module RefacCase(ifToCase) where

import RefacUtils 

ifToCase args  
  = do let fileName = args!!0              
           beginPos = (read (args!!1), read (args!!2))::(Int,Int)
           endPos   = (read (args!!3), read (args!!4))::(Int,Int)
       modInfo@(_, _, mod, toks) <- parseSourceFile fileName 
       let exp = locToExp beginPos endPos toks mod
       case exp of 
           (Exp (HsIf _ _ _))   
                -> do refactoredMod <- applyRefac (ifToCase exp) (Just modInfo) fileName          
                      writeRefactoredFiles False [refactoredMod]
           _   -> error "You haven't selected an if-then-else  expression!"
    where 

     ifToCase exp (_, _, mod)= applyTP (once_buTP (failTP `adhocTP` inExp)) mod
       where 
         inExp exp1@((Exp (HsIf  e e1 e2))::HsExpP)
           | sameOccurrence exp exp1       
           = let newExp =Exp (HsCase e [HsAlt loc0 (nameToPat "True") (HsBody e1) [],
                                        HsAlt loc0 (nameToPat "False")(HsBody e2) []])
             in update exp1 newExp exp1
         inExp _ = mzero