dotfiles/awesome/lib/lain/widget/contrib/redshift.lua

--[[

     Licensed under GNU General Public License v2
      * (c) 2017, Luca CPZ
      * (c) 2014, blueluke <http://github.com/blueluke>

--]]

local async = require('lain.helpers').async
local awful = require('awful')
local execute = os.execute
local type = type

-- Redshift
-- lain.widget.contrib.redshift
local redshift = { active = false, pid = nil }

function redshift.start()
	execute('pkill redshift')
	awful.spawn.with_shell('redshift -x') -- clear adjustments
	redshift.pid = awful.spawn.with_shell('redshift')
	redshift.active = true
	if type(redshift.update_fun) == 'function' then
		redshift.update_fun(redshift.active)
	end
end

function redshift.toggle()
	async({ awful.util.shell, '-c', string.format('ps -p %d -o pid=', redshift.pid) }, function(f)
		if f and #f > 0 then -- redshift is running
			-- Sending -USR1 toggles redshift (See project website)
			execute('pkill -USR1 redshift')
			redshift.active = not redshift.active
		else -- not started or killed, (re)start it
			redshift.start()
		end
		redshift.update_fun(redshift.active)
	end)
end

-- Attach to a widget
-- Provides a button which toggles redshift on/off on click
-- @param widget:  Widget to attach to.
-- @param fun:     Function to be run each time redshift is toggled (optional).
--                 Use it to update widget text or icons on status change.
function redshift.attach(widget, fun)
	redshift.update_fun = fun or function() end
	if not redshift.pid then
		redshift.start()
	end
	if widget then
		widget:buttons(awful.util.table.join(awful.button({}, 1, function()
			redshift.toggle()
		end)))
	end
end

return redshift