Add state utility functions

Author: HexDecimal

game/state_tools.py

@@ -5,7 +5,7 @@
 import tcod.console
 
 import g
-from game.state import Pop, Push, Reset, StateResult
+from game.state import Pop, Push, Reset, State, StateResult
 
 
 def main_draw() -> None:
@@ -42,3 +42,20 @@ def main_loop() -> None:
             tile_event = g.context.convert_event(event)
             if g.states:
                 apply_state_result(g.states[-1].on_event(tile_event))
+
+
+def get_previous_state(state: State) -> State | None:
+    """Return the state before `state` in the stack if it exists."""
+    current_index = next(index for index, value in enumerate(g.states) if value is state)
+    return g.states[current_index - 1] if current_index > 0 else None
+
+
+def draw_previous_state(state: State, console: tcod.console.Console, dim: bool = True) -> None:
+    """Draw previous states, optionally dimming all but the active state."""
+    prev_state = get_previous_state(state)
+    if prev_state is None:
+        return
+    prev_state.on_draw(console)
+    if dim and state is g.states[-1]:
+        console.rgb["fg"] //= 4
+        console.rgb["bg"] //= 4

game/states.py

@@ -12,6 +12,7 @@
 from tcod.event import KeySym
 
 import g
+import game.state_tools
 import game.world_tools
 from game.components import Gold, Graphic, Position
 from game.state import Pop, Push, Reset, State, StateResult
@@ -164,12 +165,7 @@ def on_cancel(self) -> StateResult:
 
     def on_draw(self, console: tcod.console.Console) -> None:
         """Render the menu."""
-        current_index = g.states.index(self)
-        if current_index > 0:
-            g.states[current_index - 1].on_draw(console)
-        if g.states[-1] is self:
-            console.rgb["fg"] //= 4
-            console.rgb["bg"] //= 4
+        game.state_tools.draw_previous_state(self, console)
         for i, item in enumerate(self.items):
             is_selected = i == self.selected
             console.print(