module SMR.CLI.Driver.Load
        (runLoadFileDecls)
where
import qualified SMR.Prim.Op                    as Prim
import qualified SMR.Prim.Name                  as Prim
import qualified SMR.Source.Parser              as Source
import qualified SMR.Source.Lexer               as Source
import qualified SMR.Codec.Peek                 as Codec
import SMR.Core.Exp                             (Decl)
import SMR.Prim.Op.Base                         (Prim)

import qualified Foreign.Marshal.Alloc          as Foreign

import qualified System.FilePath                as System
import qualified System.IO                      as System
import Control.Monad
import Data.Text                                (Text)


-- | Load decls from the given file.
runLoadFileDecls :: FilePath -> IO [Decl Text Prim]
runLoadFileDecls path
 -- Shimmer text source file.
 | System.takeExtension path == ".smr"
 = do   str     <- readFile path

        let (ts, _loc, _csRest)
                = Source.lexTokens (Source.L 1 1) str

        let config
                = Source.Config
                { Source.configReadSym  = Just
                , Source.configReadPrm  = Prim.readPrim Prim.primOpTextNames }

        case Source.parseDecls config ts of
         Left err       -> error $ show err
         Right decls    -> return decls


 -- Shimmer binary store file.
 | System.takeExtension path == ".sms"
 = do
        h     <- System.openBinaryFile path System.ReadMode
        nSize <- fmap fromIntegral $ System.hFileSize h
        Foreign.allocaBytes nSize $ \pBuf
         -> do  nRead <- System.hGetBuf h pBuf nSize
                when (nRead /= nSize) $ error "runConvert: short read"
                (decls, _p, _n) <- Codec.peekFileDecls pBuf nSize
                return decls

 | otherwise
 = error "runLoadFileDecls: cannot load this file"