class_name AssignmentState
extends RefCounted

# Verified assignment-ready manifest returned by the control plane. The join
# authorisation is retained in memory only and is never written to the restart
# snapshot; transport installation belongs to the explicit ENet/Steam layer.

var available := false
var match_id := ""
var server_id := ""
var slot := -1
var expires_at := ""
var protocol_version := 0
var transport := ""
var endpoint := ""
var join_authorisation := ""
var error_message := ""


func apply(payload: Dictionary, expected_player_id: String = "") -> bool:
	for key in ["match_id", "server_id", "player_id", "slot", "expires_at", "protocol_version", "transport", "endpoint", "join_authorisation"]:
		if not payload.has(key):
			return _reject("Assignment response is missing " + key)
	if not payload["match_id"] is String or not payload["server_id"] is String or not payload["player_id"] is String or not _valid_nonnegative_integer(payload["slot"]) or not payload["expires_at"] is String or not _valid_nonnegative_integer(payload["protocol_version"]) or not payload["transport"] is String or not payload["endpoint"] is String or not payload["join_authorisation"] is String:
		return _reject("Assignment response contains invalid types")
	var next_match_id := String(payload["match_id"])
	var next_server_id := String(payload["server_id"])
	var next_transport := String(payload["transport"])
	var next_endpoint := String(payload["endpoint"])
	var next_player_id := String(payload["player_id"])
	var next_expires_at := String(payload["expires_at"])
	if not is_valid_expiry_timestamp(next_expires_at):
		return _reject("Assignment response contains invalid expiry")
	var expiry_unix := Time.get_unix_time_from_datetime_string(next_expires_at)
	if not is_valid_opaque_id(next_match_id) or not is_valid_opaque_id(next_server_id) or not is_valid_opaque_id(next_player_id) or (not expected_player_id.is_empty() and next_player_id != expected_player_id) or int(payload["slot"]) < 0 or int(payload["slot"]) > 5 or int(payload["protocol_version"]) < 1 or (next_transport != "enet" and next_transport != "steam_sdr") or not _valid_endpoint(next_endpoint) or expiry_unix <= Time.get_unix_time_from_system() or String(payload["join_authorisation"]).is_empty():
		return _reject("Assignment response contains invalid values")
	match_id = next_match_id
	server_id = next_server_id
	slot = int(payload["slot"])
	expires_at = next_expires_at
	protocol_version = int(payload["protocol_version"])
	transport = next_transport
	endpoint = next_endpoint
	join_authorisation = String(payload["join_authorisation"])
	available = true
	error_message = ""
	return true


static func is_valid_expiry_timestamp(value: String) -> bool:
	if value.is_empty():
		return false
	var timestamp_pattern := RegEx.create_from_string("^\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}(?:\\.\\d+)?(?:Z|[+-]\\d{2}:\\d{2})$")
	return timestamp_pattern.search(value) != null


static func is_valid_opaque_id(value: String) -> bool:
	if value.length() < 16 or value.length() > 128:
		return false
	var resource_pattern := RegEx.create_from_string("^[A-Za-z0-9_-]+$")
	return resource_pattern.search(value) != null


static func _valid_endpoint(value: String) -> bool:
	if value.is_empty() or value.contains("/") or value.contains("?") or value.contains("#"):
		return false
	var separator := value.rfind(":")
	if separator <= 0 or separator >= value.length() - 1:
		return false
	var port := value.substr(separator + 1)
	return port.is_valid_int() and int(port) >= 1 and int(port) <= 65535


static func _valid_nonnegative_integer(value: Variant) -> bool:
	if value is int:
		return int(value) >= 0
	if value is float:
		return is_finite(float(value)) and float(value) >= 0.0 and float(value) == floor(float(value))
	return false


func _reject(reason: String) -> bool:
	available = false
	error_message = reason
	return false