Allow specifying seed on startup

Allow specifying the seed for the game's global RNG on startup, and
print the seed when the game exits. This'll allow us to more reliably
reproduce bugs - yay!

1 files changed, 9 insertions, 4 deletions

diff --git a/src/Xanthous/Game/Lenses.hs b/src/Xanthous/Game/Lenses.hs
index 101de3021c..f49477a2db 100644
--- a/src/Xanthous/Game/Lenses.hs
+++ b/src/Xanthous/Game/Lenses.hs
@@ -6,6 +6,7 @@ module Xanthous.Game.Lenses
   , characterPosition
   , updateCharacterVision
   , getInitialState
+  , initialStateFromSeed
 
     -- * Collisions
   , Collision(..)
@@ -16,6 +17,7 @@ import           Xanthous.Prelude
 --------------------------------------------------------------------------------
 import           System.Random
 import           Control.Monad.State
+import           Control.Monad.Random (getRandom)
 --------------------------------------------------------------------------------
 import           Xanthous.Game.State
 import           Xanthous.Data
@@ -28,9 +30,12 @@ import           Xanthous.Entities.Creature (Creature)
 --------------------------------------------------------------------------------
 
 getInitialState :: IO GameState
-getInitialState = do
-  _randomGen <- getStdGen
-  let char = mkCharacter
+getInitialState = initialStateFromSeed <$> getRandom
+
+initialStateFromSeed :: Int -> GameState
+initialStateFromSeed seed =
+  let _randomGen = mkStdGen seed
+      char = mkCharacter
       (_characterEntityID, _entities)
         = EntityMap.insertAtReturningID
           (Position 0 0)
@@ -42,7 +47,7 @@ getInitialState = do
       _debugState = DebugState
         { _allRevealed = False
         }
-  pure GameState {..}
+  in GameState {..}
 
 
 positionedCharacter :: Lens' GameState (Positioned Character)