const createRegex = require("../../src/utils/createRegex.js");
const os = require("os");

jest.mock("os", () => ({
  platform: jest.fn()
}));

describe("Regular expression creation function", () => {
  beforeEach(() => {
    os.platform.mockReset();
  });

  test("should throw an error for invalid regular expression", () => {
    expect(() => createRegex("invalid/regex", false)).toThrow(
      "Invalid regular expression: invalid/regex"
    );
  });

  test("should create a regular expression without modifiers", () => {
    const regex = createRegex("/test/", false);
    expect(regex).toBeInstanceOf(RegExp);
    expect(regex.source).toBe("test");
    expect(regex.flags).toBe("");
  });

  test("should create a regular expression with modifiers", () => {
    const regex = createRegex("/test/gi", false);
    expect(regex).toBeInstanceOf(RegExp);
    expect(regex.source).toBe("test");
    expect(regex.flags).toBe("gi");
  });

  test('should add "i" modifier for paths on Windows', () => {
    os.platform.mockReturnValue("win32");
    const regex = createRegex("/test/", true);
    expect(regex).toBeInstanceOf(RegExp);
    expect(regex.source).toBe("test");
    expect(regex.flags).toBe("i");
  });

  test('should not add "i" modifier for paths on non-Windows platforms', () => {
    os.platform.mockReturnValue("linux");
    const regex = createRegex("/test/", true);
    expect(regex).toBeInstanceOf(RegExp);
    expect(regex.source).toBe("test");
    expect(regex.flags).toBe("");
  });

  test('should not add "i" modifier if already present', () => {
    os.platform.mockReturnValue("win32");
    const regex = createRegex("/test/i", true);
    expect(regex).toBeInstanceOf(RegExp);
    expect(regex.source).toBe("test");
    expect(regex.flags).toBe("i");
  });

  test("should handle escaped characters in the search string", () => {
    const regex = createRegex("/test\\/path/", false);
    expect(regex).toBeInstanceOf(RegExp);
    expect(regex.source).toBe("test\\/path");
    expect(regex.flags).toBe("");
  });

  test("should handle multiple modifiers", () => {
    const regex = createRegex("/test/gim", false);
    expect(regex).toBeInstanceOf(RegExp);
    expect(regex.source).toBe("test");
    expect(regex.flags).toBe("gim");
  });

  test("should handle empty search string", () => {
    const regex = createRegex("/^$/", false);
    expect(regex).toBeInstanceOf(RegExp);
    expect(regex.source).toBe("^$");
    expect(regex.flags).toBe("");
  });
});