namespace Nbt.Test;

using System.IO.Compression;
using K4os.Compression.LZ4.Streams;
using Nbt.Serialization;
using Nbt.Tag;

public static class Program
{
    public static void Main(string[] args)
    {
        WorldFileReading();
    }

    private static void Test()
    {
        const string filePath = @"D:\Minecraft\game\profiles\test\saves\creatif\players\hbdu68.dat";

        INbtTag rootTag;

        using (var inputStream = File.OpenRead(filePath))
        {
            using var reader = NbtReader.Create(inputStream);

            rootTag = reader.ReadNamedTag().Tag;
        }

        // SNbt.Serialize(Console.Out, rootTag, new() { Style = SNbt.SerializationStyle.Indented });
        var s = JsonNbt.Serialize(rootTag);
        var t = JsonNbt.Deserialize(s);

        Console.WriteLine(rootTag.Equals(t));
    }

    private static void WorldFileReading()
    {
        const string inputFile = @"/home/hbecher/Téléchargements/sc-murder/region/r.-3.0.mca";

        // chunk coordinates and last modified timestamps
        // two 4kiB tables (1024 ints)

        var allOfTheShite = new NbtCompound();

        Span<byte> buf4 = stackalloc byte[4];

        using var inputStream = File.OpenRead(inputFile);

        for (var chunkX = 0; chunkX < 32; chunkX++)
        {
            for (var chunkZ = 0; chunkZ < 32; chunkZ++)
            {
                var chunkOffset = (chunkX + (chunkZ << 5)) << 2;

                inputStream.Position = chunkOffset;

                inputStream.Read(buf4);
                buf4.Reverse();
                var rawLoc = BitConverter.ToUInt32(buf4);
                var offset = (int)((rawLoc & ~0xFFu) << 4);
                var size = (int)((rawLoc & 0xFFu) << 12);

                if (offset == 0 && size == 0)
                {
                    continue;
                }

                using (inputStream.Mark())
                {
                    inputStream.Position += 1024 * 4;
                    inputStream.Read(buf4);
                }

                buf4.Reverse();
                var timestamp = BitConverter.ToInt32(buf4);

                using (inputStream.Mark())
                {
                    inputStream.Position = offset;

                    inputStream.Read(buf4);
                    buf4.Reverse();

                    var length = BitConverter.ToInt32(buf4);
                    var compressionMode = inputStream.ReadByte();

                    Stream inflaterStream;
                    bool leaveOpen = false;

                    switch (compressionMode)
                    {
                        case 1:
                            inflaterStream = new GZipStream(inputStream, CompressionMode.Decompress, true);
                            break;

                        case 2:
                            inflaterStream = new ZLibStream(inputStream, CompressionMode.Decompress, true);
                            break;

                        case 3:
                            inflaterStream = inputStream;
                            leaveOpen = true;
                            break;

                        case 4:
                            inflaterStream = LZ4Stream.Decode(inputStream, leaveOpen: true);
                            break;

                        default:
                            continue;
                    }

                    INbtTag tag;
                    using (var nbtReader = new NbtReader(inflaterStream, leaveOpen))
                    {
                        tag = nbtReader.ReadNamedTag().Tag;
                    }

                    allOfTheShite[$"{chunkX}-{chunkZ}"] = tag;
                }
            }
        }

        using var outputStream = File.CreateText(@"/home/hbecher/Téléchargements/a.snbt");

        // SNbt.Serialize(outputStream, allOfTheShite, new() { Style = SNbt.SerializationStyle.Indented });
        JsonNbt.ToJson(outputStream, allOfTheShite);
    }
}