import test from 'node:test'
import assert from 'node:assert/strict'
import { getTopMaskProgress } from '../src/utils/homeTopMask.js'

test('returns 0 before the title reaches the status-bar area', () => {
  assert.equal(
    getTopMaskProgress({ scrollTop: 30, startY: 80, rangeY: 40 }),
    0
  )
})

test('ramps linearly through the transition range', () => {
  assert.equal(
    getTopMaskProgress({ scrollTop: 100, startY: 80, rangeY: 40 }),
    0.5
  )
})

test('returns 1 after the full transition range', () => {
  assert.equal(
    getTopMaskProgress({ scrollTop: 180, startY: 80, rangeY: 40 }),
    1
  )
})

test('clamps invalid values into a stable progress range', () => {
  assert.equal(getTopMaskProgress({ scrollTop: -10, startY: 80, rangeY: 40 }), 0)
  assert.equal(getTopMaskProgress({ scrollTop: 90, startY: 80, rangeY: 0 }), 1)
  assert.equal(getTopMaskProgress({ scrollTop: Number.NaN, startY: 80, rangeY: 40 }), 0)
})