import { beforeEach, vi } from "vitest";
import { describe, expect, it } from "vitest";

// oxlint-disable typescript/unbound-method
import type Entity from "../entity";
import System from "../system";

function getFakeEntity() {
	return {
		id: Math.random(),
		addSystem: vi.fn(),
		removeSystem: vi.fn(),
	} as unknown as Entity;
}

describe("System", () => {
	it("should initialize", () => {
		const system = new System();
		expect(system).toBeTruthy();
	});

	describe("addEntity()", () => {
		let entity: Entity;
		let system: System;

		beforeEach(() => {
			entity = getFakeEntity();
			system = new System();
		});

		it("should add an entity to the system", () => {
			system.addEntity(entity);

			expect(system.entities.size).toEqual(1);
		});

		it("should add the system to entity systems", () => {
			system.addEntity(entity);

			expect(entity.addSystem).toHaveBeenCalledWith(system);
		});

		it("should call enter() on added entity", () => {
			system.enter = vi.fn();

			system.addEntity(entity);

			expect(system.enter).toHaveBeenCalledWith(entity);
		});
	});

	describe("removeEntity()", () => {
		let entity: Entity;
		let system: System;
		beforeEach(() => {
			entity = getFakeEntity();
			system = new System();

			system.addEntity(entity);
		});

		it("should remove an entity from the system", () => {
			system.removeEntity(entity);

			expect(system.entities.size).toEqual(0);
		});

		it("should remove the system from entity systems", () => {
			system.removeEntity(entity);

			expect(entity.removeSystem).toHaveBeenCalledWith(system);
		});

		it("should call exit() on removed entity", () => {
			system.exit = vi.fn();

			system.removeEntity(entity);

			expect(system.exit).toHaveBeenCalledWith(entity);
		});
	});

	describe("updateAll()", () => {
		it("should call update() on each entity", () => {
			const entity1 = getFakeEntity();
			const entity2 = getFakeEntity();
			const system = new System();
			system.update = vi.fn();

			system.addEntity(entity1);
			system.addEntity(entity2);
			system.updateAll(0, 0);

			expect(system.update).toHaveBeenCalledTimes(2);
		});

		it("should call preUpdate()", () => {
			const system = new System();
			system.preUpdate = vi.fn();

			system.updateAll(0, 0);

			expect(system.preUpdate).toHaveBeenCalled();
		});

		it("should call postUpdate()", () => {
			const system = new System();
			system.postUpdate = vi.fn();

			system.updateAll(0, 0);

			expect(system.postUpdate).toHaveBeenCalled();
		});
	});
});