/**
 * Mock response แบบ duck-typing แทน `Response` จริง (jsdom ไม่มี Response/fetch global)
 * service ที่ถูก test ใช้แค่ ok / status / json() / text() / blob()
 */

export interface MockHttpResponse {
  ok: boolean;
  status: number;
  json: () => Promise<unknown>;
  text: () => Promise<string>;
  blob?: () => Promise<Blob>;
}

export function mockResponse(
  options: { status?: number; body?: unknown; text?: string; blob?: Blob } = {}
): MockHttpResponse {
  const status = options.status ?? 200;
  const text = options.text ?? (options.body !== undefined ? JSON.stringify(options.body) : "");
  return {
    ok: status >= 200 && status < 300,
    status,
    json: async () => JSON.parse(text),
    text: async () => text,
    ...(options.blob !== undefined ? { blob: async () => options.blob as Blob } : {}),
  };
}

/** แทน globalThis.fetch ด้วย mock — คืนตัวจับ call กลับไปให้ assert */
export function installFetchMock(
  implementation?: (...args: unknown[]) => Promise<MockHttpResponse>
): jest.Mock {
  const fetchMock = jest.fn(
    implementation ?? (async () => mockResponse({ status: 200, body: {} }))
  );
  (globalThis as unknown as Record<string, unknown>).fetch = fetchMock;
  return fetchMock;
}

/** JWT ปลอมเพื่อ seed session — service อ่านแค่ claim `exp` / `sub` / `preferred_username` */
export function makeFakeJwt(
  expiresAtMs: number,
  subject = "user-1",
  extraClaims: Record<string, unknown> = {}
): string {
  const encode = (value: string): string =>
    btoa(value).replace(/\+/g, "-").replace(/\//g, "_").replace(/=+$/, "");
  const header = encode(JSON.stringify({ alg: "RS256", typ: "JWT" }));
  const payload = encode(
    JSON.stringify({ sub: subject, exp: Math.floor(expiresAtMs / 1000), ...extraClaims })
  );
  return `${header}.${payload}.${encode("fake-signature")}`;
}