{- This Source Code Form is subject to the terms of the Mozilla Public License,
   v. 2.0. If a copy of the MPL was not distributed with this file, You can
   obtain one at https://mozilla.org/MPL/2.0/. -}

-- | Transformers and exceptions.
module SlackBuilder.Trans
    ( SlackBuilderException(..)
    , SlackBuilderT(..)
    , relativeToRepository
    ) where

import Control.Monad.Trans.Reader (ReaderT(..), asks)
import Data.Text (Text)
import qualified Data.Text as Text
import SlackBuilder.Config
import Control.Monad.IO.Class (MonadIO(..))
import Control.Monad.Catch (MonadCatch(..), MonadThrow(..))
import Control.Exception (Exception(..))
import System.FilePath ((</>))
import Text.URI (URI)
import qualified Text.URI as URI
import qualified Codec.Compression.Lzma as Lzma

data SlackBuilderException
    = UpdaterNotFound Text
    | HttpsUrlExpected URI
    | LzmaDecompressionFailed Lzma.LzmaRet
    deriving Show

instance Exception SlackBuilderException
  where
    displayException (UpdaterNotFound updateName) = Text.unpack
        $ Text.concat ["Requested package \"", updateName, "\" was not found"]
    displayException (HttpsUrlExpected givenURI) = Text.unpack
        $ "Only https URLs are supported, got: " <> URI.render givenURI
    displayException (LzmaDecompressionFailed Lzma.LzmaRetOK) =
        "Operation completed successfully"
    displayException (LzmaDecompressionFailed Lzma.LzmaRetStreamEnd) =
        "End of stream was reached"
    displayException (LzmaDecompressionFailed Lzma.LzmaRetUnsupportedCheck) =
        "Cannot calculate the integrity check"
    displayException (LzmaDecompressionFailed Lzma.LzmaRetGetCheck) =
        "Integrity check type is now available"
    displayException (LzmaDecompressionFailed Lzma.LzmaRetMemError) =
        "Cannot allocate memory"
    displayException (LzmaDecompressionFailed Lzma.LzmaRetMemlimitError) =
        "Memory usage limit was reached"
    displayException (LzmaDecompressionFailed Lzma.LzmaRetFormatError) =
        "File format not recognized"
    displayException (LzmaDecompressionFailed Lzma.LzmaRetOptionsError) =
        "Invalid or unsupported options"
    displayException (LzmaDecompressionFailed Lzma.LzmaRetDataError) =
        "Data is corrupt"
    displayException (LzmaDecompressionFailed Lzma.LzmaRetBufError) =
        "No progress is possible"
    displayException (LzmaDecompressionFailed Lzma.LzmaRetProgError) =
        "Programming error"
 
newtype SlackBuilderT a = SlackBuilderT
    { runSlackBuilderT :: ReaderT Settings IO a
    }

relativeToRepository :: FilePath -> SlackBuilderT FilePath
relativeToRepository filePath =
    (</> filePath) <$> SlackBuilderT (asks repository)

instance Functor SlackBuilderT
  where
    fmap f (SlackBuilderT slackBuilderT) = SlackBuilderT $ f <$> slackBuilderT

instance Applicative SlackBuilderT
  where
    pure = SlackBuilderT . pure
    (SlackBuilderT f) <*> (SlackBuilderT x) = SlackBuilderT $ f <*> x

instance Monad SlackBuilderT
  where
    return = pure
    (SlackBuilderT x) >>= f = SlackBuilderT $ x >>= runSlackBuilderT . f

instance MonadIO SlackBuilderT
  where
    liftIO = SlackBuilderT . liftIO

instance MonadThrow SlackBuilderT
  where
    throwM = SlackBuilderT . throwM

instance MonadCatch SlackBuilderT
  where
    catch (SlackBuilderT action) handler =
        SlackBuilderT $ catch action $ runSlackBuilderT . handler