import test from 'node:test'
import assert from 'node:assert/strict'
import { summarizeDistribution } from '../src/lib/performance.ts'

test('zero usage is measured and ties do not count as better performance', () => {
  const summary = summarizeDistribution(
    [
      { value: 0, count: 3 },
      { value: 12, count: 2 },
      { value: 24, count: 5 },
    ],
    12,
  )
  assert.equal(summary.total, 10)
  assert.equal(summary.betterThan, 50)
  assert.equal(summary.tied, 2)
  assert.equal(summarizeDistribution([{ value: 0, count: 3 }], 0).betterThan, 0)
})

test('bin boundaries and the final upper endpoint preserve every sample', () => {
  const summary = summarizeDistribution(
    [
      { value: 0, count: 2 },
      { value: 5, count: 3 },
      { value: 100, count: 7 },
    ],
    100,
  )
  assert.equal(summary.bins[0].count, 2)
  assert.equal(summary.bins[1].count, 3)
  assert.equal(summary.bins.at(-1)!.count, 7)
  assert.equal(
    summary.bins.reduce((sum, bin) => sum + bin.count, 0),
    summary.total,
  )
  assert.ok(Math.abs(summary.bins.reduce((sum, bin) => sum + bin.percent, 0) - 100) < 1e-9)
})

test('missing measurements and invalid samples produce no percentile', () => {
  const summary = summarizeDistribution(
    [
      { value: -1, count: 3 },
      { value: NaN, count: 2 },
      { value: Infinity, count: 1 },
      { value: 10, count: -1 },
      { value: 20, count: 1.5 },
      { value: 24, count: 0 },
    ],
    null,
  )
  assert.equal(summary.total, 0)
  assert.equal(summary.betterThan, null)
  assert.equal(summary.current, null)
  assert.ok(summary.bins.every((bin) => bin.percent === 0))
  assert.equal(summarizeDistribution([{ value: 12, count: 2 }], null).betterThan, null)
  assert.equal(summarizeDistribution([{ value: 12, count: 2 }], NaN).current, null)
})

test('current measurements outside the cohort remain within the plot', () => {
  const summary = summarizeDistribution([{ value: 12, count: 2 }], 140)
  assert.ok(summary.end >= 140)
  assert.equal(summary.betterThan, 0)
  assert.equal(summary.total, 2)
})