local p = {}

function p._fetch(args)
	local template = nil
	local return_value = nil

	-- Use demo parameter if it exists, otherwise use current template name
	local namespace = mw.title.getCurrentTitle().namespace
	if args["demo"] and args["demo"] ~= "" then
		template = mw.ustring.gsub(args["demo"],"^[Tt]emplate:","")
	elseif namespace == 10 then -- Template namespace
		template = mw.title.getCurrentTitle().text
	elseif namespace == 828 then -- Module namespace
		template = (mw.site.namespaces[828].name .. ":" .. mw.title.getCurrentTitle().text)
	end

	-- If in template or module namespace, look up count in /data
	if template ~= nil then
		namespace = mw.title.new(template, "Template").namespace
		if namespace == 10 or namespace == 828 then
			template =  mw.ustring.gsub(template, "/doc$", "") -- strip /doc from end
			template =  mw.ustring.gsub(template, "/sandbox$", "") -- strip /sandbox from end
			local index = mw.ustring.sub(mw.title.new(template).text,1,1)
			local status, data = pcall(function ()
				return(mw.loadData('Module:Transclusion_count/data/' .. (mw.ustring.find(index, "%a") and index or "other")))
			end)
			if status then
				return_value = tonumber(data[mw.ustring.gsub(template, " ", "_")])
			end
		end
	end
	
	-- If database value doesn't exist, use value passed to template
	if return_value == nil and args[1] ~= nil then
		local arg1=mw.ustring.match(args[1], '[%d,]+')
		if arg1 and arg1 ~= '' then
			return_value = tonumber(mw.getCurrentFrame():callParserFunction('formatnum', arg1, 'R'))
		end
	end
	
	return return_value	
end

function p.fetch(frame)
	return p._fetch(frame.args)
end

-- Tabulate this data for [[Wikipedia:Database reports/Templates transcluded on the most pages]]
function p.tabulate()
	local list = {}
	for i = 65, 91 do
		local data = mw.loadData('Module:Transclusion count/data/' .. ((i == 91) and 'other' or string.char(i)))
		for name, count in pairs(data) do
			local title = mw.title.new(name, "Template")
			table.insert(list, {title, count})
		end
	end
	table.sort(list, function(a, b)
		return (a[2] == b[2]) and (a[1] < b[1]) or (a[2] > b[2])
	end)
	local lang = mw.getContentLanguage();
	for i = 1, #list do
		local protLevel = ""
		local title = list[i][1]
		if i < 400 then
			-- Stop at 400 to avoid breaching the expensive parser function call limit
			protLevel = title.protectionLevels.edit[1] or "(unprotected)"
		end
		list[i] = ('|-\n| %d || [[%s]] || %s || %s \n'):format(i, title.fullText:gsub('_', ' '), lang:formatNum(list[i][2]), protLevel)
	end
	return table.concat(list)
end

return p