{-# OPTIONS -cpp -fglasgow-exts #-}
-----------------------------------------------------------------------------
-- |
-- Module      :  Distribution.Verbosity
-- Copyright   :  Ian Lynagh 2007
--
-- Maintainer  :  Isaac Jones <[email protected]>
-- Stability   :  alpha
-- Portability :  portable
--
-- Verbosity for Cabal functions

{- Copyright (c) 2007, Ian Lynagh
All rights reserved.

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module Distribution.Verbosity (
  -- * Verbosity
  Verbosity,
  silent, normal, verbose, deafening,
  intToVerbosity, flagToVerbosity,
  showForCabal, showForGHC
 ) where

import Data.List (elemIndex)

data Verbosity = Silent | Normal | Verbose | Deafening
    deriving (Show, Eq, Ord)

-- We shouldn't print /anything/ unless an error occurs in silent mode
silent :: Verbosity
silent = Silent

-- Print stuff we want to see by default
normal :: Verbosity
normal = Normal

-- Be more verbose about what's going on
verbose :: Verbosity
verbose = Verbose

-- Not only are we verbose ourselves (perhaps even noisier than when
-- being "verbose"), but we tell everything we run to be verbose too
deafening :: Verbosity
deafening = Deafening

intToVerbosity :: Int -> Maybe Verbosity
intToVerbosity 0 = Just Silent
intToVerbosity 1 = Just Normal
intToVerbosity 2 = Just Verbose
intToVerbosity 3 = Just Deafening
intToVerbosity _ = Nothing

flagToVerbosity :: Maybe String -> Verbosity
flagToVerbosity Nothing = verbose -- A "-v" flag is equivalent to "-v2"
flagToVerbosity (Just s)
 = case reads s of
       [(i, "")] ->
           case intToVerbosity i of
               Just v -> v
               Nothing -> error ("Bad verbosity " ++ show i)
       _ -> error ("Can't parse verbosity " ++ s)

showForCabal, showForGHC :: Verbosity -> String

showForCabal v = maybe (error "unknown verbosity") show $
    elemIndex v [silent,normal,verbose,deafening]
showForGHC   v = maybe (error "unknown verbosity") show $
    elemIndex v [silent,normal,__,verbose,deafening]
        where __ = silent -- this will be always ignored by elemIndex