Implement world tick functionality for NPCs; add NPC spawning and movement logic, and update autosave and tick threading

Author: samclane

Discordia/GameLogic/GameSpace.py

@@ -703,6 +703,7 @@ def add_wilds(self, wilds: Wilds):
         self.map[wilds.y][wilds.x] = wilds
 
     def add_actor(self, actor: Actors.Actor, space: Space | None = None):
+        actor.parent_world = self
         if isinstance(actor, Actors.PlayerCharacter):
             actor.location = self.starting_town
             self.players.append(actor)
@@ -780,6 +781,20 @@ def pvp_attack(
                 dmg = weapon.calc_damage(int(player_character.location.distance(loc)))
         return response
 
+    def tick(self):
+        """One step of world time: NPCs spawn, wander and fight without any player input."""
+        # ponytail: no lock. Discord commands mutate the world from the bot's thread too, so a
+        # tick can interleave with a command. Wrap both in one world lock if that ever misfires.
+        self.npcs = [npc for npc in self.npcs if not npc.is_dead]
+        if self.wilds and len(self.npcs) < len(self.wilds):
+            self.add_actor(Actors.Raider.generate(1), random.choice(self.wilds))
+        for npc in self.npcs:
+            targets = [p for p in self.players if p.location == npc.location]
+            if targets:
+                npc.brain.update(random.choice(targets))
+            else:
+                npc.attempt_move(random.choice(list(DIRECTION_VECTORS.values())))
+
     def handle_player_death(self, player: Actors.PlayerCharacter):
         LOG.info(f"Player {player.name} has died")
         player.location = self.starting_town

Discordia/test/test_game_logic.py

@@ -552,3 +552,54 @@ def test_a_player_sees_their_own_neighbourhood(adapter):
 
 def test_screenshots_degrade_gracefully_without_a_renderer(adapter):
     assert adapter.get_player_screenshot(adapter.get_player(1)) == "<No Renderer>"
+
+
+# --- World tick: NPCs act on real time, not on player input ------------------------------------
+
+
+def test_ticking_spawns_npcs_and_moves_them_without_the_player(adapter):
+    world = adapter.world
+    assert not world.npcs
+
+    world.tick()
+    assert len(world.npcs) == 1
+    npc = world.npcs[0]
+    assert npc.parent_world is world
+    assert world.is_space_valid(npc.location)
+
+    # Somewhere with room to walk, so "it never moved" means the tick is broken, not that it's boxed in
+    npc.location = next(
+        space
+        for space in adapter.iter_spaces()
+        if all(
+            world.is_space_valid(neighbor)
+            for neighbor in world.get_adjacent_spaces(space)
+        )
+    )
+    start = npc.location
+    seen = {start}
+    for _ in range(50):
+        world.tick()
+        seen.add(npc.location)
+        assert world.is_space_valid(npc.location)
+    assert len(seen) > 1
+
+
+def test_a_tick_lets_an_npc_hit_a_player_sharing_its_space(adapter):
+    world = adapter.world
+    player = adapter.get_player(1)
+    npc = Actors.Raider(world, 50, "Mugger")
+    world.add_actor(npc, player.location)
+
+    world.tick()
+    assert player.hit_points < player.hit_points_max
+
+
+def test_dead_npcs_are_dropped_on_the_next_tick(adapter):
+    world = adapter.world
+    npc = Actors.Raider(world, 1, "Doomed")
+    world.add_actor(npc, world.starting_town)
+    npc.take_damage(10)
+
+    world.tick()
+    assert npc not in world.npcs

main.py

@@ -14,17 +14,18 @@
 logging.basicConfig(level=logging.INFO)
 
 AUTOSAVE_SECONDS = 60
+TICK_SECONDS = 5
 
 
-def autosave(database: Database, adapter: WorldAdapter):
-    # ponytail: a plain timer loop, so a crash loses at most AUTOSAVE_SECONDS of play. Save on each mutating
-    # command instead if that ever costs someone a real purchase.
+def every(seconds: float, action, name: str):
+    # ponytail: a plain timer loop, so a crash loses at most AUTOSAVE_SECONDS of play, and ticks
+    # drift by however long the action took. Both fine at these intervals.
     while True:
-        time.sleep(AUTOSAVE_SECONDS)
+        time.sleep(seconds)
         try:
-            database.save(adapter)
+            action()
         except Exception:
-            LOG.exception("Autosave failed")
+            LOG.exception("%s failed", name)
 
 
 def main():
@@ -50,7 +51,16 @@ def main():
     display = WindowRenderer(adapter)
 
     threading.Thread(target=update_display, args=(display, args.show_window), daemon=True).start()
-    threading.Thread(target=autosave, args=(database, adapter), daemon=True).start()
+    threading.Thread(
+        target=every,
+        args=(AUTOSAVE_SECONDS, lambda: database.save(adapter), "Autosave"),
+        daemon=True,
+    ).start()
+    threading.Thread(
+        target=every,
+        args=(TICK_SECONDS, adapter.world.tick, "World tick"),
+        daemon=True,
+    ).start()
     discord_interface = DiscordInterface(adapter)
     # discord_interface.bot.loop.create_task(update_display(display))
     # threading.Thread(target=discord_interface.bot.run, args=(ConfigParser.DISCORD_TOKEN,), daemon=True).start()