using System;
using System.Text;

namespace Assets.GAMA.net.Message
{
    public unsafe struct FixedByteString
    {
        private const int MaxWordLength = 256;
        private const int MaxWordBytes = MaxWordLength * sizeof(char);

        private fixed byte _word[MaxWordLength];
        public int _currentWordSize;

        public void SetString(string str)
        {
            if (str.Length > MaxWordLength)
                throw new ArgumentException($"str has a byte length of {str.Length} but max declared size for any given word is {MaxWordLength}");
            
            fixed (byte* wordPtr = _word)
            {
                fixed (char* strPtr = str)
                {
                    _currentWordSize = Encoding.UTF8.GetBytes(strPtr, str.Length, wordPtr, MaxWordBytes);
                }
            }
        }

        public string GetString()
        {
            if (_currentWordSize == 0)
                return string.Empty;

            fixed (byte* wordPtr = _word)
            {
                return Encoding.UTF8.GetString(wordPtr, _currentWordSize);
            }
        }
    }
}