import { renderHook, act } from '@testing-library/react';
import { describe, it, expect, beforeEach, vi } from 'vitest';
import { useSettings } from '../../../src/hooks/useSettings';
import { SettingsProvider } from '../../../src/hooks/SettingsProvider';

describe('useSettings hook', () => {
  // Mock implementation of localStorage
  const localStorageMock = (() => {
    let store: Record<string, string> = {};
    return {
      getItem: vi.fn((key: string) => store[key] || null),
      setItem: vi.fn((key: string, value: string) => {
        store[key] = value.toString();
      }),
      removeItem: vi.fn((key: string) => {
        delete store[key];
      }),
      clear: vi.fn(() => {
        store = {};
      }),
    };
  })();

  beforeEach(() => {
    vi.stubGlobal('localStorage', localStorageMock);
    vi.clearAllMocks();
    // Clear the mock store
    (localStorage as any).clear();
  });

  const wrapper = ({ children }: { children: React.ReactNode }) => (
    <SettingsProvider>{children}</SettingsProvider>
  );

  it('should return default settings when wrapped in SettingsProvider', () => {
    const { result } = renderHook(() => useSettings(), { wrapper });

    expect(result.current.settings).toEqual({
      dayStart: '07:00',
      dayEnd: '20:00',
      wakeupRef: '04:00',
      bedtimeRef: '19:00',
      statsInterval: 7,
      sessionsPerPage: 10,
    });
  });

  it('should throw an error when used outside of SettingsProvider', () => {
    expect(() => renderHook(() => useSettings())).toThrow(
      'useSettings must be used within a SettingsProvider'
    );
  });

  it('should update settings correctly via the update function', () => {
    const { result } = renderHook(() => useSettings(), { wrapper });

    act(() => {
      result.current.update('dayStart', '08:30');
    });

    expect(result.current.settings.dayStart).toBe('08:30');
    // Verify other settings remain unchanged
    expect(result.current.settings.dayEnd).toBe('20:00');
  });

  it('should persist updated settings to localStorage', () => {
    const setItemSpy = vi.spyOn(localStorage, 'setItem');
    const { result } = renderHook(() => useSettings(), { wrapper });

    act(() => {
      result.current.update('statsInterval', 14);
    });

    expect(setItemSpy).toHaveBeenCalledWith(
      'baby-sleep-settings',
      expect.stringContaining('"statsInterval":14')
    );
  });

  it('should initialize with settings from localStorage if available', () => {
    const storedSettings = {
      dayStart: '10:00',
      dayEnd: '22:00',
      wakeupRef: '06:00',
      bedtimeRef: '21:00',
      statsInterval: 5,
      sessionsPerPage: 20,
    };
    localStorage.setItem('baby-sleep-settings', JSON.stringify(storedSettings));

    const { result } = renderHook(() => useSettings(), { wrapper });

    expect(result.current.settings).toEqual(storedSettings);
  });

  it('should fallback to default settings if localStorage contains invalid JSON', () => {
    localStorage.setItem('baby-sleep-settings', 'invalid-json');

    const { result } = renderHook(() => useSettings(), { wrapper });

    expect(result.current.settings).toEqual({
      dayStart: '07:00',
      dayEnd: '20:00',
      wakeupRef: '04:00',
      bedtimeRef: '19:00',
      statsInterval: 7,
      sessionsPerPage: 10,
    });
  });

  it('should handle empty localStorage by using default settings', () => {
    localStorage.clear();
    const { result } = renderHook(() => useSettings(), { wrapper });
    expect(result.current.settings).toEqual({
      dayStart: '07:00',
      dayEnd: '20:00',
      wakeupRef: '04:00',
      bedtimeRef: '19:00',
      statsInterval: 7,
      sessionsPerPage: 10,
    });
  });
});