package ms.net.packet;

import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;

import ms.system.util.ByteBufferUtils;

/**
 * Represents the buffer used for reading/writing packets.
 * @author Emperor
 *
 */
public class IoBuffer {
	
	/**
	 * The bit masks.
	 */
	private static final int[] BIT_MASK = new int[32];
	
	/**
	 * The packet size.
	 */
	private int packetSize;
	
	/**
	 * The opcode.
	 */
	private final int opcode;

	/**
	 * The packet header.
	 */
	private final PacketHeader header;
	
	/**
	 * The byte buffer.
	 */
	private ByteBuffer buf;

	/**
	 * The bit position.
	 */
	private int bitPosition = 0;
	
	/**
	 * Constructs a new {@code IoBuffer} {@code Object}.
	 */
	public IoBuffer() {
		this(-1, PacketHeader.NORMAL, ByteBuffer.allocate(2048));
	}
	
	/**
	 * Constructs a new {@code IoBuffer} {@code Object}.
	 * @param opcode The opcode.
	 */
	public IoBuffer(int opcode) {
		this(opcode, PacketHeader.NORMAL, ByteBuffer.allocate(2048));
	}
	
	/**
	 * Constructs a new {@code IoBuffer} {@code Object}.
	 * @param opcode The opcode.
	 * @param header The packet header.
	 */
	public IoBuffer(int opcode, PacketHeader header) {
		this(opcode, header, ByteBuffer.allocate((1 << 16) + 1));
	}
	
	/**
	 * Constructs a new {@code IoBuffer} {@code Object}.
	 * @param opcode The opcode.
	 * @param header The packet header.
	 * @param buf The byte buffer.
	 */
	public IoBuffer(int opcode, PacketHeader header, ByteBuffer buf) {
		this.opcode = opcode;
		this.header = header;
		this.buf = buf;
	}

	static {
		for (int i = 0; i < 32; i++) {
			BIT_MASK[i] = (1 << i) - 1;
		}
	}
	
	/**
	 * 
	 * @return
	 */
	public IoBuffer clear() {
		buf.clear();
		bitPosition = 0;
		return this;
	}

	/**
	 * 
	 * @param val
	 * @return
	 */
	public IoBuffer put(int val) {
		buf.put((byte) val);
		return this;
	}
	
	/**
	 * 
	 * @param datas
	 * @param offset
	 * @param len
	 * @return
	 */
	public IoBuffer putBytes(byte[] datas, int offset, int len) {
		for (int i = offset; i < len; i++) {
			put(datas[i]);
		}
		return this;
	}
	
	public final void getBytes(byte data[], int off, int len) {
		for (int k = off; k < len + off; k++) {
			data[k] = data[off++];
		}
	}

	/**
	 * 
	 * @param val
	 * @return
	 */
	public IoBuffer putA(int val) {
		buf.put((byte) (val + 128));
		return this;
	}

	/**
	 * 
	 * @param val
	 * @return
	 */
	public IoBuffer putC(int val) {
		buf.put((byte) -val);
		return this;
	}

	/**
	 * 
	 * @param val
	 * @return
	 */
	public IoBuffer putS(int val) {
		buf.put((byte) (128 - val));
		return this;
	}
	
	/**
	 * 
	 * @param val
	 * @return
	 */
	public IoBuffer putTri(int val) {
		buf.put((byte) (val >> 16));
		buf.put((byte) (val >> 8));
		buf.put((byte) val);
		return this;
	}

	/**
	 * 
	 * @param val
	 * @return
	 */
	public IoBuffer putShort(int val) {
		buf.putShort((short) val);
		return this;
	}

	/**
	 * 
	 * @param val
	 * @return
	 */
	public IoBuffer putLEShort(int val) {
		buf.put((byte) val);
		buf.put((byte) (val >> 8));
		return this;
	}

	/**
	 * 
	 * @param val
	 * @return
	 */
	public IoBuffer putShortA(int val) {
		buf.put((byte) (val >> 8));
		buf.put((byte) (val + 128));
		return this;
	}

	/**
	 * 
	 * @param val
	 * @return
	 */
	public IoBuffer putLEShortA(int val) {
		buf.put((byte) (val + 128));
		buf.put((byte) (val >> 8));
		return this;
	}

	/**
	 * 
	 * @param val
	 * @return
	 */
	public IoBuffer putInt(int val) {
		buf.putInt(val);
		return this;
	}

	/**
	 * 
	 * @param val
	 * @return
	 */
	public IoBuffer putLEInt(int val) {
		buf.put((byte) val);
		buf.put((byte) (val >> 8));
		buf.put((byte) (val >> 16));
		buf.put((byte) (val >> 24));
		return this;
	}

	/**
	 * 
	 * @param val
	 * @return
	 */
	public IoBuffer putIntA(int val) {
		buf.put((byte) (val >> 8));
		buf.put((byte) val);
		buf.put((byte) (val >> 24));
		buf.put((byte) (val >> 16));
		return this;
	}

	/**
	 * 
	 * @param val
	 * @return
	 */
	public IoBuffer putIntB(int val) {
		buf.put((byte) (val >> 16));
		buf.put((byte) (val >> 24));
		buf.put((byte) val);
		buf.put((byte) (val >> 8));
		return this;
	}

	/**
	 * 
	 * @param val
	 * @return
	 */
	public IoBuffer putLong(long val) {
		buf.putLong(val);
		return this;
	}

	/**
	 * 
	 * @param val
	 * @return
	 */
	public IoBuffer putSmart(int val) {
		if (val > Byte.MAX_VALUE) {
			buf.putShort((short) (val + 32768));
		} else {
			buf.put((byte) val);
		}
		return this;
	}

	/**
	 * 
	 * @param val
	 * @return
	 */
	public IoBuffer putIntSmart(int val) {
		if (val > Short.MAX_VALUE) {
			buf.putInt(val + 32768);
		} else {
			buf.putShort((short) val);
		}
		return this;
	}

	/**
	 * 
	 * @param val
	 * @return
	 */
	public IoBuffer putString(String val) {
		buf.put(val.getBytes(StandardCharsets.UTF_8));
		buf.put((byte) 0);
		return this;
	}

	/**
	 * 
	 * @param val
	 * @return
	 */
	public IoBuffer putJagString(String val) {
		buf.put((byte) 0);
		buf.put(val.getBytes(StandardCharsets.UTF_8));
		buf.put((byte) 0);
		return this;
	}

	/**
	 * 
	 * @param val
	 * @return
	 */
	public IoBuffer putJagString2(String val) {
        byte[] packed = new byte[256];
        int length = ByteBufferUtils.packGJString2(0, packed, val);
        buf.put((byte) 0).put(packed, 0, length).put((byte) 0);
        return this;
	}

	/**
	 * 
	 * @param val
	 * @return
	 */
	public IoBuffer put(byte[] val) {
		buf.put(val);
		return this;
	}
	
	/**
	 * Puts a byte array as byte A in reverse.
	 * @param data The data to put.
	 * @param start The start index.
	 * @param offset The offset.
	 */
	public void putReverseA(byte[] data, int start, int offset) {
		for (int i = offset + start; i >= start; i--) {
			putA(data[i]);
		}
	}

	/**
	 * 
	 * @param numBits
	 * @param value
	 * @return
	 */
	public IoBuffer putBits(int numBits, int value) {
		int bytePos = getBitPosition() >> 3;
		int bitOffset = 8 - (getBitPosition() & 7);
		bitPosition += numBits;
		for (; numBits > bitOffset; bitOffset = 8) {
            byte b = buf.get(bytePos);
			buf.put(bytePos, b &= ~BIT_MASK[bitOffset]);
			buf.put(bytePos++, b |= value >> numBits - bitOffset & BIT_MASK[bitOffset]);
			numBits -= bitOffset;
		}
        byte b = buf.get(bytePos);
		if (numBits == bitOffset) {
			buf.put(bytePos, b &= ~BIT_MASK[bitOffset]);
			buf.put(bytePos, b |= value & BIT_MASK[bitOffset]);
		} else {
			buf.put(bytePos, b &= ~(BIT_MASK[numBits] << bitOffset - numBits));
			buf.put(bytePos, b |= (value & BIT_MASK[numBits]) << bitOffset - numBits);
		}
		return this;
	}

	/**
	 * 
	 * @param buffer
	 * @return
	 */
	public IoBuffer put(IoBuffer buffer) {
		buffer.toByteBuffer().flip();
		buf.put(buffer.toByteBuffer());
		return this;
	}

	/**
	 * 
	 * @param buffer
	 * @return
	 */
	public IoBuffer putA(IoBuffer buffer) {
		buffer.toByteBuffer().flip();
		while (buffer.toByteBuffer().hasRemaining()) {
			putA(buffer.toByteBuffer().get());
		}
		return this;
	}
	    
	/**
	 * 
	 * @param buffer
	 * @return
	 */
	public IoBuffer put(ByteBuffer buffer) {
		buf.put(buffer);
		return this;
	}

	/**
	 * 
	 * @return
	 */
	public IoBuffer setBitAccess() {
		bitPosition = buf.position() * 8;
		return this;
	}

	/**
	 * 
	 * @return
	 */
	public IoBuffer setByteAccess() {
		buf.position((getBitPosition() + 7) / 8);
		return this;
	}

	/**
	 * 
	 * @return
	 */
	public int get() {
		return buf.get();
	}

	/**
	 * 
	 * @return
	 */
	public int getA() {
		return (buf.get() & 0xFF) - 128;
	}

	/**
	 * 
	 * @return
	 */
	public int getC() {
		return -buf.get();
	}

	/**
	 * 
	 * @return
	 */
	public int getS() {
		return 128 - buf.get();
	}

	/**
	 * 
	 * @return
	 */
	public int getTri() {
		return ((buf.get() << 16) & 0xFF) | ((buf.get() << 8) & 0xFF) | (buf.get() & 0xFF);
	}

	/**
	 * 
	 * @return
	 */
	public int getShort() {
		return buf.getShort();
	}

	/**
	 * 
	 * @return
	 */
	public int getLEShort() {
		return (buf.get() & 0xFF) | ((buf.get() & 0xFF) << 8);
	}

	/**
	 * 
	 * @return
	 */
	public int getShortA() {
		return ((buf.get() & 0xFF) << 8) | (buf.get() - 128 & 0xFF);
	}

	/**
	 * 
	 * @return
	 */
	public int getLEShortA() {
		return (buf.get() - 128 & 0xFF) | ((buf.get() & 0xFF) << 8);
	}

	/**
	 * 
	 * @return
	 */
	public int getInt() {
		return buf.getInt();
	}

	/**
	 * 
	 * @return
	 */
	public int getLEInt() {
		return (buf.get() & 0xFF) + ((buf.get() & 0xFF) << 8)
				+ ((buf.get() & 0xFF) << 16) + ((buf.get() & 0xFF) << 24);
	}

	/**
	 * 
	 * @return
	 */
	public int getIntA() {
		return ((buf.get() & 0xFF) << 8) + (buf.get() & 0xFF)+ ((buf.get() & 0xFF) << 24) + ((buf.get() & 0xFF) << 16);
	}

	/**
	 * 
	 * @return
	 */
	public int getIntB() {
		return ((buf.get() & 0xFF) << 16) + ((buf.get() & 0xFF) << 24)
				+ (buf.get() & 0xFF) + ((buf.get() & 0xFF) << 8);
	}
	
	/**
	 * 
	 * @return
	 */
	public long getLongL() {
		long first = getIntB();
		long second = getIntB();
		if (second < 0)
			second = second & 0xffffffffL;
		return (first << -41780448) + second;
	}

	/**
	 * 
	 * @return
	 */
	public long getLong() {
		return buf.getLong();
	}

	/**
	 * 
	 * @return
	 */
	public int getIntSmart() {
		int peek = buf.getShort(buf.position());
		if (peek <= Short.MAX_VALUE) {
			return buf.getShort() & 0xFFFF;
		}
		return (buf.getInt() & 0xFFFFFFFF) - 32768;
	}

	/**
	 * 
	 * @return
	 */
	public String getString() {
		return ByteBufferUtils.getString(buf);
	}

	/**
	 * 
	 * @return
	 */
	public String getJagString() {
		buf.get();
		return ByteBufferUtils.getString(buf);
	}

	/**
	 * 
	 * @param is
	 * @param offset
	 * @param length
	 * @return
	 */
	public IoBuffer getReverseA(byte[] is, int offset, int length) {
		for (int i = (offset + length - 1); i >= offset; i--) {
			is[i] = (byte) (buf.get() - 128);
		}
		return this;
	}

	/**
	 * 
	 * @return
	 */
	public ByteBuffer toByteBuffer() {
		return buf;
	}

	/**
	 * 
	 * @return
	 */
	public int opcode() {
		return opcode;
	}

	/**
	 * 
	 * @return
	 */
	public int readableBytes() {
		return buf.capacity() - buf.remaining();
	}

	/**
	 * 
	 * @return
	 */
	public PacketHeader getHeader() {
		return header;
	}

	/**
	 * 
	 * @return
	 */
	public byte[] array() {
		return buf.array();
	}

	/**
	 * @return the packetSize.
	 */
	public int getPacketSize() {
		return packetSize;
	}

	/**
	 * @param packetSize the packetSize to set.
	 */
	public void setPacketSize(int packetSize) {
		this.packetSize = packetSize;
	}

	/**
	 * Gets the bitPosition.
	 * @return The bitPosition.
	 */
	public int getBitPosition() {
		return bitPosition;
	}

}