/*
 * This file is part of the L2J Mobius project.
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program 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 for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
package com.l2jmobius.commons.network;

import io.netty.buffer.ByteBuf;

/**
 * @author Nos
 */
public final class PacketReader
{
	private final ByteBuf _buf;
	
	public PacketReader(ByteBuf buf)
	{
		_buf = buf;
	}
	
	/**
	 * Gets the readable bytes.
	 * @return the readable bytes
	 */
	public int getReadableBytes()
	{
		return _buf.readableBytes();
	}
	
	/**
	 * Reads an unsigned byte.
	 * @return the unsigned byte
	 * @throws IndexOutOfBoundsException if {@code readableBytes} is less than {@code 1}
	 */
	public short readC()
	{
		return _buf.readUnsignedByte();
	}
	
	/**
	 * Reads an unsigned short.
	 * @return the unsigned short
	 * @throws IndexOutOfBoundsException if {@code readableBytes} is less than {@code 2}
	 */
	public int readH()
	{
		return _buf.readUnsignedShort();
	}
	
	/**
	 * Reads an integer.
	 * @return the integer
	 * @throws IndexOutOfBoundsException if {@code readableBytes} is less than {@code 4}
	 */
	public int readD()
	{
		return _buf.readInt();
	}
	
	/**
	 * Reads a long.
	 * @return the long
	 * @throws IndexOutOfBoundsException if {@code readableBytes} is less than {@code 8}
	 */
	public long readQ()
	{
		return _buf.readLong();
	}
	
	/**
	 * Reads a float.
	 * @return the float
	 * @throws IndexOutOfBoundsException if {@code readableBytes} is less than {@code 4}
	 */
	public float readE()
	{
		return _buf.readFloat();
	}
	
	/**
	 * Reads a double.
	 * @return the double
	 * @throws IndexOutOfBoundsException if {@code readableBytes} is less than {@code 8}
	 */
	public double readF()
	{
		return _buf.readDouble();
	}
	
	/**
	 * Reads a string.
	 * @return the string
	 * @throws IndexOutOfBoundsException if string {@code null} terminator is not found within {@code readableBytes}
	 */
	public String readS()
	{
		final StringBuilder sb = new StringBuilder();
		char chr;
		while ((chr = _buf.readChar()) != 0)
		{
			sb.append(chr);
		}
		return sb.toString();
	}
	
	/**
	 * Reads a fixed length string.
	 * @return the string
	 * @throws IndexOutOfBoundsException if {@code readableBytes} is less than {@code 2 + String.length * 2}
	 */
	public String readString()
	{
		final StringBuilder sb = new StringBuilder();
		final int stringLength = _buf.readShort();
		if ((stringLength * 2) > getReadableBytes())
		{
			throw new IndexOutOfBoundsException("readerIndex(" + _buf.readerIndex() + ") + length(" + (stringLength * 2) + ") exceeds writerIndex(" + _buf.writerIndex() + "): " + _buf);
		}
		
		for (int i = 0; i < stringLength; i++)
		{
			sb.append(_buf.readChar());
		}
		return sb.toString();
	}
	
	/**
	 * Reads a byte array.
	 * @param length the length
	 * @return the byte array
	 * @throws IndexOutOfBoundsException if {@code readableBytes} is less than {@code length}
	 */
	public byte[] readB(int length)
	{
		final byte[] result = new byte[length];
		_buf.readBytes(result);
		return result;
	}
	
	/**
	 * Reads a byte array.
	 * @param dst the destination
	 * @param dstIndex the destination index to start writing the bytes from
	 * @param length the length
	 * @throws IndexOutOfBoundsException if {@code readableBytes} is less than {@code length}, if the specified dstIndex is less than 0 or if {@code dstIndex + length} is greater than {@code dst.length}
	 */
	public void readB(byte[] dst, int dstIndex, int length)
	{
		_buf.readBytes(dst, dstIndex, length);
	}
}