-- last.fm scrobbler for mpv
--
-- Usage:
-- put this file in ~/.config/mpv/scripts
-- put https://github.com/hauzer/scrobbler somewhere in your PATH
-- run `scrobbler add-user` and follow the instructions
-- create a file ~/.mpv/script-opts/lastfm.conf with the following content:
-- username=<your last.fm user name>

local msg = require 'mp.msg'
require 'mp.options'

local options = {
	username = "change username in script-opts/lastfm.conf"
}
read_options(options, 'lastfm')

function mkmetatable()
	local m = {}
	for i = 0, mp.get_property("metadata/list/count") - 1 do
		local p = "metadata/list/"..i.."/"
		m[mp.get_property(p.."key")] = mp.get_property(p.."value")
	end
	return m
end

function scrobble()
	-- Parameter escaping function. Works with POSIX shells; idk if there's a better way to call stuff portably in Lua.
	function esc(s)
		return string.gsub(s, "'", "'\\''")
	end

	if artist and title then
		msg.info(string.format("Scrobbling %s - %s", artist, title))

		optargs = ''
		if album then
			optargs = string.format("%s '--album=%s'", optargs, esc(album))
		end
		if length then
			optargs = string.format("%s '--duration=%ds'", optargs, length)
		end
		args = string.format("scrobbler scrobble %s -- '%s' '%s' '%s' now > /dev/null", optargs, esc(options.username), esc(artist), esc(title))
		msg.verbose(args)
		os.execute(args)
	end
end

function enqueue()
	if artist and title then
		if tim then tim.kill(tim) end
		if length then
			timeout = math.min(240, length / 2)
		else
			timeout = 240
		end
		tim = mp.add_timeout(timeout, scrobble)
	end
end

function new_track()
	if mp.get_property("metadata/list/count") then
		local m = mkmetatable()
		local icy = m["icy-title"]
		if icy then
			-- TODO better magic
			artist, title = string.gmatch(icy, "(.+) %- (.+)")()
			album = nil
			length = nil
		else
			length = mp.get_property("duration")
			if length and tonumber(length) < 30 then return end	-- last.fm doesn't allow scrobbling short tracks
			artist = m["artist"]
			if not artist then
				artist = m["ARTIST"]
			end
			album = m["album"]
			if not album then
				album = m["ALBUM"]
			end
			title = m["title"]
			if not title then
				title = m["TITLE"]
			end
		end
		enqueue()
	end
end

function on_restart()
	audio_pts = mp.get_property("audio-pts")
	-- FIXME a better check for -loop'ing tracks
	if ((not audio_pts) or (tonumber(audio_pts) < 1)) then
		new_track()
	end
end

mp.observe_property("metadata/list/count", nil, new_track)
mp.register_event("playback-restart", on_restart)