module UInterpret where
import System.Environment
import System.IO
import qualified Data.Set as Set
import qualified Data.Map as Map
import UParse
import UModuleLoader
import URunTime
import UEnvironment
import ULambdaExpression

showPrettyValue v
	| isTrueValue v = "True"
	| isFalseValue v = "False"
	| otherwise = showValue v
	where
	isTrueValue v = case v of
		VAbs name1 (VClean (VAbs name2 (VRef name3))) -> name1==name3
		_ -> False
	isFalseValue v = case v of
		VAbs name1 (VClean (VAbs name2 (VRef name3))) -> name2==name3
		_ -> False

runInteractive :: [[Char]] -> Bool -> IO ()
runInteractive args showHints = do
	if showHints then putStrLn "; type :q to quit, :? for help" else return ()
	(c0,revimports0) <- tryImportFile SIUnqualified "prelude" defaultLoadContext []
	runRealWorld args$repl (c0,(Set.fromList [])) revimports0 Nothing
	where
	tryImportFile :: SImportMode -> [Char] -> MLoadContext -> [[Char]] -> IO (MLoadContext,[[Char]])
	tryImportFile vis modname c revimports = do
		c1_m <- addImport ("main",(0,0)) modname c
		case c1_m of
			MFail msg modname pos -> do
				putStrLn ("error loading "++modname++" at "++(show pos)++": "++msg)
				return (c,revimports)
			MSucc c1 -> return (c1,(if (vis == SIQualified) then revimports else (modname:revimports)))
	repl :: MLocalLoadContext -> [[Char]] -> Maybe STokenTree -> URealWorldEnv ()
	repl (c,locals) revimports lasttree = do
		if showHints then do
			(liftUR.putStr) ((joinStr " " (reverse revimports))++">")
			(liftUR.hFlush) stdout
		else
			return ()
		iseof <- (liftUR.hIsEOF) stdin
		if iseof then (liftUR.putStrLn) "" else do
			line <- (liftUR getLine)
			case line of
				[] -> repl (c,locals) revimports lasttree
				':':r -> case r of
					"q" -> return ()
					"?" -> do
						(liftUR.putStrLn) ":q   quit current session"
						(liftUR.putStrLn) ":?   show this help message"
						(liftUR.putStrLn) "expr compute expression"
						repl (c,locals) revimports lasttree
					'i':' ':rline -> evalLine rline
					"t" -> do
						case lasttree of
							Nothing -> (liftUR.putStrLn) "no previous statement"
							Just t -> (liftUR.putStr) (show t)
						repl (c,locals) revimports lasttree
					_ -> do
						(liftUR.putStrLn) "unknown command"
						repl (c,locals) revimports lasttree
				_ -> evalLine line
			where
			evalLine line = case (parseSTokenTreeStr line) of
				SFail msg pos -> do
					(liftUR.putStrLn) ("parser error at "++(show pos)++" "++msg)
					repl (c,locals) revimports lasttree
				SSucc (t,pt) -> case t of
					STTList [(STTNode (STAtom "def"),_),(STTNode (STAtom name),_),(e,p)] -> tryAddDef name (e,p) SVGlobal
					STTList [(STTNode (STAtom "let"),_),(STTNode (STAtom name),_),(e,p)] -> tryAddDef name (e,p) SVLocal
					STTList [(STTNode (STAtom "import*"),_),(STTNode (STAtom name),_)] -> do
						(c1,imports1) <- liftUR$tryImportFile SIUnqualified name c revimports
						repl (c1,locals) imports1 (Just t)
					STTList [(STTNode (STAtom "import"),_),(STTNode (STAtom name),_)] -> do
						(c1,imports1) <- liftUR$tryImportFile SIQualified name c revimports
						repl (c1,locals) imports1 (Just t)
					_ -> case (parseSSExp (t,pt)) of
						SFail msg pos -> do
							(liftUR.putStrLn) ("parser error at "++(show pos)++" "++msg)
							repl (c,locals) revimports (Just t)
						SSucc (e,p) -> let (MLoadContext loaded curchain) =c in
							case (mResolveNames "main" (e,p) revimports loaded locals (Set.fromList [])) of
								MFail msg modname pos -> do
									(liftUR.putStrLn) (msg++" at "++(show pos))
									repl (c,locals) revimports (Just t)
								MSucc le -> do
									eval_result <- (runUEvalEnv$executeVExp$fromLExpr$assembleChainLExpr curchain le)
									case eval_result of
										URunning () -> do
											(liftUR.putStrLn) "execution interrupted"
											repl (c,locals) revimports (Just t)
										UExited x -> do
											if (x==0) then return () else (liftUR.putStrLn) ("exit with code "++(show x))
											repl (c,locals) revimports (Just t)
										UExceptionHappened f -> do
											(liftUR.putStrLn) ("exception: "++f)
											repl (c,locals) revimports (Just t)
										UResultReturned (v,vc) -> do
											(liftUR.putStrLn) (showPrettyValue v)
											repl (c,locals) revimports (Just t)
					where
					tryAddDef :: [Char] -> (STokenTree,SPosition) -> SVisibility -> URealWorldEnv ()
					tryAddDef name (e,p) vis = case (parseSSExp (e,p)) of
						SFail msg pos -> do
							(liftUR.putStrLn) (msg++" at "++(show pos))
							repl (c,locals) revimports (Just t)
						SSucc (se,pse) -> case (mAddDef "main" revimports (SSDef name (se,pse) vis) (c,locals)) of
							MFail msg modname pos -> do
								(liftUR.putStrLn) (msg++" at "++(show pos))
								repl (c,locals) revimports (Just t)
							MSucc (c1,locals1) -> repl (c1,locals1) revimports (Just t)
	joinStr sep strs = case strs of
		[] -> []
		a:[] -> a
		a:r -> a++sep++(joinStr sep r)

runFileF :: Handle -> [Char] -> [[Char]] -> IO ()
runFileF fout ifname args = do
	loadc <- loadMainModule ifname defaultLoadContext
	case loadc of
		MFail msg modname pos -> putStrLn ("error loading "++modname++" at "++(show pos)++": "++msg)
		MSucc (MLoadContext loaded curchain)
			| (not (Set.member "main.main" loaded)) -> putStrLn "main.main not defined"
			| otherwise -> do
				eval_result <- (runRealWorld args$runUEvalEnv$executeVExp$fromLExpr$assembleChainLExpr curchain (LRef "main.main"))
				case eval_result of
					URunning () -> putStrLn "execution interrupted"
					UExited x -> if (x==0) then return () else putStrLn ("exit with code "++(show x))
					UExceptionHappened f -> putStrLn ("exception: "++f)
					UResultReturned (v,vc) -> hPutStrLn fout (showPrettyValue v)
runFile = runFileF stdout