mu3-mods/Extras/SortByInternalDifficulty/MU3.User/patch_UserDetail.cs

using MU3.Client;
using MU3.DB;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace MU3.User;

class patch_UserDetail: UserDetail {
    public extern void orig_copyTo(UserData userDetail);
    public new void copyTo(UserData userDetail) {
        orig_copyTo(userDetail);

        // Attempting to use a profile with InternalLevel sorting enabled
        // causes unpatched clients to crash thanks to enormous incompetence
        // of Sxga's interns.
        // See:
        // * MusicSelectViewDataList._sort1 set
        // * UserDetail.copyFrom()
        if(userDetail.tabSetting == (int)patch_MusicSort1ID.InternalLevel) {
            userDetail.tabSetting = (int)patch_MusicSort1ID.Level;
            stashTabSelection(userDetail.userName, true);
        } else {
            stashTabSelection(userDetail.userName, false);
        }
    }

    public extern void orig_copyFrom(UserData userDetail);
    public new void copyFrom(UserData userDetail) {
        orig_copyFrom(userDetail);

        if(userDetail.tabSetting == (int)patch_MusicSort1ID.Level && isStashedTabSelection(userDetail.userName)) {
            MusicSort1 = (MusicSort1ID)patch_MusicSort1ID.InternalLevel;
        }
    }

    private void stashTabSelection(string user, bool value) {
        var path = getStashPath();
        List<string> entries;
        try {
            entries = File.ReadAllText(path).Split('\n').ToList();
            entries = entries.Where((val) => val.Length > 0 && val != user).ToList();
        } catch(Exception) {
            entries = [];
        }

        if(value) {
            entries.Add(user);
        }

        try {
            File.WriteAllText(path, entries.Aggregate("", (acc, s) => acc + s + "\n").Trim());
        } catch(Exception e) {
            UnityEngine.Debug.Log("Unable to write tab selection: " + e.ToString());
        }
    }

    private bool isStashedTabSelection(string user) {
        try {
            var entries = File.ReadAllText(getStashPath()).Split('\n').ToList();
            return entries.Contains(user);
        } catch(Exception) {
            // Whatever, this is not mission critical
            return false;
        }
    }

    private string getStashPath() {
        using IniFile iniFile = new("mu3.ini");
        var dir = iniFile.getValue("Extra", "CacheDir", ".");
        Directory.CreateDirectory(dir);
        return Path.Combine(dir, "data_tab_cache.txt");
    }
}