Module:Library citation

local p = {}

local function checkset(var)
	local rtn = ""
	if not (var == nil or var == '') then
		rtn = var
	end
	return rtn
end

local function is_set(var)
	return not (var == nil or var == '')
end

local function removeApostrophes(str)
    return str:gsub("[\"'%`]", "")
end

local function compareStrings(a,b)
	local stringA = removeApostrophes(a):lower()
    local stringB = removeApostrophes(b):lower()
    return stringA < stringB
end

function listOfWorks(author) 
	local newMethod = mw.getCurrentFrame():callParserFunction("#dpl","namespace=Library","titleregexp=" .. author .. "/[^/]+$","format=,%TITLE%\\n")
	local catMethod = mw.getCurrentFrame():callParserFunction("#dpl","namespace=Library","category=Library works by " .. author ,"format=,%TITLE%\\n")
	local list = ""
	-- Picks whatever method of recovering pages has the higher count, usually categories
	if string.len(newMethod) > string.len(catMethod) then
		list = newMethod
		else
			list = catMethod
	end
	titleTable = mw.text.split(string.gsub(mw.text.trim(list),author .. "/",""),"\n")
	linkTable=mw.text.split(mw.text.trim(list),"\n")
	for i,v in ipairs(linkTable) do
		linkTable[i] = "Library:" .. v
	end
	table.sort(linkTable,compareStrings)
	table.sort(titleTable,compareStrings)
	return {links=linkTable,titles=titleTable}
end

function getYearFromTitle(title)
	local roughYear = mw.getCurrentFrame():callParserFunction("#dpl","namespace=Library","title=" .. title,"mode=userformat","include={Library work}:published_date")
	return roughYear:match("%d%d%d%d")
end

function p.cite(frame)
	-- Parent frame to get parameters from template calls instead of from {{#invoke: ...
	local parentFrame = frame:getParent()
	-- get arguments from "args" table pre-defined by MediaWiki/Scribunto
	local link = checkset(parentFrame.args.link)
	local author = checkset(parentFrame.args.author)
	local work = checkset(parentFrame.args.work)
	-- error("error message") to send error messages
	-- mw.log(mw.getCurrentFrame():callParserFunction("#dpl","namespace=Library","titleregexp=Vladimir Lenin/[^/]+$","format=,%PAGE%\\n"))
	-- mw.log(mw.getCurrentFrame():callParserFunction("#dpl","namespace=Library","category=Library works by Vladimir Lenin","format=,%PAGE%\\n"))
	return listOfWorks(author)
end

return p