extends RigidBody3D
signal detonated
# No timed fuse: the rifle grenade detonates on its first physical contact.
const MAX_LIFETIME := 15.0
const Explosion = preload("res://scripts/grenade_explosion.gd")
const BLAST_RADIUS := 5.0
const MAX_DAMAGE := 160.0
const Audio = preload("res://scripts/hl_audio.gd")
const Blood = preload("res://scripts/blood_effects.gd")
var age := 0.0
var exploded := false
var thrower: CharacterBody3D
var previous_position := Vector3.ZERO
var impact_position := Vector3.ZERO

func _ready() -> void:
	name = "Grenade"
	add_to_group("grenades")
	previous_position = global_position
	collision_layer = 16
	collision_mask = 1 | 4
	mass = 0.4
	continuous_cd = true
	contact_monitor = true
	max_contacts_reported = 8
	body_entered.connect(_on_body_entered)
	linear_damp = 0.15
	angular_damp = 0.6
	var physics := PhysicsMaterial.new()
	physics.bounce = 0.0
	physics.friction = 0.65
	physics_material_override = physics
	var collider := CollisionShape3D.new()
	var sphere := SphereShape3D.new()
	sphere.radius = 0.12
	collider.shape = sphere
	add_child(collider)
	var model: Node3D = load("res://assets/weapons/grenade.scn").instantiate()
	add_child(model)
	for area in model.find_children("*", "Area3D", true, false):
		area.collision_layer = 0
		area.collision_mask = 0
	for mesh in model.find_children("*", "MeshInstance3D", true, false):
		mesh.layers = 2
	if is_instance_valid(thrower):
		add_collision_exception_with(thrower)

func _physics_process(delta: float) -> void:
	age += delta
	# Window panes are Area3D on layer 8, not PhysicsBody3D. A swept ray catches
	# those too, even if a fast grenade crosses the whole pane in one tick.
	if not exploded and not previous_position.is_equal_approx(global_position):
		var query := PhysicsRayQueryParameters3D.create(previous_position, global_position, 8)
		query.collide_with_areas = true
		query.collide_with_bodies = false
		var hit := get_world_3d().direct_space_state.intersect_ray(query)
		if not hit.is_empty():
			_request_detonation(hit.position + hit.normal * 0.13)
	previous_position = global_position
	# Safety cleanup only: a projectile lost outside the map must not explode in air.
	if age >= MAX_LIFETIME and not exploded:
		queue_free()

func _integrate_forces(state: PhysicsDirectBodyState3D) -> void:
	if not exploded and state.get_contact_count() > 0:
		# Save the physics position before deferring scene/shape changes. The sphere
		# centre stays on the free side of the surface, also for damage LOS rays.
		_request_detonation(state.transform.origin)

func _on_body_entered(body: Node) -> void:
	if body != thrower:
		_request_detonation(global_position)

func _request_detonation(point: Vector3) -> void:
	if exploded:
		return
	exploded = true
	impact_position = point
	call_deferred("_explode")

func _explode() -> void:
	freeze = true
	collision_layer = 0
	collision_mask = 0
	hide()
	var world := get_parent() as Node3D
	var point := impact_position
	var targets := get_tree().get_nodes_in_group("live_zombies")
	if is_instance_valid(thrower) and not thrower.death_started:
		targets.append(thrower)
	for target in targets:
		if not is_instance_valid(target):
			continue
		var center: Vector3 = target.global_position + Vector3.UP * 0.9
		var distance := point.distance_to(center)
		if distance > BLAST_RADIUS:
			continue
		var query := PhysicsRayQueryParameters3D.create(point, center, 1)
		if not get_world_3d().direct_space_state.intersect_ray(query).is_empty():
			continue
		var damage := MAX_DAMAGE * (1.0 - distance / BLAST_RADIUS)
		if target == thrower:
			target.take_damage(damage)
		else:
			Blood.impact(world, center, (center - point).normalized())
			target.take_damage(damage, center.y)
	_effect(world, point)
	detonated.emit()
	queue_free()

func _effect(world: Node3D, point: Vector3) -> void:
	var effect := Explosion.new()
	world.add_child(effect)
	effect.global_position = point
	Audio.play(effect, "weapons/explode%d.wav" % randi_range(3, 5), true, -7)
	# Secondary embers only: the original fireball is now the main visual.
	var particles := CPUParticles3D.new()
	particles.amount = 18
	particles.lifetime = 0.85
	particles.one_shot = true
	particles.explosiveness = 1
	particles.direction = Vector3.UP
	particles.spread = 180
	particles.initial_velocity_min = 2
	particles.initial_velocity_max = 6
	particles.gravity = Vector3(0, -3, 0)
	var mesh := SphereMesh.new()
	mesh.radius = 0.018
	mesh.height = 0.036
	var material := StandardMaterial3D.new()
	material.albedo_color = Color(1, 0.3, 0.05)
	material.shading_mode = BaseMaterial3D.SHADING_MODE_UNSHADED
	mesh.material = material
	particles.mesh = mesh
	var colors := Gradient.new()
	colors.set_color(0, Color(1, 0.65, 0.1, 1))
	colors.set_color(1, Color(0.15, 0.12, 0.1, 0))
	particles.color_ramp = colors
	effect.add_child(particles)
	particles.emitting = true