import GTop from "gi://GTop"

type Snapshot = {
  total: number
  user: number
  sys: number
  idle: number
}

export function get_cpu_snapshot() {
  const cpu = new GTop.glibtop_cpu()
  GTop.glibtop_get_cpu(cpu)
  return {
    total: cpu.total,
    user: cpu.user + cpu.nice,
    sys: cpu.sys,
    idle: cpu.idle,
  }
}

export function calc_cpu_usage(a: Snapshot, b: Snapshot) {
  const total_diff = b.total - a.total
  const active_diff = b.user + b.sys - (a.user + a.sys)
  return Math.round(total_diff > 0 ? (100 * active_diff) / total_diff : 0)
}

export function get_ram_info() {
  const mem = new GTop.glibtop_mem()
  GTop.glibtop_get_mem(mem)
  return {
    total: mem.total,
    used: mem.total - mem.free - mem.cached - mem.buffer,
    free: mem.free,
  }
}

function format_bytes(bytes: number) {
  let units = ["B", "KiB", "MiB", "GiB", "TiB"]
  let i = 0
  let num: number = bytes
  while (num >= 1024 && i < units.length - 1) {
    num /= 1024
    i++
  }

  return `${num.toFixed(2)}${units[i]}`
}

export function get_disk_space() {
  const usage = new GTop.glibtop_fsusage()
  GTop.glibtop_get_fsusage(usage, "/")

  const free_bytes = usage.bavail * usage.block_size

  return format_bytes(free_bytes)
}