Mô đun:Ilh

-- based on the Chinese implementation: https://zh.wikipedia.org/wiki/模块:Ilh
-- used for Vietnamese Wikipedia

-- initial section
local ilh = {}
local getArgs = require("Module:Arguments").getArgs
local yesno = require("Module:Yesno")
--[[
   from jirutka's implementation: https://gist.github.com/jirutka/666bccf338097b87873c447544c12424
   abuse % operator for string interpolation (use a template syntax similar to JavaScript)
   you can actually use this in the same way as str.format
   for instance: "${hello} ${world}" % {['hello'] = "Hello", ['world'] = 'World'}
   or: "%s %s" % {"Hello", "World"}
   --> Hello World
--]]
function o(str)
   if type(str) ~= "string" then
      error("the o func only receives string!")
   end
   return setmetatable({str}, {
      __mod = function(str, args)
         str = str[1]
         if type(args) ~= "table" then
            args = {args}
         end
         return str:format(unpack(args)):gsub("($%b{})", function(placeholder)
            return args[mw.text.trim(placeholder:sub(3, -2))] or placeholder
         end)
      end
   })
end
function createOutputBuilder()
   local methods = {
      insert = table.insert,
      join = table.concat,
   }
   return setmetatable({}, {
      __index = function(t, key) 
         return methods[key]
      end
   });
end

-- implementating section
function ilh.main(frame)
   local args = getArgs(frame, {parentFirst = true})
   return ilh._ilh(args)
end

function ilh._ilh(args)
   local context = {}
   context.isMainPage = ilh.isMainPage()
   context.localPage = args[1] -- local page's name
   context.foreignPage = args[2] or args[1] -- foreign page's name
   context.displayName = ilh.displayName(args)
   context.langCode = args["lang-code"]
   context.lang = args.lang
   context.nocat = yesno(args.nocat, false) -- standardize the "nocat" field to boolean type

   -- does the local page exist?
   context.isExist = (args["$exist$"] and args["$exist$"] == 1) or ilh.isExist(context.localPage)

   -- get current page object
   local curPage_obj = mw.title.getCurrentTitle()

   -- is the current page in User (2) or Module (828) namespace?
   context.isNoCatWithNamespace = curPage_obj:inNamespaces(2, 828)

   -- if we are at the main page, just give the link only
   -- else, we return an "interlanguage link"
   return (context.isMainPage and ilh.onlyLink(context)) or ilh.functionLink(context)
end

--[[
   if the local page exists, return a link to it (use displayName as... display name),
   if not, return displayName
--]]
function ilh.onlyLink(context)
   return context.isExist and (o"[[${localPage}|${displayName}]]" % context) or context.displayName
end
--[[
   create interlanguage link html
--]]
function ilh.functionLink(context)
   -- escape double quote
   context._localPage = context.localPage:gsub('"', """)
   context._foreignPage = context.foreignPage:gsub('"', """)

   context._blue_link_class = (context.isExist and "ilh-blue") or ""
   context._alternativePage = context.foreignPage or context.localPage

   -- are we allowed to use Category:Interlanguage_link_template_existing_link?
   local need_cat = not (context.nocat or context.isNoCatWithNamespace)

   local output_html = createOutputBuilder()
   output_html:insert(
      o'<span class="ilh-all ${_blue_link_class}" data-orig-title="${_localPage}" data-lang-code="${langCode}" data-lang-name="${lang}" data-foreign-title="${_foreignPage}">' % context)
   output_html:insert('<span class="ilh-page">')
   output_html:insert(o"[[${localPage}|${displayName}]]" % context)
   output_html:insert("</span>")
   if context.isExist then
      if need_cat then
         -- https://en.wikipedia.org/wiki/Category:Interlanguage_link_template_existing_link
         output_html:insert("[[Thể loại:Liên kết có tồn tại trong bản mẫu Interlanguage link]]")
      end
   else
      output_html:insert('<span class="noprint ilh-comment"> (')
      output_html:insert('<span class="ilh-lang">' .. context.lang .. "</span>")

      output_html:insert('<span class="ilh-colon">: </span>')

      output_html:insert('<span class="ilh-link">')
      output_html:insert(
         o'[[:${langCode}:${_alternativePage}|<span lang="${langCode}" dir="auto">${_alternativePage}</span>]]' % context
      )
      output_html:insert("</span>")
      output_html:insert(") </span>")
   end
   output_html:insert("</span>")

   return output_html:join("")
end
-- the implementations below use some pretty expensive methods/properties of mw module
-- maybe there will be more efficient implementations in the future
--[[ 
   resolve displayName from args, return ('3' or 'd' or '1') field in args 
--]]
function ilh.displayName(args)
   return args["3"] or args["d"] or args["1"]
end

--[[ 
   check if the current page is the main page 
--]]
function ilh.isMainPage()
   local mainpage_msgobj = mw.message.new("Mainpage")
   mainpage_msgobj = mainpage_msgobj:inLanguage(mw.getContentLanguage():getCode())
   local mainPage_obj = mw.title.makeTitle(0, mainpage_msgobj:plain())
   local curpage_obj = mw.title.getCurrentTitle()
   return mw.title.equals(mainPage_obj, curpage_obj)
end

--[[ 
   a wrapper of ilh._isExist to handle its' potential thrown error 
--]]
function ilh.isExist(pageName)
   local execStatus, result = pcall(ilh._isExist, pageName)

   if execStatus then
      return result
   else
      return false
   end
end

--[[ 
   check if there is a page named <pageName>
--]]
function ilh._isExist(pageName)
   local localPage_obj = mw.title.makeTitle(0, pageName)
   return localPage_obj.exists
end

return ilh