--------------------------------------------------------------------
-- |
-- Copyright :  © Edward Kmett 2010-2014, Johan Kiviniemi 2013
-- License   :  BSD3
-- Maintainer:  Edward Kmett <ekmett@gmail.com>
-- Stability :  experimental
-- Portability: non-portable
--
--------------------------------------------------------------------
module Ersatz.Solver.Common
  ( withTempFiles
  , resultOf

  -- * Support for trying many solvers
  , trySolvers
  , NoSolvers(..)
  ) where

import Control.Exception (Exception(..), throwIO)
import Control.Monad.IO.Class
import Ersatz.Solution
import System.Exit (ExitCode(..))
import System.IO.Error (isDoesNotExistError, tryIOError)
import System.IO.Temp (withSystemTempDirectory)

withTempFiles :: MonadIO m
              => FilePath  -- ^ Problem file extension including the dot, if any
              -> FilePath  -- ^ Solution file extension including the dot, if any
              -> (FilePath -> FilePath -> IO a) -> m a
withTempFiles :: FilePath -> FilePath -> (FilePath -> FilePath -> IO a) -> m a
withTempFiles FilePath
problemExt FilePath
solutionExt FilePath -> FilePath -> IO a
f = IO a -> m a
forall (m :: * -> *) a. MonadIO m => IO a -> m a
liftIO (IO a -> m a) -> IO a -> m a
forall a b. (a -> b) -> a -> b
$
  FilePath -> (FilePath -> IO a) -> IO a
forall (m :: * -> *) a.
(MonadIO m, MonadMask m) =>
FilePath -> (FilePath -> m a) -> m a
withSystemTempDirectory FilePath
"ersatz" ((FilePath -> IO a) -> IO a) -> (FilePath -> IO a) -> IO a
forall a b. (a -> b) -> a -> b
$ \FilePath
dir -> do
    let problemPath :: FilePath
problemPath  = FilePath
dir FilePath -> FilePath -> FilePath
forall a. [a] -> [a] -> [a]
++ FilePath
"/problem"  FilePath -> FilePath -> FilePath
forall a. [a] -> [a] -> [a]
++ FilePath
problemExt
        solutionPath :: FilePath
solutionPath = FilePath
dir FilePath -> FilePath -> FilePath
forall a. [a] -> [a] -> [a]
++ FilePath
"/solution" FilePath -> FilePath -> FilePath
forall a. [a] -> [a] -> [a]
++ FilePath
solutionExt

    FilePath -> FilePath -> IO a
f FilePath
problemPath FilePath
solutionPath

resultOf :: ExitCode -> Result
resultOf :: ExitCode -> Result
resultOf (ExitFailure Int
10) = Result
Satisfied
resultOf (ExitFailure Int
20) = Result
Unsatisfied
resultOf ExitCode
_                = Result
Unsolved

-- | This error is thrown by 'trySolvers' when no solvers are found.
newtype NoSolvers = NoSolvers [IOError] deriving Int -> NoSolvers -> FilePath -> FilePath
[NoSolvers] -> FilePath -> FilePath
NoSolvers -> FilePath
(Int -> NoSolvers -> FilePath -> FilePath)
-> (NoSolvers -> FilePath)
-> ([NoSolvers] -> FilePath -> FilePath)
-> Show NoSolvers
forall a.
(Int -> a -> FilePath -> FilePath)
-> (a -> FilePath) -> ([a] -> FilePath -> FilePath) -> Show a
showList :: [NoSolvers] -> FilePath -> FilePath
$cshowList :: [NoSolvers] -> FilePath -> FilePath
show :: NoSolvers -> FilePath
$cshow :: NoSolvers -> FilePath
showsPrec :: Int -> NoSolvers -> FilePath -> FilePath
$cshowsPrec :: Int -> NoSolvers -> FilePath -> FilePath
Show

instance Exception NoSolvers where
  displayException :: NoSolvers -> FilePath
displayException NoSolvers
_ = FilePath
"no ersatz solvers were found"

-- | Try a list of solvers in order. When a solver fails due to
-- a missing executable the next solver will be tried. Throws
-- 'NoSolvers' exception if none of the given solvers were installed.
trySolvers :: [Solver s IO] -> Solver s IO
trySolvers :: [Solver s IO] -> Solver s IO
trySolvers [Solver s IO]
solvers s
problem = (Solver s IO
 -> ([IOError] -> IO (Result, IntMap Bool))
 -> [IOError]
 -> IO (Result, IntMap Bool))
-> ([IOError] -> IO (Result, IntMap Bool))
-> [Solver s IO]
-> [IOError]
-> IO (Result, IntMap Bool)
forall (t :: * -> *) a b.
Foldable t =>
(a -> b -> b) -> b -> t a -> b
foldr Solver s IO
-> ([IOError] -> IO (Result, IntMap Bool))
-> [IOError]
-> IO (Result, IntMap Bool)
forall b. (s -> IO b) -> ([IOError] -> IO b) -> [IOError] -> IO b
runSolver [IOError] -> IO (Result, IntMap Bool)
forall a. [IOError] -> IO a
noSolvers [Solver s IO]
solvers []
  where
    noSolvers :: [IOError] -> IO a
noSolvers = NoSolvers -> IO a
forall e a. Exception e => e -> IO a
throwIO (NoSolvers -> IO a)
-> ([IOError] -> NoSolvers) -> [IOError] -> IO a
forall b c a. (b -> c) -> (a -> b) -> a -> c
. [IOError] -> NoSolvers
NoSolvers ([IOError] -> NoSolvers)
-> ([IOError] -> [IOError]) -> [IOError] -> NoSolvers
forall b c a. (b -> c) -> (a -> b) -> a -> c
. [IOError] -> [IOError]
forall a. [a] -> [a]
reverse

    runSolver :: (s -> IO b) -> ([IOError] -> IO b) -> [IOError] -> IO b
runSolver s -> IO b
solver [IOError] -> IO b
next [IOError]
es =
      do Either IOError b
res <- IO b -> IO (Either IOError b)
forall a. IO a -> IO (Either IOError a)
tryIOError (s -> IO b
solver s
problem)
         case Either IOError b
res of
           Left IOError
e
             | IOError -> Bool
isDoesNotExistError IOError
e -> [IOError] -> IO b
next (IOError
eIOError -> [IOError] -> [IOError]
forall a. a -> [a] -> [a]
:[IOError]
es)
             | Bool
otherwise             -> IOError -> IO b
forall a. IOError -> IO a
ioError IOError
e
           Right b
x                   -> b -> IO b
forall (m :: * -> *) a. Monad m => a -> m a
return b
x