/**
 * Overview through the real router: Pi-hole's layout over our data.
 *
 * The behaviours of the superseded three-section build are accounted for here or
 * declared dead. The status rows and the issues list moved to the Diagnostics
 * page's health strip and its Active section; the Pause control moved to the
 * sidebar; the protection indicator is gone. What stays here is the period, the
 * window and the panels.
 */

import { fireEvent, render, screen, waitFor, within } from "@testing-library/react";
import { QueryClientProvider } from "@tanstack/react-query";
import { RouterProvider, createMemoryHistory } from "@tanstack/react-router";
import { AuthProvider } from "@/auth/store";
import { createQueryClient } from "@/lib/queryClient";
import { createAppRouter } from "@/routes";
import { clientKey, qtypeKey, seriesColor } from "./seriesColors";
import { health } from "@/lib/healthFixture";
import type { Health, Overview } from "@/lib/types";

const SINCE = Date.UTC(2026, 0, 1, 0, 0) / 1000;
const UNTIL = Date.UTC(2026, 0, 2, 0, 0) / 1000;
const COVERAGE = { complete: true, available_since: SINCE };

const OVERVIEW: Overview = {
	period: "24h",
	since: SINCE,
	until: UNTIL,
	bucket_seconds: 1800,
	totals: { queries: 1000, blocked: 250, clients: 7, avg_response_time_us: 2345 },
	buckets: [
		{ ts: SINCE, queries: 60, blocked: 20, cached: 10 },
		{ ts: SINCE + 1800, queries: 40, blocked: 0, cached: 0 },
	],
	clients: [
		{ client: "192.0.2.30", buckets: [40, 20] },
		{ client: "192.0.2.31", buckets: [20, 20] },
	],
	other: [0, 0],
	types: [
		{ qtype: 1, count: 600 },
		{ qtype: 28, count: 300 },
		{ qtype: null, count: 100 },
	],
	routes: [
		{ route: "upstream", source: "https://dns.example/dns-query", count: 500 },
		{ route: "blocked", source: null, count: 250 },
		{ route: "cache", source: null, count: 150 },
		{ route: "upstream", source: null, count: 100 },
	],
	coverage: COVERAGE,
};

/** The same shape an hour wide and empty, so a period change is observable. */
const HOUR: Overview = {
	...OVERVIEW,
	period: "1h",
	since: UNTIL - 3600,
	bucket_seconds: 60,
	totals: { queries: 12, blocked: 3, clients: 2, avg_response_time_us: 2345 },
	buckets: [],
	clients: [],
	other: [],
	types: [],
	routes: [],
};

let healthBody: Health;
let failing: boolean;
/** The registered clients, as `/api/clients` answers them. */
let registered: { ip: string; name: string; learned_name: string }[];
let coverageComplete: boolean;
/** Held in flight, so a test can look at the page while the request is pending. */
let delayed: Promise<void> | null;

function json(payload: unknown, status = 200): Response {
	return new Response(JSON.stringify(payload), { status, headers: { "content-type": "application/json" } });
}

function withCoverage<T extends { coverage: typeof COVERAGE }>(body: T): T {
	return { ...body, coverage: { ...body.coverage, complete: coverageComplete } };
}

beforeEach(() => {
	healthBody = health();
	failing = false;
	registered = [];
	coverageComplete = true;
	delayed = null;
	vi.stubGlobal(
		"fetch",
		vi.fn(async (input: RequestInfo | URL) => {
			const url = String(input);
			if (url.startsWith("/api/overview")) {
				if (failing) return json({ error: "endpoint unavailable" }, 400);
				if (delayed !== null) await delayed;
				return json(withCoverage(url.includes("period=1h") ? HOUR : OVERVIEW));
			}
			if (url === "/api/clients") {
				return json({
					clients: registered.map((client, index) => ({
						id: index + 1,
						ip: client.ip,
						name: client.name,
						learned_name: client.learned_name,
						group_id: 1,
						group: "default",
						hand_edited: client.name !== "",
						first_seen: SINCE,
						last_seen: UNTIL,
					})),
				});
			}
			if (url === "/api/health") return json(healthBody);
			if (url === "/api/version")
				return json({ version: "0.0.0-test", git_commit: "0000000", zig_version: "0.16.0", uptime_seconds: 1 });
			if (url.startsWith("/api/diagnostics")) {
				return json({ events: [], next_before: null, active: { warnings: 0, errors: 0 } });
			}
			return json({ error: "not stubbed" }, 404);
		}),
	);
});

afterEach(() => vi.unstubAllGlobals());

function renderApp(path = "/overview") {
	const queryClient = createQueryClient();
	const router = createAppRouter(createMemoryHistory({ initialEntries: [path] }), queryClient);
	render(
		<AuthProvider>
			<QueryClientProvider client={queryClient}>
				<RouterProvider router={router} />
			</QueryClientProvider>
		</AuthProvider>,
	);
	return router;
}

function panel(name: string): HTMLElement {
	const heading = screen.getByRole("heading", { name });
	const section = heading.closest("section");
	if (section === null) throw new Error(`no panel for ${name}`);
	return section;
}

test("the root path lands on Overview rather than aliasing it", async () => {
	const router = renderApp("/");
	await screen.findByRole("heading", { name: "Overview", level: 1 });
	expect(router.state.location.pathname).toBe("/overview");
});

test("every donut arc is outlined, so two slices of one hue still read as two", async () => {
	// Colour is a pure function of identity and so cannot rule out two slices of
	// one panel sharing a hue. The stroke is what stops neighbours from merging
	// into one shape, which makes it part of the contract rather than decoration.
	renderApp();
	await screen.findByText("1,000");
	await waitFor(() => expect(within(panel("Query types")).getAllByText("A")).toHaveLength(2));

	const arcs = Array.from(panel("Query types").querySelectorAll("svg path"));
	expect(arcs).toHaveLength(3);
	for (const arc of arcs) {
		expect(arc.getAttribute("stroke-width")).toBe("1");
		// The panel's own surface colour, as a token reference.
		expect(arc.getAttribute("stroke")).toMatch(/^var\(--/);
	}
});

test("the page builds a donut slice's colour from the entry's identity", async () => {
	// `Donut` renders the colour it is handed and never recomputes one, so the
	// mapping from identity to hue is the page's job and is pinned here.
	renderApp();
	await screen.findByText("1,000");
	await waitFor(() => expect(within(panel("Query types")).getAllByText("A")).toHaveLength(2));

	const item = within(panel("Query types")).getAllByText("A")[0].closest("li") as HTMLElement;
	const swatch = item.querySelector("span[aria-hidden]") as HTMLElement;
	expect(swatch.getAttribute("style")).toContain(seriesColor(qtypeKey(1)));
});

test("a request in flight leaves the heading and the picker usable behind one loading surface", async () => {
	// Through the real route, which is the point: the loader starts the request
	// and awaits it nowhere. If it awaited, the router would hold the whole page —
	// heading and period picker included — until the response landed.
	let release = () => {};
	delayed = new Promise<void>((resolve) => (release = resolve));

	renderApp();

	await screen.findByRole("heading", { name: "Overview", level: 1 });
	expect(screen.getByRole("button", { name: "1h" })).toBeTruthy();
	// One loading state for the whole page, not one per panel.
	const loading = await screen.findByText("Loading…");
	expect(loading.getAttribute("role")).toBe("status");
	expect(screen.getAllByText("Loading…")).toHaveLength(1);
	expect(screen.queryByRole("heading", { name: "Query types" })).toBeNull();

	release();
	delayed = null;
	await screen.findByText("1,000");
	expect(screen.queryByText("Loading…")).toBeNull();
});

test("a registered client is named in the chart, an unregistered one keeps its address", async () => {
	// The fixture's two clients: one registered with a typed name, one the clients
	// list has never seen.
	registered = [{ ip: "192.0.2.30", name: "kitchen-pi", learned_name: "" }];
	renderApp();
	const chart = await waitFor(() => panel("Client activity over time"));

	// Legend and the hidden table both, since the table is what a screen reader
	// gets instead of the graphic and the two must not name one client differently.
	await waitFor(() => expect(within(chart).getAllByText("kitchen-pi")).toHaveLength(2));
	expect(within(chart).queryByText("192.0.2.30")).toBeNull();
	expect(within(chart).getAllByText("192.0.2.31")).toHaveLength(2);
});

test("a client named only by reverse DNS is named by it too", async () => {
	registered = [{ ip: "192.0.2.31", name: "", learned_name: "laptop.lan" }];
	renderApp();
	const chart = await waitFor(() => panel("Client activity over time"));

	await waitFor(() => expect(within(chart).getAllByText("laptop.lan")).toHaveLength(2));
});

test("naming a client does not recolour its series", async () => {
	// The rename the palette must not notice: the swatch beside "kitchen-pi" is
	// the colour of the address it was drawn under, not of the label on screen.
	registered = [{ ip: "192.0.2.30", name: "kitchen-pi", learned_name: "" }];
	renderApp();
	const chart = await waitFor(() => panel("Client activity over time"));
	await waitFor(() => expect(within(chart).getAllByText("kitchen-pi")).toHaveLength(2));

	const item = within(chart).getAllByText("kitchen-pi")[0].closest("li") as HTMLElement;
	const swatch = item.querySelector("span[aria-hidden]") as HTMLElement;
	expect(swatch.getAttribute("style")).toContain(seriesColor(clientKey("192.0.2.30")));
});

test("the client chart drops Other in a period where it counted nothing", async () => {
	// The fixture's other series is all zeroes. An aggregation bucket that
	// aggregated nothing is a legend entry and a table column that say only that
	// they are empty; the named clients stay, because a quiet client is a fact.
	renderApp();
	await screen.findByRole("heading", { name: "Client activity over time" });

	const chart = screen.getByRole("heading", { name: "Client activity over time" }).closest("section");
	expect(chart).toBeTruthy();
	// Twice each: the legend swatch and the column header of the table a screen
	// reader gets instead of the graphic.
	await waitFor(() => expect(within(chart as HTMLElement).getAllByText("192.0.2.30")).toHaveLength(2));
	expect(within(chart as HTMLElement).queryAllByText("Other")).toHaveLength(0);
});

test("the page is four tiles, two charts and two donuts — no status or issues sections", async () => {
	renderApp();
	await screen.findByRole("heading", { name: "Overview", level: 1 });
	await screen.findByText("1,000");

	for (const name of ["Queries over time", "Client activity over time", "Query types", "Upstream servers"]) {
		expect(screen.getByRole("heading", { name })).toBeTruthy();
	}
	// The sections the layout ruling removed, and the widgets the Dashboard lost.
	expect(screen.queryByRole("heading", { name: "Current status" })).toBeNull();
	expect(screen.queryByRole("heading", { name: "Active issues" })).toBeNull();
	expect(screen.queryByRole("heading", { name: "Activity over a period" })).toBeNull();
	expect(screen.queryByText("Storage now")).toBeNull();
	expect(screen.queryByRole("columnheader", { name: "Upstream" })).toBeNull();
});

test("the four tiles report the window, and each links where its number leads", async () => {
	renderApp();
	const tiles = within((await screen.findByText("1,000")).closest("dl") as HTMLElement);
	expect(tiles.getByText("250")).toBeTruthy();
	expect(tiles.getByText("25.0%")).toBeTruthy();
	expect(tiles.getByText("7")).toBeTruthy();
	expect(tiles.getByText("2.3 ms")).toBeTruthy();

	// The bounds are the ones the stats response returned, not ones computed here.
	const queries = new URLSearchParams(
		screen.getByRole("link", { name: "Open in Activity" }).getAttribute("href")?.split("?")[1] ?? "",
	);
	expect(queries.get("mode")).toBe("history");
	expect(queries.get("since")).toBe(String(SINCE));
	expect(queries.get("until")).toBe(String(UNTIL));
	expect(queries.get("blocked")).toBeNull();

	const blocked = new URLSearchParams(
		screen.getByRole("link", { name: "Open blocked queries" }).getAttribute("href")?.split("?")[1] ?? "",
	);
	expect(blocked.get("blocked")).toBe("true");
	expect(blocked.get("since")).toBe(String(SINCE));

	expect(screen.getByRole("link", { name: "Manage clients" }).getAttribute("href")).toBe("/clients");
	// Average response time has no rows behind it to open.
	expect(screen.queryByRole("link", { name: /average/i })).toBeNull();
});

test("both donuts name every entry, nulls included, and disambiguate a nameless source", async () => {
	renderApp();
	await screen.findByText("1,000");

	const types = within(panel("Query types"));
	expect(types.getByRole("rowheader", { name: "A" })).toBeTruthy();
	expect(types.getByRole("rowheader", { name: "AAAA" })).toBeTruthy();
	// A query whose type was never recorded is its own entry, not a dropped row.
	expect(types.getByRole("rowheader", { name: "Unknown" })).toBeTruthy();

	const routes = within(panel("Upstream servers"));
	expect(routes.getByRole("rowheader", { name: "https://dns.example/dns-query (Upstream)" })).toBeTruthy();
	expect(routes.getByRole("rowheader", { name: "Blocked" })).toBeTruthy();
	expect(routes.getByRole("rowheader", { name: "Cache" })).toBeTruthy();
	// An upstream row with no recorded resolver reads as Unknown, qualified by its kind.
	expect(routes.getByRole("rowheader", { name: "Unknown (Upstream)" })).toBeTruthy();
});

test("the donut ring is decoration; the legend and the hidden table are the accessible surface", async () => {
	renderApp();
	await screen.findByText("1,000");

	const svg = panel("Query types").querySelector("svg");
	expect(svg?.getAttribute("aria-hidden")).toBe("true");
	expect(svg?.getAttribute("focusable")).toBe("false");
	expect(within(panel("Query types")).getByRole("table")).toBeTruthy();
});

test("an empty window says so in every panel instead of drawing nothing", async () => {
	renderApp("/overview?period=1h");
	await screen.findByText("12");

	// The two donuts and the client chart; the query-volume chart says it too.
	expect(screen.getAllByText("No queries in this period.").length).toBe(4);
});

test("a deep link opens on the period it names", async () => {
	renderApp("/overview?period=1h");
	await screen.findByText("12");
	expect(screen.getByRole("button", { name: "1h" }).getAttribute("aria-pressed")).toBe("true");
	expect(screen.getByRole("button", { name: "24h" }).getAttribute("aria-pressed")).toBe("false");
});

test("a period the API does not have falls back to the default without carrying it in the url", async () => {
	const router = renderApp("/overview?period=90d");
	await screen.findByText("1,000");
	expect(screen.getByRole("button", { name: "24h" }).getAttribute("aria-pressed")).toBe("true");
	expect(router.state.location.search).toEqual({});
});

test("the picker rescopes every panel and writes the period into the url", async () => {
	const router = renderApp();
	await screen.findByText("1,000");

	fireEvent.click(screen.getByRole("button", { name: "1h" }));

	await screen.findByText("12");
	await waitFor(() => expect(router.state.location.search).toEqual({ period: "1h" }));
	// No panel is left describing the period the reader left.
	expect(screen.queryByText("1,000")).toBeNull();
});

test("a failed request is one error for the whole page, stated once and retryable", async () => {
	failing = true;
	renderApp();

	await screen.findByText("endpoint unavailable");
	// One statement of the failure, not one per panel: there is a single request
	// behind every panel, so a second copy would only repeat this sentence.
	expect(screen.getAllByText("endpoint unavailable")).toHaveLength(1);
	expect(screen.getAllByRole("button", { name: "Retry" })).toHaveLength(1);
	// The heading and the picker survive it, so the reader can rescope or retry.
	expect(screen.getByRole("heading", { name: "Overview", level: 1 })).toBeTruthy();
	expect(screen.getByRole("button", { name: "1h" })).toBeTruthy();
	expect(screen.queryByText("Something went wrong")).toBeNull();

	failing = false;
	fireEvent.click(screen.getByRole("button", { name: "Retry" }));
	await screen.findByText("1,000");
	expect(screen.getByRole("img", { name: /queries over time/i })).toBeTruthy();
});

test("an incomplete window states its watermark once for the whole page", async () => {
	coverageComplete = false;
	renderApp();
	await screen.findByText("1,000");
	expect(screen.getAllByText(/Query history is available from/)).toHaveLength(1);
});