class_name AgonesSDK
extends Node

# Dependency-free REST bridge for the Agones sidecar. The Go supervisor owns
# the process-ready probe and /ready transition; this node owns the game
# process's periodic Health pings and terminal Shutdown/annotation calls.

const HEALTH_INTERVAL_SECONDS := 2.0
const REQUEST_TIMEOUT_SECONDS := 2.0
const MAX_ANNOTATION_VALUE_LENGTH := 4096

var _base_url := ""
var _health_timer: Timer = null
var _health_in_flight := false
var _health_started_msec := 0
# Set when start_health() is called before this node is inside the tree, so
# _ready() can arm the timer at the first moment it is legal to do so.
var _health_pending := false


# Health is armed here rather than by the caller. A Timer only ticks while its
# owner is inside the SceneTree, so arming it from a caller that has not yet
# parented this node produces a node that looks configured and never pings —
# which is exactly how every allocated GameServer silently failed its Agones
# health check and was recycled.
func _ready() -> void:
	if _health_pending:
		_health_pending = false
		_arm_health()


func configure_from_environment() -> bool:
	var port := OS.get_environment("AGONES_SDK_HTTP_PORT")
	if port.is_empty() or not port.is_valid_int() or int(port) < 1 or int(port) > 65535:
		return false
	_base_url = "http://127.0.0.1:%d" % int(port)
	return true


func configure_for_testing(base_url: String) -> bool:
	if not base_url.begins_with("http://127.0.0.1:") and not base_url.begins_with("http://localhost:"):
		return false
	_base_url = base_url.trim_suffix("/")
	return true


func is_available() -> bool:
	return not _base_url.is_empty()


# Returns whether health pings are running. It is a bool rather than void
# because every way this can fail used to be silent, and a game server that
# believes it is healthy while sending nothing is worse than one that refuses
# to start: Agones recycles the former every ~20 seconds forever.
func start_health() -> bool:
	if not is_available():
		push_error("AgonesSDK: start_health() before configuration; no health pings will be sent")
		return false
	if _health_timer != null:
		return true
	if not is_inside_tree():
		# Deferred rather than fatal: the caller may legitimately configure
		# before parenting. _ready() arms it. Still reported, because if the
		# node is never parented this is the whole failure.
		_health_pending = true
		push_warning("AgonesSDK: start_health() called outside the tree; deferring until ready")
		return false
	_arm_health()
	return true


func _arm_health() -> void:
	if _health_timer != null:
		return
	_health_timer = Timer.new()
	_health_timer.name = "AgonesHealth"
	_health_timer.wait_time = HEALTH_INTERVAL_SECONDS
	_health_timer.one_shot = false
	_health_timer.timeout.connect(_send_health)
	add_child(_health_timer)
	_health_timer.start()
	_send_health()


func health_is_running() -> bool:
	return _health_timer != null and is_inside_tree()


func stop_health() -> void:
	if _health_timer != null:
		_health_timer.stop()
		_health_timer.queue_free()
		_health_timer = null


func health() -> int:
	return await _request(HTTPClient.METHOD_POST, "/health", {})


func mark_ready() -> int:
	return await _request(HTTPClient.METHOD_POST, "/ready", {})


func shutdown() -> int:
	return await _request(HTTPClient.METHOD_POST, "/shutdown", {})


func set_annotation(key: String, value: String) -> int:
	if not annotation_is_valid(key, value):
		return 400
	return await _request(HTTPClient.METHOD_PUT, "/metadata/annotation", {"key": key, "value": value})


static func annotation_is_valid(key: String, value: String) -> bool:
	return not (key.is_empty() or value.is_empty() or value.length() > MAX_ANNOTATION_VALUE_LENGTH or "\n" in key or "\r" in key or "\n" in value or "\r" in value)


func _send_health() -> void:
	if not is_available():
		return
	# The latch stops overlapping requests, but it must never become permanent.
	# It is set across an await, and a request that never completes would
	# otherwise silence health for the lifetime of the process. HTTPRequest's
	# own timeout normally resolves this; the elapsed check is the backstop for
	# the case where request_completed never fires at all.
	if _health_in_flight:
		var stuck_for := Time.get_ticks_msec() - _health_started_msec
		if stuck_for < int(REQUEST_TIMEOUT_SECONDS * 2.0 * 1000.0):
			return
		push_warning("Agones health ping did not complete in %dms; sending another" % stuck_for)
	_health_in_flight = true
	_health_started_msec = Time.get_ticks_msec()
	var status := await health()
	_health_in_flight = false
	if status < 200 or status >= 300:
		push_warning("Agones health ping failed (%d)" % status)


func _request(method: int, path: String, payload: Dictionary) -> int:
	if not is_available() or not path.begins_with("/"):
		return 408
	var request := HTTPRequest.new()
	request.timeout = REQUEST_TIMEOUT_SECONDS
	add_child(request)
	var body := JSON.stringify(payload)
	var err := request.request(_base_url + path, PackedStringArray(["Content-Type: application/json"]), method, body)
	if err != OK:
		request.queue_free()
		return 599
	var result = await request.request_completed
	request.queue_free()
	return int(result[1])