{-# LANGUAGE CPP #-}
-----------------------------------------------------------------------------
-- |
-- Module      :  Distribution.Client.Run
-- Maintainer  :  cabal-devel@haskell.org
-- Portability :  portable
--
-- Implementation of the 'run' command.
-----------------------------------------------------------------------------

module Distribution.Client.Run ( run, splitRunArgs )
       where

import Distribution.Client.Utils             (tryCanonicalizePath)

import Distribution.PackageDescription       (Executable (..),
                                              TestSuite(..),
                                              Benchmark(..),
                                              PackageDescription (..),
                                              BuildInfo(buildable))
import Distribution.Simple.Compiler          (compilerFlavor, CompilerFlavor(..))
import Distribution.Simple.Build.PathsModule (pkgPathEnvVar)
import Distribution.Simple.BuildPaths        (exeExtension)
import Distribution.Simple.LocalBuildInfo    (ComponentName (..),
                                              LocalBuildInfo (..),
                                              getComponentLocalBuildInfo,
                                              depLibraryPaths)
import Distribution.Simple.Utils             (die, notice, warn,
                                              rawSystemExitWithEnv,
                                              addLibraryPath)
import Distribution.System                   (Platform (..))
import Distribution.Verbosity                (Verbosity)

import qualified Distribution.Simple.GHCJS as GHCJS

#if !MIN_VERSION_base(4,8,0)
import Data.Functor                          ((<$>))
#endif
import Data.List                             (find)
import Data.Foldable                         (traverse_)
import System.Directory                      (getCurrentDirectory)
import Distribution.Compat.Environment       (getEnvironment)
import System.FilePath                       ((<.>), (</>))


-- | Return the executable to run and any extra arguments that should be
-- forwarded to it. Die in case of error.
splitRunArgs :: Verbosity -> LocalBuildInfo -> [String]
             -> IO (Executable, [String])
splitRunArgs verbosity lbi args =
  case whichExecutable of -- Either err (wasManuallyChosen, exe, paramsRest)
    Left err               -> do
      warn verbosity `traverse_` maybeWarning -- If there is a warning, print it.
      die err
    Right (True, exe, xs)  -> return (exe, xs)
    Right (False, exe, xs) -> do
      let addition = " Interpreting all parameters to `run` as a parameter to"
                     ++ " the default executable."
      -- If there is a warning, print it together with the addition.
      warn verbosity `traverse_` fmap (++addition) maybeWarning
      return (exe, xs)
  where
    pkg_descr = localPkgDescr lbi
    whichExecutable :: Either String       -- Error string.
                              ( Bool       -- If it was manually chosen.
                              , Executable -- The executable.
                              , [String]   -- The remaining parameters.
                              )
    whichExecutable = case (enabledExes, args) of
      ([]   , _)           -> Left "Couldn't find any enabled executables."
      ([exe], [])          -> return (False, exe, [])
      ([exe], (x:xs))
        | x == exeName exe -> return (True, exe, xs)
        | otherwise        -> return (False, exe, args)
      (_    , [])          -> Left
        $ "This package contains multiple executables. "
        ++ "You must pass the executable name as the first argument "
        ++ "to 'cabal run'."
      (_    , (x:xs))      ->
        case find (\exe -> exeName exe == x) enabledExes of
          Nothing  -> Left $ "No executable named '" ++ x ++ "'."
          Just exe -> return (True, exe, xs)
      where
        enabledExes = filter (buildable . buildInfo) (executables pkg_descr)

    maybeWarning :: Maybe String
    maybeWarning = case args of
      []    -> Nothing
      (x:_) -> lookup x components
      where
        components :: [(String, String)] -- Component name, message.
        components =
          [ (name, "The executable '" ++ name ++ "' is disabled.")
          | e <- executables pkg_descr
          , not . buildable . buildInfo $ e, let name = exeName e]

          ++ [ (name, "There is a test-suite '" ++ name ++ "',"
                      ++ " but the `run` command is only for executables.")
             | t <- testSuites pkg_descr
             , let name = testName t]

          ++ [ (name, "There is a benchmark '" ++ name ++ "',"
                      ++ " but the `run` command is only for executables.")
             | b <- benchmarks pkg_descr
             , let name = benchmarkName b]

-- | Run a given executable.
run :: Verbosity -> LocalBuildInfo -> Executable -> [String] -> IO ()
run verbosity lbi exe exeArgs = do
  curDir <- getCurrentDirectory
  let buildPref     = buildDir lbi
      pkg_descr     = localPkgDescr lbi
      dataDirEnvVar = (pkgPathEnvVar pkg_descr "datadir",
                       curDir </> dataDir pkg_descr)

  (path, runArgs) <-
    case compilerFlavor (compiler lbi) of
      GHCJS -> do
        let (script, cmd, cmdArgs) =
              GHCJS.runCmd (withPrograms lbi)
                           (buildPref </> exeName exe </> exeName exe)
        script' <- tryCanonicalizePath script
        return (cmd, cmdArgs ++ [script'])
      _     -> do
         p <- tryCanonicalizePath $
            buildPref </> exeName exe </> (exeName exe <.> exeExtension)
         return (p, [])

  env  <- (dataDirEnvVar:) <$> getEnvironment
  -- Add (DY)LD_LIBRARY_PATH if needed
  env' <- if withDynExe lbi
             then do let (Platform _ os) = hostPlatform lbi
                         clbi = getComponentLocalBuildInfo lbi
                                  (CExeName (exeName exe))
                     paths <- depLibraryPaths True False lbi clbi
                     return (addLibraryPath os paths env)
             else return env
  notice verbosity $ "Running " ++ exeName exe ++ "..."
  rawSystemExitWithEnv verbosity path (runArgs++exeArgs) env'