Add a session module to save and restore the playerID sent by the server (and make hannah persistent accross her reboots)

hannah.cabal

@@ -21,15 +21,19 @@ executable hannah
   other-modules:       AI
                      , Automaton
                      , Config
+                     , Session
   -- other-extensions:    
   build-depends:       aeson
                      , base >=4.9 && <4.13
                      , bytestring
                      , containers
+                     , directory
+                     , filepath
                      , hanafuda
                      , hanafuda-APILanguage
                      , mtl
                      , text
                      , websockets
   hs-source-dirs:      src
+  ghc-options:         -Wall
   default-language:    Haskell2010

src/Config.hs

@@ -1,5 +1,6 @@
 module Config (
       host
+    , libDir
     , path
     , port
   ) where
@@ -7,6 +8,9 @@ module Config (
 host :: String
 host = "koikoi.menf.in"
 
+libDir :: FilePath
+libDir = "/var/lib/hannah"
+
 path :: String
 path = "/play/"
 

src/Session.hs

@@ -0,0 +1,42 @@
+{-# LANGUAGE NamedFieldPuns #-}
+module Session (
+      State(..)
+    , initial
+    , store
+  ) where
+
+import Config (libDir)
+import Data.Map (Map)
+import qualified Data.Map as Map (empty)
+import Hanafuda.KoiKoi (PlayerID)
+import qualified Hanafuda.Message as Message (PublicGame)
+import System.Directory (createDirectoryIfMissing, doesFileExist)
+import System.FilePath ((</>))
+
+data State =
+    New
+  | Connected {
+        playerID :: PlayerID
+      , games :: Map PlayerID Message.PublicGame
+    }
+  deriving Show
+
+stateFile :: FilePath
+stateFile = libDir </> "state"
+
+ifM :: IO Bool -> IO a -> IO a -> IO a
+ifM condition caseTrue caseFalse =
+  condition >>= (\b -> if b then caseTrue else caseFalse)
+
+initial :: IO State
+initial = do
+  createDirectoryIfMissing True libDir
+  ifM (doesFileExist stateFile)
+    (do
+      playerID <- read <$> readFile stateFile
+      return $ Connected {playerID, games = Map.empty}
+    )
+    (return New)
+
+store :: PlayerID -> IO ()
+store = writeFile stateFile . show