extends Node

const DISPLAY_NAME_FILE = "user://display_name.txt"
const DEFAULT_DISPLAY_NAME = "UnnamedPlayer"
const DEFAULT_SIGNALLER_URL = "ws://localhost:8888"
# const DEFAULT_SIGNALLER_URL = "wss://webrtc-signaller.deno.dev:443"

const DEFAULT_ICE_SERVERS = [
	# first element in this array is for STUN
	{ "urls": ["stun:localhost:3478", "stun:stun.l.google.com:19302"] },
	# { "urls": ["stun:stun.l.google.com:19302"] }, # just google
	# { "urls": ["stun:localhost:3478"] }, # just localhost
	# {} # TURN servers
]

signal lobby_data(lobbies)
signal lobby_begin_join(uuid)
signal lobby_joined(lobby_and_peer)
signal lobby_left(uuid)
signal lobby_delete(uuid)

signal peer_data(peers)
signal peer_created(peer)
signal peer_left(id)
signal peer_init(id)

signal candidate_received(cand)
signal offer_received(data)
signal answer_received(data)

# webrtc
signal webrtc_peer_connected(id)
signal webrtc_peer_disconnected(id)
signal webrtc_connection_succeeded()

# websocket
signal signaller_connected
signal signaller_connection_failure
signal signaller_disconnected

onready var webrtc = null
onready var websocket = WebSocketClient.new()

onready var display_name = DEFAULT_DISPLAY_NAME setget set_display_name
onready var current_lobby = null
onready var lobbies = {}
onready var peers = {}

onready var signaller_url = DEFAULT_SIGNALLER_URL

func _init():
	pass

func _ready():
	display_name = _load_display_name()

	websocket.connect("connection_established", self, "_signaller_connected")
	websocket.connect("data_received", self, "_signaller_data")
	websocket.connect("server_close_request", self, "_signaller_close_request")
	websocket.connect("connection_closed", self, "_signaller_closed")
	websocket.connect("connection_error", self, "_signaller_error", [false])
	websocket.connect("connection_failed", self, "_signaller_error", [false])

func is_signaller_connected():
	return websocket.get_connection_status() in [
		websocket.CONNECTION_CONNECTED,
		websocket.CONNECTION_CONNECTED,
	]
	
func is_in_lobby(): return current_lobby != null

func connect_to_signaller(url = signaller_url):
	if url == signaller_url and is_signaller_connected(): return
	signaller_url = url
	close()
	print("Attempting to connect to WebSocket signalling server at %s" % signaller_url)
	var result = websocket.connect_to_url(signaller_url)
	if result != OK:
		print("Failed to connect to WebSocket signalling server at %s: %s" % [signaller_url, result])

func close():
	if webrtc != null: webrtc.close()
	websocket.disconnect_from_host()

func set_display_name(new_display_name: String):
	display_name = new_display_name
	_send("update_display_name:%s" % display_name)

func request_lobby_list():
	return _send("request_lobby_list")

func join_lobby(id: String):
	emit_signal("lobby_begin_join", id)
	call_deferred("_send", "lobby_join:%s" % id)

func leave_lobby():
	return _send("lobby_leave")

func get_lobby_name():
	return current_lobby.name if current_lobby.has("name") else null

func create_lobby():
	_send("lobby_create")

func is_host(): return is_signaller_connected() and is_in_lobby() and get_tree().get_network_unique_id() == 1

func set_lobby_name(s: String):
	if is_host(): _send_json({"name": s}, "update_lobby")

func lock_lobby():
	if is_host(): _send_json({"locked": true}, "update_lobby")

func set_lobby_max_players(n: int):
	if is_host(): _send_json({"maxPlayers": n}, "update_lobby")

func request_peer_list(): _send("request_peer_list")

func send_candidate(id, mid, index, sdp) -> int:
	return _send_json({"id": id, "mid": mid, "index": index, "sdp": sdp}, "candidate")

func send_offer(id, offer) -> int:
	return _send_json({"id": id, "offer": offer }, "offer")

func send_answer(id, answer) -> int:
	return _send_json({"id": id, "answer": answer }, "answer")

func _webrtc_peer_connected(id):
	emit_signal("webrtc_peer_connected", id)

func _webrtc_peer_disconnected(id):
	emit_signal("webrtc_peer_disconnected", id)

func _webrtc_connection_succeeded():
	emit_signal("webrtc_connection_succeeded")

func _signaller_error(err):
	print("WebSocket error: %s" % err)
	emit_signal("signaller_connection_failure")
	_signaller_closed(err)

func _signaller_closed(code):
	print("WebSocket closed: %s: " % code)
	emit_signal("signaller_disconnected")

func _signaller_close_request(code: int, reason: String):
	print("Received WebSocket close request from signalling server - Code: %s, Reason: %s" % [code, reason])
	# TODO: does this fire _closed?

func _signaller_connected(protocol = ""):
	print("Signaller connected via WebSocket using protocol %s" % protocol)
	websocket.get_peer(1).set_write_mode(WebSocketPeer.WRITE_MODE_TEXT)
	emit_signal("signaller_connected")
	_send_json({name = display_name}, "init")

func _process(_delta: float):
	var status: int = websocket.get_connection_status()
	if status in [WebSocketClient.CONNECTION_CONNECTED, WebSocketClient.CONNECTION_CONNECTING]:
		websocket.poll()

func _signaller_data():
	var msg: String = websocket.get_peer(1).get_packet().get_string_from_utf8()
	if msg.begins_with("json:"):
		var data = JSON.parse(msg.substr(5))
		if data.error == OK:
			_process_signaller_message(data.result)
			var _result = websocket.get_peer(1).put_packet("".to_utf8())
	else:
		var d = msg.split(":", false, 2)
		_process_signaller_message({type = d[0], data = d[1]})

func _init_webrtc_peer(data):
	webrtc = WebRTCMultiplayer.new()
	webrtc.connect("connection_succeeded", self, "_webrtc_connection_succeeded")
	webrtc.connect("peer_connected", self, "_webrtc_peer_connected")
	webrtc.connect("peer_disconnected", self, "_webrtc_peer_disconnected")
	webrtc.initialize(int(data), true)
	get_tree().network_peer = webrtc

func _deinit_webrtc_peer():
	webrtc.close()
	get_tree().network_peer = null
	webrtc = null

func _process_signaller_message(data: Dictionary):
	match data["type"]:
		# "init": 
		"init_peer": _init_webrtc_peer(data.data)

		"lobby_data": emit_signal("lobby_data", data.data)
		"lobby_delete": emit_signal("lobby_delete", data.uuid)
		"lobby_joined": _lobby_joined(data)
		"lobby_left": _lobby_left(data.uuid)

		"peer_data": _signaller_peer_data([data] if data.has("id") else data.data)
		"peer_left": _signaller_peer_left(data.id)

		"candidate": _webrtc_candidate_received(data)
		"offer": _webrtc_offer_received(data)
		"answer": _webrtc_answer_received(data)
		"ping": _send("pong")
		_: print("Unhandled Message - Data: %s" % JSON.print(data))

func _lobby_joined(lobby_data):
	current_lobby = lobby_data
	print("Lobby Joined: %s" % lobby_data)
	emit_signal("lobby_joined", lobby_data)
	
func _lobby_left(uuid):
	current_lobby = null
	print("Lobby Left: %s" % uuid)
	emit_signal("lobby_left", uuid)
	_deinit_webrtc_peer()

func _create_peer(data):
	var id = data.id
	var peer: WebRTCPeerConnection = WebRTCPeerConnection.new()
	print("Creating WebRTC Peer %s" % [id])
	peer.connect("session_description_created", self, "_webrtc_offer_created", [id])
	peer.connect("ice_candidate_created", self, "_new_ice_candidate", [id])
	peer.initialize({"iceServers": DEFAULT_ICE_SERVERS})
	webrtc.add_peer(peer, int(id))
	# this guarantees only one peer sends the offer and that offers are never
	# sent to ourselves?
	if int(id) > webrtc.get_unique_id(): peer.create_offer()
	emit_signal("peer_created", data)

func _webrtc_offer_created(type, data, id):
	print("WebRTC %s created for peer %s" % [type, id])
	if not webrtc.has_peer(int(id)): return
	print("WebRTC local description set for peer %s" % id)
	webrtc.get_peer(id).connection.set_local_description(type, data)
	print("--> Local Description: %s" % JSON.print(data))
	if type == "offer": send_offer(id, data)
	else: send_answer(id, data)

func _new_ice_candidate(mid, index, sdp, id):
	print("New ICE candidate for peer %s" % id)
	send_candidate(id, mid, index, sdp)

func _signaller_peer_left(id): if peers.has(id): peers.delete(id)

func _signaller_peer_data(peers):
	for peer in peers:
		if peer.has("id") and not webrtc.has_peer(int(peer.id)):
			_create_peer(peer)
	emit_signal("peer_data", peers)

func _webrtc_offer_received(data):
	if webrtc.has_peer(int(data.id)):
		print("Setting offer remote description for peer %s" % data.id)
		print("--> Offer: %s" % JSON.print(data.offer))
		webrtc.get_peer(data.id).connection.set_remote_description("offer", data.offer)
	else:
		print("Received an offer for a peer with ID %s that hasn't been added" % data.id)

func _webrtc_answer_received(data):
	if webrtc.has_peer(data.id):
		print("Setting answer remote description for peer %s" % data.id)
		print("--> Answer: %s" % JSON.print(data.answer))
		webrtc.get_peer(data.id).connection.set_remote_description("answer", data.answer)

func _webrtc_candidate_received(data):
	if webrtc.has_peer(data.id):
		print("Adding ice candidate for peer %s" % data.id)
		print("--> Candidate: %s" % JSON.print(data.candidate))
		webrtc.get_peer(data.id).connection.add_ice_candidate(data.mid, data.index, data.sdp)
	else:
		print("Received candidate for non-existant peer %s" % data.id)

func _load_display_name():
	var _display_name = DEFAULT_DISPLAY_NAME
	var display_name_file = File.new()
	if display_name_file.open(DISPLAY_NAME_FILE, File.READ) == OK:
		_display_name = display_name_file.get_as_text()
	else:
		print("Failed to open %s for reading display_name, creating default" % DISPLAY_NAME_FILE)
		_store_display_name()
	display_name_file.close()
	return _display_name

func _store_display_name():
	var display_name_file = File.new()
	if display_name_file.open(DISPLAY_NAME_FILE, File.WRITE) == OK:
		display_name_file.store_string(display_name)
	else:
		print("Failed to open %s for writing display_name" % DISPLAY_NAME_FILE)
	display_name_file.close()

func _send(s: String):
	return websocket.get_peer(1).put_packet(s.to_utf8())

func _send_json(data: Dictionary, type=null):
	if type != null: data["type"] = type
	_send("json:%s" % JSON.print(data))