import { describe, expect, it, vi } from "vitest";
import {
  ensureFreshSession,
  refreshSession,
} from "@/lib/session-refresh";
import { createSession, getSession, type SessionData } from "@/lib/session-store";

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

// Seeds a session whose profile access token expires at `profileExpiresAt`
// (and feed at `feedExpiresAt`), with known "old" tokens.
function seedSession(
  profileExpiresAt: number | null,
  feedExpiresAt: number | null = null,
): string {
  const data: SessionData = {
    profileAccessToken: "old-access",
    profileAccessTokenExpiresAt: profileExpiresAt,
    profileRefreshToken: "old-refresh",
    feedAccessToken: "old-feed",
    feedAccessTokenExpiresAt: feedExpiresAt,
    person: { userId: "u1", name: "Pat Rivera", email: "person@example.com", pictureUrl: null },
    createdAt: Date.now(),
  };
  return createSession(data);
}

// Stub for the refresh path: refresh-token -> new profile tokens, feed -> new feed token.
function refreshFetchStub(
  overrides: Partial<Record<"refresh" | "feed", Response>> = {},
) {
  return vi.fn(async (input: RequestInfo | URL): Promise<Response> => {
    const url = String(input);
    if (url.endsWith("/api/v4/auth/refresh-token")) {
      return (
        overrides.refresh ??
        json({ data: { accessToken: "new-access", refreshToken: "new-refresh", expiresIn: 3600 } })
      );
    }
    if (url.endsWith("/api/v4/auth/external-services/feed")) {
      return overrides.feed ?? json({ accessToken: "new-feed" });
    }
    throw new Error(`unexpected fetch to ${url}`);
  });
}

describe("ensureFreshSession", () => {
  it("an access token expiring within 2 min triggers refresh; tokens change, no password", async () => {
    const id = seedSession(Date.now() + 60_000); // 1 min out: inside the 2-min window
    const fetchImpl = refreshFetchStub();

    const updated = await ensureFreshSession(id, { fetchImpl: fetchImpl as unknown as typeof fetch });

    expect(updated).not.toBeNull();
    expect(updated!.profileAccessToken).toBe("new-access");
    expect(updated!.profileRefreshToken).toBe("new-refresh");
    expect(updated!.feedAccessToken).toBe("new-feed");
    // Persisted under the same id.
    expect(getSession(id)!.profileAccessToken).toBe("new-access");
    // Refresh used the stored refresh token, never the login/password route.
    expect(fetchImpl.mock.calls.some(([u]) => String(u).endsWith("/api/v4/auth/login"))).toBe(false);
  });

  it("a feed token expiring within 2 min also triggers refresh", async () => {
    const id = seedSession(Date.now() + 60 * 60_000, Date.now() + 30_000);
    const fetchImpl = refreshFetchStub();

    const updated = await ensureFreshSession(id, { fetchImpl: fetchImpl as unknown as typeof fetch });

    expect(updated!.feedAccessToken).toBe("new-feed");
    expect(updated!.profileAccessToken).toBe("new-access");
  });

  it("tokens comfortably in the future are not refreshed", async () => {
    const id = seedSession(Date.now() + 60 * 60_000, Date.now() + 60 * 60_000);
    const fetchImpl = refreshFetchStub();

    const same = await ensureFreshSession(id, { fetchImpl: fetchImpl as unknown as typeof fetch });

    expect(same!.profileAccessToken).toBe("old-access");
    expect(fetchImpl).not.toHaveBeenCalled();
  });

  it("no cookie / unknown session is null", async () => {
    expect(await ensureFreshSession(undefined)).toBeNull();
    expect(await ensureFreshSession("does-not-exist")).toBeNull();
  });
});

describe("refreshSession failure", () => {
  it("a failed refresh deletes the session", async () => {
    const id = seedSession(Date.now() + 60_000);
    const fetchImpl = refreshFetchStub({ refresh: json({ data: null }, 401) });

    const result = await refreshSession(id, { fetchImpl: fetchImpl as unknown as typeof fetch });

    expect(result).toBeNull();
    expect(getSession(id)).toBeNull();
  });

  it("a failed feed exchange during refresh also deletes the session", async () => {
    const id = seedSession(Date.now() + 60_000);
    const fetchImpl = refreshFetchStub({ feed: json({ data: null }, 500) });

    const result = await ensureFreshSession(id, { fetchImpl: fetchImpl as unknown as typeof fetch });

    expect(result).toBeNull();
    expect(getSession(id)).toBeNull();
  });
});