# Module:Official website

local makeUrl = require('Module:URL')._url  

local p = {}  

-- Wrapper for pcall which returns nil on failure.  
local function quickPcall(func)  
local success, result = pcall(func)  
if success then  
return result  
end  
end  

-- Gets the rank for a Wikidata property table. Returns 1, 0 or -1, in  
-- order of rank.  
local function getRank(prop)  
local rank = prop.rank  
if rank == 'preferred' then  
return 1  
elseif rank == 'normal' then  
return 0  
elseif rank == 'deprecated' then  
return -1  
else  
-- No rank or undefined rank is treated as "normal".  
return 0  
end  
end  

-- Finds whether a Wikidata property is qualified as being in English.  
local function isEnglish(prop)  
local ret = quickPcall(function  
for i, lang in ipairs(prop.qualifiers.P407) do  
if lang.datavalue.value['numeric-id'] == 1860 then  
return true  
end  
end  
return false  
end)  
return ret == true  
end  

-- Fetches the official website URL from Wikidata.  
local fetchWikidataUrl  
fetchWikidataUrl = function  
-- Get objects for all official sites on Wikidata.  
local websites = quickPcall(function  
return mw.wikibase.getAllStatements(mw.wikibase.getEntityIdForCurrentPage, 'P856')  
end)  

-- Clone the objects in case other code needs them in their original order.  
websites = websites and mw.clone(websites) or {}  

-- Add the table index to the objects in case it is needed in the sort.  
for i, website in ipairs(websites) do  
website._index = i  
end  

-- Sort the websites, first by highest rank, and then by websites in the  
-- English language, then by the website's original position in the  
-- property list. When we are done, get the URL from the highest-sorted  
-- object.  
table.sort(websites, function(ws1, ws2)  
local r1 = getRank(ws1)  
local r2 = getRank(ws2)  
if r1 ~= r2 then  
return r1 > r2  
end  
local e1 = isEnglish(ws1)  
local e2 = isEnglish(ws2)  
if e1 ~= e2 then  
return e1  
end  
return ws1._index < ws2._index  
end)  
local url = quickPcall(function  
return websites[1].mainsnak.datavalue.value  
end)  

-- Cache the result so that we only do the heavy lifting once per #invoke.  
fetchWikidataUrl = function  
return url  
end  

return url  
end  

-- Render the URL link, plus other visible output.  
local function renderUrl(options)  
if not options.url and not options.wikidataurl then  
local qid = mw.wikibase.getEntityIdForCurrentPage  
local result = '<strong>' ..  
'No URL found. Please specify a URL here or add one to Wikidata.' ..  
'</strong>'  
if qid then  
result = result.. ' '  
end  
return result  
end  
local ret = {}  
ret[#ret + 1] = string.format(  
'<span>%s</span>',  
makeUrl(options.url or options.wikidataurl, options.display)  
if options.wikidataurl and not options.url then  
local qid = mw.wikibase.getEntityIdForCurrentPage  
if qid then  
ret[#ret + 1] = ''  
end  
end  
return table.concat(ret, ' ')  
end  

-- Render the tracking category.  
local function renderTrackingCategory(url, wikidataurl)  
if mw.title.getCurrentTitle.namespace ~= 0 then  
return ''  
end  
local category  
if not url and not wikidataurl then  
category = 'Official website missing URL'  
elseif not url and wikidataurl then  
return ''  
elseif url and wikidataurl then  
if url:gsub('/%s*$', *) ~= wikidataurl:gsub('/%s*$', *) then  
category = 'Official website different in Wikidata and Wikipedia'  
end  
else  
category = 'Official website not in Wikidata'  
end  
return category and string.format(*, category) or *  
end  

function p._main(args)  
local url = args[1] or args.URL or args.url  
local wikidataurl = fetchWikidataUrl  
local formattedUrl = renderUrl{  
url = url,  
wikidataurl = wikidataurl,  
display = args[2] or args.name or 'அதிகாரப்பூர்வ இணையதளம்'  
}  
return formattedUrl .. renderTrackingCategory(url, wikidataurl)  
end  

function p.main  
local args = require('Module:Arguments').getArgs(, {  
wrappers = 'Template:Official website'  
})  
return p._main(args)  
end  

return p