Module:Urltowiki

-- This module takes a URL from a Wikimedia project and returns the equivalent wikitext. 
-- Any actions such as edit, history, etc., are stripped, and percent-encoded characters 
-- are converted to normal text.

local p = {}
local current_lang = mw.language.getContentLanguage()

local interwiki_table = mw.loadData("Module:InterwikiTable")

local function getHostId(host)
 if type(host) ~= "string" then return end
 for id, t in pairs(interwiki_table) do
  if mw.ustring.match(host, t.domain) and t.domain_primary then -- Match partial domains (e.g. "www.foo.org" and "foo.org") but don't match non-primary domains.
   return id
  end
 end
end

local function getInterwiki(host)
 -- This function returns a table with information about the interwiki prefix of the specified host.
 local ret = {}

 -- Return a blank table for invalid input.
 if type(host) ~= "string" then
  return ret
 end

 -- Get the host ID.
 host = mw.ustring.lower(host)
 local host_id = getHostId(host)
 if not host_id then
  return ret
 end
 ret.host_id = host_id

 -- Find the language in the interwiki prefix, if applicable.
 local lang = mw.ustring.match(host, "^(.-)%.") -- Find the text before the first period.
 if not lang or not mw.language.isSupportedLanguage(lang) then -- Check if lang is a valid language code.
  lang = false
 end
 -- A language prefix is not necessary if there is already a language prefix for the host in the interwiki table.
 local domain_lang = mw.ustring.match(interwiki_table[host_id].domain, "^(.-)%.") -- Find the text before the first period.
 if  mw.language.isSupportedLanguage(domain_lang) then
  lang = false
 end
 ret.lang = lang

 -- No need for an interwiki link if we are on the same site as the URL.
 local current_host = mw.uri.new(mw.title.getCurrentTitle():fullUrl()).host -- Get the host portion of the current page URL.
 if host == current_host then
  return ret
 end

 -- Check if the URL language is the same as the current language.
 local same_lang
 if lang and lang == mw.ustring.match(current_host, "^(.-)%.") then
  same_lang = true
 end

 -- Check if the project is the same as the current project (but a different language).
 local current_host_id = getHostId(current_host)
 local same_project
 if current_host_id == host_id then
  same_project = true
 end

 -- Find the interwiki prefix.
 local interwiki
 local project = interwiki_table[host_id].iw_prefix[1]
 if same_lang or ( not lang and interwiki_table[host_id].takes_lang_prefix == false ) then
  interwiki = project
 elseif same_project then
  interwiki = lang
 elseif not lang then -- If the language code is bad but the rest of the host name is ok.
  interwiki = nil
 else
  interwiki = project .. ":" .. lang
 end   
 ret.interwiki = interwiki

 return ret
end

function p._urlToWiki(args)
 -- Check the input is valid.

 local input = args[1] or args.url
 if type(input) ~= "string" then
  if args.error ~= "no" then
   if type(input) == "nil" then
    error("No URL specified", 2)
   else
    error("The URL must be a string value", 2)
   end
  else
   return ""
  end
 end
 input = mw.text.trim(input)

 -- Get the URI object.
 url = mw.uri.new(input)
 local host = url.host

 -- Get the interwiki prefix.
 local interwiki, lang, host_id
 if host then
  local iw_data = getInterwiki(host)
  interwiki, lang, host_id = iw_data.interwiki, iw_data.lang, iw_data.host_id
 end
 local link = true -- This decides whether the resulting wikitext will be linked or not. Default is yes.
 if args.link == "no" then
  link = false
 end

 -- Get the page title.
 local pagetitle, title_prefix
 if host_id and not ( interwiki_table[host_id].takes_lang_prefix == true and not lang ) then
  title_prefix = interwiki_table[host_id].title_prefix
 end
 -- If the URL path starts with the title prefix in the interwiki table, use that to get the title.
 if title_prefix and mw.ustring.sub(url.path, 1, mw.ustring.len(title_prefix)) == title_prefix then
  pagetitle = mw.ustring.sub(url.path, mw.ustring.len(title_prefix) + 1, -1)
  -- Else, if the URL is a history "index.php", use url.query.title. Check for host_id
  -- in case the URL isn't of a Wikimedia site.
 elseif host_id and mw.ustring.match(url.path, "index%.php") and url.query.title then
  pagetitle = url.query.title
  -- Special case for Bugzilla.
 elseif host_id == "bugzilla" and url.query.id then
  pagetitle = url.query.id
 elseif host_id == "bugzilla" and not url.query.id then
  interwiki = false -- disable the interwiki prefix as we are returning a full URL.
  link = false -- don't use double square brackets for URLs.
  pagetitle = tostring(url)
  -- If the URL is valid but not a recognised interwiki, use the URL and don't link it.
 elseif host and not host_id then
  link = false -- Don't use double square brackets for URLs.
  pagetitle = tostring(url)
  -- Otherwise, use our original input minus any fragment
 else
  pagetitle = mw.ustring.match(input, "^(.-)#") or input
 end

 -- Get the fragment and pre-process percent-encoded characters.
 local fragment = url.fragment -- This also works for non-urls like "Foo#Bar".
 if fragment then
  fragment = mw.ustring.gsub(fragment, "%.([0-9A-F][0-9A-F])", "%%%1")
 end

 -- Assemble the wikilink.
 local wikitext = pagetitle
 if interwiki then
  wikitext = interwiki .. ":" .. wikitext
 end
 if fragment and not (args.section == "no") then
  wikitext = wikitext .. "#" .. fragment
 end

 -- Decode percent-encoded characters and convert underscores to spaces.
 wikitext = mw.uri.decode(wikitext, "WIKI")
 -- If the wikitext is to be linked, re-encode illegal characters. Don't re-encode 
 -- characters from invalid URLs to make the default [[{{{1}}}]] display correctly.
 if link and host then
  wikitext = mw.ustring.gsub(wikitext, "[<>%[%]|{}%c\n]", mw.uri.encode)
 end

 -- Find the display value
 local display
 if link then
  display = args[2] or args.display -- The display text in piped links.
  if (display and type(display) ~= "string") then
   if args.error ~= "no" then
    error("Non-string display value detected")
   else
    display = nil
   end
  end
  if display then
   display = mw.text.trim(display) -- Trim whitespace.
   -- If the page name is the same as the display value, don't pipe
   -- the link.
   if current_lang:lcfirst(wikitext) == display then
    wikitext = display
    display = nil
   elseif wikitext == display then
    display = nil
   end
  end
 end

 -- Use the [[Help:Colon trick]] with categories, interwikis, and files.
 local colon_prefix = mw.ustring.match(wikitext, "^(.-):.*$") or "" -- Get the text before the first colon.
 local ns = mw.site.namespaces
 local need_colon_trick
 if mw.language.isSupportedLanguage(colon_prefix) -- Check for interwiki links.
  or current_lang:lc(ns[6].name) == current_lang:lc(colon_prefix) -- Check for files.
  or current_lang:lc(ns[14].name) == current_lang:lc(colon_prefix) then -- Check for categories.
  need_colon_trick = true
 end
 for i,v in ipairs(ns[6].aliases) do -- Check for file namespace aliases.
  if current_lang:lc(v) == current_lang:lc(colon_prefix) then
   need_colon_trick = true
   break
  end
 end
 for i,v in ipairs(ns[14].aliases) do -- Check for category namespace aliases.
  if current_lang:lc(v) == current_lang:lc(colon_prefix) then
   need_colon_trick = true
   break
  end
 end
 -- Don't use the colon trick if the user says so or if we are not linking
 -- (due to [[bugzilla:12974]]).
 if need_colon_trick and link and args.colontrick ~= "no" then
  wikitext = ":" .. wikitext
 end

 -- Make the link
 if link then
  if display then
   wikitext = wikitext .. '|' .. display
  end
  wikitext = "[[" .. wikitext .. "]]"
 end

 return wikitext
end

function p.urlToWiki(frame)
 local args = require('Module:Arguments').getArgs(frame, {
  wrappers = {'Template:Urltowiki','Template:Urltowiki/sandbox'}
 })
 return p._urlToWiki(args)
end

return p