-- This module provides functions and objects for dealing with interwiki links.



local checkType = require('libraryUtil').checkType

local interwikiData = mw.loadData('Module:Interwiki extra/data')



--------------------------------------------------------------------------------

-- Prefix class

--------------------------------------------------------------------------------



local Prefix = {}

Prefix.__index = Prefix



function Prefix.new(code)

	checkType('Prefix.new', 1, code, 'string')

	local obj = setmetatable({}, Prefix)

	local data = interwikiData.prefixescode

	if not data then

		return nil

	end

	for k, v in pairs(data) do

		objk = v

	end

	return obj

end



function Prefix:makeUrl(page)

	checkType('makeUrl', 1, page, 'string')

	-- In MediaWiki, interlanguage links are wiki-encoded (spaces are encoded

	-- as underscores), even if the site is not a wiki and underscores don't

	-- make sense. So we do the same here.

	page = mw.uri.encode(page, 'WIKI')

	return mw.message.newRawMessage(self.url, page):plain()

end



function Prefix:isValidUrl(url)

	checkType('isValidUrl', 1, url, 'string')

	local obj1 = mw.uri.new(self.url)

	local obj2 = mw.uri.new(url)

	if not obj2 then

		return false

	elseif obj1.protocol and obj1.protocol ~= obj2.protocol then

		-- Protocols only have to match if the prefix URL isn't protocol-relative

		return false

	elseif obj1.host ~= obj2.host then

		return false

	end

	local function makePathQuery(obj)

		return obj.path .. (obj.queryString or '')

	end

	local pathQuery1 = makePathQuery(obj1)

	local pathQuery2 = makePathQuery(obj2)

	-- Turn pathQuery1 into a string pattern by escaping all punctuation, then

	-- replacing the "$1" parameter (which will have become "%$1") with ".*"

	local pattern = pathQuery1:gsub('%p', '%%%0'):gsub('%%$1', '.*')

	pattern = '^' .. pattern .. '$'

	return pathQuery2:find(pattern) ~= nil

end

local langcode = {

	'bat_smg'      = 'bat-smg',

	'be_x_old'     = 'be-x-old',

	'cbk_zam'      = 'cbk-zam',

	'fiu_vro'      = 'fiu-vro',

	'map_bms'      = 'map-bms',

	'nds_nl'       = 'nds-nl',

	'roa_rup'      = 'roa-rup',

	'roa_tara'     = 'roa-tara',

	'zh_classical' = 'zh-classical',

	'zh_min_nan'   = 'zh-min-nan', -- a comma have to be added when new lines are added

	'zh_yue'       = 'zh-yue'

	}



local siteexcludes = {

	'metawiki' = true,

	'mediawikiwiki' = true,

	'commonswiki' = true,

	'wikidatawiki' = true,

	'specieswiki' = true,

	'enwiki' = true

}

function Prefix.interwiki(frame)

	local s = setmetatable({}, {__index = table})

	local entity = mw.wikibase.getEntity()

	-- use qid parameter if provided, otherwise follow P460

	local qid = frame.args.qid or frame:getParent().args.qid or frame.args1 or frame:getParent().args1 or ''

	if not mw.wikibase.isValidEntityId(qid) then

		qid = nil

		-- access the first valid value of P460

		for i, statement in pairs(entity:getBestStatements[[P460]]) do

			if statement.mainsnak.snaktype == 'value' then

				qid = statement.mainsnak.datavalue.value'id'

				break

			end

		end

	end

	if qid then

		local entity2 = mw.wikibase.getEntity(qid)

		if entity2 and entity2.sitelinks then

			for i, j in pairs(entity2.sitelinks) do

				-- exclude the own wiki and some wikiprojects that are not Wikipedia, even if their code ends with 'wiki'

				if not siteexcludesj.site then

					-- exclude Wikisource, Wikiquote, Wikivoyage etc

					if mw.ustring.sub( j.site, mw.ustring.len(j.site) - 3 ) == 'wiki' then

						local lang = langcodemw.ustring.sub( j.site, 1, mw.ustring.len(j.site) - 4 )] or mw.ustring.sub( j.site, 1, mw.ustring.len(j.site) - 4 )

						-- exclude interwiki to projects that already have sitelinks in the present page

						if (entity and not entity.sitelinksj.site]) or not entity then

							-- put together a interwiki-link to other projects

							s:insert( '[[' .. lang .. ':' .. j.title .. ']]' )

						end

					end

				end

			end

		end

	end

	if #s > 0 then 

		s:insert("[[Category:Module:Interwiki extra: additional interwiki links]]")

	end

	return s:concat('')



end



return Prefix