{-# LANGUAGE TupleSections #-}
module Graphics.Layout.Inline where

import Data.Text.ParagraphLayout (Paragraph(..), ParagraphOptions(..),
                                    SpanLayout(..), Fragment(..),
                                    ParagraphLayout(..), layoutPlain)
import Data.Text.ParagraphLayout.Rect (Rect, width, height, x_min, y_min)
import Data.Int (Int32)

import Graphics.Layout.Box (Size(..), CastDouble(..), fromDouble)
import Graphics.Layout.CSS.Internal (Font', hbScale)

hbScale' font = (/hbScale font) . fromIntegral
c font = fromDouble . hbScale' font

inlineMinWidth :: Font' -> Paragraph -> Double
inlineMinWidth font self = hbScale' font $ width $ layoutPlain' self 0
inlineNatWidth :: Font' -> Paragraph -> Double
inlineNatWidth font self = hbScale' font $ width $ layoutPlain' self maxBound
inlineHeight :: Font' -> Double -> Paragraph -> Double
inlineHeight font width self =
    hbScale' font $ height $ layoutPlain' self $ round (hbScale font * width)

inlineSize :: (CastDouble x, CastDouble y) => Font' -> Paragraph -> Size x y
inlineSize font self = Size (c font $ width r) (c font $ height r)
  where r = paragraphRect $ layoutPlain self
inlineChildren :: [x] -> Paragraph -> [(x, Fragment)]
inlineChildren vals = concat . map inner . zip vals . spanLayouts . layoutPlain
  where inner (x, SpanLayout y) = map (x,) y

layoutPlain' :: Paragraph -> Int32 -> Rect Int32
layoutPlain' (Paragraph a b c d) width =
    paragraphRect $ layoutPlain $ Paragraph a b c d { paragraphMaxWidth = width }

fragmentSize :: (CastDouble x, CastDouble y) => Font' -> Fragment -> Size x y
fragmentSize font self = Size (c font $ width r) (c font $ height r)
    where r = fragmentRect self
fragmentSize' :: CastDouble x => Font' -> Fragment -> Size x x
fragmentSize' = fragmentSize -- Work around for typesystem.
fragmentPos :: Font' -> (Double, Double) -> Fragment -> (Double, Double)
fragmentPos font (x, y) self =
        (x + hbScale' font (x_min r), y + hbScale' font (y_min r))
    where r = fragmentRect self