using System;
using System.IO;

namespace ScreenLogicConnect.Messages
{
    public class HLMessageTypeHelper
    {
        public static string ExtractString(BinaryReader br)
        {
            var len = br.ReadInt32();
            var str = new string(br.ReadChars(len));
            while (len % 4 != 0)
            {
                br.Read();
                len++;
            }

            return str;
        }

        public static string ExtractString(ReadOnlySpan<byte> buf)
        {
            var len = BitConverter.ToInt32(buf);
            int startIdx = sizeof(int);
            Span<char> chars = stackalloc char[len];
            for (int chIdx = 0; chIdx < len; chIdx++)
            {
                chars[chIdx] = (char)buf[startIdx + chIdx];
            }

            return new string(chars);
        }

        public static RgbColor ExtractColor(BinaryReader br)
        {
            return new RgbColor(
                (byte)(br.ReadInt32() & 0xff),
                (byte)(br.ReadInt32() & 0xff),
                (byte)(br.ReadInt32() & 0xff)
                );
        }

        public static int AlignToNext4Boundary(int val)
        {
            int sub = val % 4;
            return sub == 0 ? 0 : 4 - sub;
        }
    }
}