Implement the 017-combat-conditions feature that adds D&D 5e status conditions to combatants with icon tags, color coding, and a compact toggle picker in the encounter tracker

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/domain/src/__tests__/toggle-condition.test.ts

@@ -0,0 +1,120 @@
+import { describe, expect, it } from "vitest";
+import type { ConditionId } from "../conditions.js";
+import { CONDITION_DEFINITIONS } from "../conditions.js";
+import { toggleCondition } from "../toggle-condition.js";
+import type { Combatant, Encounter } from "../types.js";
+import { combatantId, isDomainError } from "../types.js";
+
+function makeCombatant(
+	name: string,
+	conditions?: readonly ConditionId[],
+): Combatant {
+	return conditions
+		? { id: combatantId(name), name, conditions }
+		: { id: combatantId(name), name };
+}
+
+function enc(combatants: Combatant[]): Encounter {
+	return { combatants, activeIndex: 0, roundNumber: 1 };
+}
+
+function success(encounter: Encounter, id: string, condition: ConditionId) {
+	const result = toggleCondition(encounter, combatantId(id), condition);
+	if (isDomainError(result)) {
+		throw new Error(`Expected success, got error: ${result.message}`);
+	}
+	return result;
+}
+
+describe("toggleCondition", () => {
+	it("adds a condition when not present", () => {
+		const e = enc([makeCombatant("A")]);
+		const { encounter, events } = success(e, "A", "blinded");
+
+		expect(encounter.combatants[0].conditions).toEqual(["blinded"]);
+		expect(events).toEqual([
+			{
+				type: "ConditionAdded",
+				combatantId: combatantId("A"),
+				condition: "blinded",
+			},
+		]);
+	});
+
+	it("removes a condition when already present", () => {
+		const e = enc([makeCombatant("A", ["blinded"])]);
+		const { encounter, events } = success(e, "A", "blinded");
+
+		expect(encounter.combatants[0].conditions).toBeUndefined();
+		expect(events).toEqual([
+			{
+				type: "ConditionRemoved",
+				combatantId: combatantId("A"),
+				condition: "blinded",
+			},
+		]);
+	});
+
+	it("maintains definition order when adding conditions", () => {
+		const e = enc([makeCombatant("A", ["poisoned"])]);
+		const { encounter } = success(e, "A", "blinded");
+
+		expect(encounter.combatants[0].conditions).toEqual(["blinded", "poisoned"]);
+	});
+
+	it("prevents duplicate conditions", () => {
+		const e = enc([makeCombatant("A", ["blinded"])]);
+		// Toggling blinded again removes it, not duplicates
+		const { encounter } = success(e, "A", "blinded");
+		expect(encounter.combatants[0].conditions).toBeUndefined();
+	});
+
+	it("rejects unknown condition", () => {
+		const e = enc([makeCombatant("A")]);
+		const result = toggleCondition(
+			e,
+			combatantId("A"),
+			"flying" as ConditionId,
+		);
+
+		expect(isDomainError(result)).toBe(true);
+		if (isDomainError(result)) {
+			expect(result.code).toBe("unknown-condition");
+		}
+	});
+
+	it("returns error for nonexistent combatant", () => {
+		const e = enc([makeCombatant("A")]);
+		const result = toggleCondition(e, combatantId("missing"), "blinded");
+
+		expect(isDomainError(result)).toBe(true);
+		if (isDomainError(result)) {
+			expect(result.code).toBe("combatant-not-found");
+		}
+	});
+
+	it("does not mutate input encounter", () => {
+		const e = enc([makeCombatant("A")]);
+		const original = JSON.parse(JSON.stringify(e));
+		toggleCondition(e, combatantId("A"), "blinded");
+		expect(e).toEqual(original);
+	});
+
+	it("normalizes empty array to undefined on removal", () => {
+		const e = enc([makeCombatant("A", ["charmed"])]);
+		const { encounter } = success(e, "A", "charmed");
+
+		expect(encounter.combatants[0].conditions).toBeUndefined();
+	});
+
+	it("preserves order across all conditions", () => {
+		const order = CONDITION_DEFINITIONS.map((d) => d.id);
+		// Add in reverse order
+		let e = enc([makeCombatant("A")]);
+		for (const cond of [...order].reverse()) {
+			const result = success(e, "A", cond);
+			e = result.encounter;
+		}
+		expect(e.combatants[0].conditions).toEqual(order);
+	});
+});