Add a very basic, naive auto-move command

Add a very basic, naive auto-move command, which just steps the player
in a direction until they collide with something, regardless of any
surrounding beasties who might want to eat them.

There's a lot of other stuff going on here - in order to get this
working the way I wanted with a slight (I settled on 50ms) delay between
every step in these autocommands while still redrawing in between I had
to do all the extra machinery for custom Brick events with a channel,
and then at the same time adding the bits for actually executing
autocommands in a general fashion (because there will definitely be
more!) hit my threshold for size for App.hs which sent me on a big
journey to break it up into smaller files -- which seems actually like
it was quite successful. Hopefully this will help with compile times
too, though App.hs is still pretty slow (maybe more to do here).

1 files changed, 25 insertions, 4 deletions

diff --git a/src/Xanthous/Monad.hs b/src/Xanthous/Monad.hs
index 1138a7a5a0..db602de56f 100644
--- a/src/Xanthous/Monad.hs
+++ b/src/Xanthous/Monad.hs
@@ -5,12 +5,19 @@ module Xanthous.Monad
   , runAppT
   , continue
   , halt
+
     -- * Messages
   , say
   , say_
   , message
   , message_
   , writeMessage
+
+    -- * Autocommands
+  , cancelAutocommand
+
+    -- * Events
+  , sendEvent
   ) where
 --------------------------------------------------------------------------------
 import           Xanthous.Prelude
@@ -18,16 +25,16 @@ import           Control.Monad.Random
 import           Control.Monad.State
 import qualified Brick
 import           Brick (EventM, Next)
-import           Data.Aeson
+import           Brick.BChan (writeBChan)
+import           Data.Aeson (ToJSON, object)
 --------------------------------------------------------------------------------
+import           Xanthous.Data.App (AppEvent)
 import           Xanthous.Game.State
+import           Xanthous.Game.Env
 import           Xanthous.Messages (Message)
 import qualified Xanthous.Messages as Messages
 --------------------------------------------------------------------------------
 
-runAppT :: Monad m => AppT m a -> GameState -> m (a, GameState)
-runAppT appt initialState = flip runStateT initialState . unAppT $ appt
-
 halt :: AppT (EventM n) (Next GameState)
 halt = lift . Brick.halt =<< get
 
@@ -53,3 +60,17 @@ message_ msg = message msg $ object []
 
 writeMessage :: MonadState GameState m => Text -> m ()
 writeMessage m = messageHistory %= pushMessage m
+
+-- | Cancel the currently active autocommand, if any
+cancelAutocommand :: (MonadState GameState m, MonadIO m) => m ()
+cancelAutocommand = do
+  traverse_ (liftIO . cancel . snd) =<< preuse (autocommand . _ActiveAutocommand)
+  autocommand .= NoAutocommand
+
+--------------------------------------------------------------------------------
+
+-- | Send an event to the app in an environment where the game env is available
+sendEvent :: (MonadReader GameEnv m, MonadIO m) => AppEvent -> m ()
+sendEvent evt = do
+  ec <- view eventChan
+  liftIO $ writeBChan ec evt