import { describe, expect, it } from 'vitest'

import { scrollElementIntoContainer } from '@/lib/scrollElementIntoContainer'

describe('scrollElementIntoContainer', () => {
  it('scrolls down when the target overflows the container bottom', () => {
    const container = {
      getBoundingClientRect: () => ({ top: 100, bottom: 300, left: 0, right: 100, width: 100, height: 200 }),
      scrollTop: 0,
    } as HTMLElement
    const target = {
      getBoundingClientRect: () => ({ top: 280, bottom: 340, left: 0, right: 100, width: 100, height: 60 }),
    } as HTMLElement

    scrollElementIntoContainer(container, target)

    expect(container.scrollTop).toBe(40)
  })

  it('scrolls up when the target overflows the container top', () => {
    const container = {
      getBoundingClientRect: () => ({ top: 100, bottom: 300, left: 0, right: 100, width: 100, height: 200 }),
      scrollTop: 80,
    } as HTMLElement
    const target = {
      getBoundingClientRect: () => ({ top: 60, bottom: 120, left: 0, right: 100, width: 100, height: 60 }),
    } as HTMLElement

    scrollElementIntoContainer(container, target)

    expect(container.scrollTop).toBe(40)
  })

  it('does nothing when the target is already fully visible', () => {
    const container = {
      getBoundingClientRect: () => ({ top: 100, bottom: 300, left: 0, right: 100, width: 100, height: 200 }),
      scrollTop: 12,
    } as HTMLElement
    const target = {
      getBoundingClientRect: () => ({ top: 140, bottom: 200, left: 0, right: 100, width: 100, height: 60 }),
    } as HTMLElement

    scrollElementIntoContainer(container, target)

    expect(container.scrollTop).toBe(12)
  })
})