// @vitest-environment jsdom
//
// Contract of the fixed-width count pill. Uses the REAL i18n instance (not a key-passthrough) so the
// plural selection (itemCount_one/_other) and the "1M+" overflow interpolation are actually exercised —
// those are the two branches worth guarding. English is forced so the singular/plural strings are stable.
import { describe, it, expect, beforeAll, afterEach } from "vitest";
import { render, screen, cleanup } from "@testing-library/react";
import "../../i18n"; // side-effect: initialise the shared i18next instance
import i18n from "i18next";
import ItemCount from "./ItemCount";
import { formatNumber } from "../../lib/format";

beforeAll(async () => {
  await i18n.changeLanguage("en");
});
afterEach(async () => {
  cleanup();
  await i18n.changeLanguage("en"); // a case that switches language must not leak it to the next
});

const text = () => screen.getByTestId("item-count").textContent;

describe("ItemCount", () => {
  it("uses the singular string at 1 and the plural above it", () => {
    render(<ItemCount count={1} />);
    expect(text()).toBe("1 item");
  });

  it("pluralises and thousands-separates a normal count", () => {
    render(<ItemCount count={192045} />);
    // Separators come from the shared formatNumber — compare against it, not a fixed en-US string,
    // so the test asserts ItemCount's formatting path rather than the CI locale.
    expect(text()).toBe(`${formatNumber(192045)} items`);
  });

  // The pill used `count.toLocaleString()`, which groups in the BROWSER's locale: a Hungarian UI on
  // an English browser showed "192,045" instead of "192 045". The title carries the pure number (no
  // plural string), and both languages are asserted — comparing against the runtime's own default
  // would pass under the old bug on a machine whose locale happens to match the UI language.
  it("groups in the UI language, not the browser's", async () => {
    const title = () => screen.getByTestId("item-count").getAttribute("title");
    render(<ItemCount count={192045} />);
    const asEnglish = title();
    cleanup();
    await i18n.changeLanguage("hu");
    render(<ItemCount count={192045} />);
    expect(asEnglish).toBe(new Intl.NumberFormat("en").format(192045));
    expect(title()).toBe(new Intl.NumberFormat("hu").format(192045));
    expect(title()).not.toBe(asEnglish);
  });

  it("collapses a count of a million or more to 1M+, with the exact figure in the tooltip", () => {
    render(<ItemCount count={1_000_000} />);
    expect(text()).toBe("1M+ items"); // the "1M+" collapse is locale-independent
    expect(screen.getByTestId("item-count").getAttribute("title")).toBe(formatNumber(1_000_000));
  });

  it("shows the icon-only fixed box (empty label) while the count is undefined", () => {
    render(<ItemCount />);
    expect(text()).toBe(""); // the Layers icon carries no text
    expect(screen.getByTestId("item-count").getAttribute("title")).toBeNull();
  });
});