first commit

internal/combat/buff.go

@@ -0,0 +1,86 @@
+package combat
+
+import "time"
+
+// BuffDef defines a buff/debuff type.
+type BuffDef struct {
+	ID           uint32
+	Name         string
+	IsDebuff     bool
+	DamagePerTick int32 // for DoTs (debuff); heal per tick for HoTs (buff)
+	StatModifier  StatMod
+}
+
+// StatMod is a temporary stat modification from a buff.
+type StatMod struct {
+	StrBonus int32
+	DexBonus int32
+	IntBonus int32
+}
+
+// ActiveBuff is an active buff/debuff on an entity.
+type ActiveBuff struct {
+	Def          *BuffDef
+	CasterID     uint64
+	Remaining    time.Duration
+	TickInterval time.Duration
+	NextTick     time.Duration // time until next tick
+}
+
+// Tick advances the buff by dt. Returns damage/heal to apply this tick (0 if no tick).
+func (b *ActiveBuff) Tick(dt time.Duration) int32 {
+	b.Remaining -= dt
+	var tickValue int32
+
+	if b.TickInterval > 0 {
+		b.NextTick -= dt
+		if b.NextTick <= 0 {
+			tickValue = b.Def.DamagePerTick
+			b.NextTick += b.TickInterval
+		}
+	}
+
+	return tickValue
+}
+
+// IsExpired returns true if the buff has no remaining duration.
+func (b *ActiveBuff) IsExpired() bool {
+	return b.Remaining <= 0
+}
+
+// BuffRegistry holds all buff/debuff definitions.
+type BuffRegistry struct {
+	buffs map[uint32]*BuffDef
+}
+
+// NewBuffRegistry creates a registry with default buffs.
+func NewBuffRegistry() *BuffRegistry {
+	r := &BuffRegistry{buffs: make(map[uint32]*BuffDef)}
+	r.registerDefaults()
+	return r
+}
+
+// Get returns a buff definition.
+func (r *BuffRegistry) Get(id uint32) *BuffDef {
+	return r.buffs[id]
+}
+
+func (r *BuffRegistry) registerDefaults() {
+	// Poison DoT (referenced by skill ID 5, effect Value=1)
+	r.buffs[1] = &BuffDef{
+		ID:            1,
+		Name:          "Poison",
+		IsDebuff:      true,
+		DamagePerTick: 8,
+	}
+
+	// Power Up buff (referenced by skill ID 6, effect Value=2)
+	r.buffs[2] = &BuffDef{
+		ID:       2,
+		Name:     "Power Up",
+		IsDebuff: false,
+		StatModifier: StatMod{
+			StrBonus: 20,
+		},
+	}
+}