import { afterEach, describe, expect, test } from "bun:test";
import {
  HttpMethod,
  RequestContext,
} from "@kubernetes/client-node/dist/gen/http/http.js";
import http from "node:http";
import {
  createKubernetesHttpLibrary,
  delay,
  parseRetryAfter,
} from "../../lib/k8s-http";

const servers: http.Server[] = [];

async function serve(
  handler: http.RequestListener,
): Promise<{ server: http.Server; url: string }> {
  const server = http.createServer(handler);
  servers.push(server);
  await new Promise<void>((resolve) => server.listen(0, "127.0.0.1", resolve));
  const address = server.address();
  if (!address || typeof address === "string") throw new Error("Missing port");
  return { server, url: `http://127.0.0.1:${address.port}` };
}

afterEach(async () => {
  await Promise.all(
    servers.splice(0).map(
      (server) =>
        new Promise<void>((resolve, reject) => {
          server.close((error) => (error ? reject(error) : resolve()));
        }),
    ),
  );
});

describe("Kubernetes HTTP transport", () => {
  test("parses Retry-After seconds and HTTP dates", () => {
    expect(parseRetryAfter("2", 0)).toBe(2000);
    expect(parseRetryAfter("Thu, 01 Jan 1970 00:00:03 GMT", 1000)).toBe(2000);
    expect(parseRetryAfter("invalid", 0)).toBeUndefined();
  });

  test("retries 429 responses and honors the retry limit", async () => {
    let requests = 0;
    const { url } = await serve((_request, response) => {
      requests += 1;
      response.statusCode = requests < 3 ? 429 : 200;
      response.setHeader("Retry-After", "0");
      response.end(requests < 3 ? "slow down" : "ok");
    });
    const client = createKubernetesHttpLibrary({
      minIntervalMs: 0,
      baseRetryMs: 0,
      maxRetries: 3,
    });

    const response = await client
      .send(new RequestContext(url, HttpMethod.GET))
      .toPromise();
    expect(response.httpStatusCode).toBe(200);
    expect(requests).toBe(3);

    requests = 0;
    const limitedClient = createKubernetesHttpLibrary({
      minIntervalMs: 0,
      baseRetryMs: 0,
      maxRetries: 1,
    });
    const limitedResponse = await limitedClient
      .send(new RequestContext(url, HttpMethod.GET))
      .toPromise();
    expect(limitedResponse.httpStatusCode).toBe(429);
    expect(requests).toBe(2);
  });

  test("logs Kubernetes request starts, completions, and failures", async () => {
    const logs: Record<string, unknown>[] = [];
    const logger = {
      log: (entry: Record<string, unknown>) => logs.push(entry),
    };
    const { url } = await serve((_request, response) => response.end("ok"));
    const client = createKubernetesHttpLibrary({ minIntervalMs: 0, logger });

    await client.send(new RequestContext(url, HttpMethod.GET)).toPromise();
    expect(logs).toEqual(
      expect.arrayContaining([
        expect.objectContaining({
          event: "kuber.k8s.request.start",
          method: "GET",
          attempt: 1,
        }),
        expect.objectContaining({
          event: "kuber.k8s.request.end",
          status: 200,
          responseBody: "ok",
        }),
      ]),
    );

    const failedLogs: Record<string, unknown>[] = [];
    const { url: failedUrl } = await serve((request) =>
      request.socket.destroy(),
    );
    const failedClient = createKubernetesHttpLibrary({
      minIntervalMs: 0,
      logger: { log: (entry) => failedLogs.push(entry) },
    });
    await expect(
      failedClient
        .send(new RequestContext(failedUrl, HttpMethod.GET))
        .toPromise(),
    ).rejects.toBeDefined();
    expect(failedLogs).toEqual(
      expect.arrayContaining([
        expect.objectContaining({ event: "kuber.k8s.request.start" }),
        expect.objectContaining({ event: "kuber.k8s.request.failed" }),
      ]),
    );
  });

  test("paces concurrent request starts", async () => {
    const starts: number[] = [];
    const { url } = await serve((_request, response) => {
      starts.push(Date.now());
      response.end("ok");
    });
    const client = createKubernetesHttpLibrary({
      maxConcurrent: 3,
      minIntervalMs: 25,
    });

    await Promise.all(
      Array.from({ length: 3 }, () =>
        client.send(new RequestContext(url, HttpMethod.GET)).toPromise(),
      ),
    );
    expect(starts).toHaveLength(3);
    expect(starts[2]! - starts[0]!).toBeGreaterThanOrEqual(35);
  });

  test("cancels retry waits", async () => {
    const controller = new AbortController();
    const waiting = delay(10_000, controller.signal);
    controller.abort();
    await expect(waiting).rejects.toMatchObject({ name: "AbortError" });
  });
});