{-# LANGUAGE RecordWildCards #-}
module Graphics.Layout.Box where

data Border m n = Border {
    top :: m, bottom :: m, left :: n, right :: n
}
mapX :: (n -> nn) -> Border m n -> Border m nn
mapY :: (m -> mm) -> Border m n -> Border mm n
mapX cb self = self { left = cb $ left self, right = cb $ right self }
mapY cb self = self { top = cb $ top self, bottom = cb $ bottom self }

data Size m n = Size {inline :: n, block :: m} deriving (Eq, Show)

data PaddedBox m n = PaddedBox {
    min :: Size m n,
    max :: Size m n,
    size :: Size m n,
    padding :: Border m n,
    border :: Border m n,
    margin :: Border m n
}
zeroBox :: PaddedBox Double Double
zeroBox = PaddedBox {
    min = Size 0 0,
    max = Size 0 0,
    size = Size 0 0,
    padding = Border 0 0 0 0,
    border = Border 0 0 0 0,
    margin = Border 0 0 0 0
  }
lengthBox = PaddedBox {
    min = Size Auto Auto,
    max = Size Auto Auto,
    size = Size Auto Auto,
    padding = Border zero zero zero zero,
    border = Border zero zero zero zero,
    margin = Border zero zero zero zero
  } where zero = Pixels 0

width PaddedBox {..} = left margin + left border + left padding +
    inline size + right padding + right border + right margin
height PaddedBox {..} = top margin + top border + top padding +
    block size + bottom padding + bottom border + bottom margin
minWidth PaddedBox {..} = left margin + left border + left padding +
    inline min + right padding + right border + right margin
minHeight PaddedBox {..} = top margin + top border + top padding +
    block min + bottom padding + bottom border + bottom margin
maxWidth PaddedBox {..} = left margin + left border + left padding +
    inline max + right padding + right border + right margin
maxHeight PaddedBox {..} = top margin + top border + top padding +
    block max + bottom padding + bottom border + bottom margin

data Length = Pixels Double | Percent Double | Auto | Preferred | Min deriving Eq

lowerLength :: Double -> Length -> Double
lowerLength _ (Pixels x) = x
lowerLength outerwidth (Percent x) = x * outerwidth
lowerLength _ _ = 0