# An element of an application that is notified of the application life cycle
#
# Most users of _app.nit_ need only to implement `on_create` to setup the application.
#
# On mobile devices, the application can be stopped a anytime when another application takes the foreground.
# Implement the callbacks `on_save_state` and `on_load_state` to keep the state of the application between execution,
# for an illusion of continuous execution.
abstract class AppComponent

	# The application is being created
	#
	# You should build the UI at this time.
	#
	# Triggers are platform specific:
	# * Android: `Activity.onCreate`
	# * iOS: `UIApplicationDelegate application:didFinishLaunchingWithOptions`
	fun on_create do end

	# The application enters the active state, it is in the foreground and interactive
	#
	# Triggers are platform specific:
	# * Android: `Activity.onResume`
	# * iOS: `UIApplicationDelegate applicationDidBecomeActive`
	fun on_resume do end

	# The application leaves the active state but is still partially visible
	#
	# It may then go back to `on_resume` or `on_stop`.
	#
	# Triggers are platform specific:
	# * Android: `Activity.onPause`
	# * iOS: `UIApplicationDelegate applicationWillResignActive`
	fun on_pause do end

	# The application is completely hidden from the user
	#
	# It may then be destroyed or go back to a paused state with `on_restart`.
	#
	# Triggers are platform specific:
	# * Android: `Activity.onStop`
	# * iOS: `UIApplicationDelegate applicationDidEnterBackground`
	fun on_stop do end

	# The application returns to a visible state from a previous `on_stop`
	#
	# Triggers are platform specific:
	# * Android: `Activity.onRestart`
	# * iOS: `UIApplicationDelegate applicationWillEnterForeground`
	fun on_restart do end

	# The application may be destroyed soon, save its state for a future `on_restore_state`
	#
	# Triggers are platform specific:
	# * Android: `Activity.onSaveInstanceState`
	# * iOS: `UIApplicationDelegate applicationDidEnterBackground`
	fun on_save_state do end

	# The application is launching, restore its state from a previous `on_save_state`
	#
	# Triggers are platform specific:
	# * Android: `Activity.onCreate`, _not_ `Activity.onRestoreInstanceState`
	#   as it is trigged only if there is a previous Android specific save state.
	# * iOS: `UIApplicationDelegate applicationDidEnterBackground`
	fun on_restore_state do end
end