extends Node
## FriendManager - Nakama friend list, DM channels, and lobby invites
## Autoload: FriendManager

signal friends_updated(friends: Array)
signal lobby_invite_received(from_user_id: String, from_name: String, match_id: String)
signal dm_message_received(from_user_id: String, from_name: String, message: String)

## Notification codes (must match server-side RPC)
const NOTIF_LOBBY_INVITE   := 1001
const NOTIF_FRIEND_REQUEST := 1002

## Friend state codes from Nakama
const STATE_FRIEND     := 0
const STATE_INVITE_OUT := 1
const STATE_INVITE_IN  := 2
const STATE_BLOCKED    := 3

var friends: Array = []           # [{user_id, username, state}]
var _friend_ids: Dictionary = {}  # user_id -> true (mutual friends only)
var _dm_channels: Dictionary = {} # user_id -> NakamaChannel
var _has_pending_requests: bool = false  # set before UI is ready

func _ready() -> void:
	NakamaManager.connected_to_nakama.connect(_on_nakama_connected)
	AuthManager.logged_out.connect(_on_logged_out)
	if NakamaManager.socket and NakamaManager.socket.is_connected_to_host():
		_connect_socket_signals()

func _on_logged_out() -> void:
	print("[FriendManager] Clearing state on logout")
	friends.clear()
	_friend_ids.clear()
	close_all_dm_channels()
	_has_pending_requests = false
	emit_signal("friends_updated", [])

func _on_nakama_connected() -> void:
	_connect_socket_signals()
	await load_friends()
	_fetch_pending_notifications()

func _fetch_pending_notifications() -> void:
	if not NakamaManager.session or not NakamaManager.client:
		return
	print("[FriendManager] _fetch_pending_notifications: fetching...")
	# Retrieve all persistent notifications queued while offline (up to 100)
	var result = await NakamaManager.client.list_notifications_async(
		NakamaManager.session, 100, null)
	if result.is_exception():
		push_warning("[FriendManager] Failed to fetch notifications: " + result.get_exception().message)
		return
	
	print("[FriendManager] _fetch_pending_notifications: count=%d" % result.notifications.size())
	var has_friend_request := false
	var ids_to_delete: PackedStringArray = PackedStringArray()
	
	for notif in result.notifications:
		print("[FriendManager] notification: code=%d sender=%s" % [notif.code, notif.sender_id])
		ids_to_delete.append(notif.id)
		if notif.code == NOTIF_FRIEND_REQUEST:
			has_friend_request = true
	
	# Acknowledge all so they are not delivered again next login
	if ids_to_delete.size() > 0:
		NakamaManager.client.delete_notifications_async(NakamaManager.session, ids_to_delete)
	
	# If any were friend requests, reload the friends list to show them
	if has_friend_request:
		print("[FriendManager] _fetch_pending_notifications: reloading friends for pending request")
		load_friends()

func _connect_socket_signals() -> void:
	var socket = NakamaManager.socket
	if not socket:
		return
	if not socket.received_notification.is_connected(_on_notification_received):
		socket.received_notification.connect(_on_notification_received)
	if not socket.received_channel_message.is_connected(_on_channel_message):
		socket.received_channel_message.connect(_on_channel_message)

# =============================================================================
# Friend List
# =============================================================================

func load_friends() -> void:
	if not NakamaManager.session:
		print("[FriendManager] load_friends: no session")
		return
	print("[FriendManager] load_friends: fetching...")
	var result = await NakamaManager.client.list_friends_async(NakamaManager.session, null, 100, null)
	if result.is_exception():
		push_warning("[FriendManager] Failed to load friends: " + result.get_exception().message)
		return
	friends.clear()
	_friend_ids.clear()
	_has_pending_requests = false
	for f in result.friends:
		var u = f.user
		var entry := {
			"user_id": u.id,
			"username": u.display_name if u.display_name != "" else u.username,
			"state": f.state,
		}
		friends.append(entry)
		print("[FriendManager] friend: %s state=%d" % [u.username, f.state])
		if f.state == STATE_FRIEND:
			_friend_ids[u.id] = true
		if f.state == STATE_INVITE_IN:
			_has_pending_requests = true
	print("[FriendManager] load_friends done: %d entries" % friends.size())
	emit_signal("friends_updated", friends)

func get_mutual_friends() -> Array:
	return friends.filter(func(f): return f.state == STATE_FRIEND)

func is_friend(user_id: String) -> bool:
	return _friend_ids.has(user_id)

func add_friend_by_id(user_id: String) -> bool:
	if not NakamaManager.session:
		return false
	print("[FriendManager] add_friend_by_id: adding %s" % user_id)
	# Step 1: Add the friend relationship via native Nakama client API
	var result = await NakamaManager.client.add_friends_async(
		NakamaManager.session, PackedStringArray([user_id]), null)
	if result.is_exception():
		push_warning("[FriendManager] add_friend failed: " + result.get_exception().message)
		return false
	print("[FriendManager] add_friend_by_id: add_friends_async OK, sending notification RPC...")
	# Step 2: Notify the target via RPC
	var payload = JSON.stringify({"user_id": user_id})
	var rpc_result = await BackendService.send_friend_request(user_id)
	if rpc_result.get("success", false) == false:
		push_error("[FriendManager] rpcSendFriendRequest failed: " + str(rpc_result.get("error", "")))
	else:
		print("[FriendManager] rpcSendFriendRequest OK: " + str(rpc_result.payload))
	
	load_friends()
	return true

func add_friend_by_username(username: String) -> bool:
	if not NakamaManager.session:
		return false
	# Resolve username → user_id first via search, then use the RPC
	# Fall back to direct Nakama API (no notification sent to target)
	var result = await NakamaManager.client.add_friends_async(
		NakamaManager.session, null, PackedStringArray([username]))
	if result.is_exception():
		push_warning("[FriendManager] add_friend_by_username failed: " + result.get_exception().message)
		return false
	load_friends()
	return true

func remove_friend(user_id: String) -> bool:
	if not NakamaManager.session:
		return false
	var result = await NakamaManager.client.delete_friends_async(
		NakamaManager.session, PackedStringArray([user_id]), null)
	if result.is_exception():
		return false
	load_friends()
	return true

# =============================================================================
# Lobby Invites
# =============================================================================

func send_lobby_invite(to_user_id: String, match_id: String) -> void:
	if not NakamaManager.session:
		return
	var result = await BackendService.send_lobby_invite(to_user_id, match_id)
	if result.get("success", false) == false:
		push_warning("[FriendManager] send_lobby_invite failed: " + str(result.get("error", "")))

func _on_notification_received(notification) -> void:
	print("[FriendManager] _on_notification_received: code=%d sender=%s" % [notification.code, notification.sender_id])
	match notification.code:
		NOTIF_LOBBY_INVITE:
			var content = JSON.parse_string(notification.content)
			if content:
				var from_name: String = content.get("from_name", "Someone")
				var match_id: String  = content.get("match_id", "")
				emit_signal("lobby_invite_received", notification.sender_id, from_name, match_id)
		NOTIF_FRIEND_REQUEST:
			# Refresh friends list so the incoming request appears immediately
			print("[FriendManager] friend request notification received, reloading friends...")
			load_friends()

# =============================================================================
# Direct Messages
# =============================================================================

func open_dm(user_id: String) -> Object:
	if _dm_channels.has(user_id):
		return _dm_channels[user_id]
	var socket = NakamaManager.socket
	if not socket:
		return null
	var channel = await socket.join_chat_async(
		user_id, NakamaSocket.ChannelType.DirectMessage, true, false)
	if channel.is_exception():
		push_warning("[FriendManager] Failed to open DM with " + user_id)
		return null
	_dm_channels[user_id] = channel
	return channel

func get_dm_history(user_id: String, limit: int = 50) -> Array:
	if not NakamaManager.session:
		return []
	var channel = await open_dm(user_id)
	if not channel:
		return []
	var result = await NakamaManager.client.list_channel_messages_async(NakamaManager.session, channel.id, limit, false)
	if result.is_exception():
		push_warning("[FriendManager] Failed to fetch DM history: " + result.get_exception().message)
		return []
	
	var history: Array = []
	for msg in result.messages:
		var text: String = ""
		var parsed = JSON.parse_string(msg.content)
		if typeof(parsed) == TYPE_DICTIONARY:
			text = parsed.get("msg", msg.content)
		else:
			text = msg.content
		history.append({"from": msg.sender_id, "msg": text, "username": msg.username, "create_time": msg.create_time})
	
	history.reverse() # API returns newest-first; flip to oldest-first so display is top=old, bottom=new
	return history

func send_dm(user_id: String, message: String) -> bool:
	var channel = await open_dm(user_id)
	if not channel:
		return false
	var socket = NakamaManager.socket
	if not socket:
		return false
	var result = await socket.write_chat_message_async(channel.id, {"msg": message})
	return not result.is_exception()

func get_dm_channel_id(user_id: String) -> String:
	var ch = _dm_channels.get(user_id, null)
	return ch.id if ch else ""

func _on_channel_message(message) -> void:
	# Ignore global chat
	if "social_global" in message.channel_id:
		return
	
	# Ignore messages sent by ourselves (we already add them locally instantly)
	if NakamaManager.session and message.sender_id == NakamaManager.session.user_id:
		return
		
	var text: String = ""
	var parsed = JSON.parse_string(message.content)
	if typeof(parsed) == TYPE_DICTIONARY:
		text = parsed.get("msg", message.content)
	else:
		text = message.content
	emit_signal("dm_message_received", message.sender_id, message.username, text)

func close_all_dm_channels() -> void:
	var socket = NakamaManager.socket
	for user_id in _dm_channels:
		var ch = _dm_channels[user_id]
		if socket:
			socket.leave_chat_async(ch.id)
	_dm_channels.clear()