using System;
using System.Text;

namespace Test {
	public class ByteBuffer {
		public int readerIndex { get; set; }
		public int writerIndex { get; set; }
		private byte[] buffer;
		private int capacity;

		public ByteBuffer() {
			readerIndex = 0;
			writerIndex = 0;
			capacity = 32;
			buffer = new byte[capacity];
		}

		private void resizeIfNeeded(int bytesCount) {
			if (writerIndex + bytesCount < capacity) {
				return;
			}

			capacity = (int)(capacity * 1.7f) + bytesCount;
			var newBuffer = new byte[capacity];
			Array.Copy(buffer, newBuffer, buffer.Length);
			buffer = newBuffer;
		}

		public void writeByte(int value) {
			resizeIfNeeded(1);

			buffer[writerIndex++] = (byte) (value & 0x000000FF);
		}

		public void writeWord(int value) {
			resizeIfNeeded(2);

			buffer[writerIndex++] = (byte) (value & 0x000000FF);
			buffer[writerIndex++] = (byte) ((value >> 8) & 0x000000FF);
		}

		public void writeDword(int value) {
			resizeIfNeeded(4);

			buffer[writerIndex++] = (byte) (value & 0x000000FF);
			buffer[writerIndex++] = (byte) ((value >> 8) & 0x000000FF);
			buffer[writerIndex++] = (byte) ((value >> 16) & 0x000000FF);
			buffer[writerIndex++] = (byte) ((value >> 24) & 0x000000FF);
		}

		public void writeQword(ulong value) {
			resizeIfNeeded(8);

			buffer[writerIndex++] = (byte) (value & 0x00000000000000FF);
			buffer[writerIndex++] = (byte) ((value >> 8) & 0x00000000000000FF);
			buffer[writerIndex++] = (byte) ((value >> 16) & 0x00000000000000FF);
			buffer[writerIndex++] = (byte) ((value >> 24) & 0x00000000000000FF);
			buffer[writerIndex++] = (byte) ((value >> 32) & 0x00000000000000FF);
			buffer[writerIndex++] = (byte) ((value >> 40) & 0x00000000000000FF);
			buffer[writerIndex++] = (byte) ((value >> 48) & 0x00000000000000FF);
			buffer[writerIndex++] = (byte) ((value >> 56) & 0x00000000000000FF);
		}

		public void writeByteArray(byte[] bytes) {
			var length = bytes.Length;

			//string length + string will be written to the buffer
			resizeIfNeeded(length + 4);

			writeDword(length);
			Array.Copy(bytes, 0, buffer, writerIndex, length);

			writerIndex += length;
		}

		public void writeString(string value) {
			var length = value.Length;

			//string length + string will be written to the buffer
			resizeIfNeeded(length + 4);

			writeByteArray(Encoding.UTF8.GetBytes(value));
		}

		public int readByte() {
			return buffer[readerIndex++];
		}

		public int readWord() {
			int value = 0;

			value |= buffer[readerIndex++];
			value |= buffer[readerIndex++] << 8;

			return value;
		}

		public int readDword() {
			int value = 0;

			value |= buffer[readerIndex++];
			value |= buffer[readerIndex++] << 8;
			value |= buffer[readerIndex++] << 16;
			value |= buffer[readerIndex++] << 24;

			return value;
		}

		public ulong readQword() {
			ulong value = 0;

			value |= (ulong)buffer[readerIndex++];
			value |= (ulong)buffer[readerIndex++] << 8;
			value |= (ulong)buffer[readerIndex++] << 16;
			value |= (ulong)buffer[readerIndex++] << 24;
			value |= (ulong)buffer[readerIndex++] << 32;
			value |= (ulong)buffer[readerIndex++] << 40;
			value |= (ulong)buffer[readerIndex++] << 48;
			value |= (ulong)buffer[readerIndex++] << 56;

			return value;
		}

		public byte[] readByteArray() {
			var bytesCount = readDword();
			var bytes = new byte[bytesCount];

			Array.Copy(buffer, readerIndex, bytes, 0, bytesCount);
			readerIndex += bytesCount;

			return bytes;
		}

		public string readString() {
			return Encoding.UTF8.GetString(readByteArray());
		}
	}
}