--[[
	OBS Lua script
	Monitor a text file for changes
--]]


local obs = obslua
local textFile, interval, debug -- OBS settings
local activeId = 0 -- active timer id
local current = {} -- current values to compare with text file


-- called when an update to the text file is detected
-- put your code in here to update scenes, etc...
local function update(k, v)
	if debug then obs.script_log(obs.LOG_INFO, string.format("%s has changed to %s", k, v)) end

end


local function checkFile(id)
	-- if the script has reloaded then stop any old timers
	if id < activeId then
		obs.remove_current_callback()
		return
	end

	if debug then obs.script_log(obs.LOG_INFO, string.format("(%d) Checking text file...(%d)", id, interval)) end
	local f, err = io.open(textFile, "rb")
	if f then
		local line
		for line in f:lines() do
			-- check for key=value
			local k, v = line:match("^([^=]+)%=(.+)$")
			if k and v then
				-- success : now check if the value has changed
				if current[k] ~= v then
					current[k] = v
					update(k, v)
				end
			end
		end
		f:close()
	else
		if debug then obs.script_log(obs.LOG_INFO, string.format("Error reading text file : ", err)) end
	end
end


local function init()
	-- increase the timer id - old timers will be cancelled
	activeId = activeId + 1

	-- only proceed if there is a text file selected
	if not textFile then return nil end

	-- start the timer to check the text file
	local id = activeId
	obs.timer_add(function() checkFile(id) end, interval)
	obs.script_log(obs.LOG_INFO, string.format("Text monitor started"))
end


----------------------------------------------------------


-- called on startup
function script_load(settings)
end


-- called on unload
function script_unload()
end


-- called when settings changed
function script_update(settings)
	textFile = obs.obs_data_get_string(settings, "textFile")
	interval = obs.obs_data_get_int(settings, "interval")
	debug = obs.obs_data_get_bool(settings, "debug")
	init()
end


-- return description shown to user
function script_description()
	return "Monitor a text file for changes"
end


-- define properties that user can change
function script_properties()
	local props = obs.obs_properties_create()
	obs.obs_properties_add_path(props, "textFile", "Text File", obs.OBS_PATH_FILE, "", nil)
	obs.obs_properties_add_int(props, "interval", "Interval (ms)", 1000, 20000, 500)
	obs.obs_properties_add_bool(props, "debug", "Debug")
	return props
end


-- set default values
function script_defaults(settings)
	obs.obs_data_set_default_string(settings, "textFile", "")
	obs.obs_data_set_default_int(settings, "interval", 1000)
	obs.obs_data_set_default_bool(settings, "debug", false)
end


-- save additional data not set by user
function script_save(settings)
end