Create text files for the currently played media in MPV

now_playing.lua

folder_dir = "/tmp/" --must have a slash proceding the location - lua doesn't have a pathing stdlib

--[[
This is specifically for OBS, but can be altered pretty easily for other uses
It's mostly useful for documenting the MPV metadata grabbing functions, as they are a little bit of a hassle to find

Just to note, if a tag is not found, it will create a blank file - this should never happen with the title though
]]--

function save_file(filename, metadata)
	if not metadata then --metadata can be str or null
		metadata = ""
	end

	f = io.open(folder_dir .. filename .. ".txt", "w")
	metadata = metadata:gsub(" %[NCS Release%]", "") --Remove unnecessary info from Youtube title
	f:write(metadata) --No newline, since OBS doesn't seem to like it
	f:close()
end

function save_metadata()
	local metadata = mp.get_property_native("metadata")
	local x = {}
	for key, value in pairs(metadata) do --keys can be in any case, or even mixed, so to make it more consistent, turn them all lowercase
		x[key:lower()] = value
	end

	save_file("np_title",  mp.get_property("media-title"))
	save_file("np_artist", x["artist"])
	save_file("np_album",  x["album"])
end

mp.register_event("playback-restart", save_metadata) --this event is fired whenever "play" is - essentially (re)start