    @Override

    public ArrayData fastSplice(final int start, final int removed, final int added) throws UnsupportedOperationException {

        final long oldLength = length();

        final long newLength = oldLength - removed + added;

        if (newLength > SparseArrayData.MAX_DENSE_LENGTH && newLength > array.length) {

            throw new UnsupportedOperationException();

        }

        final ArrayData returnValue = removed == 0 ?

                EMPTY_ARRAY : new ObjectArrayData(Arrays.copyOfRange(array, start, start + removed), removed);

        if (newLength != oldLength) {

            final Object[] newArray;

            if (newLength > array.length) {

                newArray = new Object[ArrayData.nextSize((int)newLength)];

                System.arraycopy(array, 0, newArray, 0, start);

            } else {

                newArray = array;

            }

            System.arraycopy(array, start + removed, newArray, start + added, (int)(oldLength - start - removed));

            array = newArray;

            setLength(newLength);

        }

        return returnValue;

    }

    @Override

    public ContinuousArrayData fastConcat(final ContinuousArrayData otherData) {

        final int   otherLength = (int)otherData.length();

        final int   thisLength  = (int)length();

        assert otherLength > 0 && thisLength > 0;

        final Object[] otherArray = ((ObjectArrayData)otherData).array;

        final int      newLength  = otherLength + thisLength;

        final Object[] newArray   = new Object[ArrayData.alignUp(newLength)];

        System.arraycopy(array, 0, newArray, 0, thisLength);

        System.arraycopy(otherArray, 0, newArray, thisLength, otherLength);

        return new ObjectArrayData(newArray, newLength);

    }

    @Override

    public String toString() {

        assert length() <= array.length : length() + " > " + array.length;

        return getClass().getSimpleName() + ':' + Arrays.toString(Arrays.copyOf(array, (int)length()));

    }

}