-- This module implements Template:Engvar.

-- Template:Engvar is to be build into the template (like an infobox), with default & variant spellings defined.

-- That template should also allow parameter '|engvar=' for the editor (article page).

-- The module/template Engvar then returns the spelling variant as is set in that article (for example '|engvar=en-GB').

-- The defaultWord is returned, unless the engvar input hits on a defined (en-XX) variant word.

local p = {}

local getArgs = require('Module:Arguments').getArgs

local gsub = string.gsub

local lower = string.lower

local upper = string.upper



function p.variants(frame)

local args = getArgs(frame)

	return p._variants(args)

end



function p._variants(args)

local returnWord = nil



	local defaultWord = args.defaultWord or ''

	if args.engvar == nil then

		-- Nothing to look for; use defaultWord right away

		returnWord = defaultWord

	elseif args.defaultLang == gsub(lower(args.engvar), '^en%-(%w%w)$', formatISO) then

		-- By the defaultLang, the defaultWord is asked

		returnWord = defaultWord

	else

		returnWord = argsgsub(lower(args.engvar), '^en%-(%w%w)$', formatISO)]

	end



	if returnWord == nil then

		-- No hit so far. Search by words in the engvar entered, checking the list

		local useLang = engvarLang(args.engvar)

		if useLang == nil then

			returnWord = defaultWord .. addMaintCat(args)

		else

			returnWord = argsuseLang or defaultWord

		end

	end



	return returnWord

end



-- Returns arguments and intermediate result. Plus the template result, in front.

function p.explain(frame)

local args = getArgs(frame)

local ret = {}

	table.insert(ret, '\n\n: Settings:')

	table.insert(ret, 'defaultWord=' .. (args.defaultWord or '') .. '; ')

	table.insert(ret, 'defaultLang=' .. (args.defaultLang or '') .. '; ')

	table.insert(ret, 'engvarCat=' .. (args.engvarCat or '[default:yes]') .. '; ')

	table.insert(ret, 'engvarCatSort=' .. (args.engvarCatSort or ''))

	table.insert(ret, '\n\n: engvar=' .. (args.engvar or '') .. ' [input] ')

	local useLang = engvarLang(args.engvar or '')

	table.insert(ret, ' => Engvar code [used]: >' .. (useLang or '') .. '<.')

	

	for k, v in pairs(args) do

		if k == 'en-UK' then

			table.insert(ret, k .. ' ? better: use "en-GB"; ')

		elseif k == 'en-SA' then

			table.insert(ret, k .. ' ? misleading; use "en-ZA"; ')

		end

		

		if k == 'defaultWord' then

		elseif k == 'defaultLang' then

		elseif k == 'engvar' then

		elseif k == 'engvarcat' then

		elseif k == gsub(lower(k), '^en%-(%w%w)$', formatISO) then

			table.insert(ret, k .. '=' .. v .. '; ')

		else

			table.insert(ret, k .. ' [not standard:]=' .. v .. '; ')

		end



	end

	return (args.engvar or '') .. ' => ' .. p._variants(args) .. table.concat(ret, ' ')

end



-- Turn a match into pattern 'en-XX'

function formatISO(country)

	return ('en-' .. upper(country) or '')

end



function engvarLang(searchEngvar)

-- Search verbose language identifiers to ISO-format 'en-XX'

-- Assumed: not a blank string '' to search

local match = string.match



	searchEngvar = gsub(searchEngvar, '^%s*en%-(.*)', '%1') -- rm any opening 'en-'.

	searchEngvar = gsub(lower(searchEngvar), '[%s%(%)%-]', '') -- To lc, remove all: (, ) , ws, hyphen.

	local useLang

	--Special codes

	if match(searchEngvar, 'oxford')

		or searchEngvar == 'oed' then

			useLang = 'en-OED' -- 'oxford' to catch before anyting 'british'

	elseif match(searchEngvar, 'iupac') then

			useLang = 'en-IUPAC' -- chemistry

	-- Very often used

	elseif match(searchEngvar, 'british')

		or searchEngvar == 'uk'

		or searchEngvar == 'gbr' then

			useLang = 'en-GB'

	elseif searchEngvar == 'us'

		or match(searchEngvar, 'unitedstates')

		or searchEngvar == 'american'

		or searchEngvar == 'usa' then

			useLang = 'en-US'

	elseif match(searchEngvar, 'australia')

		or searchEngvar == 'aus' then

			useLang = 'en-AU'

	-- Often used

	elseif match(searchEngvar, 'india')

		or searchEngvar == 'ind' then

			useLang = 'en-IN'

	elseif searchEngvar == 'newzealand'

		or searchEngvar == 'nzl' then

			useLang = 'en-NZ'

	elseif match(searchEngvar, 'southafrica') -- not: en-SA

		or searchEngvar == 'zaf' then

			useLang = 'en-ZA'

	elseif searchEngvar == 'canada'

		or searchEngvar == 'can' then

			useLang = 'en-CA'

	elseif match(searchEngvar, 'hiberno')

		or match(searchEngvar, 'ireland')

		or match(searchEngvar, 'irish')

		or searchEngvar == 'irl' then

			useLang = 'en-EI'

	elseif match(searchEngvar, 'hongkong')

		or searchEngvar == 'hkg' then

			useLang = 'en-HK'

	-- Less often used

	elseif match(searchEngvar, 'jamaica')

		or searchEngvar == 'jam' then

			useLang = 'en-JM'

	elseif match(searchEngvar, 'malawi')

		or searchEngvar == 'mwi' then

			useLang = 'en-MW'

	elseif match(searchEngvar, 'nigeria')

		or searchEngvar == 'nga' then

			useLang = 'en-NG'

	elseif match(searchEngvar, 'pakistan')

		or searchEngvar == 'pak' then

			useLang = 'en-PK'

	elseif match(searchEngvar, 'philippine')

		or searchEngvar == 'phl' then

			useLang = 'en-PH'

	elseif match(searchEngvar, 'scotland')

		or match(searchEngvar, 'scottish')

		or searchEngvar == 'sco' then

			useLang = 'en-SCO' -- Has no alpha-2 code; not 'scotch'

	elseif match(searchEngvar, 'singapore')

		or searchEngvar == 'sgp' then

			useLang = 'en-SG'

	elseif match(searchEngvar, 'trinidad')

		or match(searchEngvar, 'tobago')

		or searchEngvar == 'tto' then

			useLang = 'en-TT'

	else

		useLang = nil

	end

	

	return useLang

end



function addMaintCat(args)

local catMaintenance

	if args.engvarCat == 'no' then

	else

		local title = mw.title.getCurrentTitle()

		if title:inNamespaces(0) then  -- 0=main, 10=templ, 828=module

			if args.engvarCatSort then

				catMaintenance = '|' .. args.engvarCatSort .. ', ' .. title.text

			end

			catMaintenance = '[[Category:Articles using an unknown Template:Engvar option' .. (catMaintenance or '') .. ']]'

		end

	end

	return catMaintenance or ''

end



return p