# Module:Template translation

local this = {}  

function this.checkLanguage(subpage, default)  
--[[Check first if there's an any invalid character that would cause the  
mw.language.isKnownLanguageTag function to throw an exception:  
- all ASCII controls in [\000-\031\127],  
- double quote ("), sharp sign (#), ampersand (&), apostrophe ('),  
- slash (/), colon (:), semicolon (;), lower than (<), greater than (>),  
- brackets and braces ([, ], {, }), pipe (|), backslash (\\)  
All other characters are accepted, including space and all non-ASCII  
characters (including \192, which is invalid in UTF-8).  
--]]  
if mw.language.isValidCode(subpage) and mw.language.isKnownLanguageTag(subpage)  
--However "SupportedLanguages" are too restrictive, as they discard many  
valid BCP47 script variants (only because MediaWiki still does not  
define automatic transliterators for them, e.g. "en-dsrt" or  
"fr-brai" for French transliteration in Braille), and country variants,  
(useful in localized data, even if they are no longer used for  
translations, such as zh-cn, also useful for legacy codes).  
We want to avoid matching subpagenames containing any uppercase letter,  
(even if they are considered valid in BCP 47, in which they are  
case-insensitive; they are not "SupportedLanguages" for MediaWiki, so  
they are not "KnownLanguageTags" for MediaWiki).  
To be more restrictive, we exclude tags  
- for specific uses in template subpages and unusable as language tags;
- that is not ASCII and not a lowercase letter, minus-hyphen, or digit,
or does not start by a letter or does not finish by a letter or digit;  
- or that has subtags with more than 8 characters between hyphens;
- or that has two hyphens.
---
or subpage ~= "doc"  
and subpage ~= "layout"  
and subpage ~= "button"  
and subpage ~= "buttons"  
and subpage ~= "sandbox"  
and subpage ~= "testcase"  
and subpage ~= "testcases"  
and string.find(subpage, "^[%l][%-%d%l]*[%d%l]$") ~= nil  
and string.find(subpage, "[%d%l][%d%l][%d%l][%d%l][%d%l][%d%l][%d%l][%d%l][%d%l]") == nil  
and string.find(subpage, "%-%-") == nil then  
return subpage  
end  
-- Otherwise there's currently no known language subpage  
return default  
end  

--Get the last subpage of an arbitrary page if it is a translation.  
To be used from templates.  

function this.getLanguageSubpage  
local title = and .args[1]  
if not title or title == '' then  
title = mw.title.getCurrentTitle  
end  
return this._getLanguageSubpage(title)  
end  

--Get the last subpage of an arbitrary page if it is a translation.  
To be used from Lua.  

function this._getLanguageSubpage(title)  
if type(title) == 'string' then  
title = mw.title.new(title)  
end  
if not title then  
-- invalid title  
return nil  
end  
--This code does not work in all namespaces where the Translate tool works.  
-- It works in the main namespace on Meta because it allows subpages there  
-- It would not work in the main namespace of English Wikipedia (but the  
-- articles are monolignual on that wiki).  
-- On Meta-Wiki the main space uses subpages and its pages are translated.  
-- The Translate tool allows translatng pages in all namespaces, even if  
-- the namespace officially does not have subpages.  
-- On Meta-Wiki the Category namespace still does not have subpages enabled,  
-- even if they would be very useful for categorizing templates, that DO have  
-- subpages (for documentatio and tstboxes pages). This is a misconfiguration  
-- bug of Meta-Wiki. The work-around is to split the full title and then  
-- get the last titlepart.  
local subpage = title.subpageText  
---
local titleparts = mw.text.split(title.fullText, '/')  
local subpage = titleparts[#titleparts]  
return this.checkLanguage(subpage, '')  
end  

--Get the last subpage of the current page if it is a translation.  

function this.getCurrentLanguageSubpage  
return this._getLanguageSubpage(mw.title.getCurrentTitle)  
end  

--Get the first part of the language code of the subpage, before the '-'.  
---
function this.getMainLanguageSubpage  
parts = mw.text.split(this.getCurrentLanguageSubpage, '-')  
return parts[1]  
end  

--Get the last subpage of the current if it is a translation.  
Not used locally.  
---
function this.getFrameLanguageSubpage  
return this._getLanguageSubpage(:getParent:getTitle)  
end  

--Get the language of the current page. Not used locally.  
---
function this.getLanguage  
local subpage = mw.title.getCurrentTitle.subpageText  
return this.checkLanguage(subpage, mw.language.getContentLanguage:getCode)  
end  

--Get the language of the current . Not used locally.  
---
function this.getFrameLanguage  
local titleparts = mw.text.split(:getParent:getTitle, '/')  
local subpage = titleparts[#titleparts]  
return this.checkLanguage(subpage, mw.language.getContentLanguage:getCode)  
end  

function this.title(namespace, basepagename, subpage)  
local message, title  
local pagename = basepagename  
if (subpage or *) ~= * then  
pagename = pagename .. '/' .. subpage  
end  
local valid, title = xpcall(function  
return mw.title.new(pagename, namespace) -- costly  
end, function(msg) -- catch undocumented exception (!?)  
-- thrown when namespace does not exist. The doc still  
-- says it should return a title, even in that case...  
message = msg  
end)  
if valid and title ~= nil and (title.id or 0) ~= 0 then  
return title  
end  
return { -- "pseudo" mw.title object with id = nil in case of error  
prefixedText = pagename, -- the only property we need below  
message = message -- only for debugging  
}  
end  

--If on a translation subpage (like Foobar/de), this function returns  
a given template in the same language, if the translation is available.  
Otherwise, the template is returned in its default language, without  
modification.  
This is aimed at replacing the current implementation of Template:TNTN.  

This version does not expand the returned template name: this solves the  
problem of self-recursion in TNT when translatable templates need themselves  
to transclude other translable templates (such as Tnavbar).  
---
function this.getTranslatedTemplate(, withStatus)  
local args = .args  
local pagename = args['template']  
--Check whether the pagename is actually in the Template namespace, or  
if we're transcluding a main-namespace page.  
(added for backward compatibility of Template:TNT)  

local namespace, title = args['tntns'] or ''  
if namespace ~= '' then -- Checks for tntns parameter for custom ns.  
title = this.title(namespace, pagename) -- Costly  
else -- Supposes that set page is in ns10.  
namespace = 'Template'  
title = this.title(namespace, pagename) -- Costly  
if title.id == nil then -- not found in the Template namespace, assume the main namespace (for backward compatibility)  
namespace = ''  
title = this.title(namespace, pagename) -- Costly  
end  
end  
-- Get the last subpage and check if it matches a known language code.  
local subpage = args['uselang'] or ''  
if subpage == '' then  
subpage = this.getCurrentLanguageSubpage  
end  
if subpage == '' then  
-- Check if a translation of the pagename exists in English  
local newtitle = this.title(namespace, pagename, 'en') -- Costly  
-- Use the translation when it exists  
if newtitle.id ~= nil then  
title = newtitle  
end  
else  
-- Check if a translation of the pagename exists in that language  
local newtitle = this.title(namespace, pagename, subpage) -- Costly  
if newtitle.id == nil then  
-- Check if a translation of the pagename exists in English  
newtitle = this.title(namespace, pagename, 'en') -- Costly  
end  
-- Use the translation when it exists  
if newtitle.id ~= nil then  
title = newtitle  
end  
end  
-- At this point the title should exist  
if withStatus then  
-- status returned to Lua function below  
return title.prefixedText, title.id ~= nil  
else  
-- returned directly to MediaWiki  
return title.prefixedText  
end  
end  

--If on a translation subpage (like Foobar/de), this function renders  
a given template in the same language, if the translation is available.  
Otherwise, the template is rendered in its default language, without  
modification.  
This is aimed at replacing the current implementation of Template:TNT.  

Note that translatable templates cannot transclude themselves other  
translatable templates, as it will recurse on TNT. Use TNTN instead  
to return only the effective template name to expand externally, with  
template parameters also provided externally.  
---
function this.renderTranslatedTemplate  
local title, found = this.getTranslatedTemplate(, true)  
-- At this point the title should exist prior to performing the expansion  
-- of the template, otherwise render a red link to the missing page  
-- (resolved in its assumed namespace). If we don't tet this here, a  
-- script error would be thrown. Returning a red link is consistant with  
-- MediaWiki behavior when attempting to transclude inexistant templates.  
if not found then  
return * .. title .. *  
end  
-- Copy args pseudo-table to a proper table so we can feed it to expandTemplate.  
-- Then render the pagename.  
local args = .args  
local pargs = (:getParent or {}).args  
local arguments = {}  
if (args['noshift'] or *) == * then  
for k, v in pairs(pargs) do  
local n = tonumber(k) or 0  
if n <= 0 then -- unnumbered args  
arguments[k] = v  
elseif n >= 2 then -- numbered args >= 2 need to be shifted  
arguments[n - 1] = v  
end  
end  
else -- special case where TNT is used as autotranslate  
-- (don't shift again what is shifted in the invokation)  
for k, v in pairs(pargs) do  
arguments[k] = v  
end  
end  
arguments['template'] = title -- override the existing parameter of the base template name supplied with the full name of the actual template expanded  
arguments['tntns'] = nil -- discard the specified namespace override  
arguments['uselang'] = args['uselang'] -- argument forwarded into parent  
arguments['noshift'] = args['noshift'] -- argument forwarded into parent  
return :expandTemplate{title = ':' .. title, args = arguments}  
end  

--A helper for mocking TNT in Special:TemplateSandbox. TNT breaks  
TemplateSandbox; mocking it with this method means templates won't be  
localized but at least TemplateSandbox substitutions will work properly.  
Won't work with complex uses.  
---
function this.mockTNT  
local pargs = (:getParent or {}).args  
local arguments = {}  
for k, v in pairs(pargs) do  
local n = tonumber(k) or 0  
if n <= 0 then -- unnumbered args  
arguments[k] = v  
elseif n >= 2 then -- numbered args >= 2 need to be shifted  
arguments[n - 1] = v  
end  
end  
if not pargs[1] then  
return ''  
end  
return :expandTemplate{title = 'Template:' .. pargs[1], args = arguments}  
end  

return this