module Graphics.Layout.Grid where

import Data.Text (Text)
import Data.List (intersperse)
import Graphics.Layout.Box as B

data Grid m n = Grid {
    rows :: [(Name, Either m Double)],
    columns :: [(Name, Either n Double)],
    gap :: Size m n,
    gridBox :: PaddedBox m n
}
data GridItem m n = GridItem {
    startRow :: Int, endRow :: Int, startCol :: Int, endCol :: Int,
    gridItemBox :: PaddedBox m n
}

type Name = Text

cellsForCol :: [GridItem y x] -> Int -> [GridItem y x]
cellsForCol cells ix =
    [cell | cell <- cells, startCol cell == ix, startCol cell /= endCol cell]
cellsForRow :: [GridItem y x] -> Int -> [GridItem y x]
cellsForRow cells ix =
    [cell | cell <- cells, startRow cell == ix, startRow cell /= endRow cell]

{-gridEstWidth :: Grid y Length -> [GridItem y Double] -> Double-}
gridMinWidths :: Double -> Grid y Length -> [GridItem y Double] -> (Double, [Double])
gridMinWidths parent self childs =
    (sum $ intersperse (lowerLength parent $ inline $ gap self) ret, ret)
  where
    ret = map colMinWidth $ enumerate $ map snd $ columns self
    colMinWidth (_, Left (Pixels x)) = x
    colMinWidth (_, Left (Percent x)) = x * parent
    colMinWidth arg@(ix, Left Preferred) =
        maximum $ map (inline . size . gridItemBox) $ cellsForCol childs ix
    colMinWidth (ix, _) =
        maximum $ map (inline . B.min . gridItemBox) $ cellsForCol childs ix
gridNatWidths :: Double -> Grid y Length -> [GridItem y Double] -> (Double, [Double])
gridNatWidths parent self childs =
    (sum $ intersperse (lowerLength parent $ inline $ gap self) ret, ret)
  where
    ret = map colNatWidth $ enumerate $ map snd $ columns self
    colNatWidth (_, Left (Pixels x)) = x
    colNatWidth (_, Left (Percent x)) = x * parent
    colNatWidth arg@(ix, Left Min) =
        maximum $ map (inline . B.min . gridItemBox) $ cellsForCol childs ix
    colNatWidth (ix, _) =
        maximum $ map (inline . size . gridItemBox) $ cellsForCol childs ix
gridMaxWidths :: PaddedBox y Double -> Grid y Length -> [(Double, Double)] -> (Double, [Double])
gridMaxWidths parent self subwidths =
    (sum $ intersperse (lowerLength outerwidth $ inline $ gap self) ret, ret)
  where
    ret = map (colMaxWidth fr) $ zip subwidths $ map snd $ columns self
    fr = (outerwidth - estimate)/(countFRs $ map snd $ columns self)
    outerwidth = inline $ size parent
    estimate = sum $ intersperse (lowerLength outerwidth $ inline $ gap self) $
        map (colMaxWidth 0) $ zip subwidths $ map snd $ columns self
    colMaxWidth _ (_, Left (Pixels x)) = x
    colMaxWidth _ (_, Left (Percent x)) = x
    colMaxWidth _ ((_, nat), Left Preferred) = nat
    colMaxWidth _ ((min, _), Left Min) = min
    colMaxWidth fr (_, Left Auto) = fr
    colMaxWidth fr (_, Right x) = x*fr
    countFRs (Left Auto:rest) = succ $ countFRs rest
    countFRs (Right x:rest) = x + countFRs rest
    countFRs [] = 0
{-gridWidths :: PaddedBox y Double -> Grid y Length -> (Double, [Double])
gridNatHeights :: PaddedBox Length Double -> [GridItem Length Double] -> (Double, [Double])
gridMinHeights :: Double -> Grid Length Double -> (Double, [Double])
gridMaxHeights :: Double -> Grid Length Double -> (Double, [Double])
gridHeights :: Double -> Grid Length Double -> (Double, [Double])
gridPosition :: GridLength Double Double -> [GridItem Double Double] -> [Size Double Double]
gridLayout :: PaddedBox Double Double -> Grid Length Length ->
        [GridItem Length Length] -> Bool ->
        (Grid Double Double, [(Size Double Double, GridItem Double Double)])-}

enumerate = zip [0..]