-------------------------------------------------------------------------------
-- Spine Runtimes License Agreement
-- Last updated January 1, 2020. Replaces all prior versions.
--
-- Copyright (c) 2013-2020, Esoteric Software LLC
--
-- Integration of the Spine Runtimes into software or otherwise creating
-- derivative works of the Spine Runtimes is permitted under the terms and
-- conditions of Section 2 of the Spine Editor License Agreement:
-- http://esotericsoftware.com/spine-editor-license
--
-- Otherwise, it is permitted to integrate the Spine Runtimes into software
-- or otherwise create derivative works of the Spine Runtimes (collectively,
-- "Products"), provided that each user of the Products must obtain their own
-- Spine Editor license and redistribution of the Products in any form must
-- include this license and copyright notice.
--
-- THE SPINE RUNTIMES ARE PROVIDED BY ESOTERIC SOFTWARE LLC "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 SOFTWARE LLC BE LIABLE FOR ANY
-- DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
-- (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES,
-- BUSINESS INTERRUPTION, OR LOSS OF USE, DATA, OR PROFITS) 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
-- THE SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-------------------------------------------------------------------------------

-- FIXME the logic in this file uses 0-based indexing. Each array
-- access adds 1 to the calculated index. We should switch the logic
-- to 1-based indexing eventually.

local setmetatable = setmetatable
local utils = require "spine-lua.utils"
local AttachmentType = require "spine-lua.attachments.AttachmentType"
local Attachment = require "spine-lua.attachments.Attachment"

local nextID = 0;
local SHL_11 = 2048;

local VertexAttachment = {}
VertexAttachment.__index = VertexAttachment
setmetatable(VertexAttachment, { __index = Attachment })

function VertexAttachment.new (name, attachmentType)
	local self = Attachment.new(name, attachmentType)
	self.bones = nil
	self.vertices = nil
	self.worldVerticesLength = 0
	while nextID > 65535 do
		nextID = nextID - 65535
	end
	self.id = nextID * SHL_11
	self.deformAttachment = self
	nextID = nextID + 1
	setmetatable(self, VertexAttachment)
	return self
end

function VertexAttachment:computeWorldVertices (slot, start, count, worldVertices, offset, stride)
	count = offset + (count / 2) * stride
	local skeleton = slot.bone.skeleton
	local deformArray = slot.deform
	local vertices = self.vertices
	local bones = self.bones
	if not bones then
		if #deformArray > 0 then vertices = deformArray end
		local bone = slot.bone
		x = bone.worldX
		y = bone.worldY
		local a = bone.a
		local b = bone.b
		local c = bone.c
		local d = bone.d
		local v = start
		local w = offset
		while w < count do
			local vx = vertices[v + 1]
			local vy = vertices[v + 2]
			worldVertices[w + 1] = vx * a + vy * b + x
			worldVertices[w + 2] = vx * c + vy * d + y
			v = v + 2
			w = w + stride
		end
		return
	end
	local v = 0
	local skip = 0
	local i = 0
	while i < start do
		local n = bones[v + 1]
		v = v + n + 1
		skip = skip + n
		i = i + 2
	end
	local skeletonBones = skeleton.bones
	if #deformArray == 0 then
		local w = offset
		local b = skip * 3
		while w < count do
			local wx = 0
			local wy = 0
			local n = bones[v + 1]
			v = v + 1
			n = n + v
			while v < n do
				local bone = skeletonBones[bones[v + 1]]
				local vx = vertices[b + 1]
				local vy = vertices[b + 2]
				local weight = vertices[b + 3]
				wx = wx + (vx * bone.a + vy * bone.b + bone.worldX) * weight
				wy = wy + (vx * bone.c + vy * bone.d + bone.worldY) * weight
				v = v + 1
				b = b + 3
			end
			worldVertices[w + 1] = wx
			worldVertices[w + 2] = wy
			w = w + stride
		end
	else
		local deform = deformArray
		local w = offset
		local b = skip * 3
		local f = skip * 2
		while w < count do
			local wx = 0
			local wy = 0
			local n = bones[v + 1]
			v = v + 1
			n = n + v

			while v < n do
				local bone = skeletonBones[bones[v + 1]]
				local vx = vertices[b + 1] + deform[f + 1]
				local vy = vertices[b + 2] + deform[f + 2]
				local weight = vertices[b + 3]
				wx = wx + (vx * bone.a + vy * bone.b + bone.worldX) * weight
				wy = wy + (vx * bone.c + vy * bone.d + bone.worldY) * weight
				v = v + 1
				b = b + 3
				f = f + 2
			end
			worldVertices[w + 1] = wx
			worldVertices[w + 2] = wy
			w = w + stride
		end
	end
end

function VertexAttachment:copyTo (attachment)
	if self.bones then
		attachment.bones = utils.copy(self.bones)
	else
		attachment.bones = nil
	end

	if self.vertices then
		attachment.vertices = utils.copy(self.vertices)
	else
		attachment.vertices = nil
	end

	attachment.worldVerticesLength = self.worldVerticesLength
	attachment.deformAttachment = self.deformAttachment
end

return VertexAttachment