refactored state -> screen

game/screens/menus.py

@@ -0,0 +1,100 @@
+"""Menu UI classes."""
+
+from __future__ import annotations
+
+from collections.abc import Callable
+from typing import Protocol
+
+import attrs
+import tcod.console
+import tcod.event
+from tcod.event import KeySym
+
+from game.constants import DIRECTION_KEYS
+from game.screens import Pop, Screen, ScreenResult, draw_previous_screens
+
+
+class MenuItem(Protocol):
+    """Menu item protocol."""
+
+    __slots__ = ()
+
+    def on_event(self, event: tcod.event.Event) -> ScreenResult:
+        """Handle events passed to the menu item."""
+
+    def on_draw(self, console: tcod.console.Console, x: int, y: int, highlight: bool) -> None:
+        """Draw is item at the given position."""
+
+
+@attrs.define()
+class SelectItem(MenuItem):
+    """Clickable menu item."""
+
+    label: str
+    callback: Callable[[], ScreenResult]
+
+    def on_event(self, event: tcod.event.Event) -> ScreenResult:
+        """Handle events selecting this item."""
+        match event:
+            case tcod.event.KeyDown(sym=sym) if sym in {KeySym.RETURN, KeySym.RETURN2, KeySym.KP_ENTER}:
+                return self.callback()
+            case tcod.event.MouseButtonUp(button=tcod.event.MouseButton.LEFT):
+                return self.callback()
+            case _:
+                return None
+
+    def on_draw(self, console: tcod.console.Console, x: int, y: int, highlight: bool) -> None:
+        """Render this items label."""
+        console.print(x, y, self.label, fg=(255, 255, 255), bg=(64, 64, 64) if highlight else (0, 0, 0))
+
+
+@attrs.define()
+class ListMenu(Screen):
+    """Simple list menu state."""
+
+    items: tuple[MenuItem, ...]
+    selected: int | None = 0
+    x: int = 0
+    y: int = 0
+
+    def on_event(self, event: tcod.event.Event) -> ScreenResult:
+        """Handle events for menus."""
+        match event:
+            case tcod.event.Quit():
+                raise SystemExit()
+            case tcod.event.KeyDown(sym=sym) if sym in DIRECTION_KEYS:
+                dx, dy = DIRECTION_KEYS[sym]
+                if dx != 0 or dy == 0:
+                    return self.activate_selected(event)
+                if self.selected is not None:
+                    self.selected += dy
+                    self.selected %= len(self.items)
+                else:
+                    self.selected = 0 if dy == 1 else len(self.items) - 1
+                return None
+            case tcod.event.MouseMotion(position=(_, y)):
+                y -= self.y
+                self.selected = y if 0 <= y < len(self.items) else None
+                return None
+            case tcod.event.KeyDown(sym=KeySym.ESCAPE):
+                return self.on_cancel()
+            case tcod.event.MouseButtonUp(button=tcod.event.MouseButton.RIGHT):
+                return self.on_cancel()
+            case _:
+                return self.activate_selected(event)
+
+    def activate_selected(self, event: tcod.event.Event) -> ScreenResult:
+        """Call the selected menu items callback."""
+        if self.selected is not None:
+            return self.items[self.selected].on_event(event)
+        return None
+
+    def on_cancel(self) -> ScreenResult:
+        """Handle escape or right click being pressed on menus."""
+        return Pop()
+
+    def on_draw(self, console: tcod.console.Console) -> None:
+        """Render the menu."""
+        draw_previous_screens(self, console)
+        for i, item in enumerate(self.items):
+            item.on_draw(console, x=self.x, y=self.y + i, highlight=i == self.selected)