Module:Citation

local p = {}

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

local function italics (var)
	return "''" .. var .. "''"
end

local function parenthesis (var)
	return "(" .. var .. ")"
end

function p.cite( frame )
	local pframe = frame:getParent()

	local Author = pframe.args.author
	local Year = pframe.args.year
	local Chapter = pframe.args.chapter
	local ChapterURL = pframe.args['chapter-url']
	local Section = pframe.args.section
	local Title = pframe.args.title
	local TitleURL = pframe.args['title-url']
	local Trans = pframe.args['trans-title']
	local TransLang = pframe.args['trans-lang']
	local Page = pframe.args.page
	local PDF = pframe.args.pdf
	local City = pframe.args.city
	local Publisher = pframe.args.publisher
	local ISBN = pframe.args.isbn
	local DOI = pframe.args.doi
	local LG = pframe.args.lg
	local MIA = pframe.args.mia
	local Quote = pframe.args.quote

	if is_set (Author) then
		if is_set (Year) then
			first_part = Author .. " " .. parenthesis (Year) .. "."
			else
				first_part = Author .. "."
		end
		else
			first_part = ''
	end

	if is_set (Title) then
		if is_set (TitleURL) then
			Title = "[" .. TitleURL .. " " .. Title .. "]"
			end
		if is_set (Chapter) then
			if is_set (ChapterURL) then
				if is_set (Section) then
					Chapter = "[" .. ChapterURL .. " " .. Chapter .. "]" .. ": " .. Section
				else
					Chapter = "[" .. ChapterURL .. " " .. Chapter .. "]"
				end
			end
			if is_set (Section) then
				if not is_set (ChapterURL) then
					Chapter = Chapter .. ": " .. Section
				end
			end
			second_part = "'" .. Chapter .. "'" .. " in " .. italics(Title)
			else
				second_part = italics(Title)
				if not is_set (Author) then
					if is_set (Year) then
					second_part = second_part .. " " .. parenthesis (Year)
					end
				end
		end
		
		if is_set (Trans) then
			if is_set (TransLang) then
				second_part = second_part .. " " .. "(" .. TransLang .. ": " .. Trans .. ")"
				else
					second_part = second_part .. " " .. parenthesis (Trans)
			end
		end

		if is_set (Page) then
			if tonumber(Page) ~= nil then
				Page = "p." .. " " .. Page
				else
					Page = "pp." .. " " .. Page
			end
				second_part = second_part .. " " .. parenthesis (Page) .. "."
			else
				second_part = second_part .. "."
		end
	end
	
	if is_set (PDF) then
		local span = mw.html.create ( 'span' )
		span
		:attr( 'title', 'PDF download')
		:addClass('plainlinks')
		:tag( 'small' )
		:wikitext('[' .. PDF .. " " .. mw.text.nowiki('[PDF]') .. ']')
		second_part = second_part .. " " .. tostring(span)
	end
	
	if is_set (City) then
		if is_set (Publisher) then
			third_part = City .. ": " .. Publisher .. "."
			else
				third_part = City .. "."
				end
		end

		if not is_set(City) then
			if is_set(Publisher) then
			third_part = Publisher .. "."
			else
				third_part = ''
			end
		end

	fourth_part = ''

	if is_set (ISBN) then
		local span = mw.html.create ( 'span' )
		span
		:attr( 'title', 'WorldCat')
		:addClass('plainlinks')
		:tag( 'small' )
		:wikitext('[' .. "https://www.worldcat.org/search?qt=worldcat_org_all&q=" .. ISBN .. " " .. "ISBN " .. ISBN .. ']')
		fourth_part = fourth_part .. tostring(span)
	end

	if is_set (DOI) then
		fourth_part = fourth_part .. " doi:" .. DOI
		local span = mw.html.create ( 'span' )
		span
		:attr( 'title', 'Sci-Hub link')
		:addClass('plainlinks')
		:tag( 'small' )
		:wikitext('[' .. "https://sci-hub.se/" .. DOI .. " " .. mw.text.nowiki('[HUB]') .. ']')
		fourth_part = fourth_part .." " .. tostring(span)
	end
	
	if is_set (LG) then
		local span = mw.html.create ( 'span' )
		span
		:attr( 'title', 'Library Genesis link')
		:addClass('plainlinks')
		:tag( 'small' )
		:wikitext('[' .. LG .. " " .. mw.text.nowiki('[LG]') .. ']')
		fourth_part = fourth_part .." " .. tostring(span)
	end
	
	if is_set (MIA) then
		local span = mw.html.create ( 'span' )
		span
		:attr( 'title', 'Marxists Internet Archive link')
		:addClass('plainlinks')
		:tag( 'small' )
		:wikitext('[' .. MIA .. " " .. mw.text.nowiki('[MIA]') .. ']')
		fourth_part = fourth_part .." " .. tostring(span)
	end
	
	if is_set (Quote) then
		Quote = "“" .. Quote .. "”"
		local div = mw.html.create ('div')
		div
		:attr("style", "width:80%; margin-left:10%;")
		:wikitext(Quote)
		local br = mw.html.create ('br', selfClosing)
		first_part = italics(tostring(div)) .. tostring(br) .. first_part
	end
		
	
	if is_set (second_part) then
		second_part = " " .. second_part
	end
	
	if is_set (third_part) then
		third_part = " " .. third_part
	end
	
	if is_set (fourth_part) then
		fourth_part = " " .. fourth_part
	end	

	return first_part .. second_part .. third_part .. fourth_part
end
return p