import { renderHook } from '@testing-library/react-native'
import { useFontScale } from '../../hooks/use_font_scale'

jest.mock('react-native', () => {
  const actual = jest.requireActual('react-native')
  return Object.defineProperty(actual, 'useWindowDimensions', {
    value: jest.fn(),
    configurable: true,
  })
})

const mockUseWindowDimensions = require('react-native').useWindowDimensions
const DEFAULT_NATIVE_FONT_SCALE = 1
const SMALL_NATIVE_FONT_SCALE = 0.8
const LARGE_NATIVE_FONT_SCALE = 3

describe('useFontScale', () => {
  beforeEach(() => {
    mockUseWindowDimensions.mockReturnValue({ fontScale: DEFAULT_NATIVE_FONT_SCALE })
  })

  afterEach(() => {
    jest.clearAllMocks()
  })

  test('returns native font scale when no constraints provided', () => {
    expect(renderHook(() => useFontScale()).result.current).toBe(DEFAULT_NATIVE_FONT_SCALE)
    expect(renderHook(() => useFontScale({})).result.current).toBe(DEFAULT_NATIVE_FONT_SCALE)
  })

  describe('with single constraint', () => {
    test('clamps to minimum when native scale is below minFontSizeMultiplier', () => {
      mockUseWindowDimensions.mockReturnValue({ fontScale: SMALL_NATIVE_FONT_SCALE })
      const { result } = renderHook(() => useFontScale({ minFontSizeMultiplier: 1 }))
      expect(result.current).toBe(1)
    })

    test('clamps to maximum when native scale exceeds maxFontSizeMultiplier', () => {
      mockUseWindowDimensions.mockReturnValue({ fontScale: LARGE_NATIVE_FONT_SCALE })
      const { result } = renderHook(() => useFontScale({ maxFontSizeMultiplier: 2 }))
      expect(result.current).toBe(2)
    })
  })

  describe('with both constraints', () => {
    test('returns native scale when within bounds', () => {
      const { result } = renderHook(() =>
        useFontScale({ minFontSizeMultiplier: 0.5, maxFontSizeMultiplier: 2 })
      )
      expect(result.current).toBe(DEFAULT_NATIVE_FONT_SCALE)
    })

    test('clamps to minimum when native scale is below', () => {
      mockUseWindowDimensions.mockReturnValue({ fontScale: SMALL_NATIVE_FONT_SCALE })
      const { result } = renderHook(() =>
        useFontScale({ minFontSizeMultiplier: 1, maxFontSizeMultiplier: 2 })
      )
      expect(result.current).toBe(1)
    })

    test('clamps to maximum when native scale exceeds', () => {
      mockUseWindowDimensions.mockReturnValue({ fontScale: LARGE_NATIVE_FONT_SCALE })
      const { result } = renderHook(() =>
        useFontScale({ minFontSizeMultiplier: 1, maxFontSizeMultiplier: 2 })
      )
      expect(result.current).toBe(2)
    })
  })
})