Add advantage mode store.

module/data/fields/advantage-mode-field.mjs

@@ -22,43 +22,79 @@ export default class AdvantageModeField extends foundry.data.fields.NumberField
   /* -------------------------------------------- */
 
   /**
-   * Number of advantage sources.
-   * @type {number}
+   * Advantage sources.
+   * @type {Map<string, Map<string, number>>}
    */
-  #advantage;
+  static #advantages = new Map();
 
   /* -------------------------------------------- */
 
   /**
-   * Number of disadvantage sources.
-   * @type {number}
+   * Disadvantage sources.
+   * @type {Map<string, Map<string, number>>}
    */
-  #disadvantage;
+  static #disadvantages = new Map();
 
   /* -------------------------------------------- */
 
-  /** @inheritDoc */
-  initialize(value, model, options={}) {
-    this.#advantage = Number(value === 1);
-    this.#disadvantage = Number(value === -1);
-    return value;
+  /**
+   * Add one to the count of advantages or disadvantages.
+   * @param {Actor5e} actor           The actor gaining a source of advantage or disadvantage.
+   * @param {string} path             The path to the property affected.
+   * @param {boolean} [isAdvantage]   Is this an instance of advantage or disadvantage?
+   */
+  static addSource(actor, path, isAdvantage=true) {
+    const store = isAdvantage ? this.#advantages : this.#disadvantages;
+    let map = store.get(actor.uuid);
+    if ( !map ) {
+      store.set(actor.uuid, new Map());
+      map = store.get(actor.uuid);
+    }
+    map.set(path, (map.get(path) ?? 0) + 1);
+  }
+
+  /* -------------------------------------------- */
+
+  /**
+   * Clear out any tracked values for an actor.
+   * @param {Actor5e} actor     The actor whose stored data to clear.
+   */
+  static clearSources(actor) {
+    this.#advantages.delete(actor.uuid);
+    this.#disadvantages.delete(actor.uuid);
   }
 
+  /* -------------------------------------------- */
+
+  /**
+   * Retrieve the advantage mode of a given property.
+   * @param {Actor5e} actor     The actor whose mode to determine.
+   * @param {string} path       The path to the property affected.
+   * @returns {number}          The advantage mode.
+   */
+  static getMode(actor, path) {
+    const advantages = this.#advantages.get(actor.uuid)?.get(path) ?? 0;
+    const disadvantages = this.#disadvantages.get(actor.uuid)?.get(path) ?? 0;
+    return Math.sign(advantages) - Math.sign(disadvantages);
+  }
+
+  /* -------------------------------------------- */
+
+  // /** @inheritDoc */
+  // initialize(value, model, options={}) {
+  //   // Not functional due to no known fieldPath.
+  //   if ( [-1, 1].includes(value) ) AdvantageModeField.addSource(model.parent, this.fieldPath, value === 1);
+  //   return value;
+  // }
+
   /* -------------------------------------------- */
   /*  Active Effect Integration                   */
   /* -------------------------------------------- */
 
   /** @override */
   _applyChangeAdd(value, delta, model, change) {
-    switch ( delta ) {
-      case 1:
-        this.#advantage++;
-        break;
-      case -1:
-        this.#disadvantage++;
-        break;
-    }
-    return Math.sign(this.#advantage) - Math.sign(this.#disadvantage);
+    if ( [-1, 1].includes(delta) ) AdvantageModeField.addSource(model, change.key, delta === 1);
+    return AdvantageModeField.getMode(model, change.key);
   }
 
   /* -------------------------------------------- */

module/documents/actor/actor.mjs

@@ -11,6 +11,7 @@ import SystemDocumentMixin from "../mixins/document.mjs";
 import Proficiency from "./proficiency.mjs";
 import SelectChoices from "./select-choices.mjs";
 import * as Trait from "./trait.mjs";
+import AdvantageModeField from "../../data/fields/advantage-mode-field.mjs";
 
 /**
  * Extend the base Actor class to implement additional system-specific logic.
@@ -193,6 +194,7 @@ export default class Actor5e extends SystemDocumentMixin(Actor) {
 
   /** @inheritDoc */
   prepareData() {
+    AdvantageModeField.clearSources(this);
     if ( this.system.modelProvider !== dnd5e ) return super.prepareData();
     this._clearCachedValues();
     this._preparationWarnings = [];