import test from 'brittle'
import { cpuDeltaPct } from '../server/services/collector.js'

test('cpuDeltaPct: idle is 100 with no prev', (t) => {
  const v = cpuDeltaPct(null, { user: 1, idle: 9 })
  t.is(v.idle, 100)
})

test('cpuDeltaPct: bare metal percentages sum to ~100', (t) => {
  const prev = { user: 0, nice: 0, system: 0, idle: 0, iowait: 0, irq: 0, softirq: 0, steal: 0, guest: 0, guest_nice: 0 }
  const cur = { user: 20, nice: 0, system: 10, idle: 60, iowait: 10, irq: 0, softirq: 0, steal: 0, guest: 0, guest_nice: 0 }
  const v = cpuDeltaPct(prev, cur)
  t.is(v.user, 20)
  t.is(v.system, 10)
  t.is(v.idle, 60)
  t.is(v.iowait, 10)
  const sum = Object.values(v).reduce((a, b) => a + b, 0)
  t.ok(Math.abs(sum - 100) < 0.01, `sum=${sum}`)
})

test('cpuDeltaPct: guest already in user is not double-counted (idle stays correct)', (t) => {
  // Kernel: user includes guest. True idle should be 55%, not ~45%.
  const prev = { user: 0, nice: 0, system: 0, idle: 0, iowait: 0, irq: 0, softirq: 0, steal: 0, guest: 0, guest_nice: 0 }
  const cur = {
    user: 30, // includes 20 guest
    nice: 0,
    system: 10,
    idle: 55,
    iowait: 5,
    irq: 0,
    softirq: 0,
    steal: 0,
    guest: 20,
    guest_nice: 0,
  }
  const v = cpuDeltaPct(prev, cur)
  t.ok(Math.abs(v.idle - 55) < 1e-9, `idle=${v.idle}`)
  t.is(v.guest, 20)
  t.is(v.user, 10) // 30 - 20
  t.is(v.system, 10)
  t.is(v.iowait, 5)
  const sum = Object.values(v).reduce((a, b) => a + b, 0)
  t.ok(Math.abs(sum - 100) < 0.01, `sum=${sum}`)
})