class_name Mortar
extends Gun

func calculate_projectile_velocity(source: Vector3, target: Vector3, max_height: float) -> Vector3:
	assert(is_equal_approx(source.y, target.y), "Source and target must be at the same height.")
	assert(max_height > 0.0, "Max height must be positive.")

	# Flatten to the horizontal plane and get range + direction
	var horizontal_offset := Vector3(target.x - source.x, 0.0, target.z - source.z)
	var R := horizontal_offset.length()
	assert(R > 0.0, "Source and target must not be the same point.")
	var direction := horizontal_offset / R

	var g := MortarProjectile.GRAVITY

	# Angle whose tangent is 4H/R — peaks exactly at max_height
	var angle := atan(4.0 * max_height / R)

	# Speed derived from v = sqrt(2gH + gR²/8H)
	var speed := sqrt(2.0 * g * max_height + (g * R * R) / (8.0 * max_height))

	var horizontal_speed := speed * cos(angle)
	var vertical_speed   := speed * sin(angle)

	return direction * horizontal_speed + Vector3.UP * vertical_speed

func fire(_aim_angle: float) -> void:
	var pos: Vector3 = Player.instance.get_node("%Reticle").global_position
	pos.y = global_position.y
	var vel := calculate_projectile_velocity(global_position, pos, 10.)

	var proj := preload("res://player/projectile/mortar_projectile.tscn").instantiate()
	proj.velocity = vel
	proj.global_position = global_position
	get_tree().current_scene.add_child(proj)

	fire_clock = 60. / fire_rate

	%MortarFire.play()