{-# LANGUAGE ScopedTypeVariables #-}

-- | Build everything with Shake.

module Stackage.ShakeBuild where

import           Control.Concurrent.MVar
import           Stackage.BuildConstraints
import           Stackage.BuildPlan
import           Stackage.CheckBuildPlan
import           Stackage.PackageDescription
import           Stackage.PerformBuild (PerformBuild(..),copyBuiltInHaddocks,renameOrCopy)
import           Stackage.Prelude (unFlagName)

import           Control.Concurrent.STM
import           Control.Concurrent.STM.TVar
import           Control.Exception
import           Control.Monad hiding (forM_)
import           Data.Map.Strict (Map)
import qualified Data.Map.Strict as M
import           Data.Monoid
import qualified Data.Set as S
import qualified Data.Text as T
import           Development.Shake hiding (doesFileExist,doesDirectoryExist)
import           Distribution.Package (PackageName)
import           Distribution.Text (display)
import qualified Filesystem.Path.CurrentOS as FP
import           System.Directory
import           System.Environment

-- | Run the shake builder.
performBuild :: PerformBuild -> IO ()
performBuild pb = do
    shakeDir <- fmap (<//> "shake/") (getCurrentDirectory >>= canonicalizePath)
    createDirectoryIfMissing True shakeDir
    haddockFiles <- liftIO (newTVarIO mempty)
    registerLock <- liftIO (newMVar ())
    withArgs [] $
        shakeArgs
            shakeOptions
            { shakeFiles = shakeDir
            , shakeThreads = 2
            } $
        shakePlan haddockFiles registerLock pb shakeDir

-- | The complete build plan as far as Shake is concerned.
shakePlan :: TVar (Map String FilePath)
          -> MVar ()
          -> PerformBuild
          -> FilePath
          -> Rules ()
shakePlan haddockFiles registerLock pb shakeDir = do
    fetched <- target (targetForFetched shakeDir) $
               fetchedTarget shakeDir pb
    db <- target (targetForDb' shakeDir) $
          databaseTarget shakeDir pb
    _ <- forM corePackages $
         \name ->
              let fp = targetForPackage shakeDir name
              in target fp (makeFile fp)
    packageTargets <- forM normalPackages $
                      \(name,plan) ->
                           target (targetForPackage shakeDir name) $
                           do need [db, fetched]
                              packageTarget
                                  haddockFiles
                                  registerLock
                                  pb
                                  shakeDir
                                  name
                                  plan
    want packageTargets
    where corePackages = M.keys $ siCorePackages $ bpSystemInfo $ pbPlan pb
          normalPackages = filter (not . (`elem` corePackages) . fst) $
              M.toList $ bpPackages $ pbPlan pb

-- | Initialize the database if there one needs to be, and in any case
-- create the target file.
databaseTarget :: FilePath -> PerformBuild -> Action ()
databaseTarget shakeDir pb = do
    if pbGlobalInstall pb
        then return ()
        else do
            liftIO (createDirectoryIfMissing True dir)
            liftIO (removeDirectoryRecursive dir)
            () <- cmd "ghc-pkg" "init" dir
            liftIO
                (copyBuiltInHaddocks
                     (FP.decodeString
                          (pbDocDir pb)))
    makeFile (targetForDb' shakeDir)
    where dir = buildDatabase pb

-- | Build, test and generate documentation for the package.
packageTarget :: TVar (Map String FilePath)
              -> MVar ()
              -> PerformBuild
              -> FilePath
              -> PackageName
              -> PackagePlan
              -> Action ()
packageTarget haddockFiles registerLock pb shakeDir name plan = do
    need $
        map (targetForPackage shakeDir) $
        filter (/= name) $
        M.keys $ M.filter libAndExe $ sdPackages $ ppDesc plan
    pwd <- liftIO getCurrentDirectory
    env <- liftIO (fmap (Env . (++ defaultEnv pwd)) getEnvironment)
    unpack shakeDir nameVer
    configure pkgDir env pb plan
    () <- cmd cwd env "cabal" "build" "--ghc-options=-O0"
    register pkgDir env registerLock
    makeFile (targetForPackage shakeDir name)
    where cwd = Cwd pkgDir
          defaultEnv pwd = [( "HASKELL_PACKAGE_SANDBOX"
                            , pwd <//> buildDatabase pb) | pbGlobalInstall pb]
          pkgDir = shakeDir <//> nameVer
          nameVer = display name ++
              "-" ++
              display (ppVersion plan)

{-when (pcHaddocks (ppConstraints plan) /= Don'tBuild) $
(generateHaddocks haddockFiles pb pkgDir env name nameVer)-}

-- | Make sure all package archives have been fetched.
fetchedTarget :: FilePath -> PerformBuild -> Action ()
fetchedTarget shakeDir pb = do
    () <- cmd "cabal" "fetch" "--no-dependencies" $
          map
              (\(name,plan) ->
                    display name ++
                    "-" ++
                    display (ppVersion plan)) $
          M.toList $ bpPackages $ pbPlan pb
    makeFile (targetForFetched shakeDir)

-- | Unpack the package.
unpack :: FilePath -> String -> Action ()
unpack shakeDir nameVer = do
    unpacked <- liftIO (doesDirectoryExist pkgDir)
    unless unpacked $
        cmd (Cwd shakeDir) "cabal" "unpack" nameVer
    where pkgDir = shakeDir <//> nameVer

-- | Configure the given package.
configure :: FilePath -> CmdOption -> PerformBuild -> PackagePlan -> Action ()
configure pkgDir env pb plan = do
    configured <- liftIO $ doesFileExist $ pkgDir <//> "dist" <//>
                                           "setup-config"
    unless configured $
        do pwd <- liftIO getCurrentDirectory
           cmd
               (Cwd pkgDir)
               env
               "cabal"
               "configure"
               (opts pwd)
    where opts pwd = [ "--package-db=clear"
                     , "--package-db=global"
                     , "--libdir=" ++ pwd <//> pbLibDir pb
                     , "--bindir=" ++ pwd <//> pbBinDir pb
                     , "--datadir=" ++ pwd <//> pbDataDir pb
                     , "--docdir=" ++ pwd <//> pbDocDir pb
                     , "--flags=" ++ planFlags plan] ++
              ["--package-db=" ++ pwd <//> buildDatabase pb | not (pbGlobalInstall pb)]

-- | Register the package.
--
-- TODO: Do a mutex lock in here. Does Shake already support doing
-- this out of the box?
register :: FilePath -> CmdOption -> MVar () -> Action ()
register pkgDir env registerLock = do
    () <- cmd cwd env "cabal" "copy"
    -- FIXME:
    liftIO
        (takeMVar registerLock)
    () <- cmd cwd env "cabal" "register"
    liftIO (putMVar registerLock ())
    where cwd = Cwd pkgDir

-- | Generate haddocks for the package.
generateHaddocks :: TVar (Map String FilePath)
                 -> PerformBuild
                 -> FilePath
                 -> CmdOption
                 -> PackageName
                 -> FilePattern
                 -> Action ()
generateHaddocks haddockFiles pb pkgDir env name nameVer = do
    hfs <- liftIO $ readTVarIO haddockFiles
    () <- cmd
              (Cwd pkgDir)
              env
              "cabal"
              "haddock"
              "--hyperlink-source"
              "--html"
              "--hoogle"
              "--html-location=../$pkg-$version/"
              (map
                   (\(pkgVer,hf) ->
                         concat
                             [ "--haddock-options=--read-interface="
                             , "../"
                             , pkgVer
                             , "/,"
                             , hf])
                   (M.toList hfs))
    liftIO $
        renameOrCopy
            (FP.decodeString
                 (pkgDir <//> "dist" <//> "doc" <//> "html" <//> display name))
            (FP.decodeString
                 (pbDocDir pb <//> nameVer))
    enewPath <- liftIO $
                try $
                canonicalizePath
                    (pbDocDir pb <//> nameVer <//> display name ++ ".haddock")
    case enewPath of
        Left (e :: IOException) -> return () -- FIXME: log it with Shake.
        Right newPath -> liftIO $
            atomically $
            modifyTVar haddockFiles $
            M.insert nameVer newPath

-- | Generate a flags string for the package plan.
planFlags :: PackagePlan -> String
planFlags plan = unwords $
    map go $
    M.toList
        (pcFlagOverrides
             (ppConstraints plan))
    where go (name',isOn) = concat
                  [ if isOn
                        then ""
                        else "-"
                  , T.unpack (unFlagName name')]

-- | Database location.
buildDatabase :: PerformBuild -> FilePattern
buildDatabase pb = FP.encodeString (pbInstallDest pb) <//> "pkgdb"

-- | Get the target file for confirming that all packages have been
-- pre-fetched.
targetForFetched :: FilePath -> FilePath
targetForFetched shakeDir =
    shakeDir <//> "fetched"

-- | Get the target file for a package.
targetForPackage :: FilePath -> PackageName -> FilePath
targetForPackage shakeDir name =
    shakeDir <//> "packages" <//> display name

-- | Get a package database path.
targetForDb' :: FilePath -> FilePath
targetForDb' shakeDir =
    shakeDir <//> "pkgdb"

-- | Declare a target, returning the target name.
target :: FilePattern -> Action () -> Rules FilePattern
target name act = do
    name *> const act
    return name

-- | Make a file of this name.
makeFile :: FilePath -> Action ()
makeFile fp = liftIO $ writeFile fp ""

pbBinDir, pbLibDir, pbDataDir, pbDocDir :: PerformBuild -> FilePath
pbBinDir pb = FP.encodeString (pbInstallDest pb) <//> "bin"
pbLibDir pb = FP.encodeString (pbInstallDest pb) <//> "lib"
pbDataDir pb = FP.encodeString (pbInstallDest pb) <//> "share"
pbDocDir pb = FP.encodeString (pbInstallDest pb) <//> "doc"