module Theme where

import Prelude
import CSS (ColorSpace(..), blue, brightness, contrast, darken, desaturate, isLight, lighten, mix, rotateHue, toHexString)
import Color (Color)
import Data.Foldable (intercalate)
import Data.Symbol (SProxy(..))
import Record.Builder as RB
import Theme.Types (Theme, CSSTheme)

increaseContrast ∷ Color -> Color -> Color
increaseContrast contrastWith = go 0
  where
  modify = if isLight contrastWith then darken else lighten

  go i col =
    if contrast contrastWith col >= 7.5 || i >= 20 then
      col
    else
      go (i + 1) (modify 0.1 col)

f ∷ ∀ fieldName. SProxy fieldName
f = SProxy

fromTheme ∷ Theme -> CSSTheme
fromTheme theme =
  RB.build
    ( {- background -} RB.modify (f ∷ _ "backgroundColour") toHexString
        >>> RB.modify (f ∷ _ "codeBackgroundColour") toHexString
        >>> RB.insert (f ∷ _ "backgroundColourLighter")
            (theme.backgroundColour # lighter >>> toHexString)
        >>> RB.modify (f ∷ _ "interfaceColour") toHexString
        >>> RB.insert (f ∷ _ "interfaceColourLighter")
            (theme.interfaceColour # lighter >>> toHexString)
        >>> RB.insert (f ∷ _ "interfaceColourLightest")
            (theme.interfaceColour # lighter >>> lighter >>> toHexString)
        >>> RB.insert (f ∷ _ "interfaceColourDarker")
            (theme.interfaceColour # darker >>> toHexString)
        >>> RB.insert (f ∷ _ "interfaceColourDarkest")
            (theme.interfaceColour # darker >>> darker >>> toHexString)
        -- foreground
        
        >>> RB.modify (f ∷ _ "textColour") toHexString
        >>> RB.insert (f ∷ _ "textColourLighter")
            (theme.textColour # lighter >>> toHexString)
        >>> RB.insert (f ∷ _ "textColourLightest")
            (theme.textColour # lighter >>> lighter >>> toHexString)
        >>> RB.insert (f ∷ _ "textColourDarker")
            (theme.textColour # darker >>> toHexString)
        >>> RB.insert (f ∷ _ "textColourDarkest")
            (theme.textColour # darker >>> darker >>> toHexString)
        -- highlight
        
        >>> RB.modify (f ∷ _ "highlightColour") toHexString
        >>> RB.insert (f ∷ _ "highlightColourDark")
            (theme.highlightColour # darken 0.2 # rotateHue (-10.0) # toHexString)
        -- altHighlight
        
        >>> RB.modify (f ∷ _ "altHighlightColour") toHexString
        >>> RB.insert (f ∷ _ "altHighlightColourDark")
            (theme.altHighlightColour # darken 0.2 # toHexString)
        -- palette
        
        >>> RB.modify (f ∷ _ "yellow") toHexString
        >>> RB.modify (f ∷ _ "green") toHexString
        >>> RB.modify (f ∷ _ "pink") toHexString
        >>> RB.modify (f ∷ _ "orange") toHexString
        >>> RB.modify (f ∷ _ "turquoise") toHexString
        >>> RB.modify (f ∷ _ "red") toHexString
        >>> RB.modify (f ∷ _ "blue") toHexString
        -- fonts
        
        >>> RB.modify (f ∷ _ "textFontFamily") (intercalate ",")
        >>> RB.modify (f ∷ _ "headingFontFamily") (intercalate ",")
        >>> RB.insert (f ∷ _ "isLight") isLightTheme
    )
    theme
  where
  isLightTheme = isLight theme.backgroundColour

  yellower ∷ Color -> Color
  yellower col =
    if brightness col > 0.8 then
      lighten 0.02 col
    else
      col
        # lighten 0.1
        # desaturate 0.03

  bluer col =
    mix HSL col blue 0.05
      # darken 0.1
      # desaturate 0.03

  lighter ∷ Color -> Color
  lighter = yellower

  darker ∷ Color -> Color
  darker = bluer