-- change color of wibars on numlock/capslock/scrolllock
--
local awful = require("awful")
local beautiful = require("beautiful")

local lockhl = { bg_lock = beautiful.bg_urgent, bg_normal = beautiful.bg_normal }
local target_wibars = {}

function lockhl:setup(wibars, bg_lock, bg_normal, defaults)
	target_wibars = wibars
	if bg_lock then
		self.bg_lock = bg_lock
	end
	if bg_normal then
		self.bg_normal = bg_normal
	end

	if defaults ~= nil then
		for lock, normal_state in pairs(defaults) do
			print("lock: " .. lock .. " normal_state: " .. tostring(normal_state))
			lockhl:on_lock(lock, normal_state)
		end
	end
	return lockhl
end

local function check_lock(lock, cb)
	awful.spawn.with_line_callback(
		'bash -c "sleep 0.2; xset q | grep -Po \\"' .. lock .. ' Lock:\\\\s*\\\\K(on|off)\\" 2>&1"',
		{
			stdout = function(output)
				cb(output == "on")
			end,
		}
	)
end

function lockhl:target_color(is_on, lock)
	if is_on then
		if type(self.bg_lock) == "table" then
			return self.bg_lock[lock]
		else
			return self.bg_lock
		end
	else
		return self.bg_normal
	end
end

local function xor(a, b)
	return not (not a == not b)
end

function lockhl:on_lock(lock, normal_state)
	check_lock(lock, function(is_on)
		local newbg = self:target_color(xor(is_on, normal_state), lock)
		for _, bar in pairs(target_wibars) do
			bar.bg = newbg
		end
	end)
end

return setmetatable(lockhl, {
	__call = function(_, lock, normal_state)
		return function()
			lockhl:on_lock(lock, normal_state)
		end
	end,
})