module HtmlPrinter(printHtml,printTag) where
import Html hiding (implicit)
import HtmlTags
import TagAttrs hiding (implicit)
import HtmlEntities(encode)
import Data.Char(isAlpha,isDigit)

printHtml :: Html -> String
printHtml = concatMap printItem
  where
    printItem i =
      case i of
        HtmlCommand tag -> printTag tag
	HtmlContext tag@(name,_) html ->
	  case impl of
	    Implicit    -> printHtml html
	    ImplicitEnd -> printTag (name,attrs) ++ printHtml html
	    Explicit    -> printTag tag ++ printHtml html ++ printEndTag tag
          where (impl,attrs) = implicit tag
--	HtmlChars s -> s  -- escape special chars !?
	HtmlChars s -> encode s -- yes
	HtmlGarbage tag -> printGarb tag

printTag :: HtmlTag -> String
printTag = pt ""
printEndTag (n,_) = pt "/" (n,noAttrs)
--printGarb (n,as) = pt' "?" n as
printGarb (n,as) = pt' "" n as

pt s (n,as) = pt' s (show n) as
pt' s n as = "<"++s++n++printAttrs as++">"
  where
    printAttrs (TA as) = concatMap printAttr as
    --printAttr (n,"") = " "++n
    --printAttr (n,v) | n==v = " "++n
    printAttr (n,v) = " "++n++"="++optquote v

    optquote "" = quote ""
    optquote v = if all isNoQuote v then v else quote v

    isNoQuote c = isAlpha c || isDigit c || c=='.' || c=='-'

    quote s = q++s++q
    q = ['"']
--------------------------------------------------------------------------------

data Implicit = Explicit | ImplicitEnd | Implicit

implicit (name,attrs0) =
    case attr1 of
      "implicit" -> (Implicit,attrs)
      "implicitend" -> (ImplicitEnd,attrs)
      _ -> case name of
             LI -> implicitend
             DT -> implicitend
             DD -> implicitend
             TR -> implicitend
             TH -> implicitend
             TD -> implicitend
             _ -> (Explicit,attrs0)
        where implicitend = (ImplicitEnd,attrs0)
  where
    (attr1,attrs) = case attrs0 of
	              TA ((a,_):attrs) -> (a,TA attrs)
		      _ -> ("",attrs0)