# (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)
class_name NodeDB

## Path to search for node files.
const BASE_NODE_PATH := "res://classes/deck/nodes/"
## Filepath where the index of [NodeDB.NodeDescriptor]s are saved to avoid reloading
## everything each run.
## @experimental
const NODE_INDEX_CACHE_PATH := "user://nodes_index.json"
## Filepath where the the list of favorite nodes is stored.
const FAVORITE_NODES_PATH := "user://favorite_nodes.json"

## A map of [code]snake_case[/code] category names for proper capitalization.
const CATEGORY_CAPITALIZATION := {
	"obs": "OBS"
}

## A list of nodes that the user marked favorite in the [AddNodeMenu].
static var favorite_nodes: Array[String]

# Dictionary[node_type, NodeDescriptor]
## The node index. Maps [member DeckNode.node_type]s to [NodeDB.NodeDescriptor].
static var nodes: Dictionary = {}

static var libraries: Dictionary = {}


static func init() -> void:
	load_favorites()
	#if load_node_index():
		#return

	create_descriptors(BASE_NODE_PATH)
	
	reload_libraries()

	save_node_index()


## Fills the [member nodes] index.
static func create_descriptors(path: String) -> void:
	var dir := DirAccess.open(path)
	if not dir:
		return
	dir.list_dir_begin()
	var current_file := dir.get_next()
	while current_file != "":
		if dir.current_is_dir():
			create_descriptors(path.path_join(current_file))
		elif current_file.ends_with(".gd"):
			var script_path := path.path_join(current_file)
			var node: DeckNode = load(script_path).new() as DeckNode
			var aliases: String = node.aliases.reduce(
				func(accum, el):
					return accum + el
			, "")
			var descriptor := NodeDescriptor.new(
				script_path,
				node.name,
				node.node_type,
				node.description,
				aliases,
				path.get_slice("/", path.get_slice_count("/") - 1),
				node.appears_in_search,
				false,
				)
			nodes[node.node_type] = descriptor
			print_verbose("NodeDB: freeing node %s, id %s" % [node.node_type, node.get_instance_id()])
			node.free()
		current_file = dir.get_next()


## Fills the [member libraries] index.
static func create_lib_descriptors(path: String) -> void:
	var dir := DirAccess.open(path)
	if not dir:
		return
	dir.list_dir_begin()
	var current_file := dir.get_next()
	while current_file != "":
		if dir.current_is_dir():
			create_lib_descriptors(path.path_join(current_file))
		elif current_file.ends_with(".deck"):
			var load_path := path.path_join(current_file)
			var f := FileAccess.open(load_path, FileAccess.READ)
			var deck: Dictionary = JSON.parse_string(f.get_as_text())
			if not deck.deck.has("library"):
				current_file = dir.get_next()
				continue
			var type := current_file.trim_suffix(".deck")
			if nodes.has(type):
				DeckHolder.logger.toast_error("Library group '%s' collides with a node with the same type." % type)
				current_file = dir.get_next()
				continue
			if libraries.has(type):
				DeckHolder.logger.toast_error("Library group '%s' collides with a library group with the same type." % type)
				current_file = dir.get_next()
				continue
			var lib = deck.deck.library
			var aliases: String = lib.lib_aliases.reduce(
				func(accum, el):
					return accum + el
			, "")
			var descriptor := NodeDescriptor.new(
				load_path,
				lib.lib_name,
				type,
				lib.lib_description,
				aliases,
				path.get_slice("/", path.get_slice_count("/") - 1),
				true,
				true,
			)
			libraries[descriptor.type] = descriptor
		current_file = dir.get_next()


static func reload_libraries() -> void:
	libraries.clear()
	for path in StreamGraphConfig.get_library_search_paths():
		create_lib_descriptors(path)


## Instantiates a [DeckNode] from a given [param node_type]. See [member DeckNode.node_type].
static func instance_node(node_type: String) -> DeckNode:
	if not nodes.has(node_type):
		return null

	return load(nodes[node_type]["script_path"]).new()


## Saves the index of all loaded nodes to [member NODE_INDEX_CACHE_PATH].
static func save_node_index() -> void:
	var d := {}
	for node_type in nodes:
		var nd: NodeDescriptor = nodes[node_type] as NodeDescriptor
		d[node_type] = nd.to_dictionary()

	var json := JSON.stringify(d, "\t")
	var f := FileAccess.open(NODE_INDEX_CACHE_PATH, FileAccess.WRITE)
	f.store_string(json)


## Loads the node index from [member NODE_INDEX_CACHE_PATH]. Returns [code]true[/code]
## if the index was found on the file system.
static func load_node_index() -> bool:
	var f := FileAccess.open(NODE_INDEX_CACHE_PATH, FileAccess.READ)
	if f == null:
		DeckHolder.logger.log_system("node index file does not exist", Logger.LogType.WARN)
		return false

	var data: Dictionary = JSON.parse_string(f.get_as_text()) as Dictionary
	if data.is_empty():
		DeckHolder.logger.log_system("node index file exists, but is empty",  Logger.LogType.ERROR)
		return false

	for node_type in data:
		var nd_dict: Dictionary = data[node_type]
		var nd := NodeDescriptor.from_dictionary(nd_dict)
		nodes[node_type] = nd

	DeckHolder.logger.log_system("node index file exists, loaded")
	return true


## Marks a [member DeckNode.node_type] as "favorite" for use in
## [AddNodeMenu].
static func set_node_favorite(node_type: String, favorite: bool) -> void:
	if (favorite and node_type in favorite_nodes) or (not favorite and node_type not in favorite_nodes):
		return

	if favorite:
		favorite_nodes.append(node_type)
	else:
		favorite_nodes.erase(node_type)

	var f := FileAccess.open(FAVORITE_NODES_PATH, FileAccess.WRITE)
	f.store_string(JSON.stringify(favorite_nodes, "\t"))


## Loads the list of favorite [memeber DeckNode.node_type]s from [member FAVORITE_NODES_PATH].
static func load_favorites() -> void:
	var f := FileAccess.open(FAVORITE_NODES_PATH, FileAccess.READ)
	if not f:
		return
	var data: Array = JSON.parse_string(f.get_as_text())
	favorite_nodes.clear()
	favorite_nodes.assign(data)


## Returns [code]true[/code] if the specified [member DeckNode.node_type] is marked favorite
## by the user.
static func is_node_favorite(node_type: String) -> bool:
	return node_type in favorite_nodes


static func is_library(type: String) -> bool:
	return libraries.has(type)


## Returns a capitalized category string.
static func get_category_capitalization(category: String) -> String:
	return CATEGORY_CAPITALIZATION.get(category, category.capitalize())


## Used for storing the shorthand data of a [DeckNode].
class NodeDescriptor:
	## Default name of the [DeckNode] type this is storing properties of.
	var name: String
	## The node type of the [DeckNode] reference. See [member DeckNode.node_type].
	var type: String
	## The description of the [DeckNode] reference. See [member DeckNode.description].
	var description: String
	## The aliases of the [DeckNode] reference. Stored as a flattened string of
	## the [member DeckNode.aliases] array.
	var aliases: String
	## The category of the [DeckNode] reference. See [member DeckNode.category].
	var category: String
	## Whether this [DeckNode] reference will appear when searching. See [member DeckNode.appears_in_search].
	var appears_in_search: bool
	
	var is_library: bool

	## Stores the path to this node's script for later instantiation.
	var script_path: String

	func _init(
			p_script_path: String,
			p_name: String,
			p_type: String,
			p_description: String,
			p_aliases: String,
			p_category: String,
			p_appears_in_search: bool,
			p_is_library: bool,
		) -> void:
			script_path = p_script_path

			name = p_name
			type = p_type
			description = p_description
			aliases = p_aliases
			category = p_category
			appears_in_search = p_appears_in_search
			is_library = p_is_library


	## Returns a [Dictionary] representation of this node descriptor.
	func to_dictionary() -> Dictionary:
		var d := {
			"name": name,
			"type": type,
			"description": description,
			"aliases": aliases,
			"script_path": script_path,
			"category": category,
			"appears_in_search": appears_in_search,
			"is_library": is_library,
		}
		return d


	## Creates a new [NodeDB.NodeDescriptor] from a given [Dictionary] of properties.
	static func from_dictionary(data: Dictionary) -> NodeDescriptor:
		var nd := NodeDescriptor.new(
			data.get("script_path", ""),
			data.get("name", ""),
			data.get("type", ""),
			data.get("description", ""),
			data.get("aliases", ""),
			data.get("category", ""),
			data.get("appears_in_search", false),
			data.get("is_library", false)
			)

		return nd