// node:events as guests use it: classes, EventEmitter.call(this), prototype mixins.
import { test, expect } from "@playwright/test";
import { guestLines, runGuest } from "./guest";

test("listener order, once, prepend, removal and introspection match Node", async ({ page }) => {
  const lines = await guestLines(page, {
    "/app/main.cjs": [
      'const EventEmitter = require("node:events");',
      "const e = new EventEmitter();",
      "const seen = [];",
      'const b = () => seen.push("b");',
      'e.on("x", () => seen.push("a"));',
      'e.on("x", b);',
      'e.once("x", () => seen.push("once"));',
      'e.prependListener("x", () => seen.push("first"));',
      'e.emit("x"); e.emit("x");',
      'e.off("x", b); e.emit("x");',
      "console.log(seen.join(','));",
      'console.log(e.listenerCount("x"), e.eventNames().join(","), e.emit("nobody"));',
      'console.log(EventEmitter.EventEmitter === EventEmitter, typeof EventEmitter.once, e.setMaxListeners(1) === e, e.getMaxListeners());',
    ].join("\n"),
  }, "/app/main.cjs");
  expect(lines).toEqual([
    "first,a,b,once,first,a,b,first,a",
    "2 x false",
    "true function true 1",
  ]);
});

test("EventEmitter.call(this) inheritance and prototype mixins work", async ({ page }) => {
  const lines = await guestLines(page, {
    "/app/main.cjs": [
      'const { EventEmitter } = require("events");',
      "function Legacy() { EventEmitter.call(this); }",
      "Object.setPrototypeOf(Legacy.prototype, EventEmitter.prototype);",
      "const l = new Legacy();",
      'l.on("hi", (v) => console.log("legacy", v)); l.emit("hi", 1);',
      "const app = function () {};",
      "for (const k of Object.getOwnPropertyNames(EventEmitter.prototype)) if (k !== 'constructor') app[k] = EventEmitter.prototype[k];",
      'app.on("mount", (v) => console.log("mixin", v)); app.emit("mount", 2);',
      'console.log(l instanceof EventEmitter, app.listeners("mount").length);',
    ].join("\n"),
  }, "/app/main.cjs");
  expect(lines).toEqual(["legacy 1", "mixin 2", "true 1"]);
});

test("ESM named imports and events.once resolve with the emitted args", async ({ page }) => {
  const lines = await guestLines(page, {
    "/app/main.mjs": [
      'import { EventEmitter, once } from "node:events";',
      "const e = new EventEmitter();",
      'setTimeout(() => e.emit("ready", 1, 2), 1);',
      'console.log(JSON.stringify(await once(e, "ready")));',
    ].join("\n"),
  }, "/app/main.mjs");
  expect(lines).toEqual(["[1,2]"]);
});

test("an 'error' with no listener throws the error", async ({ page }) => {
  const res = await runGuest(page, {
    "/app/main.cjs": 'const E = require("node:events"); new E().emit("error", new Error("kaboom"));\n',
  }, "/app/main.cjs");
  expect(res.code).toBe(1);
  expect(res.stderr).toContain("Error: kaboom");
});