extends CanvasLayer

# Autoload: toggleable network debug overlay (F4 by default — see
# toggle_net_overlay in project.godot's [input]). Read-only against
# NetworkManager's clock state (task 1.8). Mirrors perf_overlay.gd's pattern
# — headless-guarded, hidden by default, no gameplay-state writes.

var _label: Label


func _ready() -> void:
	if DisplayServer.get_name() == "headless":
		set_process(false)
		return
	layer = 100
	_label = Label.new()
	_label.add_theme_font_size_override("font_size", 14)
	_label.add_theme_color_override("font_color", Color(0.5, 0.8, 1.0))
	_label.add_theme_color_override("font_shadow_color", Color(0, 0, 0, 0.85))
	_label.add_theme_constant_override("shadow_offset_x", 1)
	_label.add_theme_constant_override("shadow_offset_y", 1)
	_label.position = Vector2(12, 90)
	_label.visible = false
	add_child(_label)


func _unhandled_input(event: InputEvent) -> void:
	if event.is_action_pressed("toggle_net_overlay") and _label:
		_label.visible = not _label.visible


func _process(_delta: float) -> void:
	if not _label or not _label.visible:
		return
	if NetworkManager.is_server:
		_label.text = "NET: server, %d peer(s)  out %s  in %s" % [
			MatchNet.roster.size(), _format_kbps(MatchSim.get_bytes_sent_per_sec()), _format_kbps(MatchSim.get_bytes_received_per_sec()),
		]
	elif NetworkManager.is_client:
		if NetworkManager.rtt_ms < 0.0:
			_label.text = "NET: client, connecting (no clock sample yet)"
		else:
			# task 3.7: RTT, jitter, loss, buffer depth, snapshot age,
			# bandwidth all live here now. Prediction error is intentionally
			# absent — there is no client-side prediction until Phase 4, so
			# there is nothing honest to show for it yet.
			var stats := {}
			var game := get_tree().get_first_node_in_group("game")
			if game and game.has_method("get_net_debug_stats"):
				stats = game.get_net_debug_stats()
			_label.text = "NET: client  RTT %.1fms  jitter %.1fms  offset %.1fms\nbuf depth %s  lead %s  loss %.1f%%  snap age %.1fms\nout %s  in %s" % [
				NetworkManager.rtt_ms, NetworkManager.jitter_ms, NetworkManager.clock_offset_ms,
				str(stats.get("input_buffer_depth", -1)), str(stats.get("input_lead", "-")),
				stats.get("snapshot_loss_pct", 0.0), stats.get("snapshot_age_ms", 0.0),
				_format_kbps(MatchSim.get_bytes_sent_per_sec()), _format_kbps(MatchSim.get_bytes_received_per_sec()),
			]
	else:
		_label.text = "NET: offline"


func _format_kbps(bytes_per_sec: float) -> String:
	return "%.2f KB/s" % (bytes_per_sec / 1000.0)