class_name OctopusBoss
extends Node2D

signal phase_changed(phase: int)
signal defeated

const EYE_SCENE: PackedScene = preload("res://boss/BossEye.tscn")
const MINION_SCENE: PackedScene = preload("res://boss/BossMinion.tscn")
const RETURN_SCENE: PackedScene = preload("res://boss/BossReturnSignal.tscn")
const LASER_SCENE: PackedScene = preload("res://enemies/EnemyBigLaserBeam.tscn")

enum Phase { MINION_WAVES, LASER_STORM, DEFEATED }

const EYE_COUNT: int = 6
const PHASE_TWO_EYES: int = 3
const BODY_RADIUS: float = 86.0
const TENTACLE_LENGTH: float = 235.0

@export var first_wave_delay: float = 1.5
@export var wave_interval: float = 6.0
@export var minions_per_wave: int = 5
@export var laser_interval: float = 5.5
@export var laser_charge_time: float = 1.6
@export var laser_range: float = 1500.0

var phase: int = Phase.MINION_WAVES
var wave_timer: float = 0.0
var laser_timer: float = 0.0
var wave_index: int = 0
var eyes: Array = []
var eyes_opened: int = 0
var eyes_destroyed: int = 0
var spawned_minions: Array = []
var return_signals: Array = []
var animation_phase: float = 0.0


func _ready() -> void:
	add_to_group("bosses")
	wave_timer = first_wave_delay
	laser_timer = laser_interval
	_build_eyes()
	queue_redraw()


func _build_eyes() -> void:
	for i in range(EYE_COUNT):
		var eye: Area2D = EYE_SCENE.instantiate()
		eye.position = eye_position(i)
		eye.rotation = eye.position.angle()
		add_child(eye)
		eye.destroyed.connect(_on_eye_destroyed.bind(i))
		eyes.append(eye)


func eye_position(index: int) -> Vector2:
	var angle: float = -PI / 2.0 + TAU * float(index) / float(EYE_COUNT)
	# Alternating reach keeps the silhouette organic without randomising the
	# actual weak-point layout between attempts.
	var reach: float = TENTACLE_LENGTH * (0.88 if index % 2 == 0 else 1.0)
	return Vector2.from_angle(angle) * reach


func _process(delta: float) -> void:
	if phase == Phase.DEFEATED:
		return
	animation_phase += delta
	spawned_minions = spawned_minions.filter(func(node): return is_instance_valid(node))
	return_signals = return_signals.filter(func(node): return is_instance_valid(node))

	wave_timer -= delta
	if wave_timer <= 0.0:
		spawn_wave()
		wave_timer = wave_interval * (1.25 if phase == Phase.LASER_STORM else 1.0)

	if phase == Phase.LASER_STORM:
		laser_timer -= delta
		if laser_timer <= 0.0:
			fire_laser_volley()
			laser_timer = laser_interval
	queue_redraw()


func spawn_wave() -> void:
	var fleet: Node2D = get_tree().get_first_node_in_group("player_fleet")
	if fleet == null or fleet.ships.is_empty() or get_parent() == null:
		return
	var count: int = maxi(3, minions_per_wave - (2 if phase == Phase.LASER_STORM else 0))
	var marked_slot: int = wave_index % count
	for i in range(count):
		var minion: Area2D = MINION_SCENE.instantiate()
		minion.marked = i == marked_slot
		minion.boss = self
		get_parent().add_child(minion)
		var angle: float = TAU * float(i) / float(count) + float(wave_index) * 0.47
		# Minions are siblings rather than boss children, so account for the
		# encounter scene's imposing boss scale when placing them off its body.
		var launch_radius: float = BODY_RADIUS * scale.x + 34.0
		minion.global_position = global_position + Vector2.from_angle(angle) * launch_radius
		spawned_minions.append(minion)
	wave_index += 1


func accept_marked_kill(from: Vector2) -> void:
	if phase == Phase.DEFEATED or get_parent() == null:
		return
	var returning: Node2D = RETURN_SCENE.instantiate()
	returning.target = self
	get_parent().add_child(returning)
	returning.global_position = from
	return_signals.append(returning)


func open_next_eye() -> bool:
	if phase == Phase.DEFEATED:
		return false
	for eye in eyes:
		if is_instance_valid(eye) and not bool(eye.opened):
			eye.open_eye()
			eyes_opened += 1
			return true
	return false


func _on_eye_destroyed(_index: int) -> void:
	eyes_destroyed += 1
	if eyes_destroyed >= EYE_COUNT:
		_defeat()
		return
	if phase == Phase.MINION_WAVES and eyes_destroyed >= PHASE_TWO_EYES:
		phase = Phase.LASER_STORM
		laser_timer = 0.35
		phase_changed.emit(phase)
	queue_redraw()


func fire_laser_volley() -> void:
	if phase != Phase.LASER_STORM:
		return
	var fleet: Node2D = get_tree().get_first_node_in_group("player_fleet")
	if fleet == null or fleet.ships.is_empty():
		return
	var toward: Vector2 = fleet.get_centroid() - global_position
	if toward.length() < 1.0:
		return
	# Three locked, dodgeable lanes form the second phase's distinct pattern.
	for spread in [-0.17, 0.0, 0.17]:
		var beam: Node2D = LASER_SCENE.instantiate()
		beam.charge_time = laser_charge_time
		beam.beam_range = laser_range
		beam.beam_half_width = 24.0
		beam.damage = 1
		beam.color = Color(1.0, 0.12, 0.58)
		get_tree().root.add_child(beam)
		beam.add_to_group("boss_lasers")
		beam.launch(global_position, toward.rotated(float(spread)))


func _defeat() -> void:
	if phase == Phase.DEFEATED:
		return
	phase = Phase.DEFEATED
	for minion in spawned_minions:
		if is_instance_valid(minion):
			minion.retire()
	for returning in return_signals:
		if is_instance_valid(returning):
			returning.queue_free()
	EnemyExplosionVFX.spawn(get_tree().root, global_position)
	Sfx.play(get_tree(), Sfx.ENEMY_DEATH)
	visible = false
	phase_changed.emit(phase)
	defeated.emit()


func suppress_as_defeated() -> void:
	phase = Phase.DEFEATED
	visible = false
	set_process(false)


func _draw() -> void:
	if phase == Phase.DEFEATED:
		return
	var flesh := Color(0.95, 0.18, 0.58)
	var phase_color := Color(1.0, 0.1, 0.32) if phase == Phase.LASER_STORM \
		else flesh
	var dark := Color(0.075, 0.004, 0.05)
	for i in range(EYE_COUNT):
		var end: Vector2 = eye_position(i)
		var angle: float = end.angle()
		var side := Vector2.from_angle(angle + PI / 2.0)
		var points := PackedVector2Array()
		for step in range(9):
			var t: float = float(step) / 8.0
			var sway: float = sin(animation_phase * 1.7 + float(i) * 1.4 + t * PI * 2.0)
			points.append(end * t + side * sway * 18.0 * sin(t * PI))
		NeonDraw.draw_glowing_path(self, points, phase_color, 0.8, 0.8, dark)

	var body := PackedVector2Array()
	for i in range(28):
		var angle: float = TAU * float(i) / 28.0
		var pulse: float = 1.0 + 0.045 * sin(animation_phase * 2.4 + float(i) * 1.9)
		body.append(Vector2.from_angle(angle) * BODY_RADIUS * pulse)
	NeonDraw.draw_glowing_polygon(self, body, phase_color, 0.92, dark)
	# The central eye watches but is armoured; only tentacle eyes opened by a
	# returning marked minion join the combat-target group.
	draw_set_transform(Vector2.ZERO, 0.0, Vector2(0.72, 1.0))
	NeonDraw.draw_glowing_circle(self, Vector2.ZERO, 31.0,
		Color(0.28, 0.92, 1.0), 0.8 + 0.2 * sin(animation_phase * 3.0), dark)
	NeonDraw.draw_glowing_circle(self, Vector2.ZERO, 12.0,
		Color(1.0, 0.82, 0.2), 1.0, dark)
	draw_set_transform(Vector2.ZERO, 0.0, Vector2.ONE)