import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
import type { DigestGetResult } from "./http-digest.js";

// The HTTP layer is mocked so the camera driver's RETRY logic is tested without a
// network. Hikvision returns 503 "Device Busy" (sometimes 500) transiently when its
// snapshot encoder is occupied — captureSnapshot must retry those and succeed, but
// fail FAST on a config error (401 auth / 404 path). See camera.ts.

const digestGet = vi.fn<(...a: unknown[]) => Promise<DigestGetResult>>();
vi.mock("./http-digest.js", () => ({ digestGet: (...a: unknown[]) => digestGet(...a) }));

// Import the driver AFTER the mock is registered.
const { hikvisionDriver } = await import("./camera.js");

function reply(status: number, body = "jpeg-bytes"): DigestGetResult {
  return { status, contentType: "image/jpeg", body: Buffer.from(body) };
}

function makeCamera() {
  return hikvisionDriver.create({ host: "10.0.10.12", port: 80, username: "admin", password: "x", channel: 1 });
}

beforeEach(() => {
  digestGet.mockReset();
  vi.useFakeTimers();
});
afterEach(() => {
  vi.useRealTimers();
});

describe("hikvision captureSnapshot — 503 Device Busy retry", () => {
  it("retries a transient 503 and succeeds", async () => {
    digestGet
      .mockResolvedValueOnce(reply(503))
      .mockResolvedValueOnce(reply(503))
      .mockResolvedValueOnce(reply(200, "the-frame"));
    const cam = makeCamera();
    const p = cam.captureSnapshot({ direction: "entry" });
    await vi.runAllTimersAsync(); // let the backoff sleeps fire
    const shot = await p;
    expect(shot.bytes.toString()).toBe("the-frame");
    expect(digestGet).toHaveBeenCalledTimes(3); // 503, 503, 200
  });

  it("also retries a transient 500", async () => {
    digestGet.mockResolvedValueOnce(reply(500)).mockResolvedValueOnce(reply(200));
    const cam = makeCamera();
    const p = cam.captureSnapshot({ direction: "entry" });
    await vi.runAllTimersAsync();
    await p;
    expect(digestGet).toHaveBeenCalledTimes(2);
  });

  it("gives up after the attempt cap, naming it 'device busy'", async () => {
    digestGet.mockResolvedValue(reply(503)); // always busy
    const cam = makeCamera();
    // Attach the rejection assertion BEFORE flushing timers so the rejection always
    // has a handler (no unhandled-rejection noise), then drive the backoff sleeps.
    const assertion = expect(cam.captureSnapshot({ direction: "entry" })).rejects.toThrow(/HTTP 503 \(device busy\)/);
    await vi.runAllTimersAsync();
    await assertion;
    expect(digestGet).toHaveBeenCalledTimes(4); // SNAPSHOT_MAX_ATTEMPTS
  });

  it("does NOT retry a 401 (auth error self-won't-heal) — fails fast", async () => {
    digestGet.mockResolvedValue(reply(401));
    const cam = makeCamera();
    const assertion = expect(cam.captureSnapshot({ direction: "entry" })).rejects.toThrow(/HTTP 401/);
    await vi.runAllTimersAsync();
    await assertion;
    expect(digestGet).toHaveBeenCalledTimes(1); // no retry
  });

  it("does NOT retry a 404 (wrong path/channel) — fails fast", async () => {
    digestGet.mockResolvedValue(reply(404));
    const cam = makeCamera();
    const assertion = expect(cam.captureSnapshot({ direction: "entry" })).rejects.toThrow(/HTTP 404/);
    await vi.runAllTimersAsync();
    await assertion;
    expect(digestGet).toHaveBeenCalledTimes(1);
  });

  it("succeeds first try with no retry on a clean 200", async () => {
    digestGet.mockResolvedValue(reply(200));
    const cam = makeCamera();
    const shot = await cam.captureSnapshot({ direction: "entry" });
    expect(shot.contentType).toBe("image/jpeg");
    expect(digestGet).toHaveBeenCalledTimes(1);
  });
});

describe("hikvision snapshot stream selection (main vs sub)", () => {
  function pathFor(config: Record<string, unknown>): string {
    digestGet.mockReset();
    digestGet.mockResolvedValue(reply(200));
    hikvisionDriver.create(config as never).captureSnapshot({ direction: "entry" });
    return String((digestGet.mock.calls[0]![0] as { path: string }).path);
  }

  it("defaults to the MAIN stream (…/channels/101/picture) — back-compat", () => {
    expect(pathFor({ host: "1.2.3.4", channel: 1 })).toBe("/ISAPI/Streaming/channels/101/picture");
  });

  it("stream=2 selects the SUB stream (…/channels/102/picture) — the G3H 503 fix", () => {
    expect(pathFor({ host: "1.2.3.4", channel: 1, stream: 2 })).toBe("/ISAPI/Streaming/channels/102/picture");
  });

  it("honours the channel number with the stream (ch2 sub = 202)", () => {
    expect(pathFor({ host: "1.2.3.4", channel: 2, stream: 2 })).toBe("/ISAPI/Streaming/channels/202/picture");
  });

  it("an invalid stream falls back to main (1)", () => {
    expect(pathFor({ host: "1.2.3.4", channel: 1, stream: 9 })).toBe("/ISAPI/Streaming/channels/101/picture");
  });
});