using System;
using System.Data;
using System.IO;
using NIFLib.Enums;

namespace NIFLib.Core
{
    public class NiHeader
    {
        public string VersionString;
        public NifVersion Version;
        public uint UserVersion;
        public uint UserVersion2;

        public NiString[] BlockTypes;
        public ushort[] BlockTypeIndex;
        public ushort[] BlockSizes;
        public uint NumBlocks;
        public uint UnknownUInt;

        public NiHeader(NiFile file, BinaryReader reader)
        {
            var num = 0;
            var position = reader.BaseStream.Position;
			while (reader.ReadByte() != 10)
			{
				num++;
			}
			reader.BaseStream.Position = position;
			VersionString = new string(reader.ReadChars(num));
			reader.ReadByte();
			var version = reader.ReadUInt32();
			Version = (NifVersion)version;

			// TODO: determine versions needed by any fiesta client and support only those

			if (Version >= NifVersion.VER_20_0_0_4)
			{
				// TODO: support this version! fiesta uses it
				throw new Exception($"NIF Version not supported yet: {version}");
			}
			if (Version >= NifVersion.VER_10_1_0_0)
			{
				UserVersion = reader.ReadUInt32();
			}
			if (Version >= NifVersion.VER_3_3_0_13)
			{
				NumBlocks = reader.ReadUInt32();
			}
			if (Version >= NifVersion.VER_10_1_0_0 && (UserVersion == 10u || UserVersion == 11u))
			{
				UserVersion2 = reader.ReadUInt32();
			}
			if (Version == NifVersion.VER_20_0_0_5)
			{
				throw new VersionNotFoundException("Version 20.0.0.5 not supported!");
			}
			if (Version == NifVersion.VER_10_0_1_2)
			{
				throw new Exception("NIF Version not supported yet!");
			}
			if (Version >= NifVersion.VER_10_1_0_0 && (UserVersion == 10u || UserVersion == 11u))
			{
				throw new Exception("NIF Version not supported yet!");
			}
			if (Version >= NifVersion.VER_10_0_1_0)
			{
				var num2 = reader.ReadUInt16();
				BlockTypes = new NiString[num2];
				for (var i = 0; i < (int)num2; i++)
				{
					BlockTypes[i] = new NiString(file, reader);
				}
				BlockTypeIndex = new ushort[NumBlocks];
				var num3 = 0;
				while (num3 < NumBlocks)
				{
					BlockTypeIndex[num3] = reader.ReadUInt16();
					num3++;
				}
			}
			if (Version >= NifVersion.VER_10_0_1_0)
			{
				UnknownUInt = reader.ReadUInt32();
			}
		}
    }
}