extends Node
## Headless smoke test for the tracer bullet. Run:
##   godot --headless --path . res://tests/smoke.tscn
## Asserts: arena boots, piloting moves the mech, grunts spawn, the
## weapon auto-fires with no input, a grunt dies, knockback displaces,
## build hits accrue charges, opening the hand freezes time, the HEAT
## card paints heat, and stacked heat detonates on release.
## Exit 0 = pass, 1 = fail.
##
## Await discipline: physics_frame only while time flows — with the
## hand open at dilation 0.0 physics never steps, so frozen phases
## await process_frame instead.

const ARENA := preload("res://scenes/arena.tscn")

var _failures: Array[String] = []
var _done := false


func _ready() -> void:
	get_tree().create_timer(60.0).timeout.connect(_on_global_timeout)
	await _run()
	_finish()


func _on_global_timeout() -> void:
	if not _done:
		_failures.append("global 60s timeout — test hung")
		_finish()


func _run() -> void:
	var arena := ARENA.instantiate()
	# Mechanic phases need the old endless trickle; the run-structure
	# phase re-enables rooms with tiny budgets at the end.
	arena.rooms_enabled = false
	add_child(arena)
	await get_tree().physics_frame
	await get_tree().physics_frame

	var mech := arena.get_node_or_null("Mech") as CharacterBody2D
	if mech == null:
		_failures.append("no Mech node in arena")
		return
	# God-mode the mech: the long sim phases would otherwise drain hull
	# to zero mid-test and reload the scene under our assertions.
	mech.hull_max = 1.0e9
	mech.hull = 1.0e9

	# Piloting: press right, mech must move right.
	var x0 := mech.global_position.x
	Input.action_press("move_right")
	for i in 30:
		await get_tree().physics_frame
	Input.action_release("move_right")
	if mech.global_position.x <= x0 + 10.0:
		_failures.append("piloting: mech did not move right (x %.1f -> %.1f)" % [x0, mech.global_position.x])

	# Spawner: grunts appear.
	if not await _until(func() -> bool: return get_tree().get_nodes_in_group("enemies").size() > 0, 5.0, "no grunts spawned"):
		return

	# Auto-fire: a projectile appears with zero input.
	await _until(func() -> bool: return get_tree().get_nodes_in_group("projectiles").size() > 0, 5.0, "weapon never auto-fired")

	# Lethality: at least one grunt dies to auto-fire alone.
	await _until(func() -> bool: return arena.kills >= 1, 10.0, "no grunt died to auto-fire")

	# Knockback: a zero-damage hit must displace a grunt along the hit
	# direction. Probe the healthiest grunt — one mid-death from
	# auto-fire would vanish under the probe and fake a failure.
	var g: CharacterBody2D = null
	for cand in get_tree().get_nodes_in_group("enemies"):
		if g == null or cand.hp > g.hp:
			g = cand
	if g != null:
		var gx := g.global_position.x
		g.hit(0.0, Vector2(400, 0))
		for i in 5:
			await get_tree().physics_frame
		if not is_instance_valid(g):
			_failures.append("knockback probe grunt died to a zero-damage hit")
		elif g.global_position.x <= gx + 2.0:
			_failures.append("knockback: grunt did not displace (x %.1f -> %.1f)" % [gx, g.global_position.x])

	await _test_hand(arena, mech)


func _test_hand(arena: Node, mech: CharacterBody2D) -> void:
	var hand := arena.get_node_or_null("Hand")
	if hand == null:
		_failures.append("no Hand node in arena")
		return

	# Charges accrue from kills alone (kills_per_charge, auto-fire only).
	if not await _until(func() -> bool: return hand.charges >= 2, 25.0, "kills never accrued 2 charges"):
		return

	# A grunt must be near the mech when we freeze — cards are radial
	# around M03 and nothing walks while time is stopped. The nearest
	# grunt can die to auto-fire during the toggle tap, so retry.
	var target: Node2D = null
	for attempt in 4:
		if not await _until(func() -> bool: return _nearest_grunt(mech) != null, 10.0, "no grunt approached within heat radius"):
			return
		await _tap("hand_toggle")
		if not hand.hand_open:
			_failures.append("hand did not open on hand_toggle")
			return
		# Pick the target while frozen — it can neither die nor wander.
		target = _nearest_grunt(mech)
		if target != null:
			break
		await _tap("hand_toggle")
	if target == null:
		_failures.append("grunt near mech vanished before freeze on 4 attempts")
		return
	var expect_pause: bool = (hand.meter_mode and hand.frac() >= hand.band_thaw) \
			or (not hand.meter_mode and hand.dilation_scale == 0.0)
	if expect_pause and not get_tree().paused:
		_failures.append("hand open in freeze state did not pause the world")

	# Belt white-box: slot 2 must serve HEAT twice in a row (plays
	# consume belt entries, the next slides in).
	hand.belt.assign([0, 1, 1, 0])
	var c0: int = hand.charges

	# Play HEAT twice: charges spent, heat painted past threshold.
	await _tap("card_2")
	await _tap("card_2")
	if hand.charges != c0 - 2:
		_failures.append("HEAT x2 spent %d charges, expected 2" % (c0 - hand.charges))
	if target.heat < target.heat_threshold:
		_failures.append("HEAT x2 left target below threshold (heat %.1f)" % target.heat)

	# Release: the world unpauses into the spool-up ramp (not a snap),
	# reaches full speed, and the over-threshold grunt detonates.
	await _tap("hand_toggle")
	if hand.hand_open or get_tree().paused:
		_failures.append("hand did not close / world did not resume")
		return
	if hand.release_thaw_s > 0.0 and Engine.time_scale >= 1.0:
		_failures.append("release snapped straight to full speed — no ramp")
	if not await _until(func() -> bool: return Engine.time_scale >= 0.999, 3.0, "release ramp never reached full speed"):
		return
	for i in 10:
		await get_tree().physics_frame
	if is_instance_valid(target):
		_failures.append("heated grunt failed to detonate after release (heat %.1f)" % target.heat)

	await _test_meter(hand)
	await _test_salvage(hand, mech)
	await _test_chemistry(arena, mech)
	await _test_run(arena, hand)


func _test_run(arena: Node, hand: Node) -> void:
	# Run structure with tiny budgets: clear -> fork -> draft grows the
	# belt -> room advances -> final clear -> tally (left open; the
	# relaunch path would reload the smoke scene).
	arena.rooms_per_run = 2
	arena.room = 1
	arena.room_budget_base = 2
	arena.room_budget_per_room = 0
	arena.rooms_enabled = true
	arena._begin_room()
	for e in get_tree().get_nodes_in_group("enemies"):
		e.hit(9999.0, Vector2.ZERO)
	var inter: CanvasLayer = arena.get_node("Interstitial")
	if not await _until(func() -> bool: return inter.active, 30.0, "room clear never opened the interstitial"):
		return
	if inter.mode != "fork":
		_failures.append("expected fork after non-final room, got '%s'" % inter.mode)
		return
	if not get_tree().paused:
		_failures.append("interstitial did not pause the world")
	await _tap("opt_1")
	if not inter.active or inter.mode != "draft":
		_failures.append("fork CARD choice did not open the draft (mode '%s')" % inter.mode)
		return
	var b0: int = hand.belt.size()
	await _tap("opt_1")
	if hand.belt.size() != b0 + 1:
		_failures.append("draft pick did not grow the belt (%d -> %d)" % [b0, hand.belt.size()])
	if inter.active or get_tree().paused:
		_failures.append("interstitial did not close after the draft pick")
		return
	if arena.room != 2:
		_failures.append("room did not advance after draft (room %d)" % arena.room)
		return
	if not await _until(func() -> bool: return inter.active, 30.0, "final room never reached the tally"):
		return
	if inter.mode != "tally":
		_failures.append("expected tally after final room, got '%s'" % inter.mode)


func _test_salvage(hand: Node, mech: CharacterBody2D) -> void:
	# Kills drop scrap pickups.
	if not await _until(func() -> bool: return get_tree().get_first_node_in_group("salvage") != null, 15.0, "kills never dropped salvage"):
		return
	# Collection: teleport a drop onto the mech, expect pickup + count.
	var s: Area2D = get_tree().get_first_node_in_group("salvage")
	var s0: int = hand.salvage_total
	s.global_position = mech.global_position
	for i in 10:
		await get_tree().physics_frame
	if hand.salvage_total <= s0:
		_failures.append("salvage on the mech was not collected (total %d)" % hand.salvage_total)
		return
	if is_instance_valid(s):
		_failures.append("collected salvage node was not freed")
	# Level gating: cumulative scrap crosses thresholds, white-box.
	if hand.card_level() != 1 and hand.salvage_total < hand.level2_salvage:
		_failures.append("card level %d with only %d salvage" % [hand.card_level(), hand.salvage_total])
	hand.add_salvage(hand.level3_salvage)
	if hand.card_level() != 3:
		_failures.append("card level %d after crossing level3 threshold" % hand.card_level())


func _test_meter(hand: Node) -> void:
	# Band ladder, white-box: set the meter, open, check the time state.
	# THAW band: open, unpaused, slow-mo strictly between 0 and 1.
	hand.meter = hand.meter_max * 0.3
	await _tap("hand_toggle")
	if not hand.hand_open:
		_failures.append("hand refused to open in thaw band")
		return
	if get_tree().paused:
		_failures.append("thaw band paused the world")
	if Engine.time_scale <= 0.0 or Engine.time_scale >= 1.0:
		_failures.append("thaw band time_scale %.2f not in (0,1)" % Engine.time_scale)

	# REALTIME band: open, world at full speed.
	hand.meter = hand.meter_max * 0.14
	await get_tree().process_frame
	await get_tree().process_frame
	if get_tree().paused or Engine.time_scale != 1.0:
		_failures.append("realtime band: paused=%s time_scale=%.2f, expected live x1" % [get_tree().paused, Engine.time_scale])

	# Depletion force-closes the hand...
	hand.meter = 0.0
	await get_tree().process_frame
	await get_tree().process_frame
	if hand.hand_open:
		_failures.append("hand did not force-close at meter depletion")
		return
	# ...and it will not reopen while empty (no Space-spam refreeze).
	await _tap("hand_toggle")
	if hand.hand_open:
		_failures.append("hand reopened on an empty meter")
		return

	# The Freeze charge grows while the hand is closed.
	var m0: float = hand.meter
	for i in 30:
		await get_tree().process_frame
	if hand.meter <= m0:
		_failures.append("meter did not regenerate while closed")

	# TOGGLE mode (the A/B flip) still hard-freezes at knob 0.
	hand.meter_mode = false
	await _tap("hand_toggle")
	if not hand.hand_open or not get_tree().paused:
		_failures.append("toggle mode at knob 0 did not open+pause")
	await _tap("hand_toggle")
	hand.meter_mode = true
	if get_tree().paused:
		_failures.append("world stayed paused after toggle-mode close")
	await _until(func() -> bool: return Engine.time_scale >= 0.999, 3.0, "toggle-mode release ramp never reached full speed")


func _test_chemistry(arena: Node, mech: CharacterBody2D) -> void:
	# Burster: a self-heating enemy spawns and its heat grows on its own.
	# It may die to auto-fire or pop mid-observation, so retry a few.
	var observed_growth := false
	for attempt in 4:
		if not await _until(func() -> bool: return get_tree().get_first_node_in_group("bursters") != null, 20.0, "no burster ever spawned"):
			return
		var b: Node2D = get_tree().get_first_node_in_group("bursters")
		var h0: float = b.heat
		for i in 30:
			await get_tree().physics_frame
		if is_instance_valid(b):
			if b.heat > h0:
				observed_growth = true
				break
			_failures.append("burster heat did not grow (%.2f -> %.2f)" % [h0, b.heat])
			return
	if not observed_growth:
		_failures.append("never observed a burster long enough to confirm self-heat")
		return

	# Chemistry row KINETIC+HEAT, deterministic: stage a heated striker
	# and a cold neighbor in the far corner (outside weapon range),
	# slam the striker into the neighbor, expect the proc: heat spread,
	# momentum passed, arena proc counter up.
	var plain: Array[Node2D] = []
	for e in get_tree().get_nodes_in_group("enemies"):
		if e.self_heat_rate == 0.0 and not e._dead:
			plain.append(e)
	if plain.size() < 2:
		_failures.append("not enough plain grunts alive to stage chemistry")
		return
	var striker := plain[0]
	var struck := plain[1]
	striker.global_position = Vector2(80.0, 80.0)
	struck.global_position = Vector2(104.0, 80.0)
	striker.heat = 1.0
	struck.heat = 0.0
	var procs0: int = arena.chem_procs
	striker.hit(0.0, Vector2(500.0, 0.0))
	if not await _until(func() -> bool: return arena.chem_procs > procs0, 5.0, "chemistry proc never fired on knocked-heated impact"):
		return
	if not is_instance_valid(struck) or struck.heat <= 0.0:
		_failures.append("chemistry proc fired but heat did not spread to the struck enemy")


func _nearest_grunt(mech: CharacterBody2D) -> Node2D:
	var best: Node2D = null
	var best_d := 120.0 * 120.0
	for e in get_tree().get_nodes_in_group("enemies"):
		var d: float = mech.global_position.distance_squared_to(e.global_position)
		if d < best_d:
			best_d = d
			best = e
	return best


## Synthetic key tap via the action layer, safe under freeze: presses,
## lets two process frames run so is_action_just_pressed is seen, then
## releases and lets one more run.
func _tap(action: String) -> void:
	Input.action_press(action)
	await get_tree().process_frame
	await get_tree().process_frame
	Input.action_release(action)
	await get_tree().process_frame


## Awaits process_frame, not physics_frame: physics stops under pause
## (hand freeze, interstitial) and a physics await would deadlock.
func _until(pred: Callable, timeout: float, what: String) -> bool:
	var t := 0.0
	while t < timeout:
		if pred.call():
			return true
		await get_tree().process_frame
		t += 1.0 / 60.0
	_failures.append("timeout: " + what)
	return false


func _finish() -> void:
	if _done:
		return
	_done = true
	if _failures.is_empty():
		print("SMOKE PASS")
		get_tree().quit(0)
	else:
		for f in _failures:
			printerr("SMOKE FAIL: " + f)
		get_tree().quit(1)