--------------------------------------------------------------------------------
-- | Theme for XMonad and Xmobar

module XMonad.Internal.Theme
  ( baseColor
  , bgColor
  , fgColor
  , bordersColor
  , warningColor
  , errorColor
  , selectedFgColor
  , selectedBgColor
  , selectedBordersColor
  , backdropBaseColor
  , backdropFgColor
  , backdropTextColor
  , blend'
  , darken'
  , Slant(..)
  , Weight(..)
  , FontData(..)
  , FontBuilder
  , buildFont
  , defFontData
  , defFontDep
  , defFontTree
  , fontFeature
  , fontDependency
  , tabbedTheme
  , tabbedFeature
  , promptTheme
  ) where

import           Data.Char
import           Data.Colour
import           Data.Colour.SRGB
import           Data.List

import           System.Exit

import           XMonad.Internal.Dependency
import           XMonad.Internal.Process
import           XMonad.Internal.Shell
import qualified XMonad.Layout.Decoration   as D
import qualified XMonad.Prompt              as P

--------------------------------------------------------------------------------
-- | Colors - vocabulary roughly based on GTK themes

baseColor :: String
baseColor = "#f7f7f7"

bgColor :: String
bgColor = "#d6d6d6"

fgColor :: String
fgColor = "#2c2c2c"

bordersColor :: String
bordersColor = darken' 0.3 bgColor

warningColor :: String
warningColor = "#ffca28"

errorColor :: String
errorColor = "#e53935"

selectedFgColor :: String
selectedFgColor = "#ffffff"

selectedBgColor :: String
selectedBgColor = "#4a79c7"

selectedBordersColor :: String
selectedBordersColor = "#4a79c7"

backdropBaseColor :: String
backdropBaseColor = baseColor

backdropTextColor :: String
backdropTextColor = blend' 0.95 fgColor backdropBaseColor

backdropFgColor :: String
backdropFgColor = blend' 0.75 fgColor bgColor

--------------------------------------------------------------------------------
-- | Color functions

blend' :: Float -> String -> String -> String
blend' wt c0 c1 = sRGB24show $ blend wt (sRGB24read c0) (sRGB24read c1)

darken' :: Float -> String -> String
darken' wt = sRGB24show . darken wt . sRGB24read

--------------------------------------------------------------------------------
-- | Fonts

data Slant = Roman
    | Italic
    | Oblique
    deriving (Eq, Show)

data Weight = Light
    | Medium
    | Demibold
    | Bold
    | Black
    deriving (Eq, Show)

data FontData = FontData
    { weight    :: Maybe Weight
    , slant     :: Maybe Slant
    , size      :: Maybe Int
    , pixelsize :: Maybe Int
    , antialias :: Maybe Bool
    }

type FontBuilder = FontData -> String

buildFont :: Maybe String -> FontData -> String
buildFont Nothing _ = "fixed"
buildFont (Just fam) FontData { weight = w
                            , slant = l
                            , size = s
                            , pixelsize = p
                            , antialias = a
                            }
  = intercalate ":" $ ["xft", fam] ++ elems
  where
    elems = [ k ++ "=" ++ v | (k, Just v) <- [ ("weight", showLower w)
                                             , ("slant", showLower l)
                                             , ("size", showLower s)
                                             , ("pixelsize", showLower p)
                                             , ("antialias", showLower a)
                                             ]
                            ]
    showLower :: Show a => Maybe a -> Maybe String
    showLower = fmap (fmap toLower . show)

fallbackFont :: FontBuilder
fallbackFont = buildFont Nothing

testFont :: String -> IO (Result FontBuilder)
testFont fam = do
  (rc, _, _) <- readCreateProcessWithExitCode' (shell cmd) ""
  return $ case rc of
    ExitSuccess -> Right $ PostPass (buildFont $ Just fam) []
    _           -> Left [msg]
  where
    msg = unwords ["font family", qFam, "not found"]
    cmd = fmtCmd "fc-list" ["-q", qFam]
    qFam = singleQuote fam

fontDependency :: String -> IODependency FontBuilder
fontDependency fam =
  IORead (unwords ["test if font", singleQuote fam, "exists"]) $ testFont fam

fontTree :: String -> IOTree FontBuilder
fontTree fam = Or (Only $ fontDependency fam) (Only $ IOConst fallbackFont)

fontFeature :: String -> String -> Always FontBuilder
fontFeature n fam = always1 n sfn root def
  where
    sfn = "Font family for " ++ fam
    root = IORoot id $ fontTree fam
    def = buildFont Nothing

--------------------------------------------------------------------------------
-- | Default font and data

defFontData :: FontData
defFontData = FontData
  { size = Just 10
  , antialias = Just True
  , weight = Nothing
  , slant = Nothing
  , pixelsize = Nothing
  }

defFontDep :: IODependency FontBuilder
defFontDep = fontDependency "DejaVu Sans"

defFontTree :: IOTree FontBuilder
defFontTree = fontTree "DejaVu Sans"

--------------------------------------------------------------------------------
-- | Complete themes

tabbedTheme :: FontBuilder -> D.Theme
tabbedTheme fb = D.def
  { D.fontName              = fb $ defFontData { weight = Just Bold }

  , D.activeTextColor       = fgColor
  , D.activeColor           = bgColor
  , D.activeBorderColor     = bgColor

  , D.inactiveTextColor     = backdropTextColor
  , D.inactiveColor         = backdropFgColor
  , D.inactiveBorderColor   = backdropFgColor

  , D.urgentTextColor       = darken' 0.5 errorColor
  , D.urgentColor           = errorColor
  , D.urgentBorderColor     = errorColor

  -- this is in a newer version
  -- , D.activeBorderWidth     = 0
  -- , D.inactiveBorderWidth   = 0
  -- , D.urgentBorderWidth     = 0

  , D.decoHeight            = 20
  , D.windowTitleAddons     = []
  , D.windowTitleIcons      = []
  }

tabbedFeature :: Always D.Theme
tabbedFeature = Always "theme for tabbed windows" $ Option sf fallback
  where
    sf = Subfeature niceTheme "theme with nice font" Error
    niceTheme = IORoot tabbedTheme $ Only defFontDep
    fallback = Always_ $ FallbackAlone $ tabbedTheme fallbackFont

promptTheme :: FontBuilder -> P.XPConfig
promptTheme fb = P.def
  { P.font              = fb $ defFontData { size = Just 12 }
  , P.bgColor           = bgColor
  , P.fgColor           = fgColor
  , P.fgHLight          = selectedFgColor
  , P.bgHLight          = selectedBgColor
  , P.borderColor       = bordersColor
  , P.promptBorderWidth = 1
  , P.height            = 35
  , P.position          = P.CenteredAt 0.5 0.5
  }