local widget_types = {
	arc = require("classes/backlight/arc_widget")
}

local P = {
	name = "backlight"
}
P.__index = P

---
-- Internal methods
---
function P:_get_status()
	awful.spawn.easy_async(
		"xbacklight -get",
		function(stdout, stderr, exitreason, exitcode)
			self._ready = true
			self.brightness = tonumber(stdout)
			self:_update_widget()
		end
	)
	return true
end



function P:_update_widget()
	if (not self._ready) then
		self.widget:set_state("error")
		self.widget:set_value(self.max_value);
		self.widget:set_tooltip("Backlight error");
		return
	end

	self.widget:set_value(self.brightness);
	self.widget:set_tooltip("Backlight " .. math.floor(self.brightness) .. "%");
	self.widget:set_state("ready")
end

---
-- Simple actions
---
function P:backlight_up()
	if (not self._ready) or (self.brightness >= self.max_value) then
		return
	end

	awful.spawn("xbacklight -inc 5", false)
	self.brightness = self.brightness + 5
	if self.brightness > self.max_value then
		self.brightness = self.max_value
	end
	self:_update_widget()
end

function P:backlight_down()
	if (not self._ready) or (self.brightness <= self.min_value) then
		return
	end

	awful.spawn("xbacklight -dec 5", false)
	self.brightness = self.brightness - 5
	if self.brightness < self.min_value then
		self.brightness = self.min_value
	end
	self:_update_widget()
end

function P:backlight_set(value)
	if (not self._ready) then
		return
	end

	if (value < self.min_value) then
		value = self.min_value
	end

	if (value > self.max_value) then
		value = self.max_value
	end

	awful.spawn("xbacklight -set " .. value, false)
	self.brightness = value
	self:_update_widget()
end

---
-- Create new
---
function P:new(args)
	-- Arguments
	local b = {
		update_interval = args.update_interal or 5,
		min_value = args.min_value or 1,
		max_value = args.max_value or 100,
		widget_type = args.widget_type or "arc",


		_ready = false, -- is all the information in this class up-to-date?
		-- if this is false, ui will show an error and most methods will
		-- do nothing. Updated in _get_status()
	}
	setmetatable(b, self)

	b.widget = widget_types[b.widget_type]:new()

	b.widget.widget:connect_signal("button::press",
		function(_, _, _, button, mods)
			if (button == 4) then  -- Scroll up
				b:backlight_up()
			elseif (button == 5) then  -- Scroll down
				b:backlight_down()
			end
		end
	)

	-- This timer keeps mute and volume status up-to-date.
	b.timer = gears.timer {
		timeout   = b.update_interval,
		call_now  = true,
		autostart = true,
		callback  = function()
			b:_get_status()
		end
	}

	return b
end

return P