module Stackage.CheckCabalVersion
    ( checkCabalVersion
    ) where

import           Control.Exception    (assert)
import           Control.Monad        (unless, when)
import qualified Data.Map             as Map
import           Data.Maybe           (mapMaybe)
import           Data.Set             (empty)
import qualified Data.Set             as Set
import           Distribution.Text    (simpleParse)
import           Distribution.Version (withinRange)
import           Prelude              hiding (pi)
import           Stackage.Config
import           Stackage.InstallInfo
import           Stackage.Tarballs
import           Stackage.Test
import           Stackage.Types
import           Stackage.Util
import           System.Directory     (canonicalizePath,
                                       createDirectoryIfMissing,
                                       doesDirectoryExist)
import           System.Exit          (ExitCode (ExitSuccess), exitWith)
import           System.IO            (IOMode (WriteMode), hPutStrLn,
                                       withBinaryFile)
import           System.Process       (rawSystem, readProcess, runProcess,
                                       waitForProcess)

checkCabalVersion :: IO String
checkCabalVersion = do
    putStrLn "Checking Cabal version"
    versionString <- readProcess "cabal" ["--version"] ""
    libVersion <-
        case map words $ lines versionString of
            [_,["using","version",libVersion,"of","the","Cabal","library"]] -> return libVersion
            _ -> error "Did not understand cabal --version output"

    case (simpleParse libVersion, simpleParse ">= 1.16") of
        (Nothing, _) -> error $ "cabal binary reported an invalid Cabal library version: " ++ libVersion
        (_, Nothing) -> assert False $ return ()
        (Just v, Just vr)
            | v `withinRange` vr -> return ()
            | otherwise -> error $ "cabal binary build against unsupported Cabal library version: " ++ libVersion

    return libVersion