extends Node2D

# By path, not by its `ResourcePickupVFX` global name: a bare class-name
# reference needs the global class cache already warm, which it is not when
# this script is reached indirectly - loading Main.tscn from inside a preview
# scene made it a hard parse error. Same workaround PlanetSetups and
# PlanetSetupEditor already use.
const RESOURCE_PICKUP_VFX = preload("res://vfx/ResourcePickupVFX.gd")

@export var fleet_path: NodePath = NodePath("../Fleet")
@onready var fleet: Node2D = get_node(fleet_path)
const SOURCE_COLOUR: Color = Color(0.85, 0.52, 1.0)
const CORE_COLOUR: Color = Color(0.15, 0.03, 0.22)
# Offsets from a vent's centre, and each bubble's radius.
const SOURCE_BUBBLES: Array = [
	[Vector2(-20.0, 8.0), 20.0],
	[Vector2(18.0, 14.0), 27.0],
	[Vector2(17.0, -22.0), 15.0],
]

const BUBBLES_PER_VENT: int = 4
const BUBBLE_MIN_RADIUS: float = 5.0
const BUBBLE_MAX_RADIUS: float = 14.0
const EMISSION_COLOUR: Color = Color(0.92, 0.68, 1.0)

var vents: Array[Vector2] = []
# One row of rising-bubble pieces per vent.
var bubbles: Array = []
var progress: float = 0.0
var emission_phase: float = 0.0
func _ready() -> void:
	# #91: the vents are ground features and must never cover the fleet.
	# SurfaceFeatures is added AFTER Fleet in PlanetSurface.tscn, so at the
	# default z_index of 0 the later sibling simply wins and the player flies
	# UNDER their own gas source. Same fix, and the same reason, as #50's
	# capture rings and the rocks on a rocky surface (Rock.gd) - the
	# difference is that this field draws in its own _draw() rather than
	# spawning child nodes, so the depth belongs on the field itself.
	z_index = -1
	var rng := RandomNumberGenerator.new()
	rng.seed = hash(GameState.planet_id if GameState.planet_id != "" else GameState.planet_name)
	for i in range(6): vents.append(Vector2(rng.randf_range(-800,800), rng.randf_range(-650,650)))
	_build_sources()
	_build_bubbles()
	_place_bubbles()


# The sources never move, never change colour and never fade - they were
# simply being re-tessellated every frame alongside the bubbles rising out of
# them, because one _draw() covered both. Eighteen glowing polygons a frame,
# each of which NeonDraw expands into four antialiased polylines. Rasterised
# once into a piece each now, per the rule issues #6 and #10 set.
func _build_sources() -> void:
	for vent in vents:
		var piece: NeonPiece = NeonPiece.create(self, vent, SOURCE_COLOUR)
		piece.core_color = CORE_COLOUR
		piece.z_index = -1
		for bubble in SOURCE_BUBBLES:
			var ring := PackedVector2Array()
			for i in range(12):
				var angle: float = TAU * float(i) / 12.0
				ring.append(Vector2(bubble[0]) + Vector2(cos(angle), sin(angle)) * float(bubble[1]))
			piece.add_polygon(ring, 0.9, 0.6)


# One piece per rising bubble, built as a UNIT circle and thereafter only
# moved, scaled and faded. The bubble genuinely changes size and opacity as
# it climbs, which is why this used to redraw - but size is scale and opacity
# is modulate, and neither needs the geometry rebuilding.
func _build_bubbles() -> void:
	for vent in vents:
		var row: Array = []
		for i in range(BUBBLES_PER_VENT):
			var piece: NeonPiece = NeonPiece.create(self, vent, EMISSION_COLOUR)
			piece.core_color = CORE_COLOUR
			piece.z_index = -1
			# Built at the LARGEST size a bubble reaches and scaled DOWN,
			# never up. Scaling a piece scales its stroke with it, and a unit
			# circle blown up to radius 14 took NeonDraw's widths with it -
			# a hundred pixels of glow around a fourteen pixel bubble, which
			# rendered as a bright blob rather than a bubble. Downward, the
			# stroke only ever thins, which is what a smaller bubble wants.
			var ring := PackedVector2Array()
			for point in range(10):
				var angle: float = TAU * float(point) / 10.0
				ring.append(Vector2(cos(angle), sin(angle)) * BUBBLE_MAX_RADIUS)
			piece.add_polygon(ring, 0.75, 0.45)
			row.append(piece)
		bubbles.append(row)


# Where one bubble sits, how big it is and how faded, for a point in its
# climb. Unchanged arithmetic - only the thing it is applied to changed.
func _place_bubbles() -> void:
	for v in range(vents.size()):
		for i in range(BUBBLES_PER_VENT):
			var travel: float = fmod(emission_phase + float(i) * 0.25, 1.0)
			var piece: NeonPiece = bubbles[v][i]
			piece.position = vents[v] + Vector2(
				sin((travel + float(i)) * TAU) * 11.0,
				-48.0 - travel * 92.0)
			var radius: float = lerpf(BUBBLE_MIN_RADIUS, BUBBLE_MAX_RADIUS, travel)
			var k: float = radius / BUBBLE_MAX_RADIUS
			piece.scale = Vector2(k, k)
			piece.modulate.a = 1.0 - travel * 0.72
func _process(delta: float) -> void:
	emission_phase = fmod(emission_phase + delta * 0.55, 1.0)
	# Node properties only. Nothing is rasterised after the first frame.
	_place_bubbles()
	for vent in vents:
		if fleet.get_centroid().distance_to(vent) < 90.0:
			progress += delta
			if progress >= 1.0:
				# #56: a full fleet hold rejects the deposit - keep the
				# undelivered whole units in progress rather than discarding
				# them, so gas is only ever lost by not gathering it.
				var whole: int = int(progress)
				var taken: int = GameState.collect_gas_cargo(whole)
				progress -= float(taken)
				RESOURCE_PICKUP_VFX.spawn(get_tree().root,
					to_global(vent), GameState.RESOURCE_GAS, taken)
			return
	progress = 0.0