module Dodge.HeldScroll (
    doHeldScroll,
    canHeldScrollAttach,
) where

import Control.Lens hiding ((<|), (|>))
import Data.Sequence
import Dodge.Data.World

doHeldScroll :: Int -> ScrollAttachParams -> Float -> World -> World
doHeldScroll invid hs x w  = case hs of
    ZoomScrollParams{}-> w
    CharScrollParams{} -> w & cWorld . lWorld . creatures . ix 0 . crInv . ix invid . itUse . attachParams . scrollAttachParams . scrollChar %~ cycleSignum x

cycleSignum :: Float -> Seq a -> Seq a
cycleSignum x
    | x > 0 = cycleL
    | otherwise = cycleR

cycleL, cycleR :: Seq a -> Seq a
cycleL (x :<| xs) = xs |> x
cycleL xs = xs
cycleR (xs :|> x) = x <| xs
cycleR xs = xs

canHeldScrollAttach :: Item -> ScrollAttachParams -> Bool
canHeldScrollAttach _ _ = True