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 = ""

var is_group: bool = false
## 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.
var id: String = ""
## The parent deck of this deck, if this is a group.
var _belonging_to: Deck # 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
## The ID of the group node this group is represented by, contained in this deck's parent deck.
## Used only if [member is_group] is [code]true[/code].
## @experimental
var group_node: String

## 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)


## 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].
func add_node_inst(node: DeckNode, assign_id: String = "", assign_to_self: bool = true) -> DeckNode:
	if assign_to_self:
		node._belonging_to = self

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

	node_added.emit(node)

	return node


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


## Attempt to connect two nodes. Returns [code]true[/code] if the connection succeeded.
func connect_nodes(from_node: DeckNode, to_node: DeckNode, from_output_port: int, to_input_port: int) -> bool:
	# check that we can do the type conversion
	var type_a: DeckType.Types = from_node.get_output_ports()[from_output_port].type
	var type_b: DeckType.Types = to_node.get_input_ports()[to_input_port].type
	if !DeckType.can_convert(type_a, type_b):
		print("Can not convert from %s to %s." % [DeckType.type_str(type_a), DeckType.type_str(type_b)])
		return false

	# TODO: prevent duplicate connections

	from_node.add_outgoing_connection(from_output_port, to_node._id, to_input_port)
	return true


## Remove a connection from two nodes.
func disconnect_nodes(from_node: DeckNode, to_node: DeckNode, from_output_port: int, to_input_port: int) -> void:
	var hash = {to_node._id: to_input_port}.hash()

	from_node.remove_outgoing_connection(from_output_port, hash)
	to_node.remove_incoming_connection(to_input_port)


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


## Remove a node from this deck.
func remove_node(uuid: String) -> void:
	var node = nodes.get(uuid)
	nodes.erase(uuid)

	node_removed.emit(node)


## 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

	var node_ids_to_keep := nodes_to_group.map(
		func(x: DeckNode):
			return x._id
	)

	var group := Deck.new()
	group.is_group = true
	group._belonging_to = self
	var group_id := UUID.v4()
	group.id = group_id

	var midpoint := Vector2()
	for node: DeckNode in nodes_to_group:
		if node.node_type == "group_node": # for recursive grouping
			var _group_id: String = node.group_id
			var _group: Deck = groups[_group_id]
			groups.erase(_group)
			group.groups[_group_id] = _group
			_group._belonging_to = group

		for from_port: int in node.outgoing_connections:
			for connection: Dictionary in node.outgoing_connections[from_port]:
				if !(connection.keys()[0] in node_ids_to_keep):
					disconnect_nodes(node, get_node(connection.keys()[0]), from_port, connection.values()[0])

		for to_port: int in node.incoming_connections:
			for from_node: String in node.incoming_connections[to_port]:
				if !(from_node in node_ids_to_keep):
					disconnect_nodes(get_node(from_node), node, node.incoming_connections[to_port].values()[0], to_port)

		midpoint += node.position_as_vector2()
		remove_node(node._id)
		group.add_node_inst(node, node._id)

	midpoint /= nodes_to_group.size()

	var _group_node := add_node_type("group_node")
	_group_node.group_id = group_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

	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

	_group_node.input_node = input_node
	_group_node.output_node = output_node
	_group_node.setup_connections()

	groups[group_id] = group

	return group


## Get a group belonging to this deck by its ID.
func get_group(uuid: String) -> Deck:
	return groups.get(uuid)


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

	for node_id in nodes.keys():
		inner["nodes"][node_id] = nodes[node_id].to_dict(with_meta)

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

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

	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

	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 := deck.add_node_type(nodes_data[node_id].node_type, node_id, false)
		node._id = node_id
		node.name = nodes_data[node_id].name
		node._belonging_to = deck
		node.position = nodes_data[node_id].position

		for prop in nodes_data[node_id].props:
			node.set(prop, nodes_data[node_id].props[prop])

		node._pre_connection()

		for connection_id in nodes_data[node_id].outgoing_connections:
			var connection_data = nodes_data[node_id].outgoing_connections[connection_id]
			for connection in connection_data:
				connection[connection.keys()[0]] = int(connection.values()[0])
			node.outgoing_connections[int(connection_id)] = connection_data

		for connection_id in nodes_data[node_id].incoming_connections:
			var connection_data = nodes_data[node_id].incoming_connections[connection_id]
			for connection in connection_data:
				connection_data[connection] = int(connection_data[connection])
			node.incoming_connections[int(connection_id)] = connection_data

		for i in node.ports.size():
			var port_value: Variant
			if (nodes_data[node_id].port_values as Array).size() <= i:
				port_value = null
			else:
				port_value = (nodes_data[node_id].port_values as Array)[i]
			node.ports[i].value = port_value

		for key in nodes_data[node_id].meta:
			node.set_meta(key, str_to_var(nodes_data[node_id].meta[key]))

		node._post_load()

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

	for group_id: String in groups_data:
		var group := Deck.from_dict(groups_data[group_id])
		group._belonging_to = deck
		group.is_group = true
		deck.groups[group_id] = group
		group.group_node = groups_data[group_id]["deck"]["group_node"]
		group.group_input_node = groups_data[group_id]["deck"]["group_input_node"]
		group.group_output_node = groups_data[group_id]["deck"]["group_output_node"]
		deck.get_node(group.group_node).init_io()

	return deck