Feature/api versioning (#106)

* wip

* finishes initial refactor

* prune unused code

* finished massive refactor

* remove commented deps

* fix import

* fix bug

src/Handler/Package/V0/Version.hs

@@ -0,0 +1,46 @@
+{-# LANGUAGE QuasiQuotes #-}
+
+module Handler.Package.V0.Version where
+
+import Data.Aeson (ToJSON, object, (.=))
+import Data.String.Interpolate.IsString (i)
+import Foundation (Handler)
+import Handler.Util (
+    getVersionSpecFromQuery,
+    orThrow,
+    versionPriorityFromQueryIsMin,
+ )
+import Lib.Error (S9Error (..))
+import Lib.PkgRepository (getBestVersion)
+import Lib.Types.Core (PkgId)
+import Lib.Types.Emver (Version (..))
+import Network.HTTP.Types (status404)
+import Startlude (Eq, Maybe, Show, (.), (<$>))
+import Yesod (ToContent (..), ToTypedContent, sendResponseStatus)
+import Yesod.Core (ToJSON (..), ToTypedContent (..))
+
+
+newtype AppVersionRes = AppVersionRes
+    { appVersionVersion :: Version
+    }
+    deriving (Eq, Show)
+instance ToJSON AppVersionRes where
+    toJSON AppVersionRes{appVersionVersion} = object ["version" .= appVersionVersion]
+instance ToContent AppVersionRes where
+    toContent = toContent . toJSON
+instance ToTypedContent AppVersionRes where
+    toTypedContent = toTypedContent . toJSON
+instance ToContent (Maybe AppVersionRes) where
+    toContent = toContent . toJSON
+instance ToTypedContent (Maybe AppVersionRes) where
+    toTypedContent = toTypedContent . toJSON
+
+
+getPkgVersionR :: PkgId -> Handler AppVersionRes
+getPkgVersionR pkg = do
+    spec <- getVersionSpecFromQuery
+    preferMin <- versionPriorityFromQueryIsMin
+    AppVersionRes <$> getBestVersion pkg spec preferMin
+        `orThrow` sendResponseStatus
+            status404
+            (NotFoundE [i|Version for #{pkg} satisfying #{spec}|])