require "lua/class"

local wkey = false
local skey = false
local akey = false
local dkey = false

FPSCamera = class(FPSCamera)

function FPSCamera:init(world, unit)
	self._world = world
	self._unit = unit
	self._sg = World.scene_graph(world)
	self._translation_speed = 0.05
	self._rotation_speed = 0.006
end

function FPSCamera:unit()
	return self._unit;
end

function FPSCamera:camera()
	return World.camera(self._world, self._unit)
end

function FPSCamera:update(dx, dy)
	if Keyboard.pressed(Keyboard.button_id("w")) then wkey = true end
	if Keyboard.pressed(Keyboard.button_id("s")) then skey = true end
	if Keyboard.pressed(Keyboard.button_id("a")) then akey = true end
	if Keyboard.pressed(Keyboard.button_id("d")) then dkey = true end
	if Keyboard.released(Keyboard.button_id("w")) then wkey = false end
	if Keyboard.released(Keyboard.button_id("s")) then skey = false end
	if Keyboard.released(Keyboard.button_id("a")) then akey = false end
	if Keyboard.released(Keyboard.button_id("d")) then dkey = false end

	local camera = self:camera()
	local camera_transform = SceneGraph.transform_instances(self._sg, self._unit)
	local camera_local_pose = SceneGraph.local_pose(self._sg, camera_transform)
	local camera_right_vector = Matrix4x4.x(camera_local_pose)
	local camera_position = Matrix4x4.translation(camera_local_pose)
	local camera_rotation = Matrix4x4.rotation(camera_local_pose)
	local view_dir = Matrix4x4.z(camera_local_pose)

	-- Rotation
	local rotation_around_world_up = Quaternion(Vector3(0, 1, 0), -dx * self._rotation_speed)
	local rotation_around_camera_right = Quaternion(camera_right_vector, -dy * self._rotation_speed)
	local rotation = Quaternion.multiply(rotation_around_world_up, rotation_around_camera_right)

	local old_rotation = Matrix4x4.from_quaternion(camera_rotation)
	local delta_rotation = Matrix4x4.from_quaternion(rotation)
	local new_rotation = Matrix4x4.multiply(old_rotation, delta_rotation)
	Matrix4x4.set_translation(new_rotation, camera_position)

	-- Fixme
	SceneGraph.set_local_pose(self._sg, camera_transform, new_rotation)

	-- Translation
	if wkey then camera_position = camera_position + view_dir end
	if skey then camera_position = camera_position + view_dir * -1 end
	if akey then camera_position = camera_position + camera_right_vector * -1 end
	if dkey then camera_position = camera_position + camera_right_vector end

	SceneGraph.set_local_position(self._sg, camera_transform, camera_position)
end