local awful = require("awful")
local wibox = require("wibox")
local gears = require("gears")
local beautiful = require("beautiful")
local menubar = require("menubar")
local cairo = require("lgi").cairo
local Rsvg = require("lgi").Rsvg
local longpress = require("awesome-longpress")
local posix = require "posix"
local batterystat = {
 batteries = {}, 
 iconSize = 96,
 iconPath = gears.filesystem.get_configuration_dir() .. "/awesome-batterystat/"
}

local iconNames = {
["battery-full"] = 95,
["battery-good"] = 70,
["battery-low"] = 40,
["battery-caution"] = 20,
["battery-empty"] = 0}
local function chooseIcon(status,percent)
 local bestIcon,bestPercent = "", -1
 for k,v in pairs(iconNames) do
  if v > bestPercent and percent >= v then
   bestIcon, bestPercent = k, v
  end
 end
 if status == "Charging" then
  return bestIcon.."-charging"
 end
 return bestIcon
end

-- preload icon widgets to avoid loading them on every update
local icons = {}
for k,v in pairs(iconNames) do
 icons[k] = wibox.widget{
  widget = wibox.widget.imagebox,
  forced_height = batterystat.iconSize,
  forced_width = batterystat.iconSize,
  image = string.format("%s/%s.svg",batterystat.iconPath,k)
 }
 icons[k.."-charging"] = wibox.widget{
  widget = wibox.widget.imagebox,
  forced_height = batterystat.iconSize,
  forced_width = batterystat.iconSize,
  image = string.format("%s/%s-charging.svg",batterystat.iconPath,k)
 }
end

local function getBatteryState(path)
 local state, percent
 local f = io.open(string.format("%s/status",path),"r")
 if f then
  state = f:read("*a"):match("%S+")
  f:close()
 end
 local f = io.open(string.format("%s/capacity",path),"r")
 if f then
  percent = tonumber(f:read("*a"):match("%S+"))
  f:close()
 end
 return state, tonumber(percent)
end

function batterystat.scan()
 for _,d in pairs(posix.dir("/sys/class/power_supply")) do
  local f = io.open(string.format("/sys/class/power_supply/%s/type",d))
  if f then
   local ptype = f:read("*a"):match("%S+")
   if ptype == "Battery" then
    batterystat.batteries[#batterystat.batteries+1] = string.format("/sys/class/power_supply/%s/",d)
   end
   f:close()
  end
 end
end

local function updateBatteryWidget(self)
 local state, percent = getBatteryState(self.path)
 local colour = (state == "Charging") and "lime" or "red"
 self:set(1,icons[chooseIcon(state, percent)])
 self.children[3].markup = string.format('<span foreground="%s" size="x-large">%d%%</span>',colour,percent)
end

function batterystat.new(path)
 local state, percent = getBatteryState(path)
 local name = path:match("/([^/]+)/$")
 local sbwidget = wibox.widget{
  layout = wibox.layout.stack,
  forced_width = batterystat.iconSize,
  path = path,
  update = updateBatteryWidget,
  icons[chooseIcon(state,percent)],
  wibox.widget{
   widget = wibox.widget.textbox,
   align = "center",
   valign = "top",
   text = name
  },
  wibox.widget{
   widget = wibox.widget.textbox,
   align = "right",
   valign = "bottom",
  }
 }
 sbwidget:update()
 return sbwidget
end

function batterystat.all()
 local rt = {}
 batterystat.scan()
 for k,v in pairs(batterystat.batteries) do
  rt[#rt+1] = batterystat.new(v)
 end
 return rt
end

return batterystat