-- | This is a pretty-printer for turning the internal representation
--   of generic structured XML documents into the Doc type (which can
--   later be rendered using Text.ParserCombinators.HughesPJ.render).
--   Essentially there is one pp function for each type in
--   Text.Xml.HaXml.Types, so you can pretty-print as much or as little
--   of the document as you wish.

module Text.XML.HaXml.Pretty
  (
  -- * Pretty-print a whole document
    document
  -- ** Just one content
  ,   content
  -- ** Just one tagged element
  ,   element
  -- * Pretty-print just a DTD
  , doctypedecl
  -- ** The prolog
  ,   prolog
  -- ** A content particle description
  ,   cp
  ) where

import Prelude hiding (maybe,either)
import Maybe hiding (maybe)
import List (intersperse)
import Char (isSpace)
import Text.PrettyPrint.HughesPJ
import Text.XML.HaXml.Types

either f g (Left x)  = f x
either f g (Right x) = g x

maybe f Nothing  = empty
maybe f (Just x) = f x

--peref p   = text "%" <> text p <> text ";"

----

document :: Document -> Doc
prolog   :: Prolog -> Doc
xmldecl  :: XMLDecl -> Doc
misc     :: Misc -> Doc
sddecl   :: Bool -> Doc

doctypedecl :: DocTypeDecl -> Doc
markupdecl  :: MarkupDecl -> Doc
extsubset   :: ExtSubset -> Doc
extsubsetdecl :: ExtSubsetDecl -> Doc
cp          :: CP -> Doc

element   :: Element -> Doc
attribute :: Attribute -> Doc                     --etc
content   :: Content -> Doc

----

document (Document p _ e)  = prolog p $$ element e
prolog (Prolog x dtd)      = maybe xmldecl x $$
                             maybe doctypedecl dtd
xmldecl (XMLDecl v e sd)   = text "<?xml version='" <> text v <> text "'" <+>
                             maybe encodingdecl e <+>
                             maybe sddecl sd <+>
                             text "?>"
misc (Comment s)           = text "<!--" <+> text s <+> text "-->"
misc (PI (n,s))            = text "<?" <> text n <+> text s <+> text "?>"
sddecl sd   | sd           = text "standalone='yes'"
            | otherwise    = text "standalone='no'"
doctypedecl (DTD n eid ds) = if null ds then 
                                  hd <> text ">"
                             else hd <+> text " [" $$
                                  vcat (map markupdecl ds) $$ text "]>"
                           where hd = text "<!DOCTYPE" <+> text n <+>
                                      maybe externalid eid
markupdecl (Element e)     = elementdecl e
markupdecl (AttList a)     = attlistdecl a
markupdecl (Entity e)      = entitydecl e
markupdecl (Notation n)    = notationdecl n
markupdecl (MarkupMisc m)  = misc m
--markupdecl (MarkupPE p m)  = peref p
extsubset (ExtSubset t ds) = maybe textdecl t $$
                             vcat (map extsubsetdecl ds)
extsubsetdecl (ExtMarkupDecl m)      = markupdecl m
extsubsetdecl (ExtConditionalSect c) = conditionalsect c
--extsubsetdecl (ExtPEReference p e)   = peref p

element (Elem n as []) = text "<" <> text n <+>
                         fsep (map attribute as) <> text "/>"
element e@(Elem n as cs)
--  | any isText cs    = text "<" <> text n <+> fsep (map attribute as) <>
--                       text ">" <> hcat (map content cs) <>
--                       text "</" <> text n <> text ">"
    | isText (head cs) = text "<" <> text n <+> fsep (map attribute as) <>
                         text ">" <> hcat (map content cs) <>
                         text "</" <> text n <> text ">"
    | otherwise        = let (d,c) = carryelem e empty
                         in d <> c

isText (CString _ _) = True
isText (CRef _)    = True
isText _           = False

carryelem (Elem n as []) c
                       = ( c <>
                           text "<" <> text n <+> fsep (map attribute as)
                         , text "/>")
carryelem e@(Elem n as cs) c
--  | any isText cs    =  ( c <> element e, empty)
    | otherwise        =  let (cs0,d0) = carryscan carrycontent cs (text ">")
                          in
                          ( c <>
                            text "<" <> text n <+> fsep (map attribute as) $$
                            nest 2 (vcat cs0) <> --- $$
                            d0 <> text "</" <> text n
                          , text ">")
carrycontent (CElem e) c   = carryelem e c
carrycontent (CString False s) c = (c <> chardata s, empty)
carrycontent (CString True  s) c = (c <> cdsect s, empty)
carrycontent (CRef r) c    = (c <> reference r, empty)
carrycontent (CMisc m) c   = (c <> misc m, empty)

carryscan :: (a->c->(b,c)) -> [a] -> c -> ([b],c)
carryscan f []     c = ([],c)
carryscan f (a:as) c = let (b, c0) = f a c
                           (bs,c1) = carryscan f as c0
                       in (b:bs, c1)

--carryelem e@(Elem n as cs) c
--  | isText (head cs) =
--        ( start <>
--          text ">" <> hcat (map content cs) <> text "</" <> text n
--        , text ">")
--  | otherwise =
--        let (d,c0) = foldl carrycontent (start, text ">") cs in
--        ( d <> c0 <> text "</" <> text n
--        , text ">")
--  where start = c <> text "<" <> text n <+> fsep (map attribute as)
--
--carrycontent (d,c) (CElem e)   = let (d',c') = carryelem e c in
--                                 (d $$ nest 2 d',       c')
--carrycontent (d,c) (CString _ s) = (d <> c <> chardata s, empty)
--carrycontent (d,c) (CRef r)    = (d <> c <> reference r,empty)
--carrycontent (d,c) (CMisc m)   = (d $$ c <> misc m,     empty)


attribute (n,v)        = text n <> text "=" <> attvalue v
content (CElem e)      = element e
content (CString False s) = chardata s
content (CString True s)  = cdsect s
content (CRef r)       = reference r
content (CMisc m)      = misc m

elementdecl (ElementDecl n cs) = text "<!ELEMENT" <+> text n <+>
                                 contentspec cs <> text ">"
contentspec EMPTY              = text "EMPTY"
contentspec ANY                = text "ANY"
contentspec (Mixed m)          = mixed m
contentspec (ContentSpec c)    = cp c
--contentspec (ContentPE p cs)   = peref p
cp (TagName n m)       = text n <> modifier m
cp (Choice cs m)       = parens (hcat (intersperse (text "|") (map cp cs))) <>
                           modifier m
cp (Seq cs m)          = parens (hcat (intersperse (text ",") (map cp cs))) <>
                           modifier m
--cp (CPPE p c)          = peref p
modifier None          = empty
modifier Query         = text "?"
modifier Star          = text "*"
modifier Plus          = text "+"
mixed  PCDATA          = text "(#PCDATA)"
mixed (PCDATAplus ns)  = text "(#PCDATA |" <+>
                         hcat (intersperse (text "|") (map text ns)) <>
                         text ")*"

attlistdecl (AttListDecl n ds) = text "<!ATTLIST" <+> text n <+>
                                 fsep (map attdef ds) <> text ">"
attdef (AttDef n t d)          = text n <+> atttype t <+> defaultdecl d
atttype  StringType            = text "CDATA"
atttype (TokenizedType t)      = tokenizedtype t
atttype (EnumeratedType t)     = enumeratedtype t
tokenizedtype ID               = text "ID"
tokenizedtype IDREF            = text "IDREF"
tokenizedtype IDREFS           = text "IDREFS"
tokenizedtype ENTITY           = text "ENTITY"
tokenizedtype ENTITIES         = text "ENTITIES"
tokenizedtype NMTOKEN          = text "NMTOKEN"
tokenizedtype NMTOKENS         = text "NMTOKENS"
enumeratedtype (NotationType n)= notationtype n
enumeratedtype (Enumeration e) = enumeration e
notationtype ns                = text "NOTATION" <+>
                                 parens (hcat (intersperse (text "|") (map text ns)))
enumeration ns                 = parens (hcat (intersperse (text "|") (map nmtoken ns)))
defaultdecl  REQUIRED          = text "#REQUIRED"
defaultdecl  IMPLIED           = text "#IMPLIED"
defaultdecl (DefaultTo a f)    = maybe (const (text "#FIXED")) f <+> attvalue a
conditionalsect (IncludeSect i)= text "<![INCLUDE [" <+>
                                 vcat (map extsubsetdecl i) <+> text "]]>"
conditionalsect (IgnoreSect i) = text "<![IGNORE [" <+>
                                 fsep (map ignoresectcontents i) <+> text "]]>"
ignore (Ignore)                = empty
ignoresectcontents (IgnoreSectContents i is)
                               = ignore i <+> vcat (map internal is)
                          where internal (ics,i) = text "<![[" <+>
                                                   ignoresectcontents ics <+>
                                                   text "]]>" <+> ignore i
reference (RefEntity er)       = entityref er
reference (RefChar cr)         = charref cr
entityref n                    = text "&" <> text n <> text ";"
charref c                      = text "&#" <> text (show c) <> text ";"
entitydecl (EntityGEDecl d)    = gedecl d
entitydecl (EntityPEDecl d)    = pedecl d
gedecl (GEDecl n ed)           = text "<!ENTITY" <+> text n <+> entitydef ed <>
                                 text ">"
pedecl (PEDecl n pd)           = text "<!ENTITY %" <> text n <+> pedef pd <>
                                 text ">"
entitydef (DefEntityValue ev)  = entityvalue ev
entitydef (DefExternalID i nd) = externalid i <+> maybe ndatadecl nd
pedef (PEDefEntityValue ev)    = entityvalue ev
pedef (PEDefExternalID eid)    = externalid eid
externalid (SYSTEM sl)         = text "SYSTEM" <+> systemliteral sl
externalid (PUBLIC i sl)       = text "PUBLIC" <+> pubidliteral i <+>
                                 systemliteral sl
ndatadecl (NDATA n)            = text "NDATA" <+> text n
textdecl (TextDecl vi ed)      = text "<?xml" <+> maybe text vi <+>
                                 encodingdecl ed <> text "?>"
extparsedent (ExtParsedEnt t c)= maybe textdecl t <+> content c
extpe (ExtPE t esd)            = maybe textdecl t <+>
                                 vcat (map extsubsetdecl esd)
notationdecl (NOTATION n e)    = text "<!NOTATION" <+> text n <+>
                                 either externalid publicid e <>
                                 text ">"
publicid (PUBLICID p)          = text "PUBLICID" <+> pubidliteral p
encodingdecl (EncodingDecl s)  = text "encoding='" <> text s <> text "'"
nmtoken s                      = text s
attvalue (AttValue esr)        = text "\"" <>
                                 hcat (map (either text reference) esr) <>
                                 text "\""
entityvalue (EntityValue evs)
  | containsDoubleQuote evs    = text "'"  <> hcat (map ev evs) <> text "'"
  | otherwise                  = text "\"" <> hcat (map ev evs) <> text "\""
ev (EVString s)                = text s
--ev (EVPERef p e)               = peref p
ev (EVRef r)                   = reference r
pubidliteral (PubidLiteral s)
    | '"' `elem` s             = text "'" <> text s <> text "'"
    | otherwise                = text "\"" <> text s <> text "\""
systemliteral (SystemLiteral s)
    | '"' `elem` s             = text "'" <> text s <> text "'"
    | otherwise                = text "\"" <> text s <> text "\""
chardata s                     = if all isSpace s then empty else text s
cdsect c                       = text "<![CDATA[" <> chardata c <> text "]]>"

----
containsDoubleQuote evs = any csq evs
    where csq (EVString s) = '"' `elem` s
          csq _            = False
