module Bound (boundPoints
    ,boundPointsRect) where

import qualified Control.Foldl as L
import Control.Lens
import Geometry

---- NSEW
boundPoints :: [Point2] -> Maybe (Float, Float, Float, Float)
{-# INLINE boundPoints #-}
boundPoints =
    f
        . L.fold
            ( (,,,)
                <$> L.premap (^?! _2) L.maximum
                <*> L.premap (^?! _2) L.minimum
                <*> L.premap (^?! _1) L.maximum
                <*> L.premap (^?! _1) L.minimum
            )
  where
    f (mn, ms, me, mw) = (,,,) <$> mn <*> ms <*> me <*> mw

boundPointsRect :: [Point2] -> Maybe (Point2,Point2)
boundPointsRect ps = do
    (n,s,e,w) <- boundPoints ps
    return (V2 w s, V2 e n)