const { handleSearch } = require("../src/search");

describe("handleSearch", () => {
  let req;
  let res;

  beforeEach(() => {
    req = {
      query: {}
    };

    // using .mockReturnThis() because of chainable methods
    res = {
      status: jest.fn().mockReturnThis(),
      send: jest.fn().mockReturnThis(),
      setHeader: jest.fn()
    };
  });

  // clean up the observed data after each test
  afterEach(() => {
    jest.restoreAllMocks();
  });

  test("returns 400 when query is missing", async () => {
    global.fetch = jest.fn().mockResolvedValue({
      json: jest.fn().mockResolvedValue({
        results: [
          {
            url: "https://example.com",
            title: "Example",
            content: "Content",
            irrelevant: "removed"
          }
        ]
      })
    });
    
    await handleSearch(req, res);

    expect(res.status).toHaveBeenCalledWith(400);
    expect(res.send).toHaveBeenCalledWith("Missing search query");
    expect(global.fetch).not.toHaveBeenCalled();
  });

  test("fetches search results and sends filtered JSON", async () => {
    req.query.query = "nodejs testing";

    global.fetch = jest.fn().mockResolvedValue({
      json: jest.fn().mockResolvedValue({
        results: [
          {
            url: "https://example.com",
            title: "Example",
            content: "Content",
            score: 0.8
          }
        ]
      })
    });

    await handleSearch(req, res);

    expect(global.fetch).toHaveBeenCalledTimes(1);

    const [url, options] = global.fetch.mock.calls[0];

    expect(url).toContain("/search?");
    expect(url).toContain("q=nodejs+testing");
    expect(url).toContain("engines=startpage");
    expect(url).toContain("format=json");
    expect(url).not.toContain("score=0.8");

    expect(options).toEqual({
      headers: {
        Accept: "application/json"
      }
    });

    expect(res.setHeader).toHaveBeenCalledWith(
      "Content-Type",
      "application/json; charset=utf-8"
    );

    expect(res.setHeader).toHaveBeenCalledWith(
      "Content-Disposition",
      'attachment; filename="output.json"'
    );

    expect(res.send).toHaveBeenCalledWith(
      JSON.stringify(
        [
          {
            url: "https://example.com",
            title: "Example",
            content: "Content"
          }
        ],
        null,
        2
      )
    );
  });

  test("uses an empty array when the API omits results", async () => {
    req.query.query = "empty";

    global.fetch = jest.fn().mockResolvedValue({
      json: jest.fn().mockResolvedValue({})
    });

    await handleSearch(req, res);

    expect(res.send).toHaveBeenCalledWith("[]");
  });

  test("returns 500 when fetch fails", async () => {
    req.query.query = "error";

    global.fetch = jest
      .fn()
      .mockRejectedValue(new Error("SearxNG unavailable"));

    await handleSearch(req, res);

    expect(res.status).toHaveBeenCalledWith(500);
    expect(res.send).toHaveBeenCalledWith(
      "<p><b>Search failed!<br>See the console for the error.</b></p>"
    );
  });
});