local getArgs = require('Module:Arguments').getArgs
local cd = require('Module:CountryData')
local list = require('Module:List');
local p = {}

local labels = {
 ['NA'] = "북미",
 ['EU'] = "유럽",
 ['EUR'] = "유럽",
 ['AU'] = "호주",
 ['AUS'] = "호주",
 ['PAL'] = "PAL",
 ['SEA'] = "동남아",
 ['AS'] = "아시아",
 ['SA'] = "남미",
 ['INT'] = "",
 ['WW'] = "전세계",
 ['JP'] = "일본",
 ['KR'] = "한국",
 ['CN'] = "중국",
 ['TW'] = "대만",
 ['HK'] = "홍콩",
 ['UK'] = "영국",
 ['US'] = "미국",
 ['CA'] = "캐나다",
 ['NZ'] = "뉴질랜드",
 ['NZL'] = "뉴질랜드",
 ['MO'] = "마카오",
 ['SG'] = "싱가포르",
 ['TH'] = "태국",
 ['?'] = ""

local function getLocalLabel(alias)
	local label = labels[string.upper(alias)] 

	return label
end

local countryData = {}; -- Used to store country data to avoid the need of repeated calls to Module:CountryData. This saves a little time if the same abbreviation appears multiple times in the template.

local function getCountryData
	local ualias = string.upper(alias)
	
	if(countryData[ualias] == nil) then
		local cdtable = cd.gettable
		countryData[ualias] = cdtable['alias']
	end

	return countryData[ualias]
end

local function splitLabel(s)
	local islist = true
	local res = {}
	for k,v in ipairs(mw.text.split) do
		local v1 = v:match('^%s*([A-Z][A-Z][A-Z]?)%s*$')
		if v1 then
			table.insert
		else
			local v2 = v:match('^%s*(%[%[[^%[%]|]*|[A-Z][A-Z][A-Z]?%]%])%s*$')
			if v2 then
				table.insert
			else
				islist = false
			end
		end
	end
	return islist and res or {s}
end

function p.main(frame)
	local args = getArgs(frame)
	local listformat = args['format']
	if(listformat == nil or listformat == "") then
		listformat = "unbulleted"
	end
	local items = {}
	
	-- Old syntax "Two parameter region" use case, where param 1 is an article, param 2 is a label, and param 3 is the date. We assume this case if argument 4 is nil.
	if(args[3] ~= nil and args[4] == nil) then
		local item = " " .. args[3] .. "분류:두 개의 변수 지역 없이 vgarelease가 쓰인 글"
		table.insert
	-- Old syntax "Blank region" use case, where param 1 is empty, and param 2 is the date.
	elseif(args[1] == nil and args[2] ~= nil) then
		local item = args[2] .. "분류:지역 없이 vgrelease가 쓰인 글"
		table.insert
	-- Normal use cases, region/date pairs in 1/2, 3/4, 5/6, etc.
	else
		local i = 1
		local j = 2
	 while(args[i] and args[j]) do
			local labels = {}
			for k,v in ipairs(splitLabel(args[i])) do
				local label = getLocalLabel(v);
 	
				-- Didn't find a local label? Check for country data.
				if (label == nil) then
					if not v:match('^%s*%[') then
						label = getCountryData
					end
 		
					-- Found something? Build a sitelink with it.
					if (label ~= nil) then
						label = "" .. v .. ""
					else
						label = v
					end
				end
				table.insert
			end
			local item = " " .. args[j]
			table.insert
 
			i = i + 2
			j = j + 2
		end
 end

	local out = list.makeList

	-- Set message for invalid parameters. Decide catagory based on list format chosen.
	local parameterMsg
	if(listformat == "horizontal") then
		parameterMsg = "_VALUE_"
	else
		parameterMsg = "_VALUE_"
	end
	
	-- Preview message.
 	if(frame:preprocess( "" ) == "") then
		parameterMsg = ""
	end
	
 -- Check for named parameters	
	for k, v in pairs(args) do
		if(type(k) ~= 'number' and k ~= 'format') then
			local msg = parameterMsg:gsub
			out = out .. msg
		end
	end

 return out
end