local p = {}

-- i18n support for Korean
local param_ko = {
	['국가'] = 'team',
	['선수단'] = 'team',
	['대회'] = 'competition',
	['첫참가'] = 'begin_year',
	['마지막참가'] = 'end_year',
	['연속'] = 'interval',

local data_competitions
local data_old_names
local function load_data(frame)
	-- Load data module (or its sandbox) and set variables from its exported data.
	if not data_competitions then
		frame = frame or mw.getCurrentFrame
		local sandbox = frame:getTitle:find and '/연습장' or ''
		local datamod = mw.loadData('모듈:Team appearances list/data' .. sandbox)
		data_competitions = datamod.competitions
		data_old_names = datamod.old_names
	end
end

local function strip_to_nil(text)
	-- If text is a string, return its trimmed content, or nil if empty.
	-- Otherwise return text .
	if type(text) == 'string' then
		text = text:match('(%S.-)%s*$')
	end
	return text
end

local function make_options(args)
	-- Return table of options from validated args or throw error.
	local options = {}
	local function valid_integer
		local arg = args[name]
		if arg == nil or arg == '' then
			if is_optional then
				return nil
			end
			error('' .. name .. ' 변수가 빠졌습니다')
		end
		arg = tonumber(arg)
		if type(arg) ~= 'number' then
			error('' .. name .. ' 변수에는 숫자가 들어가야 합니다')
		end
		if math.floor(arg) ~= arg then
			error('' .. name .. ' 변수에는 정수가 들어가야 합니다')
		end
		if not (min <= arg and arg <= max) then
			error('' .. name .. ' 변수가 유효하지 않습니다')
		end
		return arg
	end
	local function valid_text(name)
		local arg = args[name]
		if arg == nil or arg == '' then
			error(name .. ' 변수가 빠졌습니다')
		end
		if type(arg) ~= 'string' then
			error(name .. ' 변수는 문자열이 아닙니다')
		end
		return arg
	end

	-- i18n support for Korean
	local function localname(parameter)
		return param_ko[parameter] or parameter
	end
	local parent_args = args
	for k, v in pairs(parent_args) do
		if v ~= '' then
			args[localname(k)] = v
		end
	end

	options.competition = valid_text('competition')
	options.team = valid_text('team')
	options.competitions = data_competitions[options.competition] or data_competitions[data_old_names[options.competition]]
	local begin_optional
	if options.competitions then
		begin_optional = true
	else
		options.interval = valid_integer
	end
	options.begin_year = valid_integer
	options.end_year = valid_integer
	if options.begin_year and options.end_year then
		if options.begin_year > options.end_year then
			error('end_year 변수는 begin_year 보다 앞서지 않아야 합니다')
		end
	end
	options.disqualified_year = valid_integer
	return options
end

local function extract_range(text)
	-- Return first (if text is a single year), or first, last if a range.
	-- The returned values are numbers.
	-- Return nothing if text is invalid.
	local year = text:match('^(%d+)$')
	if year then
		if #year == 4 then
			return tonumber(year)
		end
		return
	end
	local first, dash, last = text:match('^(%d+)(%D+)(%d+)$')
	if not (first and #first == 4) then
		return
	end
	dash = strip_to_nil(dash)
	if not (dash == '-' or dash == '–') then
		return
	end
	if #last ~= 4 then
		if #last == 2 then
			last = first:sub .. last
		else
			return
		end
	end
	first = tonumber(first)
	last = tonumber(last)
	if first < last then
		return first, last
	elseif first == last then
		return first
	end
end

local function competition_absences(data)
	-- Return two tables with absent years and absent year ranges.
	-- Parameter data is an array of strings from template parameters, or
	-- numbers or strings from built-in data.
	-- Parameters that are blank or not numbers or strings are ignored.
	local absent_years, absent_ranges = {}, {}
	for _, item in ipairs(data) do
		if type(item) == 'number' then
			absent_years[item] = true
		else
			item = strip_to_nil(item)
			if type(item) == 'string' then
				local first, last = extract_range(item)
				if not first then
					error('연도 ' .. item .. ' 항목이 유효하지 않습니다')
				end
				if last then
					table.insert
				else
					absent_years[first] = true
				end
			end
		end
	end
	return absent_years, absent_ranges
end

local function competition_information(args)
	-- Return four tables with competition and team information:
	-- * List of competition years that the team attended or could have attended.
	-- * Table of disqualified years .
	-- * Table of absent years (when the team did not attend).
	-- * List of pairs of years .
	local options = make_options(args)
	local absences
	local comp_years = {}
	local begin_year = options.begin_year
	local end_year = options.end_year
	local competitions = options.competitions
	if competitions then
		absences = competitions[options.team] or competitions[data_old_names[options.team]]
		begin_year = begin_year or (absences and absences.begin_year) or 0
		end_year = end_year or (absences and absences.end_year) or 9999
		for _, y in ipairs(competitions) do
			if y > end_year then
				break
			elseif y >= begin_year then
				table.insert
			end
		end
	else
		end_year = end_year or (os.date('!*t').year + options.interval)
		for y = begin_year, end_year, options.interval do
			table.insert
		end
	end
	local disqualified_years = {}
	if options.disqualified_year then
		-- Input currently only allows entry of a single disqualified year.
		-- However processing works for any number of such years.
		disqualified_years[options.disqualified_year] = true
	end
	return comp_years, disqualified_years, competition_absences(absences or args)
end

local function gameName
	-- Modifies output of display being sent back to the hlist
	-- for games that have had a name change but are still considered
	-- the same competition.
	if inputName=="World Athletics Championships" or inputName=="World Championships in Athletics" then
		if year <= 2017 then
			return "World Championships in Athletics"
		else
			return "World Athletics Championships"
		end
	elseif (inputName=="British Empire Games"
		or inputName=="British Empire and Commonwealth Games"
		or inputName=="British Commonwealth Games"
		or inputName=="Commonwealth Games") then
			if year <= 1950 then
				return "British Empire Games"
			elseif year <= 1966 then
				return "British Empire and Commonwealth Games"
			elseif year <= 1974 then
				return "British Commonwealth Games"
			else
				return "Commonwealth Games"
			end
	elseif inputName=="Southeast Asian Peninsular Games" or inputName=="Southeast Asian Games" then
		if year <= 1975 then
			return "Southeast Asian Peninsular Games"
		else
			return "Southeast Asian Games"
		end
	elseif inputName=="Asian Indoor Games" or inputName=="Asian Indoor and Martial Arts Games" then
		if year <= 2009 then
			return "Asian Indoor Games"
		else
			return "Asian Indoor and Martial Arts Games"
		end
	elseif inputName=="Southern Cross Games" or inputName=="South American Games" then
		if year <= 1982 then
			return "Southern Cross Games"
		else
			return "South American Games"
		end
	elseif inputName=="All-Africa Games" or inputName=="African Games" then
		if year <= 2011 then
			return "All-Africa Games"
		else
			return "African Games"
		end
	else
		return inputName
	end
end

local function teamName
	-- Modifies output of display being sent back to the hlist
	-- for games that have had a name change but are still considered
	-- the same competition.
	if inputName=="Eswatini" or inputName=="Swaziland" then
		if year < 2018 or year == 2018 and comp == 'Commonwealth Games' then
			return "Swaziland"
		else
			return "Eswatini"
		end
	elseif inputName=="Upper Volta" or inputName=="Burkina Faso" then
			if year <= 1983 then
				return "Upper Volta"
			else
				return "Burkina Faso"
			end
	elseif inputName=="Democratic Republic of the Congo" or inputName=="Zaire" then
		if year >= 1984 and year <=1996 then
			return "Zaire"
		else
			return "Democratic Republic of the Congo"
		end
	elseif (inputName=="Individual Olympic Athletes" 
		or inputName=="Independent Olympic Athletes" 
		or inputName=="Independent Olympic Participants"
		or inputName=="Olympic Athletes from Russia"
		or inputName=="ROC") then
		if year == 1992 or year==2014 then
			return "Independent Olympic Participants"
		elseif year == 2000 then
			return "Individual Olympic Athletes"
		elseif year == 2012 or year==2016 then
			return "Independent Olympic Athletes"
		elseif year == 2018 then
			return "Olympic Athletes from Russia"
		elseif year == 2020 or year==2022 then
			return "ROC"
		else
			return inputName
		end
	elseif (inputName=="Independent Paralympic Participants" 
		or inputName=="Individual Paralympic Athletes" 
		or inputName=="Independent Paralympic Athletes"
		or inputName=="RPC") then
		if year == 1992 then
			return "Independent Paralympic Participants"
		elseif year == 2000 then
			return "Individual Paralympic Athletes"
		elseif year==2016 then
			return "Independent Paralympic Athletes"
		elseif year == 2020 or year==2022 then
			return "RPC"
		else
			return inputName
		end
	elseif inputName=="North Macedonia" or inputName=="Macedonia" then
		if year < 2019 then
			return "Macedonia"
		else
			return "North Macedonia"
		end
	elseif inputName=="Malaysia" or inputName=="Malaya" then
		if year < 1963 then
			return "Malaya"
		else
			return "Malaysia"
		end
	-- 대한민국 지역
	elseif inputName=="강원특별자치도" or inputName=="강원도" then
		if year <= 2022 and comp == '전국체육대회' then
			return "강원도"
		elseif year <= 2023 and comp == '전국동계체육대회' then
			return "강원도"
		elseif year <= 2023 and comp == '전국소년체육대회' then
			return "강원도"
		else
			return "강원특별자치도"
		end
	elseif inputName=="광주광역시" or inputName=="광주직할시" then
		if year <= 1994 then
			return "광주직할시"
		else
			return "광주광역시"
		end
	elseif inputName=="대구광역시" or inputName=="대구직할시" then
		if year <= 1994 then
			return "대구직할시"
		else
			return "대구광역시"
		end
	elseif inputName=="대전광역시" or inputName=="대전직할시" then
		if year <= 1994 then
			return "대전직할시"
		else
			return "대전광역시"
		end
	elseif inputName=="부산광역시" or inputName=="부산직할시" or inputName=="부산시" then
		if year <= 1980 and comp == '전국체육대회' then
			return "부산시"
		elseif year <= 1982 and comp == '전국동계체육대회' then
			return "부산시"
		elseif year <= 1980 and comp == '전국소년체육대회' then
			return "부산시"
		elseif year <= 1994 then
			return "부산직할시"
		else
			return "부산광역시"
		end
	elseif inputName=="서울특별시" or inputName=="서울특별자유시" then
		if year <= 1948 and comp == '전국체육대회' then
			return "서울특별자유시"
		elseif year <= 1949 and comp == '전국동계체육대회' then
			return "서울특별자유시"
		else
			return "서울특별시"
		end
	elseif inputName=="인천광역시" or inputName=="인천직할시" then
		if year <= 1994 then
			return "인천직할시"
		else
			return "인천광역시"
		end
	elseif inputName=="전북특별자치도" or inputName=="전라북도" then
		if year <= 2023 then
			return "전라북도"
		else
			return "전북특별자치도"
		end
	elseif inputName=="제주특별자치도" or inputName=="제주도" then
		if year <= 2005 and comp == '전국체육대회' then
			return "제주도"
		elseif year <= 2006 and comp == '전국동계체육대회' then
			return "제주도"
		elseif year <= 2006 and comp == '전국소년체육대회' then
			return "제주도"
		else
			return "제주특별자치도"
		end
	else
		return inputName
	end
end

function p._main(args)
	load_data -- in case this function is called by another module
	local hlist = require('Module:List').horizontal
	local competitions, disqualified_years, absent_years, absent_ranges = competition_information(args)
	local current_year = os.date('!*t').year
	local function is_absent(y)
		if absent_years[y] then
			return true
		end
		for _, range in ipairs(absent_ranges) do
			if range[1] <= y and y <= range[2] then
				return true
			end
		end
		return false
	end
	local appearances = {}
	local absent_first, absent_last
	for i = 1, #competitions + 1 do -- +1 to handle any trailing absences
		local y = competitions[i]
		if y and is_absent(y) then
			if absent_first then
				absent_last = y
			else
				absent_first = y
			end
		else
			if absent_first then
				table.insert
				absent_first, absent_last = nil, nil
			end
			if y then
				local display = tostring(y)
				if y > current_year then
					display = ''
				end
				if disqualified_years[y] then
					display = ''
				end
				local compName = gameName
				local teamOut = teamName
				if compName == 'FIS Alpine World Ski Championships' then
					table.insert(appearances, string.format)
				else
					table.insert(appearances, string.format)
				end
			end
		end
	end
	return hlist(appearances)
end
				
function p.main(frame)
	load_data(frame)
	return p._main(frame:getParent.args)
end