module Pas2C where

import Text.PrettyPrint.HughesPJ

import Data.Maybe

import Data.Char

import Text.Parsec.Prim hiding (State)

import Control.Monad.State

import System.IO

import System.Directory

import Control.Monad.IO.Class

import PascalPreprocessor

import Control.Exception

import System.IO.Error

import qualified Data.Map as Map

import Data.List (find)

import PascalParser

import PascalUnitSyntaxTree

data InsertOption = 

    IOInsert

    | IOLookup

    | IODeferred

type Record = (String, (String, BaseType))

data RenderState = RenderState 

    {

        currentScope :: [Record],

        lastIdentifier :: String,

        lastType :: BaseType,

        namespaces :: Map.Map String [Record]

    }

emptyState = RenderState [] "" BTUnknown

docToLower :: Doc -> Doc

docToLower = text . map toLower . render

pas2C :: String -> IO ()

pas2C fn = do

    setCurrentDirectory "../hedgewars/"

    s <- flip execStateT initState $ f fn

    renderCFiles s

    where

    printLn = liftIO . hPutStrLn stderr

    print = liftIO . hPutStr stderr

    initState = Map.empty

    f :: String -> StateT (Map.Map String PascalUnit) IO ()

    f fileName = do

        processed <- gets $ Map.member fileName

        unless processed $ do

            print ("Preprocessing '" ++ fileName ++ ".pas'... ")

            fc' <- liftIO 

                $ tryJust (guard . isDoesNotExistError) 

                $ preprocess (fileName ++ ".pas")

            case fc' of

                (Left a) -> do

                    modify (Map.insert fileName (System []))

                    printLn "doesn't exist"

                (Right fc) -> do

                    print "ok, parsing... "

                    let ptree = parse pascalUnit fileName fc

                    case ptree of

                         (Left a) -> do

                            liftIO $ writeFile "preprocess.out" fc

                            printLn $ show a ++ "\nsee preprocess.out for preprocessed source"

                            fail "stop"

                         (Right a) -> do

                            printLn "ok"

                            modify (Map.insert fileName a)

                            mapM_ f (usesFiles a)

renderCFiles :: Map.Map String PascalUnit -> IO ()

renderCFiles units = do

    let u = Map.toList units

    let nss = Map.map (toNamespace nss) units

    hPutStrLn stderr $ "Units: " ++ (show . Map.keys . Map.filter (not . null) $ nss)

    mapM_ (toCFiles nss) u

    where

    toNamespace :: Map.Map String [Record] -> PascalUnit -> [Record]

    toNamespace nss (System tvs) = 

        currentScope $ execState (mapM_ (tvar2C True) tvs) (emptyState nss)

    toNamespace _ (Program {}) = []

    toNamespace nss (Unit _ interface _ _ _) = 

        currentScope $ execState (interface2C interface) (emptyState nss)

    st <- liftM f get

withLastIdNamespace :: State RenderState Doc -> State RenderState Doc

withLastIdNamespace f = do

    li <- gets lastIdentifier

    nss <- gets namespaces

    withState' (\st -> st{currentScope = fromMaybe [] $ Map.lookup li (namespaces st)}) f

withRecordNamespace :: [(String, BaseType)] -> State RenderState Doc -> State RenderState Doc

withRecordNamespace recs = withState' f

    where

        f st = st{currentScope = records ++ currentScope st}

        records = map (\(a, b) -> (map toLower a, (a, b))) recs

toCFiles :: Map.Map String [Record] -> (String, PascalUnit) -> IO ()

toCFiles _ (_, System _) = return ()

toCFiles ns p@(fn, pu) = do

    hPutStrLn stderr $ "Rendering '" ++ fn ++ "'..."

    toCFiles' p

    where

    toCFiles' (fn, p@(Program {})) = writeFile (fn ++ ".c") $ (render2C initialState . pascal2C) p

    toCFiles' (fn, (Unit _ interface implementation _ _)) = do

        let (a, s) = runState (interface2C interface) initialState

        writeFile (fn ++ ".h") $ "#pragma once\n" ++ (render a)

        writeFile (fn ++ ".c") $ (render2C s . implementation2C) implementation

    initialState = emptyState ns

    render2C :: RenderState -> State RenderState Doc -> String

    render2C a = render . flip evalState a

usesFiles :: PascalUnit -> [String]

usesFiles (Program _ (Implementation uses _) _) = "pas2cSystem" : uses2List uses

usesFiles (Unit _ (Interface uses1 _) (Implementation uses2 _) _ _) = "pas2cSystem" : uses2List uses1 ++ uses2List uses2

usesFiles (System {}) = []

pascal2C :: PascalUnit -> State RenderState Doc

pascal2C (Unit _ interface implementation init fin) =

    liftM2 ($+$) (interface2C interface) (implementation2C implementation)

pascal2C (Program _ implementation mainFunction) = do

    impl <- implementation2C implementation

    main <- tvar2C True 

        (FunctionDeclaration (Identifier "main" BTInt) (SimpleType $ Identifier "int" BTInt) [] (Just (TypesAndVars [], mainFunction)))

    return $ impl $+$ main

interface2C :: Interface -> State RenderState Doc

interface2C (Interface uses tvars) = liftM2 ($+$) (uses2C uses) (typesAndVars2C True tvars)

implementation2C :: Implementation -> State RenderState Doc

implementation2C (Implementation uses tvars) = liftM2 ($+$) (uses2C uses) (typesAndVars2C True tvars)

typesAndVars2C :: Bool -> TypesAndVars -> State RenderState Doc

typesAndVars2C b (TypesAndVars ts) = liftM vcat $ mapM (tvar2C b) ts

setBaseType :: BaseType -> Identifier -> Identifier

setBaseType bt (Identifier i _) = Identifier i bt

uses2C :: Uses -> State RenderState Doc

uses2C uses@(Uses unitIds) = do

    mapM_ injectNamespace (Identifier "pas2cSystem" undefined : unitIds)

    mapM_ (id2C IOInsert . setBaseType BTUnit) unitIds

    return $ vcat . map (\i -> text $ "#include \"" ++ i ++ ".h\"") $ uses2List uses

    where

    injectNamespace (Identifier i _) = do

        getNS <- gets (flip Map.lookup . namespaces)

        let f = flip (foldl (flip (:))) (fromMaybe [] (getNS i))

        modify (\s -> s{currentScope = f $ currentScope s})

uses2List :: Uses -> [String]

uses2List (Uses ids) = map (\(Identifier i _) -> i) ids

id2C :: InsertOption -> Identifier -> State RenderState Doc

id2C IOInsert (Identifier i t) = do

    ns <- gets currentScope

{--    case t of 

        BTUnknown -> do

            ns <- gets currentScope

            error $ "id2C IOInsert: type BTUnknown for " ++ show i ++ "\nnamespace: " ++ show (take 100 ns)

        _ -> do --}

    modify (\s -> s{currentScope = (n, (i, t)) : currentScope s, lastIdentifier = n})

    return $ text i

    where

        n = map toLower i

id2C IOLookup (Identifier i t) = do

    let i' = map toLower i

    v <- gets $ find (\(a, _) -> a == i') . currentScope

    ns <- gets currentScope

    if isNothing v then 

        else 

        let vv = snd $ fromJust v in modify (\s -> s{lastType = snd vv, lastIdentifier = fst vv}) >> (return . text . fst $ vv)

id2C IODeferred (Identifier i t) = do

    let i' = map toLower i

    v <- gets $ find (\(a, _) -> a == i') . currentScope

    if (isNothing v) then

        return $ text i

        else

        return . text . fst . snd . fromJust $ v

id2CTyped :: TypeDecl -> Identifier -> State RenderState Doc

id2CTyped t (Identifier i _) = do

    tb <- resolveType t

    ns <- gets currentScope

    case tb of 

        BTUnknown -> do

            ns <- gets currentScope

            error $ "id2CTyped: type BTUnknown for " ++ show i ++ "\ntype: " ++ show t ++ "\nnamespace: " ++ show (take 100 ns)

        _ -> return ()

    id2C IOInsert (Identifier i tb)

resolveType :: TypeDecl -> State RenderState BaseType

resolveType st@(SimpleType (Identifier i _)) = do

    let i' = map toLower i

    v <- gets $ find (\(a, _) -> a == i') . currentScope

    if isJust v then return . snd . snd $ fromJust v else return $ f i'

    where

    f "integer" = BTInt

    f "pointer" = BTPointerTo BTVoid

    f "boolean" = BTBool

    f "float" = BTFloat

    f "char" = BTChar

    f "string" = BTString

    f _ = error $ "Unknown system type: " ++ show st

resolveType (PointerTo (SimpleType (Identifier i _))) = return . BTPointerTo $ BTUnresolved (map toLower i)

resolveType (PointerTo t) = liftM BTPointerTo $ resolveType t

resolveType (RecordType tv mtvs) = do

    tvs <- mapM f (concat $ tv : fromMaybe [] mtvs)

    return . BTRecord . concat $ tvs

    where

        f :: TypeVarDeclaration -> State RenderState [(String, BaseType)]

        f (VarDeclaration _ (ids, td) _) = mapM (\(Identifier i _) -> liftM ((,) i) $ resolveType td) ids

resolveType (ArrayDecl (Just _) t) = liftM (BTArray BTInt) $ resolveType t

resolveType (ArrayDecl Nothing t) = liftM (BTArray BTInt) $ resolveType t

resolveType (FunctionType t _) = liftM BTFunction $ resolveType t

resolveType (DeriveType (InitHexNumber _)) = return BTInt

resolveType (DeriveType (InitNumber _)) = return BTInt

resolveType (DeriveType (InitFloat _)) = return BTFloat

resolveType (DeriveType (InitString _)) = return BTString

resolveType (DeriveType (InitBinOp {})) = return BTInt

resolveType (DeriveType (InitPrefixOp {})) = return BTInt

resolveType (DeriveType (BuiltInFunction{})) = return BTInt

resolveType (DeriveType (InitReference (Identifier{}))) = return BTBool -- TODO: derive from actual type

resolveType (DeriveType _) = return BTUnknown

resolveType (String _) = return BTString

resolveType VoidType = return BTVoid

resolveType (Sequence ids) = return $ BTEnum $ map (\(Identifier i _) -> map toLower i) ids

resolveType (RangeType _) = return $ BTVoid

resolveType (Set t) = liftM BTSet $ resolveType t

fromPointer :: BaseType -> State RenderState BaseType    

fromPointer (BTPointerTo t) = f t

    where

        f (BTUnresolved s) = do

            v <- gets $ find (\(a, _) -> a == s) . currentScope

            if isJust v then

                f . snd . snd . fromJust $ v

                else

                error $ "Unknown type " ++ show t

        f t = return t

fromPointer t = do

    ns <- gets currentScope

    error $ "Dereferencing from non-pointer type " ++ show t ++ "\n\n" ++ show (take 100 ns)

tvar2C :: Bool -> TypeVarDeclaration -> State RenderState Doc

tvar2C _ (FunctionDeclaration name returnType params Nothing) = do

    t <- type2C returnType 

    p <- withState' id $ liftM hcat $ mapM (tvar2C False) params

    n <- id2C IOInsert name

    return $ t <+> n <> parens p <> text ";"

tvar2C True (FunctionDeclaration (Identifier i _) returnType params (Just (tvars, phrase))) = do

    t <- type2C returnType

    t'<- gets lastType

    n <- id2C IOInsert (Identifier i (BTFunction t'))

    (p, ph) <- withState' (\st -> st{currentScope = (lastIdentifier st, (lastIdentifier st ++ "_result", t')) : currentScope st}) $ do

        p <- liftM hcat $ mapM (tvar2C False) params

        ph <- liftM2 ($+$) (typesAndVars2C False tvars) (phrase2C' phrase)

        return (p, ph)

    let res = docToLower $ n <> text "_result"

    let phrasesBlock = case returnType of

            VoidType -> ph

            _ -> t <+> res <> semi $+$ ph $+$ text "return" <+> res <> semi

    return $ 

        t <+> n <> parens p

        $+$

        text "{" 

        $+$ 

        nest 4 phrasesBlock

        $+$

        text "}"

    where

    phrase2C' (Phrases p) = liftM vcat $ mapM phrase2C p

    phrase2C' p = phrase2C p

tvar2C False (FunctionDeclaration (Identifier name _) _ _ _) = error $ "nested functions not allowed: " ++ name

tvar2C _ td@(TypeDeclaration i' t) = do

    i <- id2CTyped t i'

    tp <- type2C t

    return $ text "type" <+> i <+> tp <> semi

tvar2C _ (VarDeclaration isConst (ids, t) mInitExpr) = do

    t' <- type2C t

    i <- mapM (id2CTyped t) ids

    ie <- initExpr mInitExpr

    return $ if isConst then text "const" else empty

        <+> t'

        <+> (hsep . punctuate (char ',') $ i)

        <+> ie

        <> text ";"

    where

    initExpr Nothing = return $ empty

    initExpr (Just e) = liftM (text "=" <+>) (initExpr2C e)

tvar2C f (OperatorDeclaration op i ret params body) = 

    tvar2C f (FunctionDeclaration i ret params body)

initExpr2C :: InitExpression -> State RenderState Doc

initExpr2C (InitBinOp op expr1 expr2) = do

    e1 <- initExpr2C expr1

    e2 <- initExpr2C expr2

    o <- op2C op

    return $ parens $ e1 <+> o <+> e2

initExpr2C (InitNumber s) = return $ text s

initExpr2C (InitFloat s) = return $ text s

initExpr2C (InitHexNumber s) = return $ text "0x" <> (text . map toLower $ s)

initExpr2C (InitString s) = return $ doubleQuotes $ text s 

initExpr2C (InitReference i) = id2C IOLookup i

initExpr2C _ = return $ text "<<expression>>"

type2C :: TypeDecl -> State RenderState Doc

type2C (SimpleType i) = id2C IOLookup i

type2C t = do

    r <- type2C' t

    rt <- resolveType t

    modify (\st -> st{lastType = rt})

    return r

    where

    type2C' VoidType = return $ text "void"

    type2C' (String l) = return $ text $ "string" ++ show l

    type2C' (PointerTo (SimpleType i)) = liftM (<> text "*") $ id2C IODeferred i

    type2C' (PointerTo t) = liftM (<> text "*") $ type2C t

    type2C' (RecordType tvs union) = do

        t <- withState' id $ mapM (tvar2C False) tvs

        return $ text "{" $+$ (nest 4 . vcat $ t) $+$ text "}"

    type2C' (RangeType r) = return $ text "<<range type>>"

    type2C' (Sequence ids) = do

        mapM_ (id2C IOInsert) ids

        return $ text "<<sequence type>>"

    type2C' (ArrayDecl r t) = return $ text "<<array type>>"

    type2C' (Set t) = return $ text "<<set>>"

    type2C' (FunctionType returnType params) = return $ text "<<function>>"

    type2C' (DeriveType _) = return $ text "<<type derived from constant literal>>"

phrase2C :: Phrase -> State RenderState Doc

phrase2C (Phrases p) = do

    ps <- mapM phrase2C p

    return $ text "{" $+$ (nest 4 . vcat $ ps) $+$ text "}"

phrase2C (ProcCall f@(FunCall {}) []) = liftM (<> semi) $ ref2C f

phrase2C (ProcCall ref params) = do

    r <- ref2C ref

    ps <- mapM expr2C params

    return $ r <> parens (hsep . punctuate (char ',') $ ps) <> semi

phrase2C (IfThenElse (expr) phrase1 mphrase2) = do

    e <- expr2C expr

    p1 <- (phrase2C . wrapPhrase) phrase1

    el <- elsePart

    return $ 

        text "if" <> parens e $+$ p1 $+$ el

    where

    elsePart | isNothing mphrase2 = return $ empty

             | otherwise = liftM (text "else" $$) $ (phrase2C . wrapPhrase) (fromJust mphrase2)

phrase2C (Assignment ref expr) = do

    r <- ref2C ref 

    e <- expr2C expr

    return $

        r <> text " = " <> e <> semi

phrase2C (WhileCycle expr phrase) = do

    e <- expr2C expr

    p <- phrase2C $ wrapPhrase phrase

    return $ text "while" <> parens e $$ p

phrase2C (SwitchCase expr cases mphrase) = do

    e <- expr2C expr

    cs <- mapM case2C cases

    return $ 

        text "switch" <> parens e <> text "of" $+$ (nest 4 . vcat) cs

    where

    case2C :: ([InitExpression], Phrase) -> State RenderState Doc

    case2C (e, p) = do

        ie <- mapM initExpr2C e

        ph <- phrase2C p

        return $ 

            text "case" <+> parens (hsep . punctuate (char ',') $ ie) <> char ':' <> nest 4 (ph $+$ text "break;")

phrase2C wb@(WithBlock ref p) = do

    r <- ref2C ref 

    t <- gets lastType

    case t of

        (BTRecord rs) -> do

            ph <- withRecordNamespace rs $ phrase2C $ wrapPhrase p

            return $ text "namespace" <> parens r $$ ph

        a -> do

            ns <- gets currentScope

            error $ "'with' block referencing non-record type " ++ show a ++ "\n" ++ show wb ++ "\nnamespace: " ++ show (take 100 ns)

phrase2C (ForCycle i' e1' e2' p) = do

    i <- id2C IOLookup i'

    e1 <- expr2C e1'

    e2 <- expr2C e2'

    ph <- phrase2C (wrapPhrase p)

    return $ 

        text "for" <> (parens . hsep . punctuate (char ';') $ [i <+> text "=" <+> e1, i <+> text "<=" <+> e2, text "++" <> i])

        $$

        ph

phrase2C (RepeatCycle e' p') = do

    e <- expr2C e'

    p <- phrase2C (Phrases p')

    return $ text "do" <+> p <+> text "while" <> parens (text "!" <> parens e)

phrase2C NOP = return $ text ";"

wrapPhrase p@(Phrases _) = p

wrapPhrase p = Phrases [p]

expr2C :: Expression -> State RenderState Doc

expr2C (Expression s) = return $ text s

expr2C (BinOp op expr1 expr2) = do

    e1 <- expr2C expr1

    e2 <- expr2C expr2

    o <- op2C op

    return $ parens $ e1 <+> o <+> e2

expr2C (NumberLiteral s) = return $ text s

expr2C (FloatLiteral s) = return $ text s

expr2C (HexNumber s) = return $ text "0x" <> (text . map toLower $ s)

expr2C (StringLiteral s) = return $ doubleQuotes $ text s 

expr2C (Reference ref) = ref2C ref

expr2C (PrefixOp op expr) = liftM2 (<+>) (op2C op) (expr2C expr)

expr2C Null = return $ text "NULL"

expr2C (BuiltInFunCall params ref) = do

    r <- ref2C ref 

    ps <- mapM expr2C params

    return $ 

        r <> parens (hsep . punctuate (char ',') $ ps)

expr2C _ = return $ text "<<expression>>"

ref2C :: Reference -> State RenderState Doc

ref2C ae@(ArrayElement exprs ref) = do

    es <- mapM expr2C exprs

    r <- ref2C ref 

    t <- gets lastType

    ns <- gets currentScope

    case t of

         (BTArray _ ta@(BTArray _ t')) 

            | length exprs == 2 -> modify (\st -> st{lastType = t'})

         (BTArray _ t') -> modify (\st -> st{lastType = t'})

         (BTString) -> modify (\st -> st{lastType = BTChar})

         a -> error $ "Getting element of " ++ show a ++ "\nReference: " ++ show ae ++ "\n" ++ show (take 100 ns)

    return $ r <> (brackets . hcat) (punctuate comma es)

ref2C (SimpleReference name) = id2C IOLookup name

ref2C rf@(RecordField (Dereference ref1) ref2) = do

    r1 <- ref2C ref1 

    t <- fromPointer =<< gets lastType

    ns <- gets currentScope

    r2 <- case t of

        BTRecord rs -> withRecordNamespace rs $ ref2C ref2

        BTUnit -> withLastIdNamespace $ ref2C ref2

        a -> error $ "dereferencing from " ++ show a ++ "\n" ++ show rf ++ "\n" ++ show (take 100 ns)

    return $ 

        r1 <> text "->" <> r2

ref2C rf@(RecordField ref1 ref2) = do

    r1 <- ref2C ref1

    t <- gets lastType

    ns <- gets currentScope