extends Node
class_name MpSnapshot

## The cross-peer sync audit: both peers describe everything they can see, and
## the two descriptions must match.
##
## This is what actually catches desyncs. Per-step assertions only look at the
## one thing the step touched, which misses the whole class of bug where some
## OTHER object quietly drifts out of sync — or where the data replicates
## perfectly but the thing on screen does not. So the description deliberately
## includes what is RENDERED, not just the replicated values behind it: a plate
## whose contained_ids arrived but whose visuals were never rebuilt looks empty
## to the player, and that has to count as a desync.

## How far apart the same object may be on two peers before it counts as a desync.
const POS_TOLERANCE := 0.08
## Physics keeps moving after a step (dropped objects fall, snaps settle), so
## give the peers this long to converge before calling a difference a failure.
const SETTLE_SEC := 3.0
## How far a cosmetic item on a plate may sit from the plate's origin. The plate
## is ~0.4m across and the furthest slot ~0.12m out, so past this it has come off.
const MAX_VISUAL_OFFSET := 0.3
## Local offset at which a cosmetic item counts as having moved from its slot.
const VISUAL_DRIFT_EPSILON := 0.05

## Stations whose on-screen state has to match on every peer.
const WATCHED_STATIONS := ["Hob", "Sink", "DirtStation", "Counter", "Counter2"]

var view: MpWorldView
var report: MpReport

## Named by the driver so a drift warning says which step was running.
var current_step := "(before any step)"

var _drift_reported := {}


func setup(p_view: MpWorldView, p_report: MpReport) -> void:
	view = p_view
	report = p_report


func take() -> Dictionary:
	var out := {}
	for child in view.pickables():
		out[str(child.name)] = describe(child as Node3D)
	for name in WATCHED_STATIONS:
		var station := view.find(name)
		if station:
			out["station:" + name] = describe_station(station)
	return out


## Everything about an object that should look identical on every peer.
func describe(item: Node3D) -> Dictionary:
	var d := {"pos": item.global_position, "visible": item.visible}
	var pc := item.get_node_or_null("PlateController")
	if pc:
		d["dirty"] = pc.is_dirty
		d["contents"] = ",".join(pc.contained_ids)
		var dirty_node := item.get_node_or_null("Dirty")
		d["dirty_shown"] = dirty_node.visible if dirty_node else false
		# The cosmetic copies the container builds from contained_ids — literally
		# what the player sees sitting on the plate.
		d["meals_shown"] = visual_count(item, "Container/MealContainer")
		d["sides_shown"] = visual_count(item, "Container/SidesContainer")
		# Food on a plate is a cosmetic child of the plate, so it must travel with
		# it. Keys starting with "_" are per-peer diagnostics that compare() skips
		# (floats will not match exactly across peers); the attached flag is
		# asserted absolutely instead, because this can — and did — go wrong on
		# both peers at once, which a diff would miss entirely.
		var off := max_visual_offset(item)
		d["_visual_offset"] = off
		d["visuals_attached"] = off <= MAX_VISUAL_OFFSET
	return d


## What a station shows the player. Only the world owner runs a station's logic
## and snap zone, so its display has to be driven from replicated state — a
## client that never updates it shows a hob that never lights up, or a sink bar
## still on screen after the plate came out clean.
##
## Bar VISIBILITY is compared across peers; the progress value is diagnostic only
## ("_" prefix), because it changes every tick and the peers are legitimately a
## frame apart.
func describe_station(station: Node3D) -> Dictionary:
	var d := {}
	var bar := station.get_node_or_null("ProgressBar3D") as ProgressBar3D
	d["bar_visible"] = bar.is_bar_visible() if bar else false
	d["_bar_progress"] = snappedf(bar.get_progress(), 1.0) if bar else -1.0
	if "cooking_result" in station:
		d["cooking"] = str(station.cooking_result)
	if "is_washing" in station:
		d["washing"] = bool(station.is_washing)
	return d


## Largest distance from a plate's origin to any cosmetic item it is displaying.
## -1 when the plate is showing nothing.
func max_visual_offset(item: Node3D) -> float:
	var worst := -1.0
	for path in ["Container/MealContainer", "Container/SidesContainer"]:
		var root := item.get_node_or_null(path)
		if not root:
			continue
		for c in root.get_children():
			if c is Node3D and not c.is_queued_for_deletion():
				worst = maxf(worst, item.global_position.distance_to((c as Node3D).global_position))
	return snappedf(worst, 0.001)


## What the cosmetic children look like, for diagnosing why they moved.
func visual_diag(item: Node3D) -> String:
	var parts: Array[String] = []
	for path in ["Container/MealContainer", "Container/SidesContainer"]:
		var root := item.get_node_or_null(path)
		if not root:
			continue
		for c in root.get_children():
			var s := "%s global=%s local=%s parent=%s (%.3fm from plate at %s)" % [
				c.name, (c as Node3D).global_position, (c as Node3D).position,
				c.get_parent().name,
				item.global_position.distance_to((c as Node3D).global_position),
				item.global_position]
			if c is RigidBody3D:
				s += " [RigidBody3D freeze=%s freeze_mode=%d layer=%d top_level=%s queued=%s]" % [
					c.freeze, c.freeze_mode, c.collision_layer, c.top_level,
					c.is_queued_for_deletion()]
			parts.append(s)
	return "; ".join(parts) if parts else "(nothing on the plate)"


func visual_count(item: Node3D, path: String) -> int:
	var n := item.get_node_or_null(path)
	if not n:
		return -1
	var count := 0
	for c in n.get_children():
		if not c.is_queued_for_deletion():
			count += 1
	return count


## Compares the server's view with the client's, returning the differences.
func compare(server: Dictionary, client: Dictionary) -> Array[String]:
	var problems: Array[String] = []
	for name in server:
		if not client.has(name):
			problems.append("'%s' exists on the server but NOT on the client" % name)
	for name in client:
		if not server.has(name):
			problems.append("'%s' exists on the client but NOT on the server (ghost copy)" % name)
	for name in server:
		if not client.has(name):
			continue
		var s: Dictionary = server[name]
		var c: Dictionary = client[name]
		# Stations are compared on their displayed state, not a position.
		if s.has("pos") and c.has("pos"):
			var dist: float = (s["pos"] as Vector3).distance_to(c["pos"])
			if dist > POS_TOLERANCE:
				problems.append("%s is %.3fm apart (server %s vs client %s)" % [name, dist, s["pos"], c["pos"]])
		for key in s:
			# "_" keys are per-peer diagnostics, not things that must match.
			if key == "pos" or key.begins_with("_"):
				continue
			if s[key] != c[key]:
				problems.append("%s.%s: server=%s client=%s" % [name, key, s[key], c[key]])
	# Absolute invariants, checked per peer. A cross-peer diff cannot catch a
	# fault that happens identically on both sides.
	for peer_name in ["server", "client"]:
		var snap: Dictionary = server if peer_name == "server" else client
		for name in snap:
			var d: Dictionary = snap[name]
			if d.has("visuals_attached") and not d["visuals_attached"]:
				problems.append("on the %s, %s's food has come off the plate (%.3fm from it, limit %.2f)"
					% [peer_name, name, d.get("_visual_offset", -1.0), MAX_VISUAL_OFFSET])
	return problems


# --- live watch on plate visuals -------------------------------------------
#
# The per-step checks tell us food ended up off a plate, but not when or why.
# This watches every frame and reports the first frame a cosmetic item departs
# from its slot, along with what was happening to the plate at the time.

func _process(_delta: float) -> void:
	if not view or not view.world:
		return
	for item in view.roots_children():
		if not (item is Node3D) or not item.get_node_or_null("PlateController"):
			continue
		_watch_plate(item as Node3D)


func _watch_plate(plate: Node3D) -> void:
	for path in ["Container/MealContainer", "Container/SidesContainer"]:
		var holder := plate.get_node_or_null(path)
		if not holder:
			continue
		for c in holder.get_children():
			if not (c is Node3D) or c.is_queued_for_deletion():
				continue
			var drift: float = (c as Node3D).position.length()
			var key := c.get_instance_id()
			if drift <= VISUAL_DRIFT_EPSILON:
				_drift_reported.erase(key)
				continue
			if _drift_reported.has(key):
				continue
			_drift_reported[key] = true
			report.log_line("VISUAL DRIFT: %s on %s moved to local %s (%.3f from its slot) during '%s'" % [
				c.name, plate.name, (c as Node3D).position, drift, current_step])
			report.log_line("  plate: pos=%s freeze=%s held_by=%s xform_authority=%d" % [
				plate.global_position, plate.freeze if plate is RigidBody3D else "-",
				plate.get_picked_up_by() if plate.has_method("get_picked_up_by") else "-",
				view.xform_authority(plate)])
			if c is RigidBody3D:
				report.log_line("  visual: freeze=%s mode=%d layer=%d top_level=%s sleeping=%s lin_vel=%s" % [
					c.freeze, c.freeze_mode, c.collision_layer, c.top_level,
					c.sleeping, c.linear_velocity])