-------------------------------------------------------------------------
-- A library to get the import structures of a program.
-------------------------------------------------------------------------

module Imports
  ( getImportedInterfaces, moduleImports, readFlatCurryFileInLoadPath
  , InterfaceOrFlatProg(..), ifOrProg, progOfIFFP )
 where

import FlatCurry.Types   ( Prog(..) )
import FlatCurry.Files   ( flatCurryFileName, readFlatCurry, readFlatCurryFile )
import FlatCurry.Goodies ( progName )
import FlatCurry.Read    ( readFlatCurryIntWithImports )
import System.CurryPath  ( getLoadPathForModule )
import System.Directory  ( findFileWithSuffix, getFileSize )

--- Get all interfaces (i.e., main and all indirectly imported modules)
--- of a program:
getImportedInterfaces :: String -> IO [(String,InterfaceOrFlatProg)]
getImportedInterfaces mod = do
  imps <- readFlatCurryIntWithImports mod
  return (map (\prog -> (progName prog, IF prog)) imps)

-- Extract a module and its imports
moduleImports :: Prog -> (String, [String])
moduleImports (Prog m is _ _ _) = (m, is)

-----------------------------------------------------------------------------
-- Unione type to distinguish between interface and FlatCurry program:
data InterfaceOrFlatProg = IF Prog | FP Prog

ifOrProg :: (Prog->a) -> (Prog->a) -> InterfaceOrFlatProg -> a
ifOrProg iffun _ (IF prog) = iffun prog
ifOrProg _ fpfun (FP prog) = fpfun prog

progOfIFFP :: InterfaceOrFlatProg -> Prog
progOfIFFP (IF prog) = prog
progOfIFFP (FP prog) = prog

--------------------------------------------------------------------------
-- Read a FlatCurry file w.r.t. a given load path.
-- If the FlatCurry file does not exist, the FlatCurry file will be generated
-- by the front end.
readFlatCurryFileInLoadPath :: (String -> IO _) -> String -> [String] -> IO Prog
readFlatCurryFileInLoadPath prt mname loadpath = do
  mbfcyfile <- findFileWithSuffix (flatCurryFileName mname) [""] loadpath
  let genmsg = "FlatCurry file of module '" ++ mname ++
               "' not found, generate it..."
  maybe (prt genmsg >> readFlatCurry mname)
        (readFlatCurryFileAndReport prt mname)
        mbfcyfile

readFlatCurryFileAndReport :: (String -> IO _) -> String -> String -> IO Prog
readFlatCurryFileAndReport prt mname filename = do
  size <- getFileSize filename
  prt $ "Reading FlatCurry file of module '" ++ mname ++ "' (" ++
        show size ++ " bytes)..."
  prog <- readFlatCurryFile filename
  seq (prog==prog) (return prog)

--------------------------------------------------------------------------