extends Object
class_name ExplosionVFX

## Cel-shaded anime explosion, shared by local projectiles and the remote
## replay RPC. Flat unshaded colors stepped through hot stages (white core ->
## yellow -> orange -> smoke), an expanding ink shockwave ring, and radiating
## star spikes — no gradients, no realistic fire, all comic-book punch.

const CORE_STAGES := [
	Color(1.0, 1.0, 0.95),   # white-hot flash
	Color(1.0, 0.85, 0.2),   # yellow
	Color(1.0, 0.45, 0.1),   # orange
]
const INK := Color(0.09, 0.08, 0.1)
const SMOKE := Color(0.82, 0.8, 0.85)


static func _flat_mat(color: Color, emissive: float = 0.0) -> StandardMaterial3D:
	var m := StandardMaterial3D.new()
	m.shading_mode = BaseMaterial3D.SHADING_MODE_UNSHADED
	m.albedo_color = color
	if emissive > 0.0:
		m.emission_enabled = true
		m.emission = color
		m.emission_energy_multiplier = emissive
	return m


static func spawn(scene_tree: SceneTree, pos: Vector3, radius: float,
		pitch_scale: float = 1.0) -> void:
	var root := scene_tree.current_scene
	if root == null:
		return

	# ── Core fireball: stepped color pops (each stage is a hard swap) ─────
	var core := MeshInstance3D.new()
	var core_mesh := SphereMesh.new()
	core_mesh.radius = 1.0
	core_mesh.height = 2.0
	core_mesh.radial_segments = 16
	core_mesh.rings = 8
	core.mesh = core_mesh
	var core_mat := _flat_mat(CORE_STAGES[0], 2.0)
	core.material_override = core_mat
	root.add_child(core)
	core.global_position = pos
	core.scale = Vector3.ONE * radius * 0.35

	var t := core.create_tween()
	t.tween_property(core, "scale", Vector3.ONE * radius * 0.9, 0.07) \
		.set_trans(Tween.TRANS_QUINT).set_ease(Tween.EASE_OUT)
	t.tween_callback(func(): core_mat.albedo_color = CORE_STAGES[1]; core_mat.emission = CORE_STAGES[1])
	t.tween_property(core, "scale", Vector3.ONE * radius * 1.05, 0.08)
	t.tween_callback(func(): core_mat.albedo_color = CORE_STAGES[2]; core_mat.emission = CORE_STAGES[2])
	t.tween_property(core, "scale", Vector3.ONE * radius * 1.15, 0.08)
	# collapse to nothing (anime explosions vanish, they don't fade)
	t.tween_property(core, "scale", Vector3.ONE * 0.01, 0.12) \
		.set_trans(Tween.TRANS_BACK).set_ease(Tween.EASE_IN)
	t.tween_callback(core.queue_free)

	# ── Ink shockwave ring: flat torus expanding outward ──────────────────
	var ring := MeshInstance3D.new()
	var ring_mesh := TorusMesh.new()
	ring_mesh.inner_radius = 0.92
	ring_mesh.outer_radius = 1.0
	ring_mesh.rings = 32
	ring_mesh.ring_segments = 6
	ring.mesh = ring_mesh
	ring.material_override = _flat_mat(INK)
	root.add_child(ring)
	ring.global_position = pos
	ring.scale = Vector3.ONE * radius * 0.3

	var rt := ring.create_tween()
	rt.tween_property(ring, "scale", Vector3(radius * 2.2, radius * 0.5, radius * 2.2), 0.28) \
		.set_trans(Tween.TRANS_CUBIC).set_ease(Tween.EASE_OUT)
	rt.parallel().tween_property(ring, "transparency", 1.0, 0.28) \
		.set_trans(Tween.TRANS_EXPO).set_ease(Tween.EASE_IN)
	rt.tween_callback(ring.queue_free)

	# ── Star spikes: stretched octahedra radiating out (impact flash) ─────
	var spike_count := 6
	for i in spike_count:
		var spike := MeshInstance3D.new()
		var spike_mesh := PrismMesh.new()
		spike_mesh.size = Vector3(0.14, 1.0, 0.14)
		spike.mesh = spike_mesh
		spike.material_override = _flat_mat(Color(1.0, 0.95, 0.6), 1.5)
		root.add_child(spike)
		var dir := Vector3(randf_range(-1, 1), randf_range(-0.3, 1), randf_range(-1, 1)).normalized()
		spike.global_position = pos + dir * radius * 0.3
		var up := Vector3.UP if absf(dir.dot(Vector3.UP)) < 0.98 else Vector3.RIGHT
		spike.look_at(pos + dir * 2.0, up)
		spike.rotate_object_local(Vector3.RIGHT, PI / 2.0)
		spike.scale = Vector3(radius * 0.25, radius * 0.9, radius * 0.25)

		var st := spike.create_tween()
		st.tween_property(spike, "global_position", pos + dir * radius * 1.5, 0.16) \
			.set_trans(Tween.TRANS_QUART).set_ease(Tween.EASE_OUT)
		st.parallel().tween_property(spike, "scale", Vector3(0.02, radius * 0.3, 0.02), 0.16)
		st.tween_callback(spike.queue_free)

	# ── Smoke puffs: flat gray spheres that pop out then shrink away ──────
	var puff_count := 5
	for i in puff_count:
		var puff := MeshInstance3D.new()
		var puff_mesh := SphereMesh.new()
		puff_mesh.radius = 1.0
		puff_mesh.height = 2.0
		puff_mesh.radial_segments = 10
		puff_mesh.rings = 5
		puff.mesh = puff_mesh
		var shade := randf_range(0.75, 0.95)
		puff.material_override = _flat_mat(Color(shade, shade, shade * 1.05))
		root.add_child(puff)
		var dir := Vector3(randf_range(-1, 1), randf_range(0.2, 1), randf_range(-1, 1)).normalized()
		puff.global_position = pos + dir * radius * 0.4
		puff.scale = Vector3.ONE * radius * randf_range(0.2, 0.35)

		var pt := puff.create_tween()
		pt.tween_property(puff, "global_position", pos + dir * radius * randf_range(0.9, 1.3), 0.3) \
			.set_trans(Tween.TRANS_CUBIC).set_ease(Tween.EASE_OUT)
		pt.parallel().tween_property(puff, "scale", Vector3.ONE * radius * randf_range(0.4, 0.55), 0.3)
		pt.tween_property(puff, "scale", Vector3.ONE * 0.01, 0.25) \
			.set_trans(Tween.TRANS_BACK).set_ease(Tween.EASE_IN)
		pt.tween_callback(puff.queue_free)

	# ── Audio: explosion samples with variation ───────────────────────────
	var am = scene_tree.root.get_node_or_null("AudioManager")
	if am and am.has_sound("explosion"):
		var size_db := clampf((radius - 2.5) * 0.42, -2.5, 2.5)
		am.play_3d("explosion", pos, size_db, clampf(pitch_scale, 0.72, 1.15))


## Comic star-flash at a weapon muzzle: 4 flat spikes + hot core, parented to
## the weapon so it tracks view sway, gone in ~70 ms. Pairs with the existing
## OmniLight pop the weapons already do.
static func muzzle_flash(parent: Node3D, local_pos: Vector3) -> void:
	if parent == null or not parent.is_inside_tree():
		return
	var flash := Node3D.new()
	parent.add_child(flash)
	flash.position = local_pos
	flash.rotation.z = randf() * TAU

	var core := MeshInstance3D.new()
	var core_mesh := SphereMesh.new()
	core_mesh.radius = 0.035
	core_mesh.height = 0.07
	core_mesh.radial_segments = 8
	core_mesh.rings = 4
	core.mesh = core_mesh
	core.material_override = _flat_mat(Color(1.0, 0.98, 0.85), 3.0)
	flash.add_child(core)

	for i in 4:
		var spike := MeshInstance3D.new()
		var spike_mesh := PrismMesh.new()
		spike_mesh.size = Vector3(0.025, 0.11, 0.012)
		spike.mesh = spike_mesh
		spike.material_override = _flat_mat(Color(1.0, 0.82, 0.25), 2.0)
		spike.position = Vector3(0, 0, 0)
		spike.rotation.z = TAU * float(i) / 4.0 + randf_range(-0.2, 0.2)
		spike.translate_object_local(Vector3(0, 0.07, 0))
		flash.add_child(spike)

	var t := flash.create_tween()
	t.tween_property(flash, "scale", Vector3.ONE * 1.4, 0.04) \
		.set_trans(Tween.TRANS_QUINT).set_ease(Tween.EASE_OUT)
	t.tween_property(flash, "scale", Vector3.ONE * 0.01, 0.03)
	t.tween_callback(flash.queue_free)