{- | This module exports functions for compiling Elm to JS.
-}
module Elm.Internal.Utils (compile, moduleName, nameAndImports) where

import qualified Data.List as List
import qualified Generate.JavaScript as JS
import qualified Build.Source as Source
import Parse.Module (getModuleName)
import Parse.Parse (dependencies)
import qualified SourceSyntax.Module as M
import qualified Text.PrettyPrint as P
import qualified Metadata.Prelude as Prelude
import System.IO.Unsafe

-- |This function compiles Elm code to JavaScript. It will return either
--  an error message or the compiled JS code.
compile :: String -> Either String String
compile source =
    case Source.build False interfaces source of
      Left docs -> Left . unlines . List.intersperse "" $ map P.render docs
      Right modul -> Right $ JS.generate modul

{-# NOINLINE interfaces #-}
interfaces :: M.Interfaces
interfaces = unsafePerformIO $ Prelude.interfaces False

-- |This function extracts the module name of a given source program.
moduleName :: String -> Maybe String
moduleName = getModuleName

-- |This function extracts the module name and imported modules from a given
--  source program.
nameAndImports :: String -> Maybe (String, [String])
nameAndImports src =
    either (const Nothing) Just (dependencies src)