local p = {}
local htmlerror = require('Module:Error').error

function p.replyto(frame)
	local origArgs = frame:getParent().args
	local args = {}
	local maxArg = 0
	for k, v in pairs(origArgs) do
		if type(k) == 'number' then
			if v:match('%S') then
				if k > maxArg then maxArg = k end
				local title = mw.title.new(v)
				if not title then
					return htmlerror{'Error in [[Template:Reply to]]: Input contains forbidden characters.'}
				end
				args[k] = title.baseText
			end
		else
			args[k] = v
		end
	end

	if maxArg == 0 then
		if frame.args.example then args[1] = frame.args.example else return htmlerror{'Error in [[Template:Reply to]]: Username not given.'} end
	end

	if maxArg > (tonumber(frame.args.max) or 50) then
		return htmlerror{'Error in [[Template:Reply to]]: More than '..tostring(frame.args.max or 50)..' names specified.'}
	else
		local outStr = '<span class="template-ping">'..(args['prefix'] or '@')..'[[:User:'..args[1]..'|'..((args['label1'] or args['label']) or args[1])..']]'
		for i = 2, maxArg do
			if ( (maxArg > 2) or ((maxArg == 2) and (args['c'] == '')) ) then outStr = outStr.."," end
			if i == maxArg then outStr = outStr.." "..(args['c'] or "and") end
			outStr = outStr.." [[:User:"..args[i].."|"..(args['label'..tostring(i)] or args[i]).."]]"
		end
		outStr = outStr..(args['p'] or ":").."</span>"
		return outStr
	end
end

return p