import { describe, it, expect, vi } from "vitest";
import { StrictMode } from "react";
import { render, screen, fireEvent, waitFor } from "@testing-library/react";
import { MemoryRouter, useLocation } from "react-router-dom";
import { RegionUrlSync, SelectionResetOnRegion } from "../src/App";
import { RegionProvider, useRegionSelection } from "../src/hooks/useRegion";

function RegionChanger() {
  const { setSelection } = useRegionSelection();
  return <button onClick={() => setSelection({ regions: [], iatas: ["YYZ"] })}>change</button>;
}

function CurrentUrl() {
  return <output data-testid="current-url">{useLocation().search}</output>;
}

it("preserves an initial Topology link but clears its node/camera focus when the shared region changes", async () => {
  render(<StrictMode><MemoryRouter initialEntries={["/?tab=Topology&iata=YVR&topoNode=node-a&topoFocus=YVR&topoWindow=24h"]}>
    <RegionProvider defaultSelection={{ regions: [], iatas: ["YVR"] }}>
      <RegionUrlSync /><RegionChanger /><CurrentUrl />
    </RegionProvider>
  </MemoryRouter></StrictMode>);
  expect(screen.getByTestId("current-url")).toHaveTextContent("topoNode=node-a");
  fireEvent.click(screen.getByText("change"));
  await waitFor(() => {
    const params = new URLSearchParams(screen.getByTestId("current-url").textContent!);
    expect(params.get("iata")).toBe("YYZ");
    expect(params.get("topoWindow")).toBe("24h");
    expect(params.has("topoNode")).toBe(false);
    expect(params.has("topoFocus")).toBe(false);
  });
});

describe("SelectionResetOnRegion", () => {
  // Regression: a deep-linked ?node/?observer selection must survive load. The reset watches the raw
  // selection (not the resolved regionKey) so the async slug→IATA expansion doesn't count as a change,
  // and compares the previous value so StrictMode's double effect invoke can't fire it on mount.
  it("does not reset on mount, even under StrictMode's double effect invoke", () => {
    const onReset = vi.fn();
    render(
      <StrictMode>
        <RegionProvider defaultSelection={{ regions: [], iatas: ["YVR"] }}>
          <SelectionResetOnRegion onRegionChange={onReset} />
        </RegionProvider>
      </StrictMode>,
    );
    expect(onReset).not.toHaveBeenCalled();
  });

  it("resets once when the user changes the region selection", () => {
    const onReset = vi.fn();
    render(
      <RegionProvider defaultSelection={{ regions: [], iatas: ["YVR"] }}>
        <SelectionResetOnRegion onRegionChange={onReset} />
        <RegionChanger />
      </RegionProvider>,
    );
    expect(onReset).not.toHaveBeenCalled();
    fireEvent.click(screen.getByText("change"));
    expect(onReset).toHaveBeenCalledTimes(1);
  });
});