{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE TemplateHaskell #-}
import           Data.Aeson                      hiding (object)
import qualified Data.ByteString.Lazy            as B
import qualified Data.Configurator               as C
import           Data.Maybe                      (fromMaybe)
import           Data.MonoTraversable.Unprefixed
import           Data.Sequences
import qualified Data.Text.IO                    as T
import           Marvin.Run                      (defaultConfigName, lookupFromAppConfig)
import           Options.Applicative
import           Prelude                         hiding (elem, filter)
import           System.Directory
import           System.FilePath
import           Text.Mustache
import           Text.Mustache.Compile


data Opts = Opts
    { adapter         :: Maybe String
    , sourceName      :: FilePath
    , sourceLocation  :: FilePath
    , targetFile      :: FilePath
    , externalScripts :: FilePath
    , configLocation  :: Maybe FilePath
    }


slackRtmData :: (String, String)
slackRtmData = ("Marvin.Adapter.Slack", "(SlackAdapter RTM)")


adapters :: [(String, (String, String))]
adapters =
    [ ("slack-rtm", slackRtmData)
    , ("telegram-poll", ("Marvin.Adapter.Telegram", "(TelegramAdapter Poll)"))
    , ("telegram-push", ("Marvin.Adapter.Telegram", "(TelegramAdapter Push)"))
    , ("shell", ("Marvin.Adapter.Shell", "ShellAdapter"))
    ]


tpl :: Template
tpl = $(embedTemplate ["preprocessor"] "Main.mustache")


main :: IO ()
main = do
    Opts{..} <- execParser infoParser

    adapter' <- maybe
        (do
            (cfg, _) <- C.autoReload C.autoConfig $ maybe [] (return . C.Optional) configLocation
            lookupFromAppConfig cfg "adapter"
        )
        (return . return)
        adapter

    let (adapterImport, adapterType) = fromMaybe slackRtmData $ adapter' >>= flip lookup adapters

    let dir = takeDirectory sourceName
    paths <- filter (not . ((||) <$> isPrefixOf "_" <*> isPrefixOf ".")) <$> getDirectoryContents dir
    files <- filterM (doesFileExist . (dir </>)) paths
    externals <- do
        exists <- doesFileExist externalScripts
        if exists
            then do
                f <- B.readFile externalScripts
                either error return $ eitherDecode f
            else return mempty
    let hsFiles = map dropExtensions $ filter (/= takeFileName sourceName) $ filter ((`elem` [".hs", ".lhs"]) . takeExtension) files
        scripts = hsFiles <> externals
        processed = substitute tpl (object [ "scripts" ~> intercalate ", " (map (<> ".script") scripts)
                                            , "imports" ~> scripts
                                            , "adapter-import" ~> adapterImport
                                            , "adapter-type" ~> adapterType
                                            ])
    T.writeFile targetFile processed
  where
    infoParser = info
        (helper <*> optsParser)
        (fullDesc <> header "marvin-pp ~ the marvin preprocessor")
    optsParser = Opts
        <$> optional
            (strOption
                $  long "adapter"
                <> short 'a'
                <> metavar "ID"
                <> help "adapter to use"
                <> showDefault
            )
        <*> argument str (metavar "NAME")
        <*> argument str (metavar "PATH")
        <*> argument str (metavar "PATH")
        <*> strOption
            (  long "external-scripts"
            <> short 's'
            <> value "external-scripts.json"
            <> metavar "PATH"
            <> help "config file of external scripts to load"
            <> showDefault
            )
        <*> optional
            (strOption
            $  long "config-location"
            <> short 'c'
            <> metavar "PATH"
            <> help "config to use"
            <> showDefault
            <> value defaultConfigName
            )