Add mergeExisting property to Aura RE (foundryvtt#9247)

So there aren't a dozen kinetic auras on a single actor: if an existing aura has the same slug as a new one on the
actor, setting `mergeExisting` to true will merge the second aura into the first, combining effects and traits.

src/module/rules/rule-element/aura.ts

@@ -3,6 +3,7 @@ import { SAVE_TYPES } from "@actor/values.ts";
 import { EffectTrait } from "@item/abstract-effect/data.ts";
 import { PredicateField } from "@system/schema-data-fields.ts";
 import { sluggify } from "@util";
+import * as R from "remeda";
 import type {
  ArrayField,
  BooleanField,
@@ -84,6 +85,7 @@ class AuraRuleElement extends RuleElementPF2e<AuraSchema> {
  },
  { required: false, nullable: true, initial: null }
  ),
+ mergeExisting: new fields.BooleanField({ required: false, nullable: false, initial: true }),
  };
  }
 
@@ -120,7 +122,21 @@ class AuraRuleElement extends RuleElementPF2e<AuraSchema> {
  }
  }
 
- this.actor.auras.set(this.slug, data);
+ const existing = this.actor.auras.get(this.slug);
+ if (existing && this.mergeExisting) {
+ existing.traits = R.uniq([...existing.traits, ...data.traits]).sort();
+ if (data.colors) existing.colors = mergeObject(existing.colors ?? {}, data.colors);
+ for (const effect of data.effects) {
+ const existingIndex = existing.effects.findIndex((e) => e.uuid === effect.uuid);
+ if (existingIndex !== -1) {
+ existing.effects.splice(existingIndex, 1, effect);
+ } else {
+ existing.effects.push(effect);
+ }
+ }
+ } else {
+ this.actor.auras.set(this.slug, data);
+ }
  }
  }
 
@@ -166,17 +182,12 @@ type AuraSchema = RuleElementSchema & {
  * Custom border and fill colors for the aura: if omitted, the border color will be black, and the fill color the
  * user's assigned color
  */
- colors: SchemaField<
- {
- border: ColorField<false, true, true>;
- fill: ColorField<false, true, true>;
- },
- AuraColors,
- AuraColors,
- false,
- true,
- true
- >;
+ colors: SchemaField<{ border: ColorField; fill: ColorField }, AuraColors, AuraColors, false, true, true>;
+ /**
+ * If another aura with the same slug is already being emitted, merge this aura's data in with the other's,
+ * combining traits and effects as well as merging `colors` data.
+ */
+ mergeExisting: BooleanField<boolean, boolean, false, false, true>;
 };
 
 type AuraEffectSchema = {