# CORE FRAMEWORK SOURCE FILE
# Copyright (c) 2024 The StarOpenSource Project & Contributors
# Licensed under the GNU Affero General Public License v3
# 
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
# 
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
# 
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

## Initializes and manages the framework.
## 
## The [b]CORE Object[/b] is responsible for initializing, managing and
## serving the CORE Framework.
extends Node
class_name Core

# Versioning
## The version number
const version_version: int = 1
## The version type. See [enum CoreTypes.VersionType] for more information.
const version_type: CoreTypes.VersionType = CoreTypes.VersionType.RELEASE
## The version type number. Resets on every new version and version type.
const version_typerelease: int = 1

# Modules
## Used internally for loading, managing and unloading modules.
const modules: Array[String] = [ "logger", "misc", "sms", "logui", "erm", "storage" ]
## CORE's configuration object.[br]
## [b]NEVER access this yourself! To change the configuration use [method reload_configuration] instead.[/b]
var config: CoreConfiguration
## The framework scheduler.[br]
## Performs various maintenance tasks every minute.
## [b]Danger: [i]Don't modify this.[/i][/b]
var scheduler: Timer
## The 'Logger' module
var logger: CoreBaseModule
## The 'Miscellaneous' module
var misc: CoreBaseModule
## The 'Scene Management System' module
var sms: CoreBaseModule
## The 'Log UI' module. Not important for you, it just displays the log graphically :3
var logui: CoreBaseModule
## The 'Easy Request Maker' module (formerly 'Easy DownLoader')
var erm: CoreBaseModule
## The 'Storage' module
var storage: CoreBaseModule

# /etc/
## Stores the path to CORE's installation directory.[br]
## [b]Danger: [i]Don't modify this.[/i][/b]
var basepath: String
## Contains a list of all registered cleanup hooks.[br]
## [b]Danger: [i]Don't modify this.[/i][/b]
var cleanup_hooks: Dictionary = {}
## Contains a list of all loaded custom modules.[br]
## [b]Danger: [i]Don't modify this.[/i][/b]
var custom_modules: Dictionary = {}
## Contains the node holding all custom modules as children.[br]
## [b]Danger: [i]Don't modify this.[/i][/b]
var custom_modules_node: Node
## The CORE Object's logger instance.
## [b]Danger: [i]Don't modify this.[/i][/b]
var loggeri: CoreLoggerInstance

# +++ initialization +++
func _init(new_config: CoreConfiguration = CoreConfiguration.new()) -> void:
	name = "CORE"
	if !check_godot_version(): return
	if !determine_basepath(): queue_free()
	custom_modules_node = Node.new()
	reload_configuration(new_config)
	initialize_modules()
	apply_configuration()
	initialize_scheduler()

func _ready() -> void:
	inject_modules()
	custom_modules_node.name = "Custom Modules"
	add_child(custom_modules_node)
	loggeri = logger.get_instance(basepath.replace("res://", "") + "src/core.gd", self)
	add_child(scheduler)
	get_tree().auto_accept_quit = false

## Initializes all built-in modules during the preinitialization phase.[br]
## [b]Danger: [i]Don't call this.[/i][/b]
func initialize_modules() -> void:
	for module in modules:
		set(module, CoreBaseModule.new())
		get(module).name = module
		get(module).set_script(load(basepath + "src/" + module + ".gd"))
		get(module).core = self
		get(module).loggeri = logger.get_instance(basepath.replace("res://", "") + "src/" + module + ".gd", get(module))
		get(module)._initialize()

## Injects CORE's builtin modules into the SceneTree.[br]
## [b]Danger: [i]Don't call this.[/i][/b]
func inject_modules() -> void: for module in modules: add_child(get(module))

## Initializes the framework scheduler.
## [b]Danger: [i]Don't call this.[/i][/b]
func initialize_scheduler() -> void:
	scheduler = Timer.new()
	scheduler.name = "Scheduler"
	scheduler.autostart = true
	scheduler.one_shot = false
	scheduler.paused = false
	scheduler.wait_time = 60
	scheduler.process_mode = Node.PROCESS_MODE_ALWAYS
	scheduler.connect("timeout", func() -> void:
		loggeri.verb("Running scheduler tasks")
		for module in modules: await get(module)._schedule()
		for module in custom_modules_node.get_children(): await module._schedule()
	)

## Waits for all modules to fully initialize.[br]
## [br]
## This ensures that all modules are fully initialized and ready for usage.[br]
## [i][b]Not calling this function during startup may lead to runtime issues.[/b][/i]
func complete_init(no_success_message: bool = false) -> void:
	var modsinit_builtin: Array[String] = ["workaround"]
	var modsinit_custom: Array[String] = ["workaround"]
	
	while modsinit_builtin.size() != 0 and modsinit_custom.size() != 0:
		# Clear arrays
		modsinit_builtin = []
		modsinit_custom = []
		
		# Check builtin modules
		for module in modules: if !get(module).initialized: modsinit_builtin.append(module)
		
		# Check custom modules
		for module_name in custom_modules:
			if !custom_modules[module_name].initialized: modsinit_custom.append(module_name)
		
		# Print and sleep
		if modsinit_builtin.size() != 0 or modsinit_custom.size() != 0:
			print("Waiting for modules to finish initialization:")
			if modsinit_builtin.size() != 0: print("  Built-in: " + str(modsinit_builtin))
			if modsinit_custom.size() != 0: print("  Custom: " + str(modsinit_custom))
			await get_tree().create_timer(1).timeout
	
	# Initialization complete
	await get_tree().process_frame
	if !no_success_message: loggeri.info("Initialized CORE successfully")

# +++ configuration +++
## Loads a (new) configuration object and applies it to all modules.
func reload_configuration(new_config: CoreConfiguration = CoreConfiguration.new()) -> void:
	var initialized = config != null
	if initialized: loggeri.verb("Reloading CORE's configuration")
	if config != null: config.queue_free()
	config = new_config.duplicate()
	if is_devmode(): # Override configuration in development mode
		config.logger_level = CoreTypes.LoggerLevel.DIAG
		if initialized: loggeri.verb("Overrode configuration (development mode)")
	if initialized: apply_configuration()

## Applies the a configuration.[br]
## [b]Danger: [i]Don't call this.[/i][/b]
func apply_configuration() -> void:
	if loggeri != null: loggeri.verb("Applying configuration")
	if is_devmode() and loggeri != null: loggeri.warn("The CORE Framework is in development mode. Here be dragons!")
	if !config.custom_modules:
		if loggeri != null: loggeri.diag("Removing all custom modules (custom modules support is disabled)")
		for module in custom_modules: unregister_custom_module(module)
	for module in modules: get(module)._pull_config()
	if config.custom_modules:
		for module in custom_modules:
			custom_modules[module]._pull_config()
	
	# Workaround
	logger.verbose_mode = OS.is_stdout_verbose()

# +++ custom module support +++
## Registers a new custom module.
func register_custom_module(module_name: String, module_origin: String, module_class: CoreBaseModule) -> bool:
	loggeri.verb("Registering new custom module \"" + module_name + "\"")
	if !config.custom_modules:
		loggeri.error("Registering module failed: Custom module support is disabled.")
		return false
	if custom_modules.has(module_name):
		loggeri.error("Registering module failed: A custom module with the name \"" + module_name + "\" already exists.")
		return false
	loggeri.diag("Updating variables")
	module_class.name = module_name
	module_class.core = self
	module_class.loggeri = logger.get_instance(module_origin, module_class)
	module_class.loggeri.framework = true
	loggeri.diag("Adding module to SceneTree")
	custom_modules_node.add_child(module_class)
	loggeri.diag("Merging module with custom_modules")
	custom_modules.merge({ module_name: module_class })
	loggeri.diag("Initializing custom module")
	module_class._initialize()
	loggeri.diag("Updating custom module configuration")
	module_class._pull_config()
	return true

## Unregisters a custom module, making it no longer available.
func unregister_custom_module(module_name: String) -> void:
	loggeri.verb("Unregistering custom module \"" + module_name + "\"")
	if !custom_modules.has(module_name):
		loggeri.error("Unregistering module failed: A custom module with the name \"" + module_name + "\" does not exist.")
		return
	var module: Node = custom_modules[module_name]
	await module._cleanup()
	module.loggeri.queue_free()
	custom_modules_node.remove_child(module)
	custom_modules.erase(module_name)
	module.queue_free()

## Returns a registered custom module.[br]
## Please note that you can't get CORE's built-in modules with this function.
func get_custom_module(module_name: String) -> CoreBaseModule:
	loggeri.diag("Getting custom module \"" + module_name + "\"")
	if !custom_modules.has(module_name):
		loggeri.error("Getting module failed: A custom module with the name \"" + module_name + "\" does not exist.")
		return null
	return custom_modules[module_name]

# +++ cleanup ++
## Makes sure that CORE does not leak memory on shutdown/unload.[br]
## Unloads all custom modules, built-in modules, frees any of CORE's classes and lastly itself.[br]
## Only call this function if you're sure that your application or game no longer uses the CORE Framework.
func cleanup() -> void:
	loggeri.info("Cleaning up")
	loggeri.verb("Calling cleanup hooks")
	for hook in cleanup_hooks:
		if !cleanup_hooks[hook].is_valid():
			loggeri.error("Cleanup hook #" + str(hook) + " is invalid")
		else:
			loggeri.diag("Calling cleanup hook #" + str(hook))
			await cleanup_hooks[hook].call()
	loggeri.verb("Unregistering custom modules")
	for module in custom_modules_node.get_children(): await unregister_custom_module(module.name)
	loggeri.verb("Removing custom module support")
	remove_child(custom_modules_node)
	custom_modules_node.queue_free()
	loggeri.verb("Unloading built-in modules")
	var modules_reverse: Array[String] = modules.duplicate()
	modules_reverse.reverse()
	for module in modules_reverse:
		await get(module)._cleanup()
		get(module).queue_free()
	print("Freeing configuration")
	config.queue_free()
	await get_tree().process_frame
	print("Freeing")
	queue_free()

# Generates a new cleanup hook id
func _generate_hook_id() -> int:
	var id = randi()
	if cleanup_hooks.has(id):
		loggeri.warn("New cleanup hook id #" + str(id) + " is already taken")
		return _generate_hook_id()
	elif id == -1:
		loggeri.warn("Invalid cleanup hook id '-1'")
		return _generate_hook_id()
	return id

## Registers a new cleanup hook.[br]
## Returns the hook id.
func register_cleanup_hook(callable: Callable) -> int:
	if !callable.is_valid():
		loggeri.error("Could not add cleanup hook: Callable is not valid")
		return -1
	
	var id: int = _generate_hook_id()
	loggeri.verb("Adding new cleanup hook #" + str(id))
	cleanup_hooks.merge({ id: callable })
	return id

## Unregisters a cleanup hook by it's id.
func unregister_cleanup_hook_by_id(id: int) -> bool:
	if !cleanup_hooks.has(id):
		loggeri.error("Could not remove cleanup hook (id): Hook #" + str(id) + " does not exist")
		return false
	loggeri.verb("Removed cleanup hook #" + str(id) + " (id)")
	cleanup_hooks.erase(id)
	return true

## Unregisters a cleanup hook by it's reference.
func unregister_cleanup_hook_by_ref(callable: Callable) -> bool:
	var id: Variant = cleanup_hooks.find_key(callable)
	if id == null:
		loggeri.error("Could not remove cleanup hook (ref): Could not find a matching hook")
		return false
	if typeof(id) != TYPE_INT: await loggeri.crash("Could not remove cleanup hook (ref): find_key did not return an integer (returned '" + str(id) + "')")
	loggeri.verb("Removed cleanup hook #" + str(id) + " (ref)")
	cleanup_hooks.erase(id)
	return true

# +++ etc +++
## Returns if the framework is in development mode.
func is_devmode() -> bool:
	return config.development

## Replaces placeholders with human-friendly strings.[br]
## You can use the following placeholders:[br]
## - [code]%version%[/code]: Returns the version number.[br]
## - [code]%version_type%[/code]: Returns the version type number[br]
## - [code]%version_semantic%[/code]: Returns the result of [method Core.get_version_semantic], example [i]5.2.3[/i][br]
## - [code]%version_type%[/code]: Returns the version type as a word, for example [i]Release Candidate[/i][br]
## - [code]%version_type_technical%[/code]: Returns the version type as one or two lowercase letters, for example [i]rc[/i][br]
## - [code]%devmode%[/code]: Returns the development mode status[br]
## - [code]%headless%[/code]: Returns the headless mode status[br]
## - [code]%custommodules%[/code]: Returns if custom module support is enabled
func get_formatted_string(string: String) -> String:
	# Version strings
	string = string.replace("%version%", str(version_version))
	string = string.replace("%version_typerelease%", str(version_typerelease))
	var semantic_version: Array[int] = get_version_semantic()
	string = string.replace("%version_semantic%", str(semantic_version[0]) + "." + str(semantic_version[1]) + "." + str(semantic_version[2]))
	match(version_type):
		CoreTypes.VersionType.RELEASE:
			string = string.replace("%version_type%", "Release")
			string = string.replace("%version_type_technical%", "r")
		CoreTypes.VersionType.RELEASECANDIDATE:
			string = string.replace("%version_type%", "Release Candidate")
			string = string.replace("%version_type_technical%", "rc")
		CoreTypes.VersionType.BETA:
			string = string.replace("%version_type%", "Beta")
			string = string.replace("%version_type_technical%", "b")
		CoreTypes.VersionType.ALPHA:
			string = string.replace("%version_type%", "Alpha")
			string = string.replace("%version_type_technical%", "a")
		_: await loggeri.crash("Invalid version type " + str(version_type))
	# Development mode
	if is_devmode(): string = string.replace("%devmode%", "Enabled")
	else: string = string.replace("%devmode%", "Disabled")
	# Headless mode
	if config.headless: string = string.replace("%headless%", "Enabled")
	else: string = string.replace("%headless%", "Disabled")
	# Custom module support
	if config.custom_modules: string = string.replace("%custommodules%", "Enabled")
	else: string = string.replace("%custommodules%", "Disabled")
	return string

## Returns CORE's versioning scheme into the semantic versioning scheme.[br]
## The first integer contains the version number, the second integer contains the version type ([code]0[/code] for alpha, [code]1[/code] for beta, [code]2[/code] for rc and [code]3[/code] for release and the last integer contains the version type number.
func get_version_semantic() -> Array[int]:
	var version_type_int: int
	match(version_type):
		CoreTypes.VersionType.RELEASE: version_type_int = 3
		CoreTypes.VersionType.RELEASECANDIDATE: version_type_int = 2
		CoreTypes.VersionType.BETA: version_type_int = 1
		CoreTypes.VersionType.ALPHA: version_type_int = 0
	return [version_version, version_type_int, version_typerelease]

## Determines CORE's installation/base path.[br]
## [b]Danger: [i]Don't call this.[/i][/b]
func determine_basepath() -> bool:
	if FileAccess.file_exists("res://.corebasepath"):
		basepath = "res://"
	elif FileAccess.file_exists("res://CORE/.corebasepath"):
		basepath = "res://CORE/"
	elif FileAccess.file_exists("res://addons/CORE/.corebasepath"):
		basepath = "res://addons/CORE/"
	else:
		assert(false, "CORE is not located at 'res://CORE/', aborting initialization")
		return false
	return true

# Checks Godot's version
## Checks compatibility with the running version.
func check_godot_version() -> bool:
	var version: Dictionary = Engine.get_version_info()
	match(version["major"]):
		4: pass
		_:
			printerr("The CORE Framework does not support Godot versions older or newer than 4.x.x")
			return false
	match(version["minor"]):
		0: printerr("The CORE Framework does not support Godot versions older than 4.2.x. Please update to Godot 4.2.x to ensure full compatibility.")
		1: printerr("The CORE Framework does not support Godot versions older than 4.2.x. Please update to Godot 4.2.x to ensure full compatibility.")
		2: pass
		_:
			printerr("The CORE Framework does not support Godot versions newer than 4.2.x. Please downgrade to Godot 4.2.x.")
			return false
	if version["status"] != "stable":
		printerr("The CORE Framework does not support unstable Godot versions. Please switch to Godot stable 4.2.x.")
		return false
	return true

## Makes sure for all log messages to be flushed and that CORE is correctly cleaned up.[br]
## Using [method SceneTree.quit] directly may cause various issues.[br]
## [b]Note: [i]Using the [code]await[/code] keyword is required for this function.[/i][/b]
func quit_safely(exitcode: int = 0) -> void:
	loggeri.info("Shutting down (code " + str(exitcode) + ")")
	await get_tree().create_timer(0.25).timeout
	await cleanup()
	get_tree().quit(exitcode)

func _notification(what) -> void:
	match(what):
		NOTIFICATION_WM_CLOSE_REQUEST:
			if config.automatic_shutdown:
				await quit_safely(0)