--  Copyright 2012 Wolfgang Thaller.
--
--  This file is part of Retro68.
--
--  Retro68 is free software: you can redistribute it and/or modify
--  it under the terms of the GNU General Public License as published by
--  the Free Software Foundation, either version 3 of the License, or
--  (at your option) any later version.
--
--  Retro68 is distributed in the hope that it will be useful,
--  but WITHOUT ANY WARRANTY; without even the implied warranty of
--  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
--  GNU General Public License for more details.
--
--  You should have received a copy of the GNU General Public License
--  along with Retro68.  If not, see <http://www.gnu.org/licenses/>.

module Main where

import Text.ParserCombinators.Parsec
import Text.ParserCombinators.Parsec.Language
import Text.ParserCombinators.Parsec.Token
import System.Directory
import System.FilePath
import Control.Monad(guard)
import Data.List(isSuffixOf)
import qualified Control.Exception
import System.IO
import qualified Text.PrettyPrint.HughesPJ as PP
import Text.PrettyPrint.HughesPJ((<+>),(<>),($$),($+$))
import Data.Char
import Numeric
import Data.Maybe(isJust)
import Control.Monad.State
import qualified Data.Map as Map
import System.Environment(getArgs)

data Item = CharItem Char
          | IgnoredItem
          | FunctionItem String String [String] [String] [Integer] (Maybe ParameterRegs)
          | PragmaParameterItem String ParameterRegs
          deriving(Show)

type Register = String
data ParameterRegs = ParameterRegs (Maybe Register) [Register]
   deriving(Show)

tp = makeTokenParser javaStyle

item  =   (char '\r' >> return (CharItem '\n'))
      <|> try externApiDeclaration
      <|> try (string "= 0x4E90" >> return IgnoredItem)
      <|> try (string "= 0x4E91" >> return IgnoredItem)
      <|> try pragmaParameter
      <|> fmap CharItem anyChar

balancedText stopAtComma = fmap (foldr ($) "") $
      many (fmap (++) paranthesized <|> fmap (:) (noneOf (if stopAtComma then "()," else "()")))
   where paranthesized = char '(' >> balancedText False >>= \xs -> char ')' >> return ('(' : xs ++ ")")


trim = dropWhile isSpace . reverse . dropWhile isSpace . reverse
cleanup = unwords . words . trim

returnType = do
   t <- identifier tp
   ptrs <- many (reservedOp tp "*" >> return '*')
   return $ t ++ ptrs

externApiDeclaration = do  
   rettype <- (reserved tp "EXTERN_API" >> (fmap trim $ parens tp (balancedText False)))
           <|> (reserved tp "pascal" >> returnType)
   name <- identifier tp
   arguments <- fmap (map cleanup) $ parens tp (commaSep tp $ balancedText True)
   
   let hexwords = commaSep tp hexword
       macroinline = do
           inlinekey <- identifier tp
           guard ("WORDINLINE" `isSuffixOf` inlinekey)
           parens tp hexwords
       plaininline = do
           reservedOp tp "="
           braces tp hexwords
         
   inlines <- macroinline <|> plaininline <|> return []
   
   semi tp
   let arguments' | arguments == ["void"] = []
                  | otherwise = arguments
       argumentNames = map (trim . reverse . takeWhile isAlphaNum . reverse . trim) arguments'
       argumentTypes = map (trim . reverse . dropWhile isAlphaNum . reverse . trim) arguments'
   return $ FunctionItem rettype name argumentTypes argumentNames inlines Nothing

pragmaParameter = do
   reservedOp tp "#"
   reserved tp "pragma"
   reserved tp "parameter"
   retval <- optionMaybe reg
   name <- identifier tp
   args <- parens tp (commaSep tp reg)
   -- args <- option [] $ parens tp (fmap return $ reg)
   -- let args = []
   return $ PragmaParameterItem name (ParameterRegs retval args)

reg = (reserved tp "__A0" >> return "%%a0")
   <|>(reserved tp "__A1" >> return "%%a1")
   <|>(reserved tp "__A2" >> return "%%a2")
   <|>(reserved tp "__D0" >> return "%%d0")
   <|>(reserved tp "__D1" >> return "%%d1")
   

data TypeCategory = ByteType | WordType | LongType | PointerType | VoidType
   deriving(Show, Eq)
classifyType tm t | "Ptr" `isSuffixOf` t = Just PointerType
                  | "*" `isSuffixOf` t = Just PointerType
                  | "Handle" `isSuffixOf` t = Just PointerType
classifyType tm "unsigned char" = Just ByteType
classifyType tm "signed char" = Just ByteType
classifyType tm "char" = Just ByteType
classifyType tm "short" = Just WordType
classifyType tm "long" = Just LongType
classifyType tm "void" = Just VoidType
classifyType tm t = Map.lookup t tm

hexword = integer tp
outputItem typeMap (CharItem c) = [c]
-- outputItem (FunctionItem rettype name argumentTypes argumentNames words) = "<fun>"

outputItem typeMap (FunctionItem rettype name argumentTypes argumentNames words Nothing)
   | True, not (null words), Just retcat <- classifyType typeMap rettype
   = let
      helper = PP.text "__magic_inline_" <> PP.text name
      magic = PP.text "__magic_inline_" <> PP.hcat (PP.punctuate (PP.char '_') (map (PP.text . hexword) words'))
      hexword w = replicate (4 - length s) '0' ++ s where s = showHex w ""
      magicArgTypes = case retcat of
         ByteType -> reverse $ "char" : argumentTypes
         WordType -> reverse $ "short" : argumentTypes
         LongType -> reverse $ "long" : argumentTypes
         PointerType -> reverse $ "long" : argumentTypes                           
         VoidType -> reverse argumentTypes
      magicArgValues = case retcat of
         VoidType -> reverse argumentNames
         _ -> reverse $ "0" : argumentNames
      words' = case retcat of
         VoidType -> words
         ByteType -> words ++ [ 0x101f ] -- move.b (a7)+,d0
         WordType -> words ++ [ 0x301f ] -- move.w (a7)+,d0
         LongType -> words ++ [ 0x201f ] -- move.l (a7)+,d0
         PointerType -> words ++ [ 0x201f ] -- move.l (a7)+,d0   
   in PP.render $
      PP.text rettype <+> PP.text "__attribute__((stdcall))" <+> helper
         <> PP.parens (PP.hsep $ PP.punctuate PP.comma $ map PP.text magicArgTypes)
         <+> PP.text("__asm__") <> PP.parens ( PP.doubleQuotes magic )
         <> PP.semi
      $+$
      PP.text "static inline" <+> PP.text rettype <+> PP.text name
         <+> PP.parens (PP.hsep $ PP.punctuate PP.comma $ zipWith (\t n -> PP.text t <+> PP.text n) argumentTypes argumentNames) $$
         PP.text "{" $+$ (PP.nest 4 $
            (if retcat == VoidType then PP.empty else PP.text "return") <+>
            helper <> PP.parens (PP.hsep $ PP.punctuate PP.comma $ map PP.text magicArgValues) <> PP.semi
         ) $+$ PP.text "}\n\n"


      

outputItem typeMap (FunctionItem rettype name argumentTypes argumentNames words mbParamRegs) = 
   PP.render $
      linkage <+> PP.text rettype <+> PP.text name
         <+> PP.parens (PP.hsep $ PP.punctuate PP.comma $ zipWith (\t n -> PP.text t <+> PP.text n) argumentTypes argumentNames) $$
      if isJust mbCategories && not (null words)
         then
            PP.text "{" $+$ (PP.nest 4 $
               addReturnValue $
               PP.text "__asm__ __volatile__ (" $+$
               PP.nest 4 (
                  PP.nest 4 (PP.vcat asmStatements) $+$
                  showConstraints outs $+$
                  showConstraints ins $+$
                  PP.text ": \"%a0\", \"%a1\", \"%d0\", \"%d1\", \"%d2\", \"memory\", \"cc\""
                  <> (if tooltrap then PP.text ", \"%a5\"" else PP.empty)
               )
               $+$ PP.text ");"
            ) $+$ PP.text "}\n\n"
         else
            PP.semi $+$ 
            PP.text "//" <+> PP.text (show words) $+$
            PP.text "//" <+> PP.text rettype <+> PP.text (show $ (classifyType typeMap) rettype) $+$
            PP.text "//" <+> PP.text (show argumentTypes) <+> PP.text (show $ map (classifyType typeMap) argumentTypes) $+$
            PP.text "\n" -- couldn't convert type
   where
      tooltrap = True -- trapnum >= 0xA800
      linkage | null words = PP.text "extern"
              | otherwise = PP.text "static inline"


      mbCategories = do
         retcat <- classifyType typeMap rettype
         argcats <- mapM (classifyType typeMap) argumentTypes
         return (retcat, argcats)

      Just (returnCategory, argumentCategories) = mbCategories

      returnsValue = returnCategory /= VoidType
      addReturnValue body 
         | returnsValue = (PP.text rettype <+> PP.text "_ret;") $+$
                    body $+$
                    PP.text "return _ret;"
         | otherwise = body
      outs | returnsValue = [PP.text "\"=g\"(_ret)"]
           | otherwise = []
      ins = zipWith inputConstraint argumentCategories argumentNames 
   
      inputConstraint PointerType name = PP.text "\"m\"(*(char*)" <> PP.text name <> PP.text ")"
      inputConstraint VoidType name = error $ "Void Parameter: " ++ name
      inputConstraint _ name = PP.text "\"g\"(" <> PP.text name <> PP.text ")"


      showConstraints constraints = PP.text ":" <+> PP.hsep (PP.punctuate PP.comma $ constraints)
      asmStatements = 
--         (if tooltrap then [-- PP.text "\"move.l %%a5, %%a4\\n\"",
--                            PP.text "\"move.l 0x904.w, %%a5\\n\""] else []) ++
         subq ++
         pushes ++
         map (\trapnum -> PP.text "\"dc.w" <+> PP.text "0x" <> PP.text (showHex trapnum "") <> PP.text "\\n\\t\"") words
         ++ pop
--         ++ (if tooltrap then [PP.text "\"move.l %%a4, %%a5\\n\""] else [])

      (subq, pop) = case returnCategory of
            VoidType -> ([], [])
            _ -> (ifpascal [PP.text "\"subq #" <> PP.int size <> PP.text ", %%sp\\n\\t\""],
                  [PP.text "\"move" <> szLetter <+> src <+> PP.text ", %0\\n\\t\""])
         where
            size = case returnCategory of
               PointerType -> 4 ; LongType -> 4 ; WordType -> 2 ; ByteType -> 2 {- keep stack aligned -}
               
            szLetter = PP.text $ case returnCategory of
               PointerType -> ".l" ; LongType -> ".l" ; WordType -> ".w" ; ByteType -> ".b"
            src = case mbParamRegs of
                     Nothing -> PP.text "%%sp@+"
                     Just (ParameterRegs (Just r) _) -> PP.text r
                     Just (ParameterRegs Nothing _) -> error $ "no reg for return value: " ++ name

            ifpascal x = case mbParamRegs of Nothing -> x ; Just _ -> []

      pushes = case mbParamRegs of
                  Nothing -> zipWith (mkPush Nothing) argumentCategories
                  Just (ParameterRegs _ regs) -> zipWith3 mkPush (map Just regs) argumentCategories
         $
               map (\i -> PP.char '%' <> PP.int i) $
               (if returnsValue then [1..] else [0..])

      endtxt = PP.text "\\n\\t\""
      mkPush Nothing PointerType operand = PP.text "\"pea" <+> operand <> endtxt
      mkPush (Just reg) PointerType operand = PP.text "\"lea" <+> operand <> PP.comma <+> PP.text reg <> endtxt
      mkPush mbReg size operand =
         PP.text "\"move" <> PP.text sz <+> operand <> PP.comma <+> dst    <> endtxt
         where
            sz = case size of
               LongType -> ".l" ; WordType -> ".w" ; ByteType -> ".b"
            dst = case mbReg of
               Nothing -> PP.text "%%sp@-"
               Just reg -> PP.text reg

outputItem _ _ = ""

collectPragmas xs = evalState (mapM doit xs) Map.empty
   where
      doit x@(PragmaParameterItem name params) = modify (Map.insert name params) >> return x
      doit (FunctionItem rettype name argumentTypes argumentNames inlines _) = do
         m <- get
         return $ FunctionItem rettype name argumentTypes argumentNames inlines (Map.lookup name m)
      doit x = return x

parseTypeMap tm = Map.fromList $ map handleLine $ lines tm
   where
      handleLine tml = case words tml of
         (x : xs) -> (trim $ unwords xs, case x of
                        "B" -> ByteType ; "W" -> WordType ; "L" -> LongType ; "P" -> PointerType)
processFile inputDir outputDir file
   | ".h" `isSuffixOf` file = do
      print $ (outputDir </> takeFileName file)
      -- readFile (inputDir </> file)
      f <- openFile (inputDir </> file) ReadMode
      hSetEncoding f latin1
      txt <- hGetContents f
      let parseResult = parse (many item) file txt
      typeMap <- fmap parseTypeMap $ readFile "../Retro68/types.txt"
      case parseResult of
         Right items -> do
            outf <- openFile (outputDir </> file) WriteMode
            hSetEncoding outf latin1
            when (file == "ConditionalMacros.h") $ do
                hPutStrLn outf $ unlines [
                        "#define TARGET_CPU_68K 1",
                        "#define TYPE_LONGLONG 1",
                        "#define pascal",
                        "#ifdef __cplusplus",
                        "#define TYPE_BOOL 1",
                        "#endif"
                    ]
            hPutStr outf $ concatMap (outputItem typeMap) $ collectPragmas $ items
            hClose outf
         Left err -> putStrLn $ file ++ ": " ++ show err
   | otherwise = do
      putStrLn $ "Unknown: " ++ file

main = do
   [inputDir,outputDir] <- getArgs
   files <- getDirectoryContents inputDir
   Control.Exception.try (createDirectory outputDir) :: IO (Either Control.Exception.IOException ())
   mapM (processFile inputDir outputDir) files
   return ()