--[[
Copyright (c) 2012-2013 Kaarle Ritvanen
See LICENSE file for license details
--]]

module(..., package.seeall)

local TreeNode = require('acf.model.field').TreeNode
local npairs = require('acf.model.node').pairs
local object = require('acf.object')


local function find(set, value)
   for i, member in npairs(set) do
      if member == value then return i end
   end
end


Set = object.class(require('acf.model.node').Collection)

function Set:init(context, params)
   assert(not object.isinstance(params.field, TreeNode))
   object.super(self, Set):init(context, params)

   local mt = getmetatable(self)
   mt.meta.type = 'set'

   function mt.__index(t, k) return find(self, k) and k end

   function mt.__newindex(t, k, v)
      assert(v == nil)
      local i = find(self, k)
      if not i then return end

      local len = #mt.members()
      while i < len do
	 mt.set(i, mt.get(i + 1))
	 i = i + 1
      end
      mt.set(len, nil)
   end
end


function add(set, value)
   local mt = getmetatable(set)
   if not find(set, value) then mt.set(#mt.members() + 1, value) end
end