Module:URL

-- -- This module implements {{URL|example.com|optional display text}} -- -- See unit tests at Module:URL/tests

local p = {}

function trim(s)

   return (mw.ustring.gsub(s, "^%s*(.-)%s*$", "%1"))

end

function safeUri(s)

   local success, uri = pcall(function()
       return mw.uri.new(s)
   end)
   if success then
       return uri
   end

end

function p._url(url, text)

   url = trim(url or )
   text = trim(text or )
   
   if url ==  then
       if text ==  then
           return mw.getCurrentFrame():expandTemplate{ title = 'tlx', args = { 'URL', "example.com", "optional display text" } }
       else
           return text
       end
   end
   
   -- If the URL contains any unencoded spaces, encode them, because MediaWiki will otherwise interpret a space as the end of the URL.
   url = mw.ustring.gsub(url, '%s', function(s) return mw.uri.encode(s, 'PATH') end)
   
   -- If there is an empty query string or fragment id, remove it as it will cause mw.uri.new to throw an error
   url = mw.ustring.gsub(url, '#$', )
   url = mw.ustring.gsub(url, '%?$', )
   
   -- If it's an HTTP[S] URL without the double slash, fix it.
   url = mw.ustring.gsub(url, '^[Hh][Tt][Tt][Pp]([Ss]?):(/?)([^/])', 'http%1://%3')

   -- Handle URLs from Wikidata of the format http://
   url = mw.ustring.gsub(url, '^[Hh][Tt][Tt][Pp]([Ss]?)://', 'http%1://')
   
   local uri = safeUri(url)
   
   -- Handle URL's without a protocol and URL's that are protocol-relative, 
   -- e.g. www.example.com/foo or www.example.com:8080/foo, and //www.example.com/foo
   if uri and (not uri.protocol or (uri.protocol and not uri.host)) and url:sub(1, 2) ~= '//' then
       url = 'http://' .. url
       uri = safeUri(url)
   end
   
   if text ==  then
       if uri then
           if uri.path == '/' then uri.path =  end
           
           local port = 
           if uri.port then port = ':' .. uri.port end
           
           text = mw.ustring.lower(uri.host or ) .. port .. (uri.relativePath or )
       else -- URL is badly-formed, so just display whatever was passed in
           text = url
       end
   end

   return mw.ustring.format('[%s %s]', url, text)

end

function p.url(frame)

   local templateArgs = frame.args
   local url = templateArgs[1] or 
   local text = templateArgs[2] or 
   return p._url(url, text)

end

return p