{-# LANGUAGE NoMonomorphismRestriction #-}

module Text.HTML.Moe
(
    module Text.HTML.Moe.Element
  , module Text.HTML.Moe.Attribute
  , (/)
  , render
)
where

import Control.Monad.Writer (tell, execWriter)
import Prelude hiding ((/), (-), head, (>), (.))
import MPS.Light ((-), (>), (.), join, times)
import Text.HTML.Moe.Type hiding (name, value)
import qualified Text.HTML.Moe.Type as T
import Text.HTML.Moe.Element
import Text.HTML.Moe.Attribute

(/) :: MoeUnit
(/) = return ()

render :: MoeUnit -> String
render = execWriter > map render_element > join "\n"

indent_space :: Int
indent_space = 2

render_element' :: Int -> Element -> String
render_element' _ (Raw x)   = x

render_element' n (Data x)  = execWriter - do
  tell - (n * indent_space).times ' '
  tell - escape - x
  tell - "\n"
  
render_element' n x = execWriter - do
  tell - indent
  tell - "<" ++ x.T.name ++ ""
  tell - x.attributes.map render_attribute. join_attribute
  tell - ">"
  tell - "\n"
  
  tell - x.elements.map (render_element' (n+1)) .concat
  
  tell - indent
  tell - "</" ++ x.T.name ++ ">"
  tell - "\n"
  
  where
    join_attribute xs = xs.map (" " ++) .concat
    indent = (n * indent_space).times ' '


render_element :: Element -> String
render_element = render_element' 0

render_attribute :: Attribute -> String
render_attribute x = x.key ++ "=" ++ "\"" ++ x.T.value.escape ++ "\""

escape :: String -> String
escape = escape_html

escape_html :: String -> String
escape_html = concatMap fixChar
  where
    fixChar '&'   = "&amp;"
    fixChar '<'  = "&lt;"
    fixChar '>'  = "&gt;"
    fixChar '\'' = "&#39;"
    fixChar '"'  = "&quot;"
    fixChar x    = [x]