-- | Create a chain based on given arguments and run it.
--
-- Overall development policy:
--
-- * If you seek /elegant/ abstraction, you will get /elephant/ abstraction.
--
-- * All intermediate-languages should be interpretable in 'IO' monad with exactly same behavior,
--   or at least have such semantics.
--
-- * Interpreters should not try to optimize, use simplest implementation while keeping the order low.
--
-- See the source of 'help' for detailed description\/specification of features.
module Main where
import Control.Monad
import System.Environment
import System.FilePath.Posix
import System.IO
import qualified Paths_hs2bf

import Util
import qualified Front
import qualified Core
import qualified GMachine
import qualified SAM
import qualified SCGR
import qualified Brainfuck


main=execCommand =<< liftM parseArgs getArgs

-- | Complete description of /hs2bf/ behavior
data Command
    =ShowMessage String
    |Interpret Option String
    |Compile Option String

data Language
    =LangCore String
    |LangGM   String
    |LangSAM  String
    |LangBF
    deriving(Show,Eq,Ord)

-- | All /global options/
data Option=Option
    {addrSpace :: Int
    ,verbose :: Bool
    ,debug :: Bool
    ,tolang :: Language
    }

-- | Parse arguments to 'Command'. Note this is a total function.
parseArgs :: [String] -> Command
parseArgs []=ShowMessage $ version++"\n"++help
parseArgs ("-v":_)=ShowMessage version
parseArgs ("--version":_)=ShowMessage version
parseArgs ("-h":_)=ShowMessage $ version++"\n"++help
parseArgs ("--help":_)=ShowMessage $ version++"\n"++help
parseArgs ("--run":n:as)=Interpret (parseOption as) n
parseArgs ("--make":n:as)=Compile (parseOption as) n
parseArgs _=ShowMessage "Invalid command. See 'hs2bf --help' for usage."



parseOption :: [String] -> Option
parseOption []=Option{addrSpace=2,verbose=True,debug=False,tolang=LangBF}
parseOption (term:xs)=case term of
    '-':'S':'c':xs -> o{tolang=LangCore xs}
    '-':'S':'g':xs -> o{tolang=LangGM   xs}
    '-':'S':'s':xs -> o{tolang=LangSAM  xs}
    "-Sb" -> o{tolang=LangBF}
    _ -> error $ "unknown option:"++term
    where o=parseOption xs





execCommand :: Command -> IO ()
execCommand (ShowMessage x)=putStrLn x
execCommand (Interpret opt from)=partialChain opt from $
    (error "Core interpreter is not implemented"
    ,error "Core interpreter is not implemented"
    ,f GMachine.interpret
    ,f GMachine.interpretR
    ,f SAM.interpret
    ,f SAM.interpret
    ,f Brainfuck.interpret
    )
    where
        f g=runProcessWithIO (\x->setio >> g x)
        setio=hSetBuffering stdin NoBuffering >> hSetBuffering stdout NoBuffering
execCommand (Compile opt from)=partialChain opt from $
    (f Core.pprint
    ,f Core.pprint
    ,f GMachine.pprint
    ,f GMachine.pprint
    ,f SAM.pprint
    ,f SAM.pprint
    ,f Brainfuck.pprint
    )
    where f g=runProcessWithIO (putStr . g)

partialChain opt from (c0,c1,g0,g1,s0,s1,b)=do
    dir<-Paths_hs2bf.getDataDir
    let (mod,env)=analyzeName from dir
    xs<-Front.collectModules env mod
    let cr  =xs   >>= Front.compile
        cr' =cr   >>= Core.simplify
        gm  =cr'  >>= Core.compile
        gm' =gm   >>= GMachine.simplify
        sam =gm'  >>= GMachine.compile
        sam'=sam  >>= SAM.simplify
        bf  =sam' >>= SAM.compile
    case tolang opt of
        LangCore ""  -> c0 cr
        LangCore "s" -> c1 cr'
        LangGM  ""   -> g0 gm
        LangGM  "r"  -> g1 gm'
        LangSAM ""   -> s0 sam
        LangSAM "f"  -> s1 sam'
        LangBF       -> b  bf

version :: String
version="Haskell to Brainfuck Compiler: version 0.6.2"

help :: String
help=unlines $
    ["Usage: hs2bf <command>"
    ,""
    ,"command:"
    ,"  --help: show help"
    ,"  --version: show version"
    ,"  --run <module> <option>*: interpret <module>"
    ,"  --make <module> <option>*: compile <module>"
    ,""
    ,"option:"
    ,"  -o <file> : output path (stdout if omitted)"
    ,"  -Sc : to Core code"
    ,"  -Scs: to Core code (simplified)"
    ,"  -Sg : to GMachine"
    ,"  -Sgr: to GMachine (simplified)"
    ,"  -Ss : to SAM"
    ,"  -Ssf: to SAM (most simplified)"
--    ,"  -Sr : to SCGR" -- not implemented
    ,"  -Sb : to BF"
    ,"  --addr n : use n byte for pointer arithmetic"
    ,"  --debug : include detailed error message (this will make the program a LOT larger)"
    ,""
    ,"examples:"
    ,"  hs2bf --make path/to/App.hs -o app : compile App.hs to bf"
    ,"  hs2bf --run Main -Sm : compile module Main to GMachine code and interpret it"
    ]





analyzeName :: String -> FilePath -> (String,Front.ModuleEnv)
analyzeName n lib=(takeBaseName n,Front.ModuleEnv [dirPrefix++takeDirectory n,lib])
    where dirPrefix=if isAbsolute n then "" else "./"