extends Area2D

# A gatherable crystal of asteroid ore lying on a planet's surface. Picked
# up by flying any ship over it; the fleet doesn't need to stop.
#
# Deliberately drawn as a PERFECT HEXAGON rather than the irregular lumpy
# polygon Asteroid.gd uses. The two are never on screen
# together (asteroids are space-only, rocks surface-only), so the player
# can only tell "collect this" from "this hurts" by learned shape language:
# irregular and jagged reads as a natural hazard, regular and faceted reads
# as something valuable and meant to be picked up.
#
# It also drifts toward a nearby ship (see _physics_process). Nothing
# harmful moves helpfully toward you, so the pull doubles as a readability
# cue on top of making gathering feel less fiddly.

signal collected

@export var attract_radius: float = 220.0
@export var attract_speed: float = 260.0
@export var attract_accel: float = 420.0

var shape_points: PackedVector2Array = PackedVector2Array()
var facet_points: PackedVector2Array = PackedVector2Array()
var size_scale: float = 1.0
var velocity: Vector2 = Vector2.ZERO


func _ready() -> void:
	add_to_group("rocks")
	z_index = -1
	area_entered.connect(_on_area_entered)
	queue_redraw()


func build_shape(shape_seed: int) -> void:
	# Only the SIZE varies, never the silhouette: every ore node is the same
	# regular hexagon, which is the whole point of the cue.
	var rng: RandomNumberGenerator = RandomNumberGenerator.new()
	rng.seed = shape_seed
	size_scale = rng.randf_range(0.85, 1.25)

	var r: float = 13.0 * size_scale
	shape_points = PackedVector2Array()
	for i in range(6):
		var a: float = (float(i) / 6.0) * TAU - PI / 2.0
		shape_points.append(Vector2(cos(a), sin(a)) * r)
	# One flat-to-flat line across the middle, so it reads as a cut face
	# rather than a plain outline at small sizes.
	facet_points = PackedVector2Array([
		shape_points[5], shape_points[2],
	])
	queue_redraw()


func _physics_process(delta: float) -> void:
	# Drift toward the closest ship inside attract_radius. No redraw here:
	# position is a transform property and the crystal's shape is fixed.
	var target: Node2D = _nearest_ship()
	if target == null:
		velocity = velocity.move_toward(Vector2.ZERO, attract_accel * delta)
	else:
		var desired: Vector2 = (target.position - position).normalized() * attract_speed
		velocity = velocity.move_toward(desired, attract_accel * delta)
	position += velocity * delta


func _nearest_ship() -> Node2D:
	var nearest: Node2D = null
	var best: float = attract_radius
	for ship in get_tree().get_nodes_in_group("player_ships"):
		if not is_instance_valid(ship):
			continue
		var d: float = position.distance_to(ship.position)
		if d <= best:
			best = d
			nearest = ship
	return nearest


func _on_area_entered(area: Area2D) -> void:
	if area.is_in_group("player_ships"):
		GameState.rocks += 1
		collected.emit()
		queue_free()


func _draw() -> void:
	if shape_points.is_empty():
		return
	# Deep teal with a near-black core: a dark, saturated colour reads
	# clearly against the bright lunar regolith (sampled at ~0.75 grey),
	# where the original warm yellow disappeared into it.
	var glow: Color = Color(0.0, 0.62, 0.7)
	var core: Color = Color(0.0, 0.12, 0.15)
	NeonDraw.draw_glowing_polygon(self, shape_points, glow, 1.0, core)
	# One line only - the hexagon has a single flat-to-flat facet. This used
	# to draw two lines from a 4-point array; the hexagon rewrite left only
	# 2 points, so the second line indexed out of bounds and every rock
	# threw on every draw.
	if facet_points.size() >= 2:
		NeonDraw.draw_glowing_line(self, facet_points[0], facet_points[1], glow, 0.7, 0.3, core)