namespace GUI
{
	public static class CheckUtil
	{
		public static void Func_sum_check(byte[] data, int offset, int len, byte[] check)
		{
			int i;
			ushort result = 0;
			for (i = 0; i < len; i++)
			{
				result += data[i + offset];
			}
			check[0] = (byte)result;
			check[1] = (byte)(result >> 8);
		}
		
		public static void Func_Xor_check(byte[] data, int offset, int len, out byte check)
		{
			int i;
			check = data[offset];
			for (i = 1; i < len; i++)
			{
				check ^= data[i + offset];
			}
		}

		public static bool ArrayEquals<T>(this T[] src, T[] other, int offset = 0)
		{
			for (int i = 0; i < src.Length; i++)
				if (!src[i].Equals(other[i + offset]))
					return false;
			return true;
		}

		public static T[] ArrayCombine<T>(this T[] src, T[] other)
		{
			T[] newT = new T[src.Length + other.Length];
			for (int i = 0; i < src.Length; i++) newT[i] = src[i];
			for (int i = 0; i < other.Length; i++) newT[i + src.Length] = other[i];
			return newT;
		}

		public static bool CheckData(this byte[] data)
        {
			byte[] check2 = new byte[2];
			Func_sum_check(data, 0, data.Length - 3, check2);
			if (!check2.ArrayEquals(data, data.Length - 3)) return false;
			Func_Xor_check(data, 0, data.Length - 1, out byte check);
			if (check != data[^1]) return false;
			return true;
        }

		public static byte[] PackData(this byte[] data)
		{
			byte[] check2 = new byte[2];
			Func_sum_check(data, 0, data.Length, check2);
			byte[] withSumCheck = data.ArrayCombine(check2);
			Func_Xor_check(withSumCheck, 0, withSumCheck.Length, out byte last);
			return withSumCheck.ArrayCombine(new byte[1] { last });
		}

		public static byte t(this bool b) => (byte)(b ? 1 : 0);
	}
}