import { afterEach, describe, expect, it, vi } from "vitest";
import {
  AUDIT_USER_AGENT,
  buildAuditHeaders,
  fetchForAudit,
} from "./crawl-request";

afterEach(() => {
  vi.unstubAllGlobals();
  vi.useRealTimers();
});

describe("buildAuditHeaders", () => {
  it("sends a browser navigation header set", () => {
    const headers = buildAuditHeaders();
    expect(headers["User-Agent"]).toBe(AUDIT_USER_AGENT);
    expect(AUDIT_USER_AGENT).toMatch(/Chrome\/\d+\.0\.0\.0 Safari/);
    expect(headers["Accept-Language"]).toContain("en");
    expect(headers["Sec-Fetch-Mode"]).toBe("navigate");
    expect(headers["Upgrade-Insecure-Requests"]).toBe("1");
  });

  it("lets callers override individual entries", () => {
    expect(buildAuditHeaders({ Accept: "text/plain" }).Accept).toBe(
      "text/plain",
    );
  });
});

describe("fetchForAudit", () => {
  it("returns the first response when it is not a transient block", async () => {
    const fetchMock = vi
      .fn()
      .mockResolvedValue(new Response("ok", { status: 200 }));
    vi.stubGlobal("fetch", fetchMock);

    const res = await fetchForAudit("https://example.com");
    expect(res.status).toBe(200);
    expect(fetchMock).toHaveBeenCalledTimes(1);
  });

  it("applies the browser headers", async () => {
    let seen: HeadersInit | undefined;
    vi.stubGlobal(
      "fetch",
      vi.fn((_url: string, init?: RequestInit) => {
        seen = init?.headers;
        return Promise.resolve(new Response("ok", { status: 200 }));
      }),
    );

    await fetchForAudit("https://example.com");
    expect(seen).toMatchObject({ "User-Agent": AUDIT_USER_AGENT });
  });

  it("retries once on 503 and returns the retry response", async () => {
    const fetchMock = vi
      .fn()
      .mockResolvedValueOnce(new Response("busy", { status: 503 }))
      .mockResolvedValueOnce(new Response("ok", { status: 200 }));
    vi.stubGlobal("fetch", fetchMock);
    vi.useFakeTimers();

    const promise = fetchForAudit("https://example.com");
    await vi.runAllTimersAsync();
    const res = await promise;

    expect(res.status).toBe(200);
    expect(fetchMock).toHaveBeenCalledTimes(2);
  });

  it("does not retry a hard 403", async () => {
    const fetchMock = vi
      .fn()
      .mockResolvedValue(new Response("no", { status: 403 }));
    vi.stubGlobal("fetch", fetchMock);

    const res = await fetchForAudit("https://example.com");
    expect(res.status).toBe(403);
    expect(fetchMock).toHaveBeenCalledTimes(1);
  });
});