// Vitest coverage for the SubscribeEvents stream consumer in
// `src/api/events.svelte.ts`. The tests drive the singleton through
// its lifecycle with a `createRouterTransport` fake — the same
// pattern `galaxy-client.test.ts` uses for unary calls, extended to
// async-generator handlers for server-streaming RPCs.
//
// The session store is mocked so `signOut("revoked")` is observable
// without instantiating the real keystore/IndexedDB chain.

import { afterEach, beforeEach, describe, expect, test, vi } from "vitest";
import { create } from "@bufbuild/protobuf";
import {
	Code,
	ConnectError,
	createClient,
	createRouterTransport,
} from "@connectrpc/connect";
import {
	EdgeGateway,
	GatewayEventSchema,
	type GatewayEvent,
} from "../src/proto/galaxy/gateway/v1/edge_gateway_pb";

let sessionStatus: "anonymous" | "authenticated" = "anonymous";
const signOutSpy = vi.fn();
vi.mock("../src/lib/session-store.svelte", () => ({
	session: {
		get status(): string {
			return sessionStatus;
		},
		signOut: (...args: unknown[]) => signOutSpy(...args),
	},
}));

// The import must come after vi.mock so the module reads the mocked
// session reference.
const {
	eventStream,
} = await import("../src/api/events.svelte");

import type { Core } from "../src/platform/core/index";
import type { DeviceKeypair } from "../src/platform/store/index";

beforeEach(() => {
	eventStream.resetForTests();
	signOutSpy.mockReset();
	sessionStatus = "anonymous";
});

afterEach(() => {
	eventStream.resetForTests();
});

function mockCore(overrides?: Partial<Core>): Core {
	return {
		signRequest: () => new Uint8Array([1, 2, 3]),
		verifyResponse: () => true,
		verifyEvent: () => true,
		verifyPayloadHash: () => true,
		driveEffective: () => 0,
		emptyMass: () => 0,
		weaponsBlockMass: () => 0,
		fullMass: () => 0,
		speed: () => 0,
		cargoCapacity: () => 0,
		carryingMass: () => 0,
		blockUpgradeCost: () => 0,
		...overrides,
	} as Core;
}

function mockKeypair(): DeviceKeypair {
	return {
		publicKey: new Uint8Array(32),
		sign: async () => new Uint8Array(64),
	};
}

function buildEvent(eventType: string, payload: Uint8Array): GatewayEvent {
	return create(GatewayEventSchema, {
		eventType,
		eventId: `event-${eventType}-${Math.random().toString(16).slice(2, 8)}`,
		timestampMs: 1n,
		payloadBytes: payload,
		payloadHash: new Uint8Array(32).fill(0xaa),
		signature: new Uint8Array(64).fill(0xbb),
		requestId: "req-1",
		traceId: "trace-1",
	});
}

function makeRouter(
	streamFactory: () => AsyncIterable<GatewayEvent>,
): ReturnType<typeof createClient<typeof EdgeGateway>> {
	const transport = createRouterTransport(({ service }) => {
		service(EdgeGateway, {
			executeCommand() {
				throw new Error("not used in this test");
			},
			async *subscribeEvents() {
				for await (const e of streamFactory()) {
					yield e;
				}
			},
		});
	});
	return createClient(EdgeGateway, transport);
}

describe("EventStream", () => {
	test("verified events reach the registered handler", async () => {
		const handler = vi.fn();
		eventStream.on("game.turn.ready", handler);

		const event = buildEvent(
			"game.turn.ready",
			new TextEncoder().encode(JSON.stringify({ game_id: "g", turn: 2 })),
		);
		const client = makeRouter(async function* () {
			yield event;
		});

		const sleep = vi.fn(async () => {});

		eventStream.start({
			core: mockCore(),
			keypair: mockKeypair(),
			deviceSessionId: "device-1",
			gatewayResponsePublicKey: new Uint8Array(32),
			client,
			sleep,
			random: () => 0,
		});

		await vi.waitFor(() => {
			expect(handler).toHaveBeenCalled();
		});
		expect(handler).toHaveBeenCalledTimes(1);
		expect(handler.mock.calls[0]?.[0].eventType).toBe("game.turn.ready");
		eventStream.stop();
	});

	test("handlers for other event types are not invoked", async () => {
		const turnHandler = vi.fn();
		const mailHandler = vi.fn();
		eventStream.on("game.turn.ready", turnHandler);
		eventStream.on("mail.received", mailHandler);

		const event = buildEvent(
			"game.turn.ready",
			new TextEncoder().encode("{}"),
		);
		const client = makeRouter(async function* () {
			yield event;
		});
		eventStream.start({
			core: mockCore(),
			keypair: mockKeypair(),
			deviceSessionId: "device-1",
			gatewayResponsePublicKey: new Uint8Array(32),
			client,
			sleep: async () => {},
			random: () => 0,
		});

		await vi.waitFor(() => {
			expect(turnHandler).toHaveBeenCalled();
		});
		expect(mailHandler).not.toHaveBeenCalled();
		eventStream.stop();
	});

	test("unsubscribe removes the handler", async () => {
		const handler = vi.fn();
		const off = eventStream.on("game.turn.ready", handler);
		off();

		const event = buildEvent(
			"game.turn.ready",
			new TextEncoder().encode("{}"),
		);
		const client = makeRouter(async function* () {
			yield event;
		});
		const sleepSpy = vi.fn(async () => {});
		eventStream.start({
			core: mockCore(),
			keypair: mockKeypair(),
			deviceSessionId: "device-1",
			gatewayResponsePublicKey: new Uint8Array(32),
			client,
			sleep: sleepSpy,
			random: () => 0,
		});

		await vi.waitFor(() => {
			// Stream finished — either status became idle, or the loop
			// is at backoff after a clean close on an anonymous
			// session (which goes straight to idle as well).
			expect(eventStream.connectionStatus).toBe("idle");
		});
		expect(handler).not.toHaveBeenCalled();
		eventStream.stop();
	});

	test("bad signature tears down the stream and reconnects", async () => {
		const handler = vi.fn();
		eventStream.on("game.turn.ready", handler);

		let verifyCalls = 0;
		const core = mockCore({
			verifyEvent: () => {
				verifyCalls += 1;
				return verifyCalls > 1; // first event fails, then passes
			},
		});

		let streamCalls = 0;
		const client = makeRouter(async function* () {
			streamCalls += 1;
			yield buildEvent(
				"game.turn.ready",
				new TextEncoder().encode("{}"),
			);
		});

		const sleepCalls: number[] = [];
		eventStream.start({
			core,
			keypair: mockKeypair(),
			deviceSessionId: "device-1",
			gatewayResponsePublicKey: new Uint8Array(32),
			client,
			sleep: async (ms) => {
				sleepCalls.push(ms);
			},
			random: () => 0, // full-jitter = 0 → instant retry
		});

		await vi.waitFor(() => {
			expect(handler).toHaveBeenCalled();
		});
		// Two stream openings: first one rejected on bad signature,
		// second one delivered the good event.
		expect(streamCalls).toBeGreaterThanOrEqual(2);
		// Backoff was scheduled between attempts.
		expect(sleepCalls.length).toBeGreaterThanOrEqual(1);
		eventStream.stop();
	});

	test("unauthenticated error signs the session out", async () => {
		sessionStatus = "authenticated";
		const client = makeRouter(async function* () {
			yield* [];
			throw new ConnectError("revoked", Code.Unauthenticated);
		});
		eventStream.start({
			core: mockCore(),
			keypair: mockKeypair(),
			deviceSessionId: "device-1",
			gatewayResponsePublicKey: new Uint8Array(32),
			client,
			sleep: async () => {},
			random: () => 0,
		});

		await vi.waitFor(() => {
			expect(signOutSpy).toHaveBeenCalled();
		});
		expect(signOutSpy).toHaveBeenCalledWith("revoked");
		eventStream.stop();
	});

	test("clean end-of-stream on an authenticated session is the revocation signal", async () => {
		sessionStatus = "authenticated";
		const client = makeRouter(async function* () {
			yield* [];
		});
		eventStream.start({
			core: mockCore(),
			keypair: mockKeypair(),
			deviceSessionId: "device-1",
			gatewayResponsePublicKey: new Uint8Array(32),
			client,
			sleep: async () => {},
			random: () => 0,
		});
		await vi.waitFor(() => {
			expect(signOutSpy).toHaveBeenCalledWith("revoked");
		});
		eventStream.stop();
	});

	test("connectionStatus transitions through connecting → connected → idle", async () => {
		expect(eventStream.connectionStatus).toBe("idle");
		const event = buildEvent(
			"game.turn.ready",
			new TextEncoder().encode("{}"),
		);
		const observed: string[] = [];
		const client = makeRouter(async function* () {
			yield event;
		});
		const handler = vi.fn(() => {
			observed.push(eventStream.connectionStatus);
		});
		eventStream.on("game.turn.ready", handler);
		eventStream.start({
			core: mockCore(),
			keypair: mockKeypair(),
			deviceSessionId: "device-1",
			gatewayResponsePublicKey: new Uint8Array(32),
			client,
			sleep: async () => {},
			random: () => 0,
		});
		await vi.waitFor(() => {
			expect(handler).toHaveBeenCalled();
		});
		// Inside the handler, status had already flipped to connected.
		expect(observed).toContain("connected");
		eventStream.stop();
	});
});