----------------------------------------------------------------------
-- |
-- Module      : PrSRGS
-- Maintainer  : BB
-- Stability   : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 2005/11/01 20:09:04 $ 
-- > CVS $Author: bringert $
-- > CVS $Revision: 1.2 $
--
-- This module prints a CFG as an SRGS XML grammar.
--
-- FIXME: remove \/ warn \/ fail if there are int \/ string literal
-- categories in the grammar
-----------------------------------------------------------------------------

module GF.Speech.PrSRGS (srgsXmlPrinter) where

import GF.Data.Utilities
import GF.Speech.SRG
import GF.Infra.Ident

import GF.Formalism.CFG
import GF.Formalism.Utilities (Symbol(..), NameProfile(..), Profile(..), forestName)
import GF.Conversion.Types
import GF.Infra.Print
import GF.Infra.Option
import GF.Probabilistic.Probabilistic (Probs)

import Data.Char (toUpper,toLower)

data XML = Data String | Tag String [Attr] [XML] | Comment String
 deriving (Eq,Show)

type Attr = (String,String)

srgsXmlPrinter :: Ident -- ^ Grammar name
	       -> Options 
               -> Bool  -- ^ Whether to include semantic interpretation 
	       -> Maybe Probs
	       -> CGrammar -> String
srgsXmlPrinter name opts sisr probs cfg = prSrgsXml sisr srg ""
    where srg = makeSRG name opts probs cfg

prSrgsXml :: Bool -> SRG -> ShowS
prSrgsXml sisr (SRG{grammarName=name,startCat=start,
               origStartCat=origStart,grammarLanguage=l,rules=rs})
    = header . showsXML xmlGr
    where
    header = showString "<?xml version=\"1.0\" encoding=\"UTF-8\" ?>"
    root = prCat start
    xmlGr = grammar root l ([meta "description" 
                             ("SRGS XML speech recognition grammar for " ++ name
                              ++ ". " ++ "Original start category: " ++ origStart),
                             meta "generator" "GF"]
			  ++ map ruleToXML rs)
    ruleToXML (SRGRule cat origCat alts) = 
	rule (prCat cat) (comments ["Category " ++ origCat] ++ [prRhs alts])
    prRhs rhss = oneOf (map prAlt rhss)
    prAlt (SRGAlt p n@(Name _ pr) rhs) 
          | sisr = prodItem (Just n) p (map (uncurry (symItem pr)) (numberCats 0 rhs))
          | otherwise = prodItem Nothing p (map (\s -> symItem [] s 0) rhs)
    numberCats _ [] = []
    numberCats n (s@(Cat _):ss) = (s,n):numberCats (n+1) ss
    numberCats n (s:ss) = (s,n):numberCats n ss

rule :: String -> [XML] -> XML
rule i = Tag "rule" [("id",i)]

prodItem :: Maybe Name -> Maybe Double -> [XML] -> XML
prodItem n mp xs = Tag "item" w (t++cs)
  where 
  w = maybe [] (\p -> [("weight", show p)]) mp
  t = maybe [] prodTag n
  cs = case xs of
	       [Tag "item" [] xs'] -> xs'
	       _ -> xs

prodTag :: Name -> [XML]
prodTag (Name f prs) = [Tag "tag" [] [Data (join "; " ts)]]
  where 
  ts = ["$.name=" ++ showFun f] ++
       ["$.arg" ++ show n ++ "=" ++ argInit (prs!!n) 
            | n <- [0..length prs-1]]
  argInit (Unify _) = metavar
  argInit (Constant f) = maybe metavar showFun (forestName f)
  showFun = show . prIdent
  metavar = show "?"

symItem :: [Profile a] -> Symbol String Token -> Int -> XML
symItem prs (Cat c) x = Tag "item" [] ([Tag "ruleref" [("uri","#" ++ prCat c)] []]++t)
  where 
  t = if null ts then [] else [Tag "tag" [] [Data (join "; " ts)]]
  ts = ["$.arg" ++ show n ++ "=$$" 
            | n <- [0..length prs-1], inProfile x (prs!!n)]
symItem _ (Tok t) _ = Tag "item" [] [Data (showToken t)]

inProfile :: Int -> Profile a -> Bool
inProfile x (Unify xs) = x `elem` xs
inProfile _ (Constant _) = False

prCat :: String -> String
prCat c = c -- FIXME: escape something?

showToken :: Token -> String
showToken t = t -- FIXME: escape something?

oneOf :: [XML] -> XML
oneOf [x] = x
oneOf xs = Tag "one-of" [] xs

grammar :: String  -- ^ root
        -> String -- ^languageq
	-> [XML] -> XML
grammar root l = Tag "grammar" [("xml:lang", l),
                                ("xmlns","http://www.w3.org/2001/06/grammar"),
			        ("version","1.0"),
			        ("mode","voice"),
			        ("root",root)]

meta :: String -> String -> XML
meta n c = Tag "meta" [("name",n),("content",c)] []

comments :: [String] -> [XML]
comments = map Comment

showsXML :: XML -> ShowS
showsXML (Data s) = showString s
showsXML (Tag t as []) = showChar '<' . showString t . showsAttrs as . showString "/>"
showsXML (Tag t as cs) = 
    showChar '<' . showString t . showsAttrs as . showChar '>' 
		 . concatS (map showsXML cs) . showString "</" . showString t . showChar '>'
showsXML (Comment c) = showString "<!-- " . showString c . showString " -->"

showsAttrs :: [Attr] -> ShowS
showsAttrs = concatS . map (showChar ' ' .) . map showsAttr

showsAttr :: Attr -> ShowS
showsAttr (n,v) = showString n . showString "=\"" . showString (escape v) . showString "\""

-- FIXME: escape strange charachters with &#xxx;
escape :: String -> String
escape = concatMap escChar
  where
  escChar c | c `elem` ['"','\\'] = '\\':[c]
            | otherwise = [c]