extends Node

# Manual two-process smoke test for NetSim (task 2.8 acceptance:
# "--net-sim-latency 80 measurably raises observed RTT"). Deliberately not
# part of the pure-function suite — needs two real processes and real wall
# time to observe a delayed pong.
#
# NetSim reads its own --net-sim-* flags directly from OS.get_cmdline_user_args()
# (see net_sim.gd) — this driver only needs --role= and passes any
# --net-sim-* flags straight through untouched. The host is where the
# _pong reply gets delayed, so --net-sim-latency=/--net-sim-loss= belong on
# the HOST invocation; the client just observes NetworkManager.rtt_ms.
#
# Usage:
#   godot --headless --path Game res://tests/net_sim_smoke.tscn -- --role=host --net-sim-latency=80
#   godot --headless --path Game res://tests/net_sim_smoke.tscn -- --role=client --min-rtt=70
#
# For the loss scenario:
#   godot --headless --path Game res://tests/net_sim_smoke.tscn -- --role=host --net-sim-loss=1.0
#   godot --headless --path Game res://tests/net_sim_smoke.tscn -- --role=client-loss

const DEFAULT_PORT := 7810
const TIMEOUT_SECONDS := 12.0
const HOST_LIFETIME_SECONDS := 8.0
# Loose ceiling, not a tight bound: real localhost jitter plus one full
# PING_INTERVAL_SEC of scheduling slack is possible before the first sample
# lands, so this only needs to catch a badly broken (e.g. no-op) NetSim.
const MAX_RTT_SLACK_MS := 400.0

var _role := ""
var _port := DEFAULT_PORT
var _min_rtt_ms := 0.0
var _finished := false


func _ready() -> void:
	for arg: String in OS.get_cmdline_user_args():
		if arg.begins_with("--role="):
			_role = arg.substr("--role=".length())
		elif arg.begins_with("--port="):
			_port = int(arg.substr("--port=".length()))
		elif arg.begins_with("--min-rtt="):
			_min_rtt_ms = arg.substr("--min-rtt=".length()).to_float()

	if _role == "host":
		var err := NetworkManager.host(_port)
		if err != OK:
			_finish(false, "host() failed: %s" % error_string(err))
			return
		print("SMOKE: hosting on port %d (net-sim latency=%.1fms jitter=%.1fms loss=%.2f)" % [
			_port, NetSim.latency_ms, NetSim.jitter_ms, NetSim.loss_fraction
		])
		get_tree().create_timer(HOST_LIFETIME_SECONDS).timeout.connect(func() -> void:
			_finish(true, "host ran for %.1fs" % HOST_LIFETIME_SECONDS))
	elif _role == "client":
		NetworkManager.clock_updated.connect(_on_clock_updated)
		var err := NetworkManager.join("127.0.0.1", _port)
		if err != OK:
			_finish(false, "join() failed: %s" % error_string(err))
			return
		print("SMOKE: joining 127.0.0.1:%d, expecting rtt >= %.1fms ..." % [_port, _min_rtt_ms])
	elif _role == "client-loss":
		NetworkManager.clock_updated.connect(_on_unexpected_clock_updated)
		var err := NetworkManager.join("127.0.0.1", _port)
		if err != OK:
			_finish(false, "join() failed: %s" % error_string(err))
			return
		print("SMOKE: joining 127.0.0.1:%d, expecting NO rtt sample (100%% loss) ..." % _port)
		get_tree().create_timer(HOST_LIFETIME_SECONDS - 1.0).timeout.connect(func() -> void:
			_finish(NetworkManager.rtt_ms < 0.0, "rtt_ms=%.1f after %.1fs (expected -1, no pong ever arrived)" % [
				NetworkManager.rtt_ms, HOST_LIFETIME_SECONDS - 1.0
			]))
	else:
		_finish(false, "missing or unrecognised --role= (expected host|client|client-loss)")
		return

	get_tree().create_timer(TIMEOUT_SECONDS).timeout.connect(_on_timeout)


func _process(_delta: float) -> void:
	NetworkManager.poll()


func _physics_process(_delta: float) -> void:
	NetworkManager.poll()


func _on_clock_updated(rtt_ms: float, _offset_ms: float) -> void:
	var ceiling := _min_rtt_ms * 4.0 + MAX_RTT_SLACK_MS
	var ok := rtt_ms >= _min_rtt_ms and rtt_ms <= ceiling
	print("SMOKE INFO: observed rtt_ms=%.2f (want >= %.1f, <= %.1f)" % [rtt_ms, _min_rtt_ms, ceiling])
	_finish(ok, "client observed rtt_ms=%.2f against min=%.1f" % [rtt_ms, _min_rtt_ms])


func _on_unexpected_clock_updated(rtt_ms: float, _offset_ms: float) -> void:
	_finish(false, "client received a pong (rtt_ms=%.2f) despite --net-sim-loss=1.0 on the host" % rtt_ms)


func _on_timeout() -> void:
	if not _finished:
		_finish(false, "timed out waiting for a clock sample")


func _finish(success: bool, message: String) -> void:
	if _finished:
		return
	_finished = true
	print("SMOKE %s: %s" % ["PASS" if success else "FAIL", message])
	await get_tree().create_timer(0.3).timeout
	NetworkManager.shutdown()
	get_tree().quit(0 if success else 1)