public static partial class DisplayFusionFunction {

  record HistoricPosition(
    bool Maximized, 
    int Monitor, 
    Point Cell, 
    Point RowsCols, 
    Rectangle Pos, 
    int? NumKey = null, 
    bool? Ctrl = null
  );

  class ExpirableEntryList(uint Age): List<HistoricPosition> { 
    public uint Age { get; set; } = Age;
  };

  class Context: Dictionary<uint, ExpirableEntryList> {
    const uint MAX_AGE = 12; // 12hrs
    static readonly DateTime Epoch = new DateTime(2025, 1, 1);
    
    static uint Now => (uint)DateTime.Now.Subtract(Epoch).TotalHours;
    
    static uint ToKey(IntPtr whnd) => unchecked((uint)whnd.ToInt32());
    
    public ExpirableEntryList Get(IntPtr whnd) => this.TryGetValue(ToKey(whnd), out var list) ? list : null;
    
    public void Load() {
      this.Clear();
      uint now = (uint)DateTime.Now.Subtract(Epoch).TotalHours;
      var dict = JsonSerializer.Deserialize<Dictionary<uint, ExpirableEntryList>>(
        BFS.ScriptSettings.ReadValue("NumpadPositions.WindowHistory") ?? "{}"
      );
      foreach(var (Key, Value) in dict) {
        if(Value.Age < now - MAX_AGE) continue; # Skip expired entries
        this.Add(Key, Value);
      }
    }

    public void AddRecord(IntPtr whnd, HistoricPosition entry) {
      var list = this.Get(whnd);
      if(list != null) {
        list.Age = Now;
        list.Add(entry);
      } else { 
        this.Add(ToKey(whnd), new ExpirableEntryList(now) { entry });
      }
      BFS.ScriptSettings.WriteValue("NumpadPositions.WindowHistory", JsonSerializer.Serialize(this));
    }
  }
}