feat: add deterministic order to mob/player tick processing, document how tick processing works

1 files changed, 60 insertions, 0 deletions

diff --git a/internal/game/tick_systems.go b/internal/game/tick_systems.go
new file mode 100644
index 0000000..4d8d4b6
--- /dev/null
+++ b/internal/game/tick_systems.go
@@ -0,0 +1,60 @@
+package game
+
+// tickSystem is one step of the canonical per-tick system sequence. Name is
+// the human-readable identifier also encoded in building_guide/tick_order.md;
+// Run invokes the underlying system. The slice tickSystemOrder is the single
+// executable source of truth for the order in which per-tick systems fire.
+//
+// The order is what callers like the master subscriber in cmd/thoi/main.go
+// (registered as engine subscription ID 1, which the engine fires before all
+// dynamically-registered combat/aggro/respawn callbacks per processTick's
+// registration-ID sort) depend on. Reordering this slice is a breaking change
+// to game behavior; keep building_guide/tick_order.md in sync.
+type tickSystem struct {
+	Name string
+	Run  func(*Game)
+}
+
+// TickSystemOrder returns the canonical per-tick system sequence. It is a
+// copy of the internal slice so callers cannot mutate the canonical order.
+func TickSystemOrder() []struct{ Name string } {
+	out := make([]struct{ Name string }, len(tickSystemOrder))
+	for i, s := range tickSystemOrder {
+		out[i] = struct{ Name string }{s.Name}
+	}
+	return out
+}
+
+var tickSystemOrder = []tickSystem{
+	{"ProcessQueuedCommands", (*Game).ProcessQueuedCommands},
+	{"MoveTick", (*Game).MoveTick},
+	{"SequenceTick", (*Game).SequenceTick},
+	{"TransientMobTick", (*Game).TransientMobTick},
+	{"World.Tick", func(g *Game) { g.World.Tick() }},
+	{"MobStore.Tick", func(g *Game) { g.MobStore.Tick() }},
+	{"RegenTick", (*Game).RegenTick},
+	{"EnergyRegenTick", (*Game).EnergyRegenTick},
+	{"DisconnectTick", (*Game).DisconnectTick},
+	{"WanderTick", (*Game).WanderTick},
+	{"SharedDepletionTick", (*Game).SharedDepletionTick},
+	{"FireTick", (*Game).FireTick},
+	{"AdvanceActions", (*Game).AdvanceActions},
+	{"TechTick", (*Game).TechTick},
+	{"ConsumeTick", (*Game).ConsumeTick},
+	{"BroadcastRespawns", (*Game).BroadcastRespawns},
+	{"VisualTick", (*Game).VisualTick},
+	{"SneakTick", (*Game).SneakTick},
+	{"FarmTick", (*Game).FarmTick},
+	{"BuffTick", (*Game).BuffTick},
+	{"SafespotTick", (*Game).SafespotTick},
+	{"HazardTick", (*Game).HazardTick},
+}
+
+// RunTickSystems fires every canonical per-tick system in registration order.
+// It is the body of the master per-tick subscriber in cmd/thoi/main.go and the
+// single place that encodes per-tick system execution order.
+func (g *Game) RunTickSystems() {
+	for _, s := range tickSystemOrder {
+		s.Run(g)
+	}
+}
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