Added a updateArmorValue function that updates armoreffects according to an auto order

module/data/activeEffect/armorEffect.mjs

@@ -115,6 +115,34 @@ export default class ArmorEffect extends foundry.data.ActiveEffectTypeDataModel
         await this.parent.update({ 'system.changes': newChanges });
     }
 
+    static orderEffectsForAutoChange(armorEffects, increasing) {
+        const getEffectWeight = effect => {
+            switch (effect.parent.type) {
+                case 'loot':
+                case 'consumable':
+                    return 2;
+                case 'class':
+                case 'subclass':
+                case 'ancestry':
+                case 'community':
+                case 'feature':
+                case 'domainCard':
+                    return 3;
+                case 'weapon':
+                case 'armor':
+                    return 4;
+                case 'character':
+                    return 5;
+                default:
+                    return 1;
+            }
+        };
+
+        return armorEffects.sort((a, b) =>
+            increasing ? getEffectWeight(b) - getEffectWeight(a) : getEffectWeight(a) - getEffectWeight(b)
+        );
+    }
+
     /* Overrides */
 
     prepareBaseData() {

module/data/actor/character.mjs

@@ -458,11 +458,6 @@ export default class DhCharacter extends BaseDataActor {
         return this.parent.items.find(x => x.type === 'armor' && x.system.equipped);
     }
 
-    /* TODO: Prep datastructure to be useful when applying automatic armor damage order */
-    get armorEffects() {
-        return Array.from(this.parent.allApplicableEffects());
-    }
-
     get activeBeastform() {
         return this.parent.effects.find(x => x.type === 'beastform');
     }
@@ -512,6 +507,53 @@ export default class DhCharacter extends BaseDataActor {
         }
     }
 
+    async updateArmorValue(armorChange) {
+        if (armorChange === 0) return;
+
+        const increasing = armorChange >= 0;
+        let remainingChange = Math.abs(armorChange);
+        const armorEffects = Array.from(this.parent.allApplicableEffects()).filter(x => x.type === 'armor');
+        const orderedEffects = game.system.api.data.activeEffects.ArmorEffect.orderEffectsForAutoChange(
+            armorEffects,
+            increasing
+        );
+
+        const embeddedUpdates = [];
+        for (const armorEffect of orderedEffects) {
+            let usedArmorChange = 0;
+            if (increasing) {
+                const remainingArmor = armorEffect.system.armorChange.max - armorEffect.system.armorChange.value;
+                usedArmorChange = Math.min(remainingChange, remainingArmor);
+                remainingChange -= usedArmorChange;
+            } else {
+                const changeChange = Math.min(armorEffect.system.armorChange.value, remainingChange);
+                usedArmorChange -= changeChange;
+                remainingChange -= changeChange;
+            }
+
+            if (!usedArmorChange) continue;
+            else {
+                if (!embeddedUpdates[armorEffect.parent.id])
+                    embeddedUpdates[armorEffect.parent.id] = { doc: armorEffect.parent, updates: [] };
+
+                embeddedUpdates[armorEffect.parent.id].updates.push({
+                    '_id': armorEffect.id,
+                    'system.changes': [
+                        {
+                            ...armorEffect.system.armorChange,
+                            value: armorEffect.system.armorChange.value + usedArmorChange
+                        }
+                    ]
+                });
+            }
+
+            if (remainingChange === 0) break;
+        }
+
+        for (const { doc, updates } of Object.values(embeddedUpdates))
+            doc.updateEmbeddedDocuments('ActiveEffect', updates);
+    }
+
     get sheetLists() {
         const ancestryFeatures = [],
             communityFeatures = [],