/**
 * Unit tests for the pure zoom helpers: clamping garbage input, the
 * percent <-> zoom-level conversion the settings UI relies on, and the
 * roundtrip stability of the preset percentages.
 */

const test = require('node:test')
const assert = require('node:assert/strict')

const { ZOOM_STORAGE_KEY, clampZoomLevel, percentToZoomLevel, zoomLevelToPercent } = require('./zoom.cjs')

test('storage key stays stable so persisted zoom survives upgrades', () => {
  assert.equal(ZOOM_STORAGE_KEY, 'hermes:desktop:zoomLevel')
})

test('clampZoomLevel rejects garbage and enforces bounds', () => {
  assert.equal(clampZoomLevel(NaN), 0)
  assert.equal(clampZoomLevel(Infinity), 0)
  assert.equal(clampZoomLevel(undefined), 0)
  assert.equal(clampZoomLevel('2'), 0)
  assert.equal(clampZoomLevel(0.3), 0.3)
  assert.equal(clampZoomLevel(-42), -9)
  assert.equal(clampZoomLevel(42), 9)
})

test('level 0 is exactly 100 percent', () => {
  assert.equal(zoomLevelToPercent(0), 100)
  assert.equal(percentToZoomLevel(100), 0)
})

test('percentToZoomLevel rejects garbage', () => {
  assert.equal(percentToZoomLevel(NaN), 0)
  assert.equal(percentToZoomLevel(0), 0)
  assert.equal(percentToZoomLevel(-50), 0)
  assert.equal(percentToZoomLevel(undefined), 0)
})

test('preset percentages roundtrip within rounding', () => {
  for (const percent of [90, 100, 110, 125, 150, 175]) {
    assert.equal(zoomLevelToPercent(percentToZoomLevel(percent)), percent)
  }
})

test('conversion is monotonic across the preset range', () => {
  const levels = [90, 100, 110, 125, 150, 175].map(percentToZoomLevel)
  for (let i = 1; i < levels.length; i++) {
    assert.ok(levels[i] > levels[i - 1])
  }
})

test('extreme percentages clamp to the level bounds', () => {
  assert.equal(percentToZoomLevel(1), -9)
  assert.equal(percentToZoomLevel(1_000_000), 9)
})