first commit

game/components.py

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+"""Collection of common components."""
+
+from __future__ import annotations
+
+from typing import Final, Self
+
+import attrs
+import tcod.ecs.callbacks
+from tcod.ecs import Entity
+
+
+@attrs.define(frozen=True)
+class Position:
+    """An entities position."""
+
+    x: int
+    y: int
+
+    def __add__(self, direction: tuple[int, int]) -> Self:
+        """Add a vector to this position."""
+        x, y = direction
+        return self.__class__(self.x + x, self.y + y)
+
+
+@tcod.ecs.callbacks.register_component_changed(component=Position)
+def on_position_changed(entity: Entity, old: Position | None, new: Position | None) -> None:
+    """Mirror position components as a tag."""
+    if old == new:
+        return
+    if old is not None:
+        entity.tags.discard(old)
+    if new is not None:
+        entity.tags.add(new)
+
+
+@attrs.define(frozen=True)
+class Graphic:
+    """An entities icon and color."""
+
+    ch: int = ord("!")
+    fg: tuple[int, int, int] = (255, 255, 255)
+
+
+Gold: Final = ("Gold", int)
+"""Amount of gold."""