# (c) 2023-present Eroax
# (c) 2023-present Yagich
# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
extends Object
class_name Deck
## A deck/graph with nodes.
##
## A container for [DeckNode]s, managing connections between them.

## The [DeckNode]s that belong to this deck. The key is the node's id, the value
## is the [DeckNode] instance.
var nodes: Dictionary


## A map of variables set on this deck.
var variable_stack: Dictionary = {}
## The path to save this deck on the file system.
var save_path: String = ""

## The connections graph.
var connections := NodeConnections.new()

## Whether this deck is a group instance.
var is_group: bool = false
## Whether this deck is a library. Implies [member is_group].
var is_library: bool = false

var group_descriptors := GroupDescriptors.new()

#region library group props
## The initial name of the library. Displayed by the group node and [SearchProvider].
var lib_name: String
## The description of this library, shown to the user by a renderer.
var lib_description: String
## A list of aliases for this library, used by search.
var lib_aliases: Array[String]
#endregion

## List of groups belonging to this deck, in the format of[br]
## [code]Dictionary[String -> Deck.id, Deck][/code]
#var groups: Dictionary = {}
## A unique identifier for this deck, or an ID for the group this deck represents.
var id: String = ""
## If this is a group, this is the local ID of this instance of the group.
var instance_id: String = ""
## The parent deck of this deck, if this is a group.
@warning_ignore("unused_private_class_variable")
var _belonging_to: String = "" # for groups
## The ID of this group's input node. Used only if [member is_group] is [code]true[/code].
var group_input_node: String
## The ID of this group's input node. Used only if [member is_group] is [code]true[/code].
var group_output_node: String

var emit_group_signals: bool = true
var emit_node_added_signal: bool = true

## Emitted when a node has been added to this deck.
signal node_added(node: DeckNode)
## Emitted when a node has been removed from this deck.
signal node_removed(node: DeckNode)
## Emitted when nodes have been connected.
signal nodes_connected(from_node_id: String, to_node_id: String, from_output_port: int, to_input_port: int)
## Emitted when nodes have been disconnected.
signal nodes_disconnected(from_node_id: String, to_node_id: String, from_output_port: int, to_input_port: int)
## Emitted when the [member variable_stack] has been modified.
signal variables_updated()
## Emitted when a node has been moved to a different deck.
signal node_moved_to_deck(node: DeckNode, other: Deck)

#region group signals
signal node_added_to_group(node: DeckNode, assign_id: String, assign_to_self: bool, deck: Deck)
signal node_removed_from_group(node_id: String, remove_connections: bool, deck: Deck)
signal node_port_value_updated(node_id: String, port_idx: int, new_value: Variant, deck: Deck)
signal node_ports_updated(node_id: String, deck: Deck)
signal node_renamed(node_id: String, new_name: String, deck: Deck)
signal node_moved(node_id: String, new_position: Dictionary, deck: Deck)
#endregion


func _init() -> void:
	group_descriptors.deck = self


## Instantiate a node by its' [member DeckNode.node_type] and add it to this deck.[br]
## See [method add_node_inst] for parameter descriptions.
func add_node_type(type: String, assign_id: String = "", assign_to_self: bool = true) -> DeckNode:
	var node_inst: DeckNode = NodeDB.instance_node(type)

	return add_node_inst(node_inst, assign_id, assign_to_self)


## Add a [DeckNode] instance to this deck.[br]
## If [param assign_id] is empty, the node will get its' ID (re-)assigned.
## Otherwise, it will be assigned to be that value.[br]
## If [param assign_to_self] is [code]true[/code], the node's
## [member DeckNode._belonging_to] property will be set to [code]self[/code].[br]
## Returns [code]null[/code] if the node cannot be insantiated.
func add_node_inst(node: DeckNode, assign_id: String = "", assign_to_self: bool = true) -> DeckNode:
	if node.node_type == "group_input" and not group_input_node.is_empty():
		DeckHolder.logger.toast_error("Cannot add group input node, one already exists!")
		node.free()
		return null
	if node.node_type == "group_output" and not group_output_node.is_empty():
		DeckHolder.logger.toast_error("Cannot add group output node, one already exists!")
		node.free()
		return null
	if assign_to_self:
		node._belonging_to = self
		#node._belonging_to_instance = instance_id

	if assign_id == "":
		var uuid := UUID.v4()
		nodes[uuid] = node
		node._id = uuid
	else:
		nodes[assign_id] = node
		node._id = assign_id

	if node.node_type == "group_input":
		group_input_node = node._id
		node.about_to_free.connect(
			func():
				group_input_node = ""
		)
	
	if node.node_type == "group_output":
		group_output_node = node._id
		node.about_to_free.connect(
			func():
				group_output_node = ""
		)

	if emit_node_added_signal:
		node_added.emit(node)

	if is_group and emit_group_signals:
		node_added_to_group.emit(node, node._id, assign_to_self, self)

	node.port_value_updated.connect(
		func(port_idx: int, new_value: Variant):
			if is_group and emit_group_signals:
				node_port_value_updated.emit(node._id, port_idx, new_value, self)
	)

	node.renamed.connect(
		func(new_name: String):
			if is_group and emit_group_signals:
				node_renamed.emit(node._id, new_name, self)
	)

	node.position_updated.connect(
		func(new_position: Dictionary):
			if is_group and emit_group_signals:
				node_moved.emit(node._id, new_position, self)
	)
	
	node.ports_updated.connect(
		func():
			if is_group and emit_group_signals:
				node_ports_updated.emit(node._id, self)
	)
	
	print_verbose("Deck %s::%s: added node %s, id %s" % [id, instance_id, node.node_type, node.get_instance_id()])

	return node


func add_lib_group_node(type: String) -> DeckNode:
	var group_node := add_node_type("group_node")
	var lib := DeckHolder.add_lib_instance(type, id)
	group_node.is_library = true
	group_node.group_id = lib.id
	group_node.group_instance_id = lib.instance_id
	
	for node_id: String in lib.nodes:
		var node := lib.get_node(node_id)
		if node.node_type == "group_input":
			group_node.input_node = node
			group_node.input_node_id = node._id
			node.group_node = group_node
			lib.group_input_node = node._id
			continue
		
		if node.node_type == "group_output":
			group_node.output_node = node
			group_node.output_node_id = node._id
			node.group_node = group_node
			lib.group_output_node = node._id
			continue
	group_node.init_io()
	group_node.rename(NodeDB.get_library_descriptor(type).name)
	return group_node


## Get a node belonging to this deck by its' ID.
func get_node(uuid: String) -> DeckNode:
	return nodes.get(uuid)


func get_connections_dict() -> Dictionary:
	return connections.data


## Returns [code]true[/code] if the connection between two nodes is legal.
func is_valid_connection(from_node_id: String, to_node_id: String, from_output_port: int, to_input_port: int) -> bool:
	# do not connect to self
	if from_node_id == to_node_id:
		return false
	
	var from_node := get_node(from_node_id)
	var to_node := get_node(to_node_id)
	
	var usage_from: Port.UsageType = from_node.get_output_ports()[from_output_port].usage_type
	var usage_to: Port.UsageType = to_node.get_input_ports()[to_input_port].usage_type
	# incompatible usages
	if (usage_from != Port.UsageType.BOTH) and (usage_to != Port.UsageType.BOTH):
		if usage_from != usage_to:
			return false
	
	var type_from: DeckType.Types = from_node.get_output_ports()[from_output_port].type
	var type_to: DeckType.Types = to_node.get_input_ports()[to_input_port].type
	# incompatible types
	if not DeckType.can_convert(type_from, type_to):
		return false
	
	# duplicate connection
	if connections.has_outgoing_connection_exact(from_node_id, from_output_port, to_node_id, to_input_port):
		return false
	
	return true


## Attempt to connect two nodes. Returns [code]true[/code] if the connection succeeded.
func connect_nodes(from_node_id: String, to_node_id: String, from_output_port: int, to_input_port: int) -> bool:
	if not is_valid_connection(from_node_id, to_node_id, from_output_port, to_input_port):
		return false

	var from_node := get_node(from_node_id)
	var to_node := get_node(to_node_id)

	if connections.has_incoming_connection(to_node_id, to_input_port):
		var connection := connections.get_incoming_connection(to_node_id, to_input_port)
		disconnect_nodes(connection.from_node, to_node_id, connection.from_port, to_input_port)

	connections.add_connection(from_node_id, to_node_id, from_output_port, to_input_port)
	nodes_connected.emit(from_node_id, to_node_id, from_output_port, to_input_port)
	from_node.outgoing_connection_added.emit(from_output_port)
	to_node.incoming_connection_added.emit(to_input_port)
	return true


## Remove a connection from two nodes.
func disconnect_nodes(from_node_id: String, to_node_id: String, from_output_port: int, to_input_port: int) -> void:
	connections.remove_connection(from_node_id, to_node_id, from_output_port, to_input_port)
	nodes_disconnected.emit(from_node_id, to_node_id, from_output_port, to_input_port)
	
	var from_node := get_node(from_node_id)
	var to_node := get_node(to_node_id)
	from_node.outgoing_connection_removed.emit(from_output_port)
	to_node.incoming_connection_removed.emit(to_input_port)


func disconnect_pair(pair: ConnectionPair) -> void:
	connections.remove_pair(pair)
	var from_node_id := pair.incoming.from_node
	var to_node_id := pair.outgoing.to_node
	var from_output_port := pair.incoming.from_port
	var to_input_port := pair.outgoing.to_port
	connections.remove_connection(from_node_id, to_node_id, from_output_port, to_input_port)
	nodes_disconnected.emit(from_node_id, to_node_id, from_output_port, to_input_port)
	
	var from_node := get_node(from_node_id)
	var to_node := get_node(to_node_id)
	from_node.outgoing_connection_removed.emit(from_output_port)
	to_node.incoming_connection_removed.emit(to_input_port)


## Returns true if this deck has no nodes and no variables.
func is_empty() -> bool:
	return nodes.is_empty() and variable_stack.is_empty()


## Remove a node from this deck.
func remove_node(uuid: String, remove_connections: bool = false, force: bool = false, keep_group_instances: bool = false) -> void:
	var node := get_node(uuid)
	if node == null:
		return

	if not node.user_can_delete and not force:
		return

	if node.node_type == "group_node" and not keep_group_instances:
		DeckHolder.close_group_instance(node.group_id, node.group_instance_id)

	if remove_connections:
		# var outgoing_connections := connections.get_all_outgoing_connections(uuid)
		# for from_port: int in outgoing_connections.keys():
		# 	for outgoing: OutgoingConnection in outgoing_connections[from_port]:
		# 		var incoming := outgoing.counterpart.get_ref() as IncomingConnection
		# 		disconnect_nodes(uuid, outgoing.to_node, incoming.from_port, outgoing.to_port)
		
		# var incoming_connections := connections.get_all_incoming_connections(uuid)
		# for to_port: int in incoming_connections.keys():
		# 	var incoming := connections.get_incoming_connection(uuid, to_port)
		# 	disconnect_nodes(incoming.from_node, uuid, incoming.from_port, to_port)
		var pairs := connections.get_node_pairs(uuid)
		for pair in pairs:
			disconnect_pair(pair)
		
	nodes.erase(uuid)

	node_removed.emit(node)

	if is_group and emit_group_signals:
		node_removed_from_group.emit(uuid, remove_connections, self)
	
	print_verbose("Deck %s::%s: freeing node %s, id %s" % [id, instance_id, node.node_type, node.get_instance_id()])
	node.free()


func pre_exit_cleanup() -> void:
	for node_id: String in nodes:
		var node := get_node(node_id)
		print_verbose("Deck %s::%s: freeing node %s, id %s" % [id, instance_id, node.node_type, node.get_instance_id()])
		node.free()


## Set a variable on this deck.
func set_variable(var_name: String, value: Variant) -> void:
	variable_stack[var_name] = value
	variables_updated.emit()


func update_variable(old_name: String, new_name: String, new_value: Variant) -> void:
	variable_stack.erase(old_name)
	variable_stack[new_name] = new_value


func remove_variable(name: String) -> void:
	variable_stack.erase(name)


## Group the [param nodes_to_group] into a new deck and return it.
## Returns [code]null[/code] on failure.[br]
## Adds a group node to this deck, and adds group input and output nodes in the group.
func group_nodes(nodes_to_group: Array) -> Deck:
	if nodes_to_group.is_empty():
		return null
		
	# don't include nodes that can't be grouped/deleted
	nodes_to_group = nodes_to_group.filter(
		func(x: DeckNode):
			return x.user_can_delete
	)
	
	var node_ids_to_keep := nodes_to_group.map(
		func(x: DeckNode):
			return x._id
	)

	var group := DeckHolder.add_empty_group(id)
	var connection_pairs := connections.filter_pairs(node_ids_to_keep)

	for pair in connection_pairs:
		group.connections.add_pair(pair)

	var midpoint := Vector2()
	
	var rightmost := -INF
	var leftmost := INF
	for node: DeckNode in nodes_to_group:

		if node.position.x > rightmost:
			rightmost = node.position.x
		if node.position.x < leftmost:
			leftmost = node.position.x

		var pairs := connections.get_node_pairs(node._id)
		for pair in pairs:
			disconnect_pair(pair)

		midpoint += node.position_as_vector2()
		# remove_node(node._id, false, true)
		# group.add_node_inst(node, node._id)
		move_node_to_deck(node, group)

	midpoint /= nodes_to_group.size()

	emit_node_added_signal = false
	var _group_node := add_node_type("group_node")
	_group_node.group_id = group.id
	_group_node.group_instance_id = group.instance_id
	_group_node.position.x = midpoint.x
	_group_node.position.y = midpoint.y
	_group_node.position_updated.emit(_group_node.position)
	#group.group_node = _group_node._id
	node_added.emit(_group_node)
	emit_node_added_signal = true
	
	var input_node := group.add_node_type("group_input")
	var output_node := group.add_node_type("group_output")
	group.group_input_node = input_node._id
	group.group_output_node = output_node._id
	
	input_node.position.x = leftmost - 350
	output_node.position.x = rightmost + 350
	input_node.position.y = midpoint.y
	output_node.position.y = midpoint.y
	input_node.position_updated.emit(input_node.position)
	output_node.position_updated.emit(output_node.position)

	input_node.group_node = _group_node
	output_node.group_node = _group_node

	_group_node.input_node_id = input_node._id
	_group_node.output_node_id = output_node._id
	#_group_node.setup_connections()
	_group_node.init_io()

	return group


func move_node_to_deck(node: DeckNode, other: Deck) -> void:
	if not node._id in nodes:
		return
	
	nodes.erase(node._id)
	other.nodes[node._id] = node
	# node_moved_to_deck.emit(node, other)
	
	node._belonging_to = other
	
	node_removed.emit(node)
	other.node_added.emit(node)
	
	if is_group and emit_group_signals:
		node_removed_from_group.emit(node._id, false, self)
	if other.is_group and other.emit_group_signals:
		node_added_to_group.emit(node, node._id, true, other)


func copy_nodes(nodes_to_copy: Array[String]) -> Dictionary:
	var d := {
		"nodes": {},
		"connections": connections.filter_pairs(nodes_to_copy),
	}

	for node_id: String in nodes_to_copy:
		d.nodes[node_id] = get_node(node_id).to_dict()

	for node: Dictionary in d.nodes.values().slice(1):
		node.position.x = node.position.x - d.nodes.values()[0].position.x
		node.position.y = node.position.y - d.nodes.values()[0].position.y

	d.nodes.values()[0].position.x = 0
	d.nodes.values()[0].position.y = 0

	return d


func copy_nodes_json(nodes_to_copy: Array[String]) -> String:
	var res := copy_nodes(nodes_to_copy)
	res.connections = res.connections.map(
		func(x: ConnectionPair):
			return x.to_dict()
	)
	return JSON.stringify(res)


func allocate_ids(count: int) -> Array[String]:
	var res: Array[String] = []
	for i in count:
		res.append(UUID.v4())
	return res


func paste_nodes_from_dict(nodes_to_paste: Dictionary, position: Vector2 = Vector2()) -> void:
	if not nodes_to_paste.get("nodes"):
		return

	var pairs = (nodes_to_paste.connections as Array).map(
		func(x: Dictionary):
			return ConnectionPair.from_dict(x)
	)

	var new_ids := allocate_ids(nodes_to_paste.nodes.size())
	var ids_map := {}
	for i: int in nodes_to_paste.nodes.keys().size():
		var node_id: String = nodes_to_paste.nodes.keys()[i]
		ids_map[node_id] = new_ids[i]

	for old_id: String in ids_map:
		for pair: ConnectionPair in pairs:
			pair.remap_id(old_id, ids_map[old_id])

	for pair: ConnectionPair in pairs:
		connections.add_pair(pair)

	for node_id: String in nodes_to_paste.nodes:
		nodes_to_paste.nodes[node_id]._id = ids_map[node_id]

		nodes_to_paste.nodes[node_id].position.x += position.x
		nodes_to_paste.nodes[node_id].position.y += position.y

		var node := DeckNode.from_dict(nodes_to_paste.nodes[node_id])
		var group_needs_unique := false
		if node.node_type == "group_node":
			if not node.is_library:
				var group := DeckHolder.make_new_group_instance(node.group_id, id)
				var old_group := DeckHolder.get_group_instance(node.group_id, node.group_instance_id)
				group_needs_unique = old_group._belonging_to != id
				node.group_instance_id = group.instance_id
				group.get_node(group.group_input_node).group_node = node
				group.get_node(group.group_output_node).group_node = node
				
				node.input_node = group.get_node(group.group_input_node)
				node.output_node = group.get_node(group.group_output_node)
				node.init_io()
			else:
				var type: String = node.group_id.get_file().trim_suffix(".deck")
				var lib := DeckHolder.add_lib_instance(type, id)
				node.group_instance_id = lib.instance_id
				for l_node_id: String in lib.nodes:
					var l_node := lib.get_node(l_node_id)
					if l_node.node_type == "group_input":
						node.input_node = l_node
						node.input_node_id = l_node._id
						l_node.group_node = node
						lib.group_input_node = l_node_id
						continue
					
					if l_node.node_type == "group_output":
						node.output_node = l_node
						node.output_node_id = l_node._id
						l_node.group_node = node
						lib.group_output_node = l_node_id
						continue
				node.init_io()
				
		add_node_inst(node, ids_map[node_id])
		if group_needs_unique:
			node.make_unique()
			DeckHolder.logger.toast_warn("Group was made unique.")


func paste_nodes_from_json(json: String, position: Vector2 = Vector2()) -> void:
	var d = JSON.parse_string(json)
	if not d:
		DeckHolder.logger.toast_error("Paste failed.")
		return
	paste_nodes_from_dict(d, position)


func duplicate_nodes(nodes_to_copy: Array[String]) -> void:
	if nodes_to_copy.is_empty():
		return

	var position := get_node(nodes_to_copy[0]).position_as_vector2() + Vector2(50, 50)
	var d := copy_nodes(nodes_to_copy)
	paste_nodes_from_dict(d, position)


## Send [param data] from [param from_node_id] to all outgoing connections on port [param from_output_port].[br]
## See [method DeckNode.send].
func send(from_node_id: String, from_output_port: int, data: Variant, send_id: String) -> void:
	var outgoing_connections := connections.get_outgoing_connections(from_node_id, from_output_port)
	for connection in outgoing_connections:
		var node := get_node(connection.to_node)
		node.handle_receive(connection.to_port, data, send_id)


## Asynchronously request a value from an incoming connection on the node at [param node_id]'s input port at [param on_input_port].
## Returns [code]null[/code] if no incoming connection exists on that port.
## The connected node may also return [code]null[/code].[br]
## See [method DeckNode.request_value_async].
func request_value_async(node_id: String, on_input_port: int) -> Variant:
	var connection := connections.get_incoming_connection(node_id, on_input_port)
	if connection == null:
		return null
	
	var other_node := get_node(connection.from_node)
	
	return await other_node._value_request(connection.from_port)


func send_event(event_name: StringName, event_data: Dictionary = {}) -> void:
	for node: DeckNode in nodes.values():
		node._event_received(event_name, event_data)


func get_referenced_groups() -> Array[String]:
	# this is expensive
	# recursively returns a list of all groups referenced by this deck
	var res: Array[String] = []
	for node_id: String in nodes:
		var node := get_node(node_id)
		if node.node_type == "group_node" and not node.is_library:
			res.append(node.group_id)
			res.append_array(DeckHolder.get_deck(node.group_id).get_referenced_groups())
	return res


func get_referenced_group_instances() -> Array[Dictionary]:
	var res: Array[Dictionary] = []
	for node_id: String in nodes:
		var node := get_node(node_id)
		if node.node_type == "group_node" and not node.is_library:
			res.append({
				"group_id": node.group_id,
				"instance_id": node.group_instance_id,
				"parent_id": node._belonging_to,
				"group_node": node_id,
			})
			res.append_array(DeckHolder.get_group_instance(node.group_id, node.group_instance_id).get_referenced_group_instances())
	return res


func _to_string() -> String:
	if not is_group:
		return "DeckNode:%s" % id
	else:
		return "DeckNode:%s::%s" % [id, instance_id]


## Returns a [Dictionary] representation of this deck.
func to_dict(with_meta: bool = true, group_ids: Array = []) -> Dictionary:
	var inner := {
		"nodes": {},
		"variable_stack": variable_stack,
		"id": id,
		"groups": {},
		"connections": connections.to_dict(),
	}

	if not group_descriptors.is_empty():
		inner["group_descriptors"] = group_descriptors.to_dict()

	for node_id: String in nodes.keys():
		inner["nodes"][node_id] = nodes[node_id].to_dict(with_meta)
		if get_node(node_id).node_type == "group_node" and not get_node(node_id).is_library:
			if nodes[node_id].group_id not in group_ids:
				inner["groups"][nodes[node_id].group_id] = DeckHolder.get_deck(nodes[node_id].group_id).to_dict(with_meta, group_ids)
				group_ids.append(nodes[node_id].group_id)

	#for group_id in groups.keys():
		#inner["groups"][group_id] = groups[group_id].to_dict(with_meta)

	if is_group:
		inner["instance_id"] = instance_id
		inner["group_input_node"] = group_input_node
		inner["group_output_node"] = group_output_node

	# don't save library stuff if this is not a library
	if not lib_name.is_empty():
		var lib := {
			"lib_name": lib_name,
			"lib_description": lib_description,
			"lib_aliases": lib_aliases,
		}
		inner["library"] = lib

	var d := {"deck": inner}

	if with_meta:
		d["meta"] = {}
		for meta in get_meta_list():
			d["meta"][meta] = var_to_str(get_meta(meta))
	return d


## Create a new deck from a [Dictionary] representation, such as one created by [method to_dict].
static func from_dict(data: Dictionary, path: String = "") -> Deck:
	var deck := Deck.new()
	deck.save_path = path
	deck.variable_stack = data.deck.variable_stack
	deck.id = data.deck.id
	deck.connections = NodeConnections.from_dict(data.deck.connections)

	if data.deck.has("library"):
		var lib_data: Dictionary = data.deck.library
		deck.lib_name = lib_data.get("lib_name", "")
		deck.lib_description = lib_data.get("lib_description", "")
		# deck.lib_aliases = lib_data.get("lib_aliases", [])

	if data.deck.has("group_descriptors"):
		deck.group_descriptors = GroupDescriptors.from_dict(data.deck.group_descriptors)
		deck.group_descriptors.deck = deck

	for key in data.meta:
		deck.set_meta(key, str_to_var(data.meta[key]))

	var nodes_data: Dictionary = data.deck.nodes as Dictionary

	for node_id in nodes_data:
		var node := DeckNode.from_dict(nodes_data[node_id], deck.connections)
		deck.add_node_inst(node, node_id)
		node._post_deck_load()

	var groups_data: Dictionary = data.deck.groups as Dictionary

	for node_id: String in deck.nodes:
		var node := deck.get_node(node_id)
		if node.node_type != "group_node":
			continue
		var group_id: String = node.group_id
		var group_instance_id: String = node.group_instance_id
		var group: Deck
		if not node.is_library:
			var group_data: Dictionary = groups_data[group_id]
			group = DeckHolder.add_group_from_dict(group_data, group_id, group_instance_id, deck.id)
		else:
			group = DeckHolder.add_lib_instance(
				node.group_id.get_file(),
				deck.id,
				node.group_instance_id
			)
		
		if not node.input_node_id.is_empty():
			group.get_node(node.input_node_id).group_node = node
		if not node.output_node_id.is_empty():
			group.get_node(node.output_node_id).group_node = node
		node.init_io()

	return deck


class NodeConnections:
	# Dictionary[String -> node id, Dictionary["incoming": Dictionary[int -> input port idx, IncomingConnection], "outgoing": Dictionary[int - > output port idx, Array[OutgoingConnection]]]
	var data := {}
	
	
	func add_connection(from_node_id: String, to_node_id: String, from_output_port: int, to_input_port: int) -> void:
		var from_connection: Dictionary = data.get(from_node_id, _create_empty_connection())
		var to_connection: Dictionary = data.get(to_node_id, _create_empty_connection())
		var pair := ConnectionPair.new(from_node_id, to_node_id, from_output_port, to_input_port)
		
		var out_list: Array = (from_connection.outgoing as Dictionary).get(from_output_port, [])
		out_list.append(pair.outgoing)
		(from_connection.outgoing as Dictionary)[from_output_port] = out_list
		
		(to_connection.incoming as Dictionary)[to_input_port] = pair.incoming
		
		data[from_node_id] = from_connection
		data[to_node_id] = to_connection
	
	
	func remove_connection(from_node_id: String, to_node_id: String, from_output_port: int, to_input_port: int) -> void:
		var from_connection: Dictionary = data.get(from_node_id, {})
		if from_connection.is_empty():
			return
		
		var out_list: Array = (from_connection.outgoing as Dictionary).get(from_output_port, [])
		if out_list.is_empty():
			return
		
		var comp := ConnectionPair.new(from_node_id, to_node_id, from_output_port, to_input_port)
		
		for i in out_list.size():
			var out: OutgoingConnection = out_list[i]
			var pair := ConnectionPair.from_outgoing(out)
			if pair.is_equivalent(comp):
				var to_connection: Dictionary = data.get(to_node_id).incoming
				to_connection.erase(to_input_port)
				out_list.erase(out)
				break
		
		# remove if empty
		if data[from_node_id] == _create_empty_connection():
			data.erase(from_node_id)
		
		if data[to_node_id] == _create_empty_connection():
			data.erase(to_node_id)
		
		if (data[from_node_id].outgoing[from_output_port] as Array).is_empty():
			(data[from_node_id].outgoing as Dictionary).erase(from_output_port)
	
	
	func has_incoming_connection(node_id: String, on_port: int) -> bool:
		return data.get(node_id, _create_empty_connection()).incoming.has(on_port)
	
	
	func get_incoming_connection(node_id: String, on_port: int) -> IncomingConnection:
		return data.get(node_id, _create_empty_connection()).incoming.get(on_port)
	
	
	func has_outgoing_connection_exact(node_id: String, from_port: int, to_node: String, to_port: int) -> bool:
		if not data.get(node_id, _create_empty_connection()).outgoing.has(from_port):
			return false
		
		var has = false
		for connection: OutgoingConnection in data.get(node_id, _create_empty_connection()).outgoing.get(from_port):
			var inc := connection.counterpart.get_ref() as IncomingConnection
			if connection.to_node == to_node \
			and connection.to_port == to_port\
			and inc.from_port == from_port:
				has = true
	
		return has
	
	
	func get_outgoing_connections(node_id: String, from_port: int) -> Array[OutgoingConnection]:
		if data.get(node_id, _create_empty_connection()).outgoing.is_empty():
			return []
		
		if not (data[node_id].outgoing as Dictionary).has(from_port):
			return []
		
		var res: Array[OutgoingConnection] = []
		
		res.assign(data[node_id].outgoing[from_port])
		
		return res
	
	
	func get_all_outgoing_connections(node_id: String) -> Dictionary:
		return data.get(node_id, _create_empty_connection()).outgoing
	
	
	func get_all_incoming_connections(node_id: String) -> Dictionary:
		return data.get(node_id, _create_empty_connection()).incoming
	
	
	func filter_pairs(nodes: Array) -> Array[ConnectionPair]:
		var res: Array[ConnectionPair] = []
		
		for node_id: String in nodes:
			var connections: Dictionary = data.get(node_id, _create_empty_connection())
			for to_port: int in connections.outgoing:
				for outgoing: OutgoingConnection in connections.outgoing[to_port]:
					if outgoing.to_node in nodes:
						res.append(ConnectionPair.from_outgoing(outgoing))
		
		return res
	
	
	func get_node_pairs(node: String) -> Array[ConnectionPair]:
		var res: Array[ConnectionPair] = []
		
		var connections: Dictionary = data.get(node, _create_empty_connection())
		for to_port: int in connections.outgoing:
			for outgoing: OutgoingConnection in connections.outgoing[to_port]:
				res.append(ConnectionPair.from_outgoing(outgoing))
		for from_port: int in connections.incoming:
			res.append(ConnectionPair.from_incoming(connections.incoming[from_port]))
		
		return res

	
	
	func add_pair(pair: ConnectionPair) -> void:
		var outgoing := pair.outgoing
		var incoming := pair.incoming
		add_connection(incoming.from_node, outgoing.to_node, incoming.from_port, outgoing.to_port)
	
	
	func remove_pair(pair: ConnectionPair) -> void:
		var outgoing := pair.outgoing
		var incoming := pair.incoming
		remove_connection(incoming.from_node, outgoing.to_node, incoming.from_port, outgoing.to_port)
	
	
	func _create_empty_connection() -> Dictionary:
		return {
			"incoming": {},
			"outgoing": {},
		}
	
	
	func to_dict() -> Dictionary:
		var res := {}
		for node_id: String in data:
			res[node_id] = _create_empty_connection()
			for to_port: int in data[node_id].incoming:
				res[node_id].incoming[to_port] = (data[node_id].incoming[to_port] as IncomingConnection).to_dict()
			
			for from_port: int in data[node_id].outgoing:
				for i: OutgoingConnection in data[node_id].outgoing[from_port]:
					var arr: Array = res[node_id].outgoing.get(from_port, [])
					arr.append(i.to_dict())
					res[node_id].outgoing[from_port] = arr
		return res
	
	
	static func from_dict(d: Dictionary) -> NodeConnections:
		var res := NodeConnections.new()
		for node_id: String in d:
			for from_port in d[node_id].outgoing:
				for connection: Dictionary in d[node_id].outgoing[from_port]:
					res.add_connection(node_id, connection.to_node, int(from_port), int(connection.to_port))
		return res


class ConnectionPair:
	var from_node_id: String
	var to_node_id: String
	var from_output_port: int
	var to_input_port: int
	
	var incoming: IncomingConnection
	var outgoing: OutgoingConnection
	
	
	func _init(
		p_from_node_id: String,
		p_to_node_id: String,
		p_from_output_port: int,
		p_to_input_port: int,
		p_outgoing: OutgoingConnection = null,
		p_incoming: IncomingConnection = null
		) -> void:
		from_node_id = p_from_node_id
		to_node_id = p_to_node_id
		from_output_port = p_from_output_port
		to_input_port = p_to_input_port
		
		if not p_outgoing:
			outgoing = OutgoingConnection.new()
			outgoing.to_node = to_node_id
			outgoing.to_port = to_input_port
			
			incoming = IncomingConnection.new()
			incoming.from_port = from_output_port
			incoming.from_node = from_node_id
			
			incoming.counterpart = weakref(outgoing)
			outgoing.counterpart = weakref(incoming)
		else:
			outgoing = p_outgoing
			incoming = p_incoming
	
	
	func remap_id(old_id: String, new_id: String) -> void:
		if old_id == from_node_id:
			from_node_id = new_id
			incoming.from_node = new_id
		elif old_id == to_node_id:
			to_node_id = new_id
			outgoing.to_node = new_id
	
	
	func is_equivalent(other: ConnectionPair) -> bool:
		if from_node_id == other.from_node_id and \
			to_node_id == other.to_node_id and \
			from_output_port == other.from_output_port and \
			to_input_port == other.to_input_port:
				return true
		return false
	
	
	func to_dict() -> Dictionary:
		return {
			"incoming": incoming.to_dict(),
			"outgoing": outgoing.to_dict(),
		}
	
	
	static func from_incoming(p_incoming: IncomingConnection) -> ConnectionPair:
		@warning_ignore("shadowed_variable")
		var outgoing := p_incoming.counterpart.get_ref() as OutgoingConnection
		
		return ConnectionPair.new(
			p_incoming.from_node, outgoing.to_node,
			p_incoming.from_port, outgoing.to_port,
			outgoing, p_incoming
		)
	
	
	static func from_outgoing(p_outgoing: OutgoingConnection) -> ConnectionPair:
		@warning_ignore("shadowed_variable")
		var incoming := p_outgoing.counterpart.get_ref() as IncomingConnection
		
		return ConnectionPair.new(
			incoming.from_node, p_outgoing.to_node,
			incoming.from_port, p_outgoing.to_port,
			p_outgoing, incoming
		)
	
	
	static func from_dict(d: Dictionary) -> ConnectionPair:
		@warning_ignore("shadowed_variable")
		var outgoing := OutgoingConnection.new()
		outgoing.to_node = d.outgoing.to_node
		outgoing.to_port = d.outgoing.to_port
		
		@warning_ignore("shadowed_variable")
		var incoming := IncomingConnection.new()
		incoming.from_node = d.incoming.from_node
		incoming.from_port = d.incoming.from_port
		
		outgoing.counterpart = weakref(incoming)
		incoming.counterpart = weakref(outgoing)
		
		return from_incoming(incoming)


class IncomingConnection:
	var from_node: String
	var from_port: int
	
	var counterpart: WeakRef # OutgoingConnection
	
	
	func _to_string() -> String:
		return str({"from_node": from_node, "from_port": from_port})
	
	
	func to_dict() -> Dictionary:
		return {"from_node": from_node, "from_port": from_port}


class OutgoingConnection:
	var to_node: String
	var to_port: int
	
	var counterpart: WeakRef # IncomingConnection
	
	
	func _to_string() -> String:
		return str({"to_node": to_node, "to_port": to_port})
	
	
	func to_dict() -> Dictionary:
		return {"to_node": to_node, "to_port": to_port}


class GroupDescriptors:
	var input_ports: Dictionary = {} # Dictionary[int -> input port idx, GroupPort]
	var output_ports: Dictionary = {} # Dictionary[int -> output port idx, GroupPort]
	var deck: Deck
	
	
	func is_empty() -> bool:
		if input_ports.is_empty() and output_ports.is_empty():
			return true
		
		var test := func(e: GroupPort) -> bool:
			return not e.is_empty()
		
		var has_inputs = input_ports.values().any(test)
		var has_outputs = output_ports.values().any(test)
		
		if has_inputs or has_outputs:
			return false
		
		return true
	
	
	func _on_input_updated(port_idx: int) -> void:
		var node := deck.get_node(deck.group_input_node)
		var port := node.get_output_ports()[port_idx]
		var port_override := get_input_port(port_idx)
		
		if port_override.label.is_empty():
			port.label = "Input %s" % port_idx
		else:
			port.label = port_override.label
		
		port.type = port_override.type
		port.descriptor = port_override.descriptor
		port.usage_type = port_override.usage_type
		
		node.ports_updated.emit()
	
	
	func _on_output_updated(port_idx: int) -> void:
		var node := deck.get_node(deck.group_output_node)
		var port := node.get_input_ports()[port_idx]
		var port_override := get_output_port(port_idx)
		if port_override.label.is_empty():
			port.label = "Output %s" % port_idx
		else:
			port.label = port_override.label
		
		port.type = port_override.type
		port.descriptor = port_override.descriptor
		port.usage_type = port_override.usage_type
		
		node.ports_updated.emit()
	
	
	func _get_or_create_input(port_idx: int) -> GroupPort:
		var res := input_ports.get(port_idx, null) as GroupPort
		if res == null:
			var gr := GroupPort.new()
			input_ports[port_idx] = gr
			res = gr
		
		Util.safe_connect(res.updated, _on_input_updated.bind(port_idx))
		
		return res
	
	
	func _get_or_create_output(port_idx: int) -> GroupPort:
		var res := output_ports.get(port_idx, null) as GroupPort
		if res == null:
			var gr := GroupPort.new()
			output_ports[port_idx] = gr
			res = gr
		
		Util.safe_connect(res.updated, _on_output_updated.bind(port_idx))
		
		return res
	
	
	func get_input_port(port_idx: int) -> GroupPort:
		return _get_or_create_input(port_idx)
	
	
	func get_output_port(port_idx: int) -> GroupPort:
		return _get_or_create_output(port_idx)
	
	
	func to_dict() -> Dictionary:
		var res := {
			"input_ports": {},
			"output_ports": {},
		}
		
		for port_idx: int in input_ports:
			var gp := input_ports[port_idx] as GroupPort
			if gp.is_empty():
				continue
			res["input_ports"][port_idx] = gp.to_dict()

		for port_idx: int in output_ports:
			var gp := output_ports[port_idx] as GroupPort
			if gp.is_empty():
				continue
			res["output_ports"][port_idx] = gp.to_dict()
		
		return res


	static func from_dict(d: Dictionary) -> GroupDescriptors:
		var res := GroupDescriptors.new()
		
		for port_idx in d.input_ports:
			res.input_ports[int(port_idx)] = GroupPort.from_dict(d.input_ports[port_idx])

		for port_idx in d.output_ports:
			res.output_ports[int(port_idx)] = GroupPort.from_dict(d.output_ports[port_idx])
		
		return res


class GroupPort:
	var type: DeckType.Types = DeckType.Types.ANY:
		set(v):
			type = v
			updated.emit()
	var label: String:
		set(v):
			label = v
			updated.emit()
	var descriptor: String:
		set(v):
			descriptor = v
			updated.emit()
	var usage_type: Port.UsageType = Port.UsageType.BOTH:
		set(v):
			usage_type = v
			updated.emit()
	
	signal updated()
	
	
	func is_empty() -> bool:
		return\
			type == DeckType.Types.ANY and\
			label.is_empty() and\
			descriptor.is_empty() and\
			usage_type == Port.UsageType.BOTH
	
	
	func to_dict() -> Dictionary:
		var res := {
			"type": type,
			"label": label,
			"descriptor": descriptor,
			"usage_type": usage_type,
		}
		
		return res


	static func from_dict(d: Dictionary) -> GroupPort:
		var res := GroupPort.new()
		res.type = d.type as DeckType.Types
		res.label = d.label
		res.descriptor = d.descriptor
		res.usage_type = d.usage_type as Port.UsageType
		return res