import base
import std/[strutils,os]

const battery = "BAT0"
const ok_fg = lightgreen
const default_fg = white
const default_bg = black
const warning_fg = black
const warning_bg = red
const low_bg = black
const low_fg = red
const alert_fg = black
const alert_bg = yellow
const med_fg = green
const med_bg = black


proc batteryExists(): bool =
  try:
    let state = strip(readFile("/sys/class/power_supply/" & battery & "/present"))
    if state == "1":
      return true
  except:
    echo "Error getting battery : " & getCurrentExceptionMsg()
  return false

proc isCharging(): bool =
  try:
    let state = strip(readFile("/sys/class/power_supply/" & battery & "/status"))
    if state == "Charging":
      return true
  except:
    echo "Error getting charging status : " & getCurrentExceptionMsg()
  return false

proc getCharge(): int =
  var charge = 0
  try:
    let chg = strip(readFile("/sys/class/power_supply/" & battery & "/capacity"))
    if chg != "":
      charge = parseInt(chg)
  except:
    echo "Error getting battery level : " & getCurrentExceptionMsg()
  return charge

proc getDesign(charge: int, state: bool): (string, string, string, string, string) =
  var icon = " "
  var icon_colour = ok_fg
  var col = default_fg
  var bg = default_bg
  var border = ok_fg
  if isCharging():
    icon = " "
  else:
    case charge:
      of 0..5:
        icon_colour = warning_fg
        col = warning_fg
        bg = warning_bg
      of 6..19:
        icon_colour = low_fg
        border = low_bg
        bg = default_bg
      of 20..39:
        icon_colour = alert_fg
        border = alert_bg
        icon = " "
      of 40..59:
        icon_colour = med_fg
        border= med_fg
        icon = " "
      of 60..79:
        icon_colour =  med_fg
        border = med_fg
        icon = " "
      of 80..100:
        icon_colour = ok_fg
        border = ok_fg
        icon = " "
      else:
        icon = "x "

  let main_text = icon & " " & $charge & "%"
  # This next line is here for i3bar purposes
  let html_text = "<span foreground=\"" & icon_colour & "\">" & icon & "</span>" & $charge & "%" 

  return (html_text,main_text, col, bg, border)

proc getOutput(charge: int, state: bool): Info =
  let (html_text,main_text,col,bg_col,highlight_col) = get_design(charge, state)
  var data = newInfo("Battery")
  data.full_text = main_text
  data.selected_bg = highlight_col
  data.selected_fg = col # may just want `black` here
  # i3bar stuff
  data.html_text = html_text
  data.color = col
  data.border = highlight_col
  data.background = bg_col
  return data


proc getBatteryInfo() =
  var last_charge = -1
  var last_state = false
  while true:
    let charge = getCharge()
    let state = isCharging()
    if charge != last_charge or state != last_state:
      let data = getoutput(charge, state)
      outputData(data)
      last_charge = charge
      last_state = state
    if stoploop:
      break
    sleep(1000)

proc main() =
  if batteryExists():
    getBatteryInfo()
  else:
    switchTwmMode()

if isMainModule:
  main()