load database on start

package.yaml

@@ -22,6 +22,7 @@ description:         Please see the README on GitHub at <https://github.com/jlam
 dependencies:
 - base >= 4.7 && < 5
 - aeson >= 1.4.4.0 && < 1.5
+- easy-file >= 0.2.2 && < 0.3
 - extra >= 1.6.17 && < 1.7
 - microlens-th >= 0.4.2.3 && < 0.5
 - ncurses >= 0.2.16 && < 0.3

src/Mtlstats.hs

@@ -19,15 +19,23 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 -}
 
+{-# LANGUAGE ScopedTypeVariables #-}
+
 module Mtlstats (initState, mainLoop) where
 
+import Control.Exception (IOException, catch)
 import Control.Monad (void)
 import Control.Monad.Extra (whenM)
+import Control.Monad.IO.Class (liftIO)
 import Control.Monad.Trans.Class (lift)
 import Control.Monad.Trans.State (get, gets)
-import Data.Maybe (fromJust)
+import Data.Aeson (decodeFileStrict)
+import Data.Maybe (fromJust, fromMaybe)
+import Lens.Micro ((&), (.~))
+import System.EasyFile (getAppUserDataDirectory, (</>))
 import qualified UI.NCurses as C
 
+import Mtlstats.Config
 import Mtlstats.Control
 import Mtlstats.Types
 
@@ -36,7 +44,15 @@ initState :: C.Curses ProgState
 initState = do
   C.setEcho False
   void $ C.setCursorMode C.CursorInvisible
-  return newProgState
+  db <- liftIO $ do
+    dir <- getAppUserDataDirectory appName
+    let dbFile = dir </> dbFname
+    fromMaybe newDatabase <$> catch
+      (decodeFileStrict dbFile)
+      (\(_ :: IOException) -> return Nothing)
+  return
+    $ newProgState
+    & database .~ db
 
 -- | Main program loop
 mainLoop :: Action ()

src/Mtlstats/Config.hs

@@ -28,3 +28,11 @@ myTeam = "MONTREAL"
 -- | The maximum number of function keys
 maxFunKeys :: Int
 maxFunKeys = 9
+
+-- | The application name
+appName :: String
+appName = "mtlstats"
+
+-- | The database filename
+dbFname :: String
+dbFname = "database.json"