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

module(..., package.seeall)

local copy = require('acf.util').copy


local function keys(tbl)
   local res = {}
   for k, v in pairs(tbl) do table.insert(res, k) end
   return res
end


backend = require('acf.object').class()

function backend:init(data) self.data = data or {} end

function backend:_get(path)
   local res = self.data
   for _, comp in ipairs(path) do
      if res == nil then return end
      assert(type(res) == 'table')
      res = res[comp]
   end
   return res
end

function backend:get(path, tpe)
   local res = self:_get(path)
   return type(res) == 'table' and keys(res) or res
end

function backend:_set(path, tpe, value)
   if tpe == 'table' then value = {} end

   if #path == 0 then self.data = value

   else
      local comps = copy(path)
      local name = comps[#comps]
      table.remove(comps)
      self:_get(comps)[name] = value
   end
end

function backend:set(mods)
   for _, mod in ipairs(mods) do self:_set(unpack(mod)) end
end