Display error descriptions

lib/SlackBuilder/Trans.hs

@@ -11,12 +11,14 @@ module SlackBuilder.Trans
 
 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
@@ -26,7 +28,34 @@ data SlackBuilderException
     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
     }

src/Main.hs

@@ -6,6 +6,7 @@ module Main
     ( main
     ) where
 
+import Control.Exception (Exception(..), handle)
 import Data.Char (isNumber)
 import Data.List.NonEmpty (NonEmpty(..))
 import Control.Monad.Catch (MonadThrow(..))
@@ -20,7 +21,6 @@ import SlackBuilder.Update
 import qualified Toml
 import Data.Text (Text)
 import qualified Data.Text as Text
-import qualified Data.Text.IO as Text.IO
 import Control.Monad.Trans.Reader (ReaderT(..))
 import SlackBuilder.Package (PackageDescription(..))
 import qualified SlackBuilder.Package as Package
@@ -28,6 +28,13 @@ import Text.URI.QQ (uri)
 import Data.Foldable (for_, find)
 import GHC.Records (HasField(..))
 import System.Process (CmdSpec(..))
+import System.Console.ANSI
+    ( setSGR
+    , SGR(..)
+    , ColorIntensity(..)
+    , Color(..)
+    , ConsoleLayer(..)
+    )
 
 autoUpdatable :: [PackageDescription]
 autoUpdatable =
@@ -294,17 +301,20 @@ check = for_ autoUpdatable go
         >>= mapM_ checkUpdateAvailability
         >> liftIO (putStrLn "")
 
-
 main :: IO ()
 main = do
     programCommand <- execParser slackBuilderParser
     settings <- Toml.decodeFile settingsCodec "config/config.toml"
-    latestVersion <- flip runReaderT settings
+    handle handleException
+        $ flip runReaderT settings
         $ runSlackBuilderT
         $ executeCommand programCommand
-
-    maybe (pure ()) Text.IO.putStrLn latestVersion
   where
+    handleException :: SlackBuilderException -> IO ()
+    handleException slackBuilderException
+        = setSGR [SetColor Foreground Dull Red]
+        >> putStrLn (displayException slackBuilderException)
+        >> setSGR [Reset]
     executeCommand = \case
-        CheckCommand -> check >> pure Nothing
-        Up2DateCommand packageName -> up2Date packageName >> pure Nothing
+        CheckCommand -> check
+        Up2DateCommand packageName -> up2Date packageName