Untangle state changes into actions

WIP: still unclear if we really need the IORefs!

1 files changed, 32 insertions, 15 deletions

diff --git a/src/Game/Entities.hs b/src/Game/Entities.hs
index 4e5a686..4d8b12b 100644
--- a/src/Game/Entities.hs
+++ b/src/Game/Entities.hs
@@ -17,6 +17,7 @@ import Game.Entities.Types
 import qualified Game.Map as M
 import qualified Game.Sprites as S
 import qualified Game.State as GS
+import SDL (($~))
 import qualified SDL
 
 mkEntities :: S.SpriteSheet -> M.Map -> IORef C.Controls -> IORef GS.State -> IO Entities
@@ -30,9 +31,9 @@ mkEntities sprites m controls stateRef = do
   pure $ Entities sprites playerRef stateRef (player : entities)
   where
     toEntity :: IORef Entity -> M.Object -> IO Entity
-    toEntity playerRef (M.SlimeEntity x y) = mkSlime sprites x y (collision playerRef 16) (M.isBlocked m) (hitPlayer stateRef)
-    toEntity playerRef (M.RobotEntity x y) = mkRobot sprites x y (collision playerRef 24) (M.isBlocked m) (hitPlayer stateRef)
-    toEntity playerRef (M.BatteryEntity x y) = mkBattery sprites x y (collision playerRef 16) (collectedBattery stateRef)
+    toEntity playerRef (M.SlimeEntity x y) = mkSlime sprites x y (collision playerRef 16) (M.isBlocked m)
+    toEntity playerRef (M.RobotEntity x y) = mkRobot sprites x y (collision playerRef 24) (M.isBlocked m)
+    toEntity playerRef (M.BatteryEntity x y) = mkBattery sprites x y (collision playerRef 16)
     toEntity _ (M.PlayerEntity _ _) = error "Player already processed"
 
 -- | Return the player's entity position (x, y).
@@ -42,32 +43,48 @@ playerPosition (Entities _ _ _ entities) =
   where
     player = head entities
 
-processSpawn :: S.SpriteSheet -> Spawn -> IO Entity
-processSpawn sprites (DustEffectSpawn x y) = mkEffect sprites x y "dust"
-
 updateAll :: Entities -> IO Entities
 updateAll es = do
   -- update the player first (including the reference)
   updatedPlayer <- player.update player
   void $ writeIORef es.player updatedPlayer
-  state <- readIORef es.state
+  state <- readIORef stateRef
   -- update hit delay if the player was hit
   let playerWasHit = state.hitDelay > 0
-  when playerWasHit (writeIORef es.state state {GS.hitDelay = state.hitDelay - 1})
+  when playerWasHit (writeIORef stateRef state {GS.hitDelay = state.hitDelay - 1})
   -- then the other entities
   updated <- (updatedPlayer :) <$> traverse (updateFilter playerWasHit) others
-  -- collect new entities
-  new <- traverse (processSpawn es.sprites) (concatMap (\e -> e.spawns) updated)
-  -- is the player dead?
-  updated' <- do
-    s <- readIORef es.state
-    pure $ if s.lives == 0 && updatedPlayer.dir /= Dying then (head updated) {dir = Dying, gravity = gravityUp, frame = 0} : tail updated else updated
+  -- process actions
+  updated' <- processActions updated (concatMap (\e -> e.actions) updated)
   -- clear spawns (new entities), filter out destroyed entities, and add the new ones
-  pure es {entities = map (\e -> e {spawns = []}) (filter (\e -> not e.destroy) updated') ++ new}
+  pure es {entities = map (\e -> e {actions = []}) (filter (\e -> not e.destroy) updated')}
   where
+    stateRef = es.state
     player = head es.entities
     others = tail es.entities
 
+    processActions :: [Entity] -> [Action] -> IO [Entity]
+    processActions ents (a : t) =
+      case a of
+        ActionAddDustEffect x y -> do
+          effect <- mkEffect es.sprites x y "dust"
+          processActions (ents ++ [effect]) t
+        ActionAddBattery -> do
+          stateRef $~ (\s -> s {GS.batteries = s.batteries + 1})
+          processActions ents t
+        ActionHitPlayer -> do
+          s <- readIORef stateRef
+          ents' <-
+            if s.lives == 1
+              then do
+                writeIORef stateRef s {GS.lives = 0, GS.gameOverDelay = gameOverDelay}
+                pure $ (head ents) {dir = Dying, gravity = gravityUp, frame = 0} : tail ents
+              else do
+                writeIORef stateRef s {GS.lives = s.lives - 1, GS.hitDelay = hitDelay}
+                pure ents
+          processActions ents' t
+    processActions ents [] = pure ents
+
     -- Update entities skipping enemies if the player was hit.
     updateFilter :: Bool -> Entity -> IO Entity
     updateFilter False e = e.update e