-------------------------------------------------------------------------------
 -- Copyright (c) 2013, Esoteric Software
 -- All rights reserved.
 -- 
 -- Redistribution and use in source and binary forms, with or without
 -- modification, are permitted provided that the following conditions are met:
 -- 
 -- 1. Redistributions of source code must retain the above copyright notice, this
 --    list of conditions and the following disclaimer.
 -- 2. Redistributions in binary form must reproduce the above copyright notice,
 --    this list of conditions and the following disclaimer in the documentation
 --    and/or other materials provided with the distribution.
 -- 
 -- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 THE COPYRIGHT OWNER OR CONTRIBUTORS 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 Skin = {}
function Skin.new (name)
	if not name then error("name cannot be nil", 2) end
	
	local self = {
		name = name,
		attachments = {}
	}

	function self:addAttachment (slotIndex, name, attachment)
		if not name then error("name cannot be nil.", 2) end
		self.attachments[slotIndex .. ":" .. name] = { slotIndex, name, attachment }
	end

	function self:getAttachment (slotIndex, name)
		if not name then error("name cannot be nil.", 2) end
		local values = self.attachments[slotIndex .. ":" .. name]
		if not values then return nil end
		return values[3]
	end

	function self:findNamesForSlot (slotIndex)
		local names = {}
		for k,v in self.attachments do
			if v[1] == slotIndex then table.insert(names, v[2]) end
		end
	end

	function self:findAttachmentsForSlot (slotIndex)
		local attachments = {}
		for k,v in self.attachments do
			if v[1] == slotIndex then table.insert(attachments, v[3]) end
		end
	end

	return self
end
return Skin