BeatSaber/Assets/Script/BeatSageConverter.cs

using System.Collections.Generic;
using UnityEngine;

[System.Serializable]
public class SongMetadata
{
    public string title;
    public string artist;
    public float  bpm;
}

[System.Serializable]
public class BeatSageInfoDat
{
    public string _songName;
    public string _songAuthorName;
    public float  _beatsPerMinute;
}

[System.Serializable]
public class BeatSageRoot
{
    public string          _version;
    public List<BeatSageNote> _notes;
}

[System.Serializable]
public class BeatSageNote
{
    public float _time;
    public int   _lineIndex;
    public int   _lineLayer;
    public int   _type;
    public int   _cutDirection;
}

public static class BeatSageConverter
{
    private static readonly bool LogConversions = false;

    public static List<NoteData> Convert(string rawJson, float bpm)
    {
        var result = new List<NoteData>();

        var root = JsonUtility.FromJson<BeatSageRoot>(rawJson);
        if (root?._notes == null)
        {
            Debug.LogWarning("[BeatSageConverter] Parse failed or no notes.");
            return result;
        }

        foreach (var note in root._notes)
        {
            // Only process normal notes (0=red, 1=blue); skip bombs (3) etc.
            if (note._type != 0 && note._type != 1) continue;

            result.Add(new NoteData
            {
                time         = (note._time * 60f) / bpm,
                position     = note._lineIndex,
                lineLayer    = note._lineLayer,
                colorType    = note._type,
                cutDirection = note._cutDirection,
            });
        }

        if (LogConversions)
            Debug.Log($"[BeatSageConverter] Converted {result.Count} notes.");
        return result;
    }

    public static string ToMapJson(List<NoteData> notes)
    {
        return JsonUtility.ToJson(new MapData { target = notes }, true);
    }

    public static SongMetadata ParseInfoDat(string json)
    {
        var info = JsonUtility.FromJson<BeatSageInfoDat>(json);
        if (info == null) return null;
        return new SongMetadata
        {
            title  = (info._songName        ?? "").Trim(),
            artist = (info._songAuthorName  ?? "").Trim(),
            bpm    = info._beatsPerMinute,
        };
    }
}