-------------------------------------------------------------------------------
-- Spine Runtimes Software License
-- Version 2.3
-- 
-- Copyright (c) 2013-2015, Esoteric Software
-- All rights reserved.
-- 
-- You are granted a perpetual, non-exclusive, non-sublicensable and
-- non-transferable license to use, install, execute and perform the Spine
-- Runtimes Software (the "Software") and derivative works solely for personal
-- or internal use. Without the written permission of Esoteric Software (see
-- Section 2 of the Spine Software License Agreement), 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 SOFTWARE 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 = require "spine-lua.Bone"
local Slot = require "spine-lua.Slot"
local IkConstraint = require "spine-lua.IkConstraint"
local AttachmentLoader = require "spine-lua.AttachmentLoader"

local Skeleton = {}
function Skeleton.new (skeletonData)
	if not skeletonData then error("skeletonData cannot be nil", 2) end

	local self = {
		data = skeletonData,
		bones = {},
		slots = {},
		slotsByName = {},
		drawOrder = {},
		ikConstraints = {},
		r = 1, g = 1, b = 1, a = 1,
		skin = nil,
		flipX = false, flipY = false,
		time = 0,
		x = 0, y = 0
	}

	-- Caches information about bones and IK constraints. Must be called if bones or IK constraints are added or removed.
	function self:updateCache ()
		self.boneCache = {}
		local boneCache = self.boneCache
		local ikConstraints = self.ikConstraints
		local ikConstraintsCount = #ikConstraints

		local arrayCount = ikConstraintsCount + 1
		while #boneCache < arrayCount do
			table.insert(boneCache, {})
		end

		local nonIkBones = boneCache[1]

		for i,bone in ipairs(self.bones) do
			local current = bone
			local continueOuter
			repeat
				for ii,ikConstraint in ipairs(ikConstraints) do
					local parent = ikConstraint.bones[0]
					local child = ikConstraint.bones[#ikConstraint.bones - 1]
					while true do
						if current == child then
							table.insert(boneCache[ii], bone)
							table.insert(boneCache[ii + 1], bone)
							ii = ikConstraintsCount
							continueOuter = true
							break
						end
						if child == parent then break end
						child = child.parent
					end
				end
				if continueOuter then break end
				current = current.parent
			until not current
			table.insert(nonIkBones, bone)
		end
	end

	-- Updates the world transform for each bone and applies IK constraints.
	function self:updateWorldTransform ()
		local bones = self.bones
		for i,bone in ipairs(self.bones) do
			bone.rotationIK = bone.rotation
		end
		local boneCache = self.boneCache
		local ikConstraints = self.ikConstraints
		local i = 1
		local last = #boneCache
		while true do
			for ii,bone in ipairs(boneCache[i]) do
				bone:updateWorldTransform()
			end
			if i == last then break end
			ikConstraints[i]:apply()
			i = i + 1
		end
	end

	function self:setToSetupPose ()
		self:setBonesToSetupPose()
		self:setSlotsToSetupPose()
	end

	function self:setBonesToSetupPose ()
		for i,bone in ipairs(self.bones) do
			bone:setToSetupPose()
		end

		for i,ikConstraint in ipairs(self.ikConstraints) do
			ikConstraint.bendDirection = ikConstraint.data.bendDirection
			ikConstraint.mix = ikConstraint.data.mix
		end
	end

	function self:setSlotsToSetupPose ()
		for i,slot in ipairs(self.slots) do
			self.drawOrder[i] = slot
			slot:setToSetupPose()
		end
	end

	function self:getRootBone ()
		return self.bones[1]
	end

	function self:findBone (boneName)
		if not boneName then error("boneName cannot be nil.", 2) end
		for i,bone in ipairs(self.bones) do
			if bone.data.name == boneName then return bone end
		end
		return nil
	end

	function self:findSlot (slotName)
		if not slotName then error("slotName cannot be nil.", 2) end
		return self.slotsByName[slotName]
	end

	-- Sets the skin used to look up attachments before looking in the {@link SkeletonData#getDefaultSkin() default skin}. 
	-- Attachments from the new skin are attached if the corresponding attachment from the old skin was attached. If there was 
	-- no old skin, each slot's setup mode attachment is attached from the new skin.
	function self:setSkin (skinName)
		local newSkin
		if skinName then
			newSkin = self.data:findSkin(skinName)
			if not newSkin then error("Skin not found = " .. skinName, 2) end
			if self.skin then
				-- Attach all attachments from the new skin if the corresponding attachment from the old skin is currently attached.
				for k,v in pairs(self.skin.attachments) do
					local attachment = v[3]
					local slotIndex = v[1]
					local slot = self.slots[slotIndex]
					if slot.attachment == attachment then
						local name = v[2]
						local newAttachment = newSkin:getAttachment(slotIndex, name)
						if newAttachment then slot:setAttachment(newAttachment) end
					end
				end
			else
				-- No previous skin, attach setup pose attachments.
				for i,slot in ipairs(self.slots) do
					local name = slot.data.attachmentName
					if name then
						local attachment = newSkin:getAttachment(i, name)
						if attachment then slot:setAttachment(attachment) end
					end
				end
			end
		end
		self.skin = newSkin
	end

	function self:getAttachment (slotName, attachmentName)
		if not slotName then error("slotName cannot be nil.", 2) end
		if not attachmentName then error("attachmentName cannot be nil.", 2) end
		local slotIndex = skeletonData.slotNameIndices[slotName]
		if slotIndex == -1 then error("Slot not found = " .. slotName, 2) end
		if self.skin then
			local attachment = self.skin:getAttachment(slotIndex, attachmentName)
			if attachment then return attachment end
		end
		if self.data.defaultSkin then
			return self.data.defaultSkin:getAttachment(slotIndex, attachmentName)
		end
		return nil
	end

	function self:setAttachment (slotName, attachmentName)
		if not slotName then error("slotName cannot be nil.", 2) end
		for i,slot in ipairs(self.slots) do
			if slot.data.name == slotName then
				if not attachmentName then 
					slot:setAttachment(nil)
				else
					slot:setAttachment(self:getAttachment(slotName, attachmentName))
				end
				return
			end
		end
		error("Slot not found = " .. slotName, 2)
	end

	function self:update (delta)
		self.time = self.time + delta
	end

	function self:setColor (r, g, b, a)
		self.r = r
		self.g = g
		self.b = b
		self.a = a
	end

	for i,boneData in ipairs(skeletonData.bones) do
		local parent
		if boneData.parent then parent = self.bones[spine.utils.indexOf(skeletonData.bones, boneData.parent)] end
		table.insert(self.bones, Bone.new(boneData, self, parent))
	end

	for i,slotData in ipairs(skeletonData.slots) do
		local bone = self.bones[spine.utils.indexOf(skeletonData.bones, slotData.boneData)]
		local slot = Slot.new(slotData, bone)
		table.insert(self.slots, slot)
		self.slotsByName[slot.data.name] = slot
		table.insert(self.drawOrder, slot)
	end

	for i,ikConstraintData in ipairs(skeletonData.ikConstraints) do
		table.insert(self.ikConstraints, IkConstraint.new(ikConstraintData, self))
	end
	
	self:updateCache()

	return self
end
return Skeleton