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

type RenderState = [(String, String)]

pas2C :: String -> IO ()

pas2C fn = do

    setCurrentDirectory "../hedgewars/"

    s <- flip execStateT initState $ f fn

    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)

toCFiles :: (String, PascalUnit) -> IO ()

toCFiles (_, System _) = return ()

toCFiles p@(fn, pu) = do

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

    toCFiles' p

    where

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

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

        writeFile (fn ++ ".h") $ "#pragma once\n" ++ (render2C . interface2C $ interface)

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

render2C = render . flip evalState []

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

uses2C :: Uses -> State RenderState Doc

uses2C uses = return $ vcat . map (\i -> text $ "#include \"" ++ i ++ ".h\"") $ uses2List uses

uses2List :: Uses -> [String]

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

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

id2C True (Identifier i _) = do

    modify (\s -> (map toLower i, i) : s)

    return $ text i

id2C False (Identifier i _) = do

    let i' = map toLower i

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

    if isNothing v then 

        error $ "Not defined: " ++ i' 

        else 

        return . text . snd . fromJust $ v

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

tvar2C _ (FunctionDeclaration name returnType params Nothing) = do

    t <- type2C returnType 

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

    n <- id2C True name

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

tvar2C True (FunctionDeclaration name returnType params (Just (tvars, phrase))) = do

    t <- type2C returnType 

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

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

    n <- id2C True name

    return $ 

        t <+> n <> parens p

        $+$

        text "{" 

        $+$ 

        nest 4 ph

        $+$

        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 _ (TypeDeclaration (Identifier i _) t) = do

    tp <- type2C t

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

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

    t' <- type2C t

    i <- mapM (id2C True) 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 _ ret params body) = 

    tvar2C f (FunctionDeclaration (Identifier ("<op " ++ op ++ ">") Unknown) 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 False i

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

type2C :: TypeDecl -> State RenderState Doc

type2C UnknownType = return $ text "void"

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

type2C (PointerTo t) = liftM (<> text "*") $ type2C t

type2C (RecordType tvs union) = do

    t <- mapM (tvar2C False) tvs

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

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

type2C (Sequence 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>>"

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 (WithBlock ref p) = do

    r <- ref2C ref 

    ph <- phrase2C $ wrapPhrase p

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

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

    i <- id2C False 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 (ArrayElement exprs ref) = do

    r <- ref2C ref 

    es <- mapM expr2C exprs

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

ref2C (SimpleReference name) = id2C False name

ref2C (RecordField (Dereference ref1) ref2) = do

    r1 <- ref2C ref1 

    r2 <- ref2C ref2

    return $ 

        r1 <> text "->" <> r2

ref2C (RecordField ref1 ref2) = do

    r1 <- ref2C ref1 

    r2 <- ref2C ref2

    return $ 

        r1 <> text "." <> r2

ref2C (Dereference ref) = liftM ((parens $ text "*") <>) $ ref2C ref

ref2C (FunCall params ref) = do

    r <- ref2C ref

    ps <- mapM expr2C params

    return $ 

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

ref2C (Address ref) = do

    r <- ref2C ref

    return $ text "&" <> parens r

ref2C (TypeCast t' expr) = do

    t <- id2C False t'

    e <- expr2C expr

    return $ parens t <> e

ref2C (RefExpression expr) = expr2C expr

op2C :: String -> State RenderState Doc

op2C "or" = return $ text "|"

op2C "and" = return $ text "&"

op2C "not" = return $ text "!"

op2C "xor" = return $ text "^"

op2C "div" = return $ text "/"

op2C "mod" = return $ text "%"

op2C "shl" = return $ text "<<"

op2C "shr" = return $ text ">>"

op2C "<>" = return $ text "!="

op2C "=" = return $ text "=="

op2C a = return $ text a

maybeVoid "" = "void"

maybeVoid a = a