import { beforeEach, describe, expect, it, vi } from "vitest";
import { fireEvent, render, screen, waitFor, within } from "@testing-library/react";
import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
import { MemoryRouter, useLocation } from "react-router-dom";
import { CompareObserversTab } from "../../../src/features/stats/CompareObserversTab";
import { getObserverComparison, getObserversPage, getObserver } from "../../../src/api/client";
import i18n from "../../../src/i18n";

const region = { iatas: ["YVR"], regionKey: "YVR" };
vi.mock("../../../src/hooks/useRegion", () => ({ useRegion: () => region }));
vi.mock("../../../src/api/client", () => ({
  getObserverComparison: vi.fn(), getObserversPage: vi.fn(), getObserver: vi.fn(),
}));
vi.mock("../../../src/features/stats/EChart", () => ({ EChart: () => null }));
// resetAllMocks below also wipes the global matchMedia stub the tooltip hover check reads
vi.mock("../../../src/hooks/useMediaQuery", async (orig) => ({ ...(await orig<object>()), useHasHover: () => true }));

const a = "11111111-1111-1111-1111-111111111111";
const b = "22222222-2222-2222-2222-222222222222";
const query = `?tab=Analytics&statsTab=compare&compareA=${a}&compareB=${b}&compareSince=1000&compareUntil=2000`;
const counts = { observerA: a, observerB: b, since: 1000, until: 2000, totalPackets: 4, onlyA: 1, onlyB: 2, both: 1 };

function Location() { return <output aria-label="Current URL">{useLocation().search}</output>; }
async function pick(label: string, name: RegExp) {
  fireEvent.click(screen.getByRole("button", { name: new RegExp(`^${label}:`) }));
  fireEvent.click(await within(screen.getByRole("listbox", { name: label })).findByRole("option", { name }));
}
function mount(url = "?statsTab=compare") {
  const client = new QueryClient({ defaultOptions: { queries: { retry: false, gcTime: 0 } } });
  return render(<QueryClientProvider client={client}><MemoryRouter initialEntries={[url]}><CompareObserversTab /><Location /></MemoryRouter></QueryClientProvider>);
}

beforeEach(() => {
  vi.resetAllMocks();
  region.iatas = ["YVR"]; region.regionKey = "YVR";
  vi.mocked(getObserversPage).mockResolvedValue({ items: [
    { id: a, displayName: "Rooftop", iata: "YVR", status: "online" },
    { id: b, displayName: "Hilltop", iata: "YVR", status: "online" },
  ], hasMore: false, nextCursor: null });
  vi.mocked(getObserver).mockImplementation(async (id) => ({ id, displayName: id === a ? "Rooftop" : "Hilltop", iata: "YVR", status: "online", publicKey: "00", firstSeen: 0, lastSeen: 0, observationCount: 0, brokers: [] }));
  vi.mocked(getObserverComparison).mockResolvedValue(counts);
});

describe("observer comparison", () => {
  it("accepts a comparison longer than three days", async () => {
    mount();
    await pick("Observer A", /Rooftop/);
    await pick("Observer B", /Hilltop/);
    fireEvent.change(screen.getByLabelText("Start (local time)"), { target: { value: "2026-01-01T00:00" } });
    fireEvent.change(screen.getByLabelText("End (local time)"), { target: { value: "2026-01-05T00:00" } });
    fireEvent.click(screen.getByRole("button", { name: "Compare" }));
    await waitFor(() => expect(getObserverComparison).toHaveBeenCalled());
    expect(screen.queryByRole("alert")).not.toBeInTheDocument();
  });
  it("waits for Compare, sends explicit dates and region, and puts the selection in the URL", async () => {
    mount();
    expect(getObserverComparison).not.toHaveBeenCalled();
    await pick("Observer A", /Rooftop/);
    await pick("Observer B", /Hilltop/);
    fireEvent.change(screen.getByLabelText("Start (local time)"), { target: { value: "2026-01-01T00:00" } });
    fireEvent.change(screen.getByLabelText("End (local time)"), { target: { value: "2026-01-03T00:00" } });
    expect(getObserverComparison).not.toHaveBeenCalled();
    fireEvent.click(screen.getByRole("button", { name: "Compare" }));
    await waitFor(() => expect(getObserverComparison).toHaveBeenCalledWith(["YVR"], {
      observerA: a, observerB: b, since: new Date("2026-01-01T00:00").getTime(), until: new Date("2026-01-03T00:00").getTime(),
    }, expect.any(AbortSignal)));
    expect(screen.getByLabelText("Current URL").textContent).toContain(`compareA=${a}`);
  });

  it("restores a shared comparison and shows disjoint counts and union percentages", async () => {
    mount(query);
    const table = await screen.findByRole("table", { name: "Flood packet comparison" });
    expect(within(table).getByRole("row", { name: /Only A.*1.*25.0%/ })).toBeInTheDocument();
    expect(within(table).getByRole("row", { name: /Only B.*2.*50.0%/ })).toBeInTheDocument();
    expect(within(table).getByRole("row", { name: /Both.*1.*25.0%/ })).toBeInTheDocument();
    expect(screen.getByRole("button", { name: /Percentages are of all flood packets/ })).toBeInTheDocument();
  });

  it("offers only a different observer and rejects an incomplete pair without querying", async () => {
    mount();
    await pick("Observer A", /Rooftop/);
    fireEvent.click(screen.getByRole("button", { name: /^Observer B:/ }));
    const list = screen.getByRole("listbox", { name: "Observer B" });
    await within(list).findByRole("option", { name: /Hilltop/ });
    expect(within(list).queryByRole("option", { name: /Rooftop/ })).not.toBeInTheDocument();
    fireEvent.click(screen.getByRole("button", { name: "Compare" }));
    expect(screen.getByRole("alert")).toHaveTextContent(/different observers/);
    expect(getObserverComparison).not.toHaveBeenCalled();
  });

  it("renders an empty period without NaN percentages", async () => {
    vi.mocked(getObserverComparison).mockResolvedValue({ ...counts, totalPackets: 0, onlyA: 0, onlyB: 0, both: 0 });
    mount(query);
    expect(await screen.findByText(/Neither observer heard a flood packet/)).toBeInTheDocument();
    expect(document.body).not.toHaveTextContent("NaN");
  });

  it("searches the server beyond the initial observer page", async () => {
    mount();
    fireEvent.click(screen.getByRole("button", { name: /^Observer A:/ }));
    fireEvent.change(screen.getByRole("searchbox", { name: /Observer A/ }), { target: { value: "Distant station" } });
    await waitFor(() => expect(getObserversPage).toHaveBeenCalledWith(["YVR"], { name: "Distant station", limit: 50 }));
  });

  it("keeps applied result labels when the draft selection changes", async () => {
    mount(query);
    await screen.findByRole("table", { name: "Flood packet comparison" });
    expect(await screen.findByText("A: Rooftop · B: Hilltop")).toBeInTheDocument();
    fireEvent.change(screen.getByLabelText("Start (local time)"), { target: { value: "2026-01-02T00:00" } });
    expect(screen.getByText("A: Rooftop · B: Hilltop")).toBeInTheDocument();
    expect(getObserverComparison).toHaveBeenCalledTimes(1);
  });

  it("rejects malformed shared dates without issuing a comparison", async () => {
    mount(query.replace("compareUntil=2000", "compareUntil=bad"));
    expect(screen.getByRole("alert")).toHaveTextContent(/invalid or missing/);
    expect(screen.getByRole("button", { name: /^Observer A:/ })).toBeInTheDocument();
    await waitFor(() => expect(getObserverComparison).not.toHaveBeenCalled());
  });

  it("shows query failures and retries only when requested", async () => {
    vi.mocked(getObserverComparison).mockRejectedValueOnce(new Error("comparison timed out; try a shorter time period"));
    mount(query);
    expect(await screen.findByRole("alert")).toHaveTextContent(/shorter time period/);
    fireEvent.click(screen.getByRole("button", { name: "Retry comparison" }));
    await screen.findByRole("table", { name: "Flood packet comparison" });
    expect(getObserverComparison).toHaveBeenCalledTimes(2);
  });

  it("uses minute precision and flags a start older than packet retention", async () => {
    mount();
    const start = screen.getByLabelText("Start (local time)");
    expect(start).toHaveAttribute("step", "60");
    expect(screen.getByLabelText("End (local time)")).toHaveAttribute("step", "60");
    expect((start as HTMLInputElement).value).toMatch(/^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}$/);
    expect(screen.queryByText(/Only recent packets are kept/)).not.toBeInTheDocument();
    fireEvent.change(start, { target: { value: "2020-01-01T00:00" } });
    expect(screen.getByText(/Only recent packets are kept/)).toBeInTheDocument();
  });

  it("renders the comparison in French", async () => {
    await i18n.changeLanguage("fr");
    mount(query);
    const table = await screen.findByRole("table", { name: "Comparaison des paquets flood" });
    expect(within(table).getByRole("row", { name: /A seulement.*1.*25.0%/ })).toBeInTheDocument();
    expect(screen.queryByText("Comparer les observateurs")).not.toBeInTheDocument();
    expect(screen.getByText("A : Rooftop · B : Hilltop")).toBeInTheDocument();
    expect(screen.getByText(/4 paquets flood/)).toBeInTheDocument();
    expect(screen.getByRole("button", { name: "Comparer" })).toBeInTheDocument();
  });
});