-- Provides:
-- evil::battery
--      percentage (integer)
-- evil::charger
--      plugged (boolean)

local awful = require("awful")

local update_interval = 30

-- Subscribe to power supply status changes with acpi_listen
local charger_script = [[
    sh -c '
    acpi_listen | grep --line-buffered ac_adapter
    '
]]

-- First get battery file path
-- If there are multiple, only get the first one
-- TODO support multiple batteries
awful.spawn.easy_async_with_shell(
	'sh -c \'out="$(find /sys/class/power_supply/BAT?/capacity)" && (echo "$out" | head -1) || false\' ',
	function(battery_file, _, __, exit_code)
		-- No battery file found
		if not (exit_code == 0) then
			return
		end
		-- Periodically get battery info
		awful.widget.watch("cat " .. battery_file, update_interval, function(_, stdout)
			awesome.emit_signal("evil::battery", tonumber(stdout))
		end)
	end
)

-- First get charger file path
awful.spawn.easy_async_with_shell(
	'sh -c \'out="$(find /sys/class/power_supply/*/online)" && (echo "$out" | head -1) || false\' ',
	function(charger_file, _, __, exit_code)
		-- No charger file found
		if not (exit_code == 0) then
			return
		end
		-- Then initialize function that emits charger info
		local emit_charger_info = function()
			awful.spawn.easy_async_with_shell("cat " .. charger_file, function(out)
				local status = tonumber(out) == 1
				awesome.emit_signal("evil::charger", status)
			end)
		end

		-- Run once to initialize widgets
		emit_charger_info()

		-- Kill old acpi_listen process
		awful.spawn.easy_async_with_shell(
			"ps x | grep \"acpi_listen\" | grep -v grep | awk '{print $1}' | xargs kill",
			function()
				-- Update charger status with each line printed
				awful.spawn.with_line_callback(charger_script, {
					stdout = function(_)
						emit_charger_info()
					end,
				})
			end
		)
	end
)