let move x' y' (shape, _, _, height, width) =
    (shape, x', y', height, width)

type Event =
    | ShapeCreated of shape:string * x:int * y:int * id:int64
    | ShapeMoved of x: int * y: int * id: int64
    | ShapeDeleted of id: int64

let folder state event =
    match event with
    | ShapeCreated(shape, x, y, id) ->
        Map.add id (shape ,x, y, 50, 50) state
    | ShapeMoved(x', y', id) ->
        Map.map (fun key shape ->
            if key = id then move x' y' shape
            else shape)
            state
    | ShapeDeleted id ->
        Map.remove id state