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._id = assign_id

	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_id: String, to_node_id: String, from_output_port: int, to_input_port: int) -> bool:
	var from_node := get_node(from_node_id)
	var to_node := get_node(to_node_id)
	# 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_id: String, to_node_id: String, from_output_port: int, to_input_port: int) -> void:
	var from_node := get_node(from_node_id)
	var to_node := get_node(to_node_id)
	from_node.remove_outgoing_connection(from_output_port, to_node_id, to_input_port)
	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, remove_connections: bool = false) -> void:
	var node := get_node(uuid)
	if node == null:
		return

	if remove_connections:
		var outgoing_connections := node.outgoing_connections.duplicate(true)

		for output_port: int in outgoing_connections:
			for connection: Dictionary in outgoing_connections[output_port]:
				disconnect_nodes(uuid, connection.keys()[0], output_port, connection.values()[0])

		var incoming_connections := node.incoming_connections.duplicate(true)

		for input_port: int in incoming_connections:
			for from_node: String in incoming_connections[input_port]:
				disconnect_nodes(from_node, uuid, incoming_connections[input_port][from_node], input_port)

	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

		var outgoing_connections := node.outgoing_connections.duplicate(true)

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

		var incoming_connections := node.incoming_connections.duplicate(true)

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


func copy_nodes_json(nodes_to_copy: Array[String]) -> String:
	var d := {"nodes": {}}

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

	for node: String in d.nodes:
		var outgoing_connections: Dictionary = d.nodes[node].outgoing_connections.duplicate(true)

		for from_port: int in outgoing_connections:
			for to_node: String in outgoing_connections[from_port]:
				if !(to_node in nodes_to_copy):
					(d.nodes[node].outgoing_connections[from_port] as Dictionary).erase(to_node)

		var incoming_connections: Dictionary = d.nodes[node].incoming_connections.duplicate(true)

		for to_port: int in incoming_connections:
			for from_node: String in incoming_connections[to_port]:
				if !(from_node in nodes_to_copy):
					(d.nodes[node].incoming_connections[to_port] as Dictionary).erase(from_node)

	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 JSON.stringify(d)


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_json(json: String, position: Vector2 = Vector2()) -> void:
	var d: Dictionary = JSON.parse_string(json) as Dictionary
	if !d.get("nodes"):
		return

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

	var new_json := json
	for old_id: String in ids_map:
		new_json = new_json.replace(old_id, ids_map[old_id])

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

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

		var outgoing_connections: Dictionary = d.nodes[node_id].outgoing_connections as Dictionary
		var outgoing_connections_res := {}
		for from_port: String in outgoing_connections:
			outgoing_connections_res[from_port] = {}
			for to_node_id: String in outgoing_connections[from_port]:
				outgoing_connections_res[from_port][ids_map[to_node_id]] = outgoing_connections[from_port][to_node_id]

		var incoming_connections: Dictionary = d.nodes[node_id].incoming_connections as Dictionary
		var incoming_connections_res := {}
		for to_port: String in incoming_connections:
			incoming_connections_res[to_port] = {}
			for from_node_id: String in incoming_connections[to_port]:
				incoming_connections_res[to_port][ids_map[from_node_id]] = incoming_connections[to_port][from_node_id]

		d.nodes[node_id].outgoing_connections = outgoing_connections_res
		d.nodes[node_id].incoming_connections = incoming_connections_res

		var node := DeckNode.from_dict(d.nodes[node_id])
		add_node_inst(node, ids_map[node_id])


## 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 := DeckNode.from_dict(nodes_data[node_id])
		deck.add_node_inst(node, node_id)

	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