/*

  * #%L

  * UuidElement.java - mongodb-async-driver - Allanbank Consulting, Inc.

  * %%

  * Copyright (C) 2011 - 2014 Allanbank Consulting, Inc.

  * %%

  * Licensed under the Apache License, Version 2.0 (the "License");

  * you may not use this file except in compliance with the License.

  * You may obtain a copy of the License at

  * 

  *      http://www.apache.org/licenses/LICENSE-2.0

  * 

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  * #L%

  */

 package com.allanbank.mongodb.bson.element;

 import static com.allanbank.mongodb.util.Assertions.assertNotNull;

 import java.util.UUID;

 import com.allanbank.mongodb.bson.io.EndianUtils;

 import com.allanbank.mongodb.util.IOUtils;

 /**

  * UuidElement provides a helper element for handling UUID {@link BinaryElement}

  * sub-types.

  * <p>

  * If no sub-type is provided this class defaults to the standardized sub-type 4

  * binary element which encodes the UUID from most significant byte to least

  * significant byte. If the deprecated sub-type 3 is specified this class

  * assumes the legacy Java encoding of the UUID which encodes the most

  * significant long in least-significant-byte order and then the least

  * significant long in least-significant-byte order.

  * </p>

  * 

  * @api.yes This class is part of the driver's API. Public and protected members

  *          will be deprecated for at least 1 non-bugfix release (version

  *          numbers are <major>.<minor>.<bugfix>) before being

  *          removed or modified.

  * @copyright 2012-2013, Allanbank Consulting, Inc., All Rights Reserved

  */

 public class UuidElement extends BinaryElement {

     /**

      * The legacy (reverse byte order for high and low long values) subtype for

      * the UUID.

      */

     public static final byte LEGACY_UUID_SUBTTYPE = 3;

     /** The length for the UUID binary value. */

     public static final int UUID_BINARY_LENGTH = 16;

     /** The default subtype for the UUID. */

     public static final byte UUID_SUBTTYPE = 4;

     /** The serialization version for the class. */

     private static final long serialVersionUID = 6461067538910973839L;

     /**

      * Converts the UUID value to a byte array based on the subtype.

      * 

      * @param uuidSubttype

      *            The subtype for the UUID encoding.

      * @param value

      *            The UUID value to convert.

      * @return The byte encoding.

      */

     private static byte[] toBytes(final byte uuidSubttype, final UUID value) {

         assertNotNull(value,

                 "The UUID value for a UuidElement must not be null.");

         long high = value.getMostSignificantBits();

         long low = value.getLeastSignificantBits();

         if (uuidSubttype == LEGACY_UUID_SUBTTYPE) {

             high = EndianUtils.swap(high);

             low = EndianUtils.swap(low);

         }

         final byte[] result = new byte[16];

         result[0] = (byte) ((high >> 56) & 0xFF);

         result[1] = (byte) ((high >> 48) & 0xFF);

         result[2] = (byte) ((high >> 40) & 0xFF);

         result[3] = (byte) ((high >> 32) & 0xFF);

         result[4] = (byte) ((high >> 24) & 0xFF);

         result[5] = (byte) ((high >> 16) & 0xFF);

         result[6] = (byte) ((high >> 8) & 0xFF);

         result[7] = (byte) (high & 0xFF);

         result[8] = (byte) ((low >> 56) & 0xFF);

         result[9] = (byte) ((low >> 48) & 0xFF);

         result[10] = (byte) ((low >> 40) & 0xFF);

         result[11] = (byte) ((low >> 32) & 0xFF);

         result[12] = (byte) ((low >> 24) & 0xFF);

         result[13] = (byte) ((low >> 16) & 0xFF);

         result[14] = (byte) ((low >> 8) & 0xFF);

         result[15] = (byte) (low & 0xFF);

         return result;

     }

     /** The UUID value created. */

     private final UUID myUuid;

     /**

      * Creates a new UuidElement.

      * 

      * @param name

      *            The name for the element.

      * @param subType

      *            The subtype for the UUID element.

      * @param value

      *            The UUID bytes for the element.

      * @throws IllegalArgumentException

      *             If the {@code name} or {@code value} is <code>null</code>. If

      *             the subType is not {@link #UUID_SUBTTYPE} or

      *             {@link #LEGACY_UUID_SUBTTYPE}. If the value is not a 16 bytes

      *             long.

      */

     public UuidElement(final String name, final byte subType, final byte[] value) {

         super(name, subType, value);

         myUuid = toUuid(subType, value);

     }

     /**

      * Creates a new UuidElement.

      * 

      * @param name

      *            The name for the element.

      * @param subType

      *            The subtype for the UUID element.

      * @param value

      *            The UUID bytes for the element.

      * @param size

      *            The size of the element when encoded in bytes. If not known

      *            then use the

      *            {@link UuidElement#UuidElement(String, byte, byte[])}

      *            constructor instead.

      * @throws IllegalArgumentException

      *             If the {@code name} or {@code value} is <code>null</code>. If

      *             the subType is not {@link #UUID_SUBTTYPE} or

      *             {@link #LEGACY_UUID_SUBTTYPE}. If the value is not a 16 bytes

      *             long.

      */

     public UuidElement(final String name, final byte subType,

             final byte[] value, final long size) {

         super(name, subType, value, size);

         myUuid = toUuid(subType, value);

     }

     /**

      * Creates a new UuidElement.

      * 

      * @param name

      *            The name for the element.

      * @param subType

      *            The subtype for the UUID element.

      * @param value

      *            The UUID value for the element.

      * @throws IllegalArgumentException

      *             If the {@code name} or {@code value} is <code>null</code>.

      */

     public UuidElement(final String name, final byte subType, final UUID value) {

         super(name, subType, toBytes(subType, value));

         myUuid = value;

     }

     /**

      * Creates a new UuidElement.

      * 

      * @param name

      *            The name for the element.

      * @param value

      *            The UUID value for the element.

      * @throws IllegalArgumentException

      *             If the {@code name} or {@code value} is <code>null</code>.

      */

     public UuidElement(final String name, final UUID value) {

         super(name, UUID_SUBTTYPE, toBytes(UUID_SUBTTYPE, value));

         myUuid = value;

     }

     /**

      * Determines if the passed object is of this same type as this object and

      * if so that its fields are equal.

      * 

      * @param object

      *            The object to compare to.

      * 

      * @see java.lang.Object#equals(java.lang.Object)

      */

     @Override

     public boolean equals(final Object object) {

         boolean result = false;

         if (this == object) {

             result = true;

         }

         else if ((object != null) && (getClass() == object.getClass())) {

             final UuidElement other = (UuidElement) object;

             result = super.equals(object) && myUuid.equals(other.myUuid);

         }

         return result;

     }

     /**

      * Returns the {@link UUID} value.

      * 

      * @return The {@link UUID} value.

      */

     public UUID getUuid() {

         return myUuid;

     }

     /**

      * {@inheritDoc}

      * <p>

      * Returns the UUID value.

      * </p>

      * <p>

      * <b>Note:</b> This value will not be recreated is a Object-->Element

      * conversion. The sub type is lost in this conversion to an {@link Object}.

      * </p>

      */

     @Override

     public UUID getValueAsObject() {

         return myUuid;

     }

     /**

      * {@inheritDoc}

      * <p>

      * Returns the result of the {@link UUID#toString()}.

      * </p>

      */

     @Override

     public String getValueAsString() {

         return myUuid.toString();

     }

     /**

      * Computes a reasonable hash code.

      * 

      * @return The hash code value.

      */

     @Override

     public int hashCode() {

         int result = 1;

         result = (31 * result) + super.hashCode();

         result = (31 * result) + myUuid.hashCode();

         return result;

     }

     /**

      * {@inheritDoc}

      * <p>

      * Returns a new {@link BinaryElement}.

      * </p>

      */

     @Override

     public UuidElement withName(final String name) {

         if (getName().equals(name)) {

             return this;

         }

         return new UuidElement(name, getSubType(), myUuid);

     }

     /**

      * Converts the UUID binary form into a UUID object.

      * 

      * @param subType

      *            The sub-type for the UUID encoding.

      * @param value

      *            The encoded UUID.

      * @return The UUID encoded in the {@code value}.

      * @throws IllegalArgumentException

      *             If the length of the {@code value} array is not

      *             {@value #UUID_BINARY_LENGTH}.

      */

     private UUID toUuid(final byte subType, final byte[] value)

             throws IllegalArgumentException {

         if (value.length == UUID_BINARY_LENGTH) {

             long high = 0;

             long low = 0;

             for (int i = 0; i < 8; ++i) {

                 high <<= Byte.SIZE;

                 high += (value[i] & 0xFF);

             }

             for (int i = 8; i < 16; ++i) {

                 low <<= Byte.SIZE;

                 low += (value[i] & 0xFF);

             }

             if (subType == LEGACY_UUID_SUBTTYPE) {

                 high = EndianUtils.swap(high);

                 low = EndianUtils.swap(low);

             }

             return new UUID(high, low);

         }

         throw new IllegalArgumentException(

                 "The value for a UUID must be 16 bytes long: "

                         + IOUtils.toHex(value));

     }

 }