Erinfest/mods/PLAYER/mcl_music/init.lua

local modname = minetest.get_current_modname()
local modpath = minetest.get_modpath(modname)

local music_enabled = minetest.settings:get_bool("mcl_game_music", true)

local pianowtune  = "diminixed-pianowtune01"
local end_tune    = "diminixed-ambientwip"
local nether_tune = "horizonchris96-traitor"

local dimension_to_base_track = {
	["overworld"] = {pianowtune},
	["nether"]    = {nether_tune},
	["end"]       = {end_tune},
}

local listeners = {}

local weather_state

local function pick_track(dimension, below_ground)
	if dimension == "overworld" and below_ground then
		-- Play mining track
	else
		-- Pick random dimension song
	end
	-- Maybe just change the key to lookup and it's explicit what songs are for what context

	local dimension_tracks = dimension_to_base_track[dimension]
	local chosen_track = dimension_tracks[math.random(1, #dimension_tracks)]
	return chosen_track
end


local function stop_music_for_listener_name(listener_name)
	if not listener_name then return end
	local listener = listeners[listener_name]
	if not listener then return end
	local handle = listener.handle
	if not handle then return end
	minetest.sound_stop(handle)
	listeners[listener_name].handle = nil
end

local function stop_music_for_all()
	for _, player in pairs(minetest.get_connected_players()) do
		local player_name = player:get_player_name()
		stop_music_for_listener_name(player_name)
	end
end

local function play_song(track, player_name, hp, dimension, day_count)
	local spec = {
		name  = track,
		gain  = 0.3,
		pitch = 1.0,
	}
	local parameters = {
		to_player = player_name,
		gain      = 1.0,
		fade      = 0.0,
		pitch     = 1.0,
	}
	local handle = minetest.sound_play(spec, parameters, false)
	listeners[player_name] = {
		spec       = spec,
		parameters = parameters,
		handle     = handle,
		hp         = hp,
		dimension  = dimension,
		day_count  = day_count,
	}
end

local function play()
	local new_weather_state = mcl_weather.get_weather()
	local was_good_weather = weather_state == "none" or weather_state == "clear"
	weather_state = new_weather_state
	local is_good_weather = weather_state == "none" or weather_state == "clear"
	local is_weather_changed = weather_state ~= new_weather_state
	local time = minetest.get_timeofday()
	if time < 0.25 or time >= 0.75 then
		stop_music_for_all()
		minetest.after(10, play)
		return
	end
	local day_count = minetest.get_day_count()
	for _, player in pairs(minetest.get_connected_players()) do
		local player_name = player:get_player_name()
		local hp          = player:get_hp()
		local pos         = player:get_pos()

		local below_ground = pos and pos.y < 0

		local dimension   = mcl_worlds.pos_to_dimension(pos)

		local listener      = listeners[player_name]

		local handle = listener and listener.handle

		local old_hp        = listener and listener.hp
		local old_dimension = listener and listener.dimension

		local is_dimension_changed = old_dimension and (old_dimension ~= dimension) or false
		local is_hp_changed = old_hp and (math.abs(old_hp - hp) > 0.00001) or false


		-- TODO if y is less than 1, then pick mining track or not morning music
		local track = pick_track(dimension, below_ground)

		if is_hp_changed or is_dimension_changed
				or (dimension == "overworld" and (is_weather_changed or not is_good_weather))
				or not track then
			stop_music_for_listener_name(player_name)
			if not listeners[player_name] then
				listeners[player_name] = {}
			end
			listeners[player_name].hp = hp
			listeners[player_name].dimension = dimension
		elseif not handle and (not listener or (listener.day_count ~= day_count)) then
			play_song(track, player_name, hp, dimension, day_count)
		end
	end

	minetest.after(7, play)
end

if music_enabled then
	minetest.log("action", "[mcl_music] In-game music is activated")
	minetest.after(15, play)

	minetest.register_on_joinplayer(function(player, last_login)
		local player_name = player:get_player_name()
		stop_music_for_listener_name(player_name)
	end)

	minetest.register_on_respawnplayer(function(player)
		local player_name = player:get_player_name()
		stop_music_for_listener_name(player_name)
	end)
else
	minetest.log("action", "[mcl_music] In-game music is deactivated")
end