-------------------------------------------------------------------------------
-- Spine Runtimes Software License
-- Version 2.1
-- 
-- Copyright (c) 2013, Esoteric Software
-- All rights reserved.
-- 
-- You are granted a perpetual, non-exclusive, non-sublicensable and
-- non-transferable license to install, execute and perform the Spine Runtimes
-- Software (the "Software") solely for internal use. Without the written
-- permission of Esoteric Software (typically granted by licensing Spine), you
-- may not (a) modify, translate, adapt or otherwise create derivative works,
-- improvements of the Software or develop new applications using the Software
-- or (b) remove, delete, alter or obscure any trademarks or any copyright,
-- trademark, patent or other intellectual property or proprietary rights
-- notices on or in the Software, including any copy thereof. Redistributions
-- in binary or source form must include this license and terms.
-- 
-- THIS SOFTWARE IS PROVIDED BY ESOTERIC SOFTWARE "AS IS" AND ANY EXPRESS OR
-- IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
-- MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
-- EVENT SHALL ESOTERIC SOFTARE BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-- SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
-- PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
-- OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
-- WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
-- OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
-- ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-------------------------------------------------------------------------------

local Bone = {}

function Bone.new (data, parent)
	if not data then error("data cannot be nil", 2) end
	
	local self = {
		data = data,
		parent = parent,
		x = 0, y = 0,
		rotation = 0,
		scaleX = 1, scaleY = 1,
		m00 = 0, m01 = 0, worldX = 0, -- a b x
		m10 = 0, m11 = 0, worldY = 0, -- c d y
		worldRotation = 0,
		worldScaleX = 1, worldScaleY = 1,
	}

	function self:updateWorldTransform (flipX, flipY)
		local parent = self.parent
		if parent then
			self.worldX = self.x * parent.m00 + self.y * parent.m01 + parent.worldX
			self.worldY = self.x * parent.m10 + self.y * parent.m11 + parent.worldY
			if (self.data.inheritScale) then
				 self.worldScaleX = parent.worldScaleX * self.scaleX
				 self.worldScaleY = parent.worldScaleY * self.scaleY
			else
				 self.worldScaleX = self.scaleX
				 self.worldScaleY = self.scaleY
			end
			if (self.data.inheritRotation) then
				 self.worldRotation = parent.worldRotation + self.rotation
			else
				 self.worldRotation = self.rotation
			end
		else
			if flipX then
				self.worldX = -self.x
			else
				self.worldX = self.x
			end
			if flipY then
				self.worldY = -self.y
			else
				self.worldY = self.y
			end
			self.worldScaleX = self.scaleX
			self.worldScaleY = self.scaleY
			self.worldRotation = self.rotation
		end
		local radians = math.rad(self.worldRotation)
		local cos = math.cos(radians)
		local sin = math.sin(radians)
		self.m00 = cos * self.worldScaleX
		self.m10 = sin * self.worldScaleX
		self.m01 = -sin * self.worldScaleY
		self.m11 = cos * self.worldScaleY
		if flipX then
			self.m00 = -self.m00
			self.m01 = -self.m01
		end
		if flipY then
			self.m10 = -self.m10
			self.m11 = -self.m11
		end
	end

	function self:setToSetupPose ()
		local data = self.data
		self.x = data.x
		self.y = data.y
		self.rotation = data.rotation
		self.scaleX = data.scaleX
		self.scaleY = data.scaleY
	end

	self:setToSetupPose()
	return self
end
return Bone