/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project licenses this file to you 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.
 */
package net.lax1dude.eaglercraft.v1_8.netty;

import java.io.DataOutput;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.charset.StandardCharsets;

/**
 * An {@link OutputStream} which writes data to a {@link ByteBuf}.
 * <p>
 * A write operation against this stream will occur at the {@code writerIndex}
 * of its underlying buffer and the {@code writerIndex} will increase during the
 * write operation.
 * <p>
 * This stream implements {@link DataOutput} for your convenience. The
 * endianness of the stream is not always big endian but depends on the
 * endianness of the underlying buffer.
 *
 * @see ByteBufInputStream
 */
public class ByteBufOutputStream extends OutputStream implements DataOutput {

	private final ByteBuf buffer;
	private final int startIndex;
	private final DataOutputStream utf8out = new DataOutputStream(this);

	/**
	 * Creates a new stream which writes data to the specified {@code buffer}.
	 */
	public ByteBufOutputStream(ByteBuf buffer) {
		if (buffer == null) {
			throw new NullPointerException("buffer");
		}
		this.buffer = buffer;
		startIndex = buffer.writerIndex();
	}

	/**
	 * Returns the number of written bytes by this stream so far.
	 */
	public int writtenBytes() {
		return buffer.writerIndex() - startIndex;
	}

	@Override
	public void write(byte[] b, int off, int len) throws IOException {
		if (len == 0) {
			return;
		}

		buffer.writeBytes(b, off, len);
	}

	@Override
	public void write(byte[] b) throws IOException {
		buffer.writeBytes(b);
	}

	@Override
	public void write(int b) throws IOException {
		buffer.writeByte(b);
	}

	@Override
	public void writeBoolean(boolean v) throws IOException {
		buffer.writeBoolean(v);
	}

	@Override
	public void writeByte(int v) throws IOException {
		buffer.writeByte(v);
	}

	@Override
	public void writeBytes(String s) throws IOException {
		buffer.writeBytes(s.getBytes(StandardCharsets.UTF_8));
	}

	@Override
	public void writeChar(int v) throws IOException {
		buffer.writeChar(v);
	}

	@Override
	public void writeChars(String s) throws IOException {
		int len = s.length();
		for (int i = 0; i < len; i++) {
			buffer.writeChar(s.charAt(i));
		}
	}

	@Override
	public void writeDouble(double v) throws IOException {
		buffer.writeDouble(v);
	}

	@Override
	public void writeFloat(float v) throws IOException {
		buffer.writeFloat(v);
	}

	@Override
	public void writeInt(int v) throws IOException {
		buffer.writeInt(v);
	}

	@Override
	public void writeLong(long v) throws IOException {
		buffer.writeLong(v);
	}

	@Override
	public void writeShort(int v) throws IOException {
		buffer.writeShort((short) v);
	}

	@Override
	public void writeUTF(String s) throws IOException {
		utf8out.writeUTF(s);
	}

	/**
	 * Returns the buffer where this stream is writing data.
	 */
	public ByteBuf buffer() {
		return buffer;
	}
}
