using System.IO;
using System.Text;

namespace BeyondTools.SparkBuffer.Extensions
{
    public static class BinaryReaderExtensions
    {
        public static SparkType ReadSparkType(this BinaryReader reader)
            => (SparkType)reader.ReadByte();

        public static long Seek(this BinaryReader reader, long pos, SeekOrigin seekOrigin = SeekOrigin.Begin)
            => reader.BaseStream.Seek(pos, seekOrigin);

        public static string ReadSparkBufferString(this BinaryReader reader)
        {
            using MemoryStream buffer = new();
            while (true)
            {
                byte b = reader.ReadByte();
                if (b == 0)
                    break;
                buffer.WriteByte(b);
            }

            return Encoding.UTF8.GetString(buffer.ToArray());
        }

        public static string ReadSparkBufferStringOffset(this BinaryReader reader)
        {
            var stringOffset = reader.ReadInt32();
            if (stringOffset == -1)
                return string.Empty;

            var oldPosition = reader.BaseStream.Position;

            reader.Seek(stringOffset);
            var tmp = reader.ReadSparkBufferString();

            reader.BaseStream.Position = oldPosition;
            return tmp;
        }

        public static void Align4Bytes(this BinaryReader reader)
            => reader.Seek((reader.BaseStream.Position - 1) + (4 - ((reader.BaseStream.Position - 1) % 4)));
    }
}