module FontSpec where
import Fudgets(argReadKey,argKey)
import Data.Ix

data FontSpec
  = F { charset :: CharSet,
        weight :: Weight,
	spacing :: Spacing,
	serif :: Serif,
	slant :: Slant,
	fontsize :: FontSize }
    deriving (Bounded,Eq,Ord,Ix)

defaultFont = F IsoLatin1 Medium Proportional Serif Roman fontsize
  where
    fontsize = FontSize (argReadKey "fontsize" 4)

    bigger = adjsize 1
smaller = adjsize (-1)
adjsize n fs@(F {fontsize=fontsize}) = fs{fontsize=adjsize' n fontsize}
adjsize' n (FontSize s) = FontSize (s+n)
setsize n fs = fs{fontsize=n}
setWeight w fs = fs{weight=w}
setCharset s fs = fs{charset=s}
setSlant s fs = fs{slant=s}
setSpacing s fs = fs{spacing=s}
setSerif s fs = fs{serif=s}

data CharSet = IsoLatin1 | AdobeSymbol deriving (Bounded,Eq,Ord,Ix)
data Weight = Medium | Bold deriving (Bounded,Eq,Ord,Ix)
data Spacing = Fixed | Proportional deriving (Bounded,Eq,Ord,Ix)
data Serif = Serif | SansSerif deriving (Bounded,Eq,Ord,Ix)
data Slant = Roman | Italic deriving (Bounded,Eq,Ord,Ix)
newtype FontSize = FontSize Int deriving (Eq,Ord,Ix)

fontname (F {charset=charset,weight=weight,spacing=spacing,serif=serif,slant=slant,fontsize=fontsize}) =
    "-*-"++fmly++wght++slnt++"-*-*"++pxlsz++"-*-*-*-*-*-"++encdng
  where
    (fmly,encdng) =
	case charset of
	   AdobeSymbol -> ("symbol","*-*")
	   _ -> (case (spacing,serif) of
	            (Fixed,Serif) -> fixedFamily
		    (Fixed,SansSerif) -> fixedsansFamily
		    (Proportional,SansSerif) -> sansFamily
		    (Proportional,Serif) -> serifFamily,
		 normalcharset)
    wght = case weight of Bold -> "-bold"; _ -> "-medium"
    slnt = case slant of Italic -> italic; _ -> "-r"
    pxlsz = "-"++show (pixelsize fontsize)
    italic = if fmly `elem` ["courier","helvetica"] then "-o" else "-i"
    serifFamily = argKey "serif" "new century schoolbook"
    sansFamily  = argKey "sans" "helvetica"
    fixedFamily = argKey "fixed" "courier"
    fixedsansFamily = argKey "fixedsans" fixedFamily  --"lucidatypewriter"
    normalcharset = argKey "charset" "iso8859-1"

pixelsize (FontSize n) =
  case n of
    3  -> 12
    4  -> 14
    5  -> 18
    6  -> 24
    7  -> 34
    8  -> 40
    2  -> 10
    1  -> 8
    _  -> if n<3 then 7 else 50

instance Bounded FontSize where
  minBound = FontSize 0
  maxBound = FontSize 9