import assert from "node:assert/strict";

import * as lib from "@clusterio/lib";


describe("lib/SyncHook", function() {
	describe("class SyncHook", function() {
		let hook;
		beforeEach(function() {
			hook = new lib.SyncHook();
		});

		describe(".attach()", function() {
			it("should track attached handlers", function() {
				assert.equal(hook.size, 0);
				hook.attach("alpha", value => value);
				hook.attach("beta", value => value);
				assert.equal(hook.size, 2);
				assert.deepEqual([...hook.attached], ["alpha", "beta"]);
			});
			it("should reject duplicate handler names", function() {
				hook.attach("alpha", value => value);
				assert.throws(
					() => hook.attach("alpha", value => value),
					new Error("Handler with name alpha is already attached")
				);
			});
		});
		describe(".detach()", function() {
			it("should remove the named handler", function() {
				hook.attach("alpha", value => value);
				hook.attach("beta", value => value);
				hook.detach("alpha");
				assert.deepEqual([...hook.attached], ["beta"]);
			});
		});
		describe(".clear()", function() {
			it("should remove all handlers", function() {
				hook.attach("alpha", value => value);
				hook.attach("beta", value => value);
				hook.clear();
				assert.equal(hook.size, 0);
			});
		});
		describe(".reduce()", function() {
			it("should pass the value through handlers in attach order", function() {
				hook.attach("alpha", value => [...value, "alpha"]);
				hook.attach("beta", value => [...value, "beta"]);
				assert.deepEqual(hook.reduce([]), ["alpha", "beta"]);
			});
			it("should return the value unchanged with no handlers", function() {
				const value = {};
				assert.equal(hook.reduce(value), value);
			});
			it("should rethrow errors as a PluginError named after the handler", function() {
				hook.attach("alpha", () => { throw new Error("failed"); });
				assert.throws(
					() => hook.reduce(1),
					err => err instanceof lib.PluginError && err.pluginName === "alpha"
						&& err.original.message === "failed"
				);
			});
		});
	});
});