import base
import std/[os,strutils,osproc,math]

const backlight = "intel_backlight"
const default_bg = yellow
const default_fg = black
const backlight_cmd = "xbacklight"
const backlight_up = backlight_cmd & " -inc %v" # %v is amount by
const backlight_down = backlight_cmd & " -dec %v" # %v is amount by
const backlight_set = backlight_cmd & " -set %v" # %v is amount by
const default_value = "5"

proc getLimit(): int =
  try:
    let back_l = readFile("/sys/class/backlight/" & backlight & "/max_brightness")
    return parseInt(strip(back_l))
  except:
    echo "Error getting backlight max : ", getCurrentExceptionMsg()
  return -1

let limit = getLimit()

proc getDesign(pcnt: float): string =
  var icon = "🌑"
  case pcnt:
    of 85..100:
      icon = "🌕"
    of 75..85:
      icon = "🌖"
    of 50..75:
      icon = "🌗"
    of 35..50:
      icon = "🌘"
    else:
      icon = "🌑"
  let percent = toInt(round(pcnt,0))
  let text = icon & " " & $percent & "%"
  return text

proc brightnessUp() =
  let cmd = replace(backlight_up,"%v",default_value)
  discard execCmd(cmd)
proc brightnessDown() =
  let cmd = replace(backlight_down,"%v",default_value)
  discard execCmd(cmd)

proc getBrightness*(run_once: bool = false) =
  var last_pcnt: float = 0
  while true:
    let current = parseInt(strip(readFile("/sys/class/backlight/" & backlight & "/actual_brightness")))
    let pcnt = (current/limit)*100
    if pcnt != last_pcnt:
      let text = getDesign(pcnt)
      var data = newInfo("Brightness")
      data.full_text = text
      data.selected_bg = default_fg
      data.selected_fg = default_bg
      # i3bar stuff
      data.border = default_fg
      let args = @["up", "down"]
      let option = outputData(data,args)
      if option in args:
        case option:
          of "up":
            brightnessUp()
            getBrightness(true)
          of "down":
            brightnessDown()
            getBrightness(true)
      else:
        try:
          let i = parseInt(option)
          let cmd = replace(backlight_set,"%v",$i)
          discard execCmd(cmd)
          getBrightness(true)
        except:
          echo getCurrentExceptionMsg()

      if run_once:
        break
    if stoploop:
      break
    last_pcnt = pcnt
    sleep(1000)

proc main() =
  if limit == -1:
    switchTwmMode()
    return
  getBrightness()

if isMainModule:
  block start:
    for arg in args:
      case arg:
        of "up":
          brightnessUp()
          break start
        of "down":
          brightnessDown()
          break start

    main()