import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
import { fetchDiff } from "./diffApi";

const ORIGINAL_ENV = process.env;

beforeEach(() => {
  process.env = { ...ORIGINAL_ENV, NEXT_PUBLIC_VERSIONING_API_URL: "http://backend.test", NEXT_PUBLIC_USER_ID: "user-a" };
});

afterEach(() => {
  process.env = ORIGINAL_ENV;
  vi.restoreAllMocks();
});

describe("diffApi", () => {
  it("fetchDiff ruft den erwarteten Endpunkt mit from/to/caller auf", async () => {
    const fetchMock = vi.fn().mockResolvedValue(new Response(JSON.stringify({ text: [], metadata: [] }), { status: 200 }));
    vi.stubGlobal("fetch", fetchMock);
    await fetchDiff("doc-1", "rev-a", "rev-b");
    expect(fetchMock.mock.calls[0][0]).toBe(
      "http://backend.test/documents/doc-1/diff?caller=user-a&from=rev-a&to=rev-b"
    );
  });

  it("fetchDiff liefert Text- und Metadatendiff bei Erfolg", async () => {
    const body = {
      text: [{ op: "equal", text: "a" }, { op: "delete", text: "b" }, { op: "insert", text: "c" }],
      metadata: [{ field: "comment", before: "alt", after: "neu" }],
    };
    vi.stubGlobal("fetch", vi.fn().mockResolvedValue(new Response(JSON.stringify(body), { status: 200 })));
    await expect(fetchDiff("doc-1", "rev-a", "rev-b")).resolves.toEqual(body);
  });

  it("fetchDiff wirft bei 403 eine verstaendliche Fehlermeldung", async () => {
    vi.stubGlobal("fetch", vi.fn().mockResolvedValue(new Response(null, { status: 403 })));
    await expect(fetchDiff("doc-1", "rev-a", "rev-b")).rejects.toThrow(/Berechtigung/);
  });
});