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

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";
import { expectDomainError } from "./test-helpers.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,
		);

		expectDomainError(result, "unknown-condition");
	});

	it("returns error for nonexistent combatant", () => {
		const e = enc([makeCombatant("A")]);
		const result = toggleCondition(e, combatantId("missing"), "blinded");

		expectDomainError(result, "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);
	});
});