/*

  * #%L

  * WriteVisitor.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.io;

 import java.io.IOException;

 import java.io.OutputStream;

 import java.util.List;

 import com.allanbank.mongodb.bson.Document;

 import com.allanbank.mongodb.bson.Element;

 import com.allanbank.mongodb.bson.ElementType;

 import com.allanbank.mongodb.bson.element.ObjectId;

 import com.allanbank.mongodb.bson.element.SizeAwareVisitor;

 /**

  * A visitor to myOutput.write the BSON document to a {@link OutputStream}. The

  * BSON specification uses prefixed length integers in several locations. This

  * visitor uses a {@link StringEncoder} and the {@link Element#size()} to

  * compute the size item about to be written removing the requirements to buffer

  * the data being written.

  * 

  * @api.no This class is <b>NOT</b> part of the drivers API. This class may be

  *         mutated in incompatible ways between any two releases of the driver.

  * @copyright 2011-2013, Allanbank Consulting, Inc., All Rights Reserved

  */

 /* package */class WriteVisitor implements SizeAwareVisitor {

     /** Stream to myOutput.write to. */

     protected final BsonOutputStream myOutput;

     /**

      * Creates a new {@link WriteVisitor}.

      * 

      * @param output

      *            The stream to myOutput.write to.

      */

     public WriteVisitor(final BsonOutputStream output) {

         myOutput = output;

     }

     /**

      * Creates a new {@link WriteVisitor}.

      * 

      * @param output

      *            The stream to myOutput.write to.

      */

     public WriteVisitor(final OutputStream output) {

         this(new BsonOutputStream(output));

     }

     /**

      * Returns the I/O exception encountered by the visitor.

      * 

      * @return The I/O exception encountered by the visitor.

      */

     public IOException getError() {

         return myOutput.getError();

     }

     /**

      * Returns true if the visitor had an I/O error.

      * 

      * @return True if the visitor had an I/O error, false otherwise.

      */

     public boolean hasError() {

         return myOutput.hasError();

     }

     /**

      * Clears the internal buffer and prepares to myOutput.write another

      * document.

      */

     public void reset() {

         myOutput.reset();

     }

     /**

      * Determines the size of the document written in BSON format. The

      * {@link Document}'s size is cached for subsequent write operations.

      * 

      * @param doc

      *            The document to determine the size of.

      * @return The number of bytes require to Write the document.

      * @deprecated Replaced with {@link Document#size()}. This method will be

      *             removed after the 2.2.0 release.

      */

     @Deprecated

     public int sizeOf(final Document doc) {

         return (int) doc.size();

     }

     /**

      * Computes the size of the encoded UTF8 String.

      * 

      * @param string

      *            The string to determine the length of.

      * @return The length of the string encoded as UTF8.

      * @see StringEncoder#utf8Size(String)

      */

     public int utf8Size(final String string) {

         return StringEncoder.utf8Size(string);

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public void visit(final List<Element> elements) {

         int size = 4 + 1; // Length (int,4) and null.

         for (final Element element : elements) {

             size += element.size();

         }

         writeElements(elements, size);

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public void visitArray(final String name, final List<Element> elements) {

         myOutput.writeByte(ElementType.ARRAY.getToken());

         myOutput.writeCString(name);

         visit(elements);

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public void visitArray(final String name, final List<Element> elements,

             final long totalSize) {

         myOutput.writeByte(ElementType.ARRAY.getToken());

         myOutput.writeCString(name);

         writeElements(elements,

                 ((int) totalSize) - (myOutput.sizeOfCString(name) + 1));

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public void visitBinary(final String name, final byte subType,

             final byte[] data) {

         myOutput.writeByte(ElementType.BINARY.getToken());

         myOutput.writeCString(name);

         switch (subType) {

         case 2: {

             myOutput.writeInt(data.length + 4);

             myOutput.writeByte(subType);

             myOutput.writeInt(data.length);

             myOutput.writeBytes(data);

             break;

         }

         case 0:

         default:

             myOutput.writeInt(data.length);

             myOutput.writeByte(subType);

             myOutput.writeBytes(data);

             break;

         }

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public void visitBoolean(final String name, final boolean value) {

         myOutput.writeByte(ElementType.BOOLEAN.getToken());

         myOutput.writeCString(name);

         myOutput.writeByte(value ? (byte) 0x01 : 0x00);

     }

     /**

      * {@inheritDoc}

      */

     @SuppressWarnings("deprecation")

     @Override

     public void visitDBPointer(final String name, final String databaseName,

             final String collectionName, final ObjectId id) {

         myOutput.writeByte(ElementType.DB_POINTER.getToken());

         myOutput.writeCString(name);

         myOutput.writeString(databaseName + "." + collectionName);

         // Just to be complicated the Object ID is big endian.

         myOutput.writeInt(EndianUtils.swap(id.getTimestamp()));

         myOutput.writeLong(EndianUtils.swap(id.getMachineId()));

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public void visitDocument(final String name, final List<Element> elements) {

         myOutput.writeByte(ElementType.DOCUMENT.getToken());

         myOutput.writeCString(name);

         visit(elements);

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public void visitDocument(final String name, final List<Element> elements,

             final long totalSize) {

         myOutput.writeByte(ElementType.DOCUMENT.getToken());

         myOutput.writeCString(name);

         writeElements(elements,

                 ((int) totalSize) - (myOutput.sizeOfCString(name) + 1));

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public void visitDouble(final String name, final double value) {

         myOutput.writeByte(ElementType.DOUBLE.getToken());

         myOutput.writeCString(name);

         myOutput.writeLong(Double.doubleToLongBits(value));

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public void visitInteger(final String name, final int value) {

         myOutput.writeByte(ElementType.INTEGER.getToken());

         myOutput.writeCString(name);

         myOutput.writeInt(value);

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public void visitJavaScript(final String name, final String code) {

         myOutput.writeByte(ElementType.JAVA_SCRIPT.getToken());

         myOutput.writeCString(name);

         myOutput.writeString(code);

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public void visitJavaScript(final String name, final String code,

             final Document scope) {

         myOutput.writeByte(ElementType.JAVA_SCRIPT_WITH_SCOPE.getToken());

         myOutput.writeCString(name);

         myOutput.writeInt(4 + StringEncoder.computeStringSize(code)

                 + (int) scope.size());

         myOutput.writeString(code);

         scope.accept(this);

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public void visitLong(final String name, final long value) {

         myOutput.writeByte(ElementType.LONG.getToken());

         myOutput.writeCString(name);

         myOutput.writeLong(value);

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public void visitMaxKey(final String name) {

         myOutput.writeByte(ElementType.MAX_KEY.getToken());

         myOutput.writeCString(name);

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public void visitMinKey(final String name) {

         myOutput.writeByte(ElementType.MIN_KEY.getToken());

         myOutput.writeCString(name);

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public void visitMongoTimestamp(final String name, final long value) {

         myOutput.writeByte(ElementType.MONGO_TIMESTAMP.getToken());

         myOutput.writeCString(name);

         myOutput.writeLong(value);

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public void visitNull(final String name) {

         myOutput.writeByte(ElementType.NULL.getToken());

         myOutput.writeCString(name);

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public void visitObjectId(final String name, final ObjectId id) {

         myOutput.writeByte(ElementType.OBJECT_ID.getToken());

         myOutput.writeCString(name);

         // Just to be complicated the Object ID is big endian.

         myOutput.writeInt(EndianUtils.swap(id.getTimestamp()));

         myOutput.writeLong(EndianUtils.swap(id.getMachineId()));

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public void visitRegularExpression(final String name, final String pattern,

             final String options) {

         myOutput.writeByte(ElementType.REGEX.getToken());

         myOutput.writeCString(name);

         myOutput.writeCString(pattern);

         myOutput.writeCString(options);

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public void visitString(final String name, final String value) {

         myOutput.writeByte(ElementType.STRING.getToken());

         myOutput.writeCString(name);

         myOutput.writeString(value);

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public void visitSymbol(final String name, final String symbol) {

         myOutput.writeByte(ElementType.SYMBOL.getToken());

         myOutput.writeCString(name);

         myOutput.writeString(symbol);

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public void visitTimestamp(final String name, final long timestamp) {

         myOutput.writeByte(ElementType.UTC_TIMESTAMP.getToken());

         myOutput.writeCString(name);

         myOutput.writeLong(timestamp);

     }

     /**

      * Writes a list of elements.

      * 

      * @param elements

      *            The sub elements of the document.

      * @param size

      *            The size of the elements.

      */

     protected void writeElements(final List<Element> elements, final int size) {

         myOutput.writeInt(size);

         for (final Element element : elements) {

             element.accept(this);

         }

         myOutput.writeByte((byte) 0);

     }

 }