Module:Portal
--[==[ This module is a Lua implementation of the old {{Portal}} template. As of February 2019 it is used on nearly 7,900,000 articles.
 -- Please take care when updating it! It outputs two functions: p.portal, which generates a list of portals, and p.image, which
 -- produces the image name for an individual portal.
 
 -- The portal image data is kept in submodules of [[Module:Portal/images]], listed below:
 -- [[Module:Portal/images/a]]		- for portal names beginning with &quot;A&quot;.
 -- [[Module:Portal/images/b]]		- for portal names beginning with &quot;B&quot;.
 -- [[Module:Portal/images/c]]		- for portal names beginning with &quot;C&quot;.
 -- [[Module:Portal/images/d]]		- for portal names beginning with &quot;D&quot;.
 -- [[Module:Portal/images/e]]		- for portal names beginning with &quot;E&quot;.
 -- [[Module:Portal/images/f]]		- for portal names beginning with &quot;F&quot;.
 -- [[Module:Portal/images/g]]		- for portal names beginning with &quot;G&quot;.
 -- [[Module:Portal/images/h]]		- for portal names beginning with &quot;H&quot;.
 -- [[Module:Portal/images/i]]		- for portal names beginning with &quot;I&quot;.
 -- [[Module:Portal/images/j]]		- for portal names beginning with &quot;J&quot;.
 -- [[Module:Portal/images/k]]		- for portal names beginning with &quot;K&quot;.
 -- [[Module:Portal/images/l]]		- for portal names beginning with &quot;L&quot;.
 -- [[Module:Portal/images/m]]		- for portal names beginning with &quot;M&quot;.
 -- [[Module:Portal/images/n]]		- for portal names beginning with &quot;N&quot;.
 -- [[Module:Portal/images/o]]		- for portal names beginning with &quot;O&quot;.
 -- [[Module:Portal/images/p]]		- for portal names beginning with &quot;P&quot;.
 -- [[Module:Portal/images/q]]		- for portal names beginning with &quot;Q&quot;.
 -- [[Module:Portal/images/r]]		- for portal names beginning with &quot;R&quot;.
 -- [[Module:Portal/images/s]]		- for portal names beginning with &quot;S&quot;.
 -- [[Module:Portal/images/t]]		- for portal names beginning with &quot;T&quot;.
 -- [[Module:Portal/images/u]]		- for portal names beginning with &quot;U&quot;.
 -- [[Module:Portal/images/v]]		- for portal names beginning with &quot;V&quot;.
 -- [[Module:Portal/images/w]]		- for portal names beginning with &quot;W&quot;.
 -- [[Module:Portal/images/x]]		- for portal names beginning with &quot;X&quot;.
 -- [[Module:Portal/images/y]]		- for portal names beginning with &quot;Y&quot;.
 -- [[Module:Portal/images/z]]		- for portal names beginning with &quot;Z&quot;.
 -- [[Module:Portal/images/other]]	- for portal names beginning with any other letters. This includes numbers,
 -- 									  letters with diacritics, and letters in non-Latin alphabets.
 -- [[Module:Portal/images/aliases]]	- for adding aliases for existing portal names. Use this page for variations
 -- 									  in spelling and diacritics, etc., no matter what letter the portal begins with.
 --
 -- The images data pages are separated by the first letter to reduce server load when images are added, changed, or removed.
 -- Previously all the images were on one data page at [[Module:Portal/images]], but this had the disadvantage that all
 -- 5,000,000 pages using this module needed to be refreshed every time an image was added or removed.
 ]==]
 
 local p = {}
 
 local trackingEnabled = true
 
 local templatestyles = 'Module:Portal/styles.css'
 
 local yesno = require('Module:Yesno')
 
 -- Check whether to do tracking in this namespace
 -- Returns true unless the page is one of the banned namespaces
 local function checkTrackingNamespace()
 	local thisPage = mw.title.getCurrentTitle()
 	if (thisPage.namespace == 1) -- Talk
 		or (thisPage.namespace == 2) -- User
 		or (thisPage.namespace == 3) -- User talk
 		or (thisPage.namespace == 5) -- Wikipedia talk
 		or (thisPage.namespace == 7) -- File talk
 		or (thisPage.namespace == 11) -- Template talk
 		or (thisPage.namespace == 15) -- Category talk
 		or (thisPage.namespace == 101) -- Portal talk
 		or (thisPage.namespace == 109) -- Book talk
 		or (thisPage.namespace == 118) -- Draft
 		or (thisPage.namespace == 119) -- Draft talk
 		or (thisPage.namespace == 829) -- Module talk
 		then
 		return false
 	end
 	return true
 end
 
 -- Check whether to do tracking on this pagename
 -- Returns false if the page title matches one of the banned strings
 -- Otherwise returns true
 local function checkTrackingPagename()
 	local thisPage = mw.title.getCurrentTitle()
 	local thisPageLC = mw.ustring.lower(thisPage.text)
 	if (string.match(thisPageLC, &quot;/archive&quot;) ~= nil) then
 		return false
 	end
 	if (string.match(thisPageLC, &quot;/doc&quot;) ~= nil) then
 		return false
 	end
 	if (string.match(thisPageLC, &quot;/test&quot;) ~= nil) then
 		return false
 	end
 	return true
 end
 
 
 local function matchImagePage(s)
 	-- Finds the appropriate image subpage given a lower-case
 	-- portal name plus the first letter of that portal name.
 	if type(s) ~= 'string' or #s &lt; 1 then return end
 	local firstLetter = mw.ustring.sub(s, 1, 1)
 	local imagePage
 	if mw.ustring.find(firstLetter, '^[a-z]') then
 		imagePage = 'Module:Portal/images/' .. firstLetter
 	else
 		imagePage = 'Module:Portal/images/other'
 	end
 	return mw.loadData(imagePage)[s]
 end
 
 local function getAlias(s)
 	-- Gets an alias from the image alias data page.
 	local aliasData = mw.loadData('Module:Portal/images/aliases')
 	for portal, aliases in pairs(aliasData) do
 		for _, alias in ipairs(aliases) do
 			if alias == s then
 				return portal
 			end
 		end
 	end
 end
 
 local function getImageName(s)
 	-- Gets the image name for a given string.
 	local default = 'Portal-puzzle.svg|link=|alt='
 	if type(s) ~= 'string' or #s &lt; 1 then
 		return default
 	end
 	s = mw.ustring.lower(s)
 	return matchImagePage(s) or matchImagePage(getAlias(s)) or default
 end
 
 local function checkPortalExists(portal)
 	return not (mw.title.makeTitle(100, portal).id == 0)
 end
 
 function p._portal(portals, args)
 	-- This function builds the portal box used by the {{portal}} template.
 	local root = mw.html.create('div')
 		:attr('role', 'navigation')
 		:attr('aria-label', 'Portals')
 		:addClass('noprint portal plainlist')
 		:addClass(args.left and 'tleft' or 'tright')
 		:css('margin', args.margin or nil)
 		:newline()
 
 	-- Tracking is on by default.
 	-- It is disabled if any of the following is true
 	-- 1/ the parameter &quot;tracking&quot; is set to 'no, 'n', or 'false'
 	-- 2/ the current page fails the namespace tests in checkTrackingNamespace()
 	-- 3/ the current page fails the pagename tests in checkTrackingPagename()
 	trackingEnabled = yesno(args.tracking, trackingEnabled)
 	if (checkTrackingNamespace() == false) then
 		trackingEnabled = false
 	end
 	if (checkTrackingPagename() == false) then
 		trackingEnabled = false
 	end
 
 	-- If no portals have been specified, display an error and add the page to a tracking category.
 	if not portals[1] then
 		if yesno(args.nominimum) then
 		-- if nominimum as been set to yes (or similar), omit the warning
 			
 		else
 			root:wikitext('&lt;strong class=&quot;error&quot;&gt;No portals specified: please specify at least one portal&lt;/strong&gt;')
 		end
 		if (trackingEnabled) then
 			root:wikitext('[[Category:Portal templates without a parameter]]')
 		end
 		return tostring(root)
 	end
 	
 	-- scan for nonexistent portals, if they exist remove them from the portals table. If redlinks=yes, then don't remove
 	local portallen = #portals
 	-- traverse the list backwards to ensure that no portals are missed (table.remove also moves down the portals in the list, so that the next portal isn't checked if going fowards.
 	-- going backwards allows us to circumvent this issue
 	for i=portallen,1,-1 do
 		-- the use of pcall here catches any errors that may occour when attempting to locate pages when the page name is invalid
 		-- if pcall returns true, then rerun the function to find if the page exists
 		if not pcall(checkPortalExists, portals[i]) or not checkPortalExists(portals[i]) then
 			-- Getting here means a redlinked portal has been found
 			if yesno(args.redlinks) or (args.redlinks == 'include') then
 				-- if redlinks as been set to yes (or similar), add the cleanup category and then break the loop before the portal is removed from the list
 				if (trackingEnabled) then
 					root:wikitext('[[Category:Portal templates with redlinked portals]]')
 				end
 				break
 			end
 			-- remove the portal (this does not happen if redlinks=yes)
 			table.remove(portals,i)
 		end
 	end
 	
 	-- if the length of the table is different, then rows were removed from the table, so portals were removed. If this is the case add the cleanup category
 	if not (portallen == #portals) then
 		if (trackingEnabled) then
 			if #portals == 0 then
 				return '[[Category:Portal templates with all redlinked portals]]'
 			else
 				root:wikitext('[[Category:Portal templates with redlinked portals]]')
 			end
 		end
 	end
 
 	-- Start the list. This corresponds to the start of the wikitext table in the old [[Template:Portal]].
 	local listroot = root:tag('ul')
 		:css('width', type(args.boxsize) == 'string' and (args.boxsize .. 'px') or nil)
 
 	-- Display the portals specified in the positional arguments.
 	for _, portal in ipairs(portals) do
 		local image = getImageName(portal)
 
 		-- Generate the html for the image and the portal name.
 		listroot
 			:newline()
 			:tag('li')
 				:tag('span')
 					:wikitext(string.format('[[File:%s|32x28px|class=noviewer]]', image))
 					:done()
 				:tag('span')
 					:wikitext(string.format('[[வலைவாசல்:%s|%s%sவலைவாசல்]]', portal, portal, args['break'] and '&lt;br /&gt;' or ' '))
 	end
 	return tostring(root)
 end
 
 function p._image(portals)
 	-- Wrapper function to allow getImageName() to be accessed through #invoke.
 	local name = getImageName(portals[1])
 	return name:match('^(.-)|') or name -- FIXME: use a more elegant way to separate borders etc. from the image name
 end
 
 local function getAllImageTables()
 	-- Returns an array containing all image subpages (minus aliases) as loaded by mw.loadData.
 	local images = {}
 	for i, subpage in ipairs{'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'other'} do
 		images[i] = mw.loadData('Module:Portal/images/' .. subpage)
 	end
 	return images
 end
 
 function p._displayAll(portals, args)
 	-- This function displays all portals that have portal images. This function is for maintenance purposes and should not be used in
 	-- articles, for two reasons: 1) there are over 1500 portals with portal images, and 2) the module doesn't record how the portal
 	-- names are capitalized, so the portal links may be broken.
 	local lang = mw.language.getContentLanguage()
 	local count = 1
 	for _, imageTable in ipairs(getAllImageTables()) do
 		for portal in pairs(imageTable) do
 			portals[count] = lang:ucfirst(portal)
 			count = count + 1
 		end
 	end
 	return p._portal(portals, args)
 end
 
 function p._imageDupes()
 	-- This function searches the image subpages to find duplicate images. If duplicate images exist, it is not necessarily a bad thing,
 	-- as different portals might just happen to choose the same image. However, this function is helpful in identifying images that
 	-- should be moved to a portal alias for ease of maintenance.
 	local exists, dupes = {}, {}
 	for _, imageTable in ipairs(getAllImageTables()) do
 		for portal, image in pairs(imageTable) do
 			if not exists[image] then
 				exists[image] = portal
 			else
 				table.insert(dupes, string.format('The image &quot;[[:File:%s|%s]]&quot; is used for both portals &quot;%s&quot; and &quot;%s&quot;.', image, image, exists[image], portal))
 			end
 		end
 	end
 	if #dupes &lt; 1 then
 		return 'No duplicate images found.'
 	else
 		return 'The following duplicate images were found:\n* ' .. table.concat(dupes, '\n* ')
 	end
 end
 
 local function processPortalArgs(args)
 	-- This function processes a table of arguments and returns two tables: an array of portal names for processing by ipairs, and a table of
 	-- the named arguments that specify style options, etc. We need to use ipairs because we want to list all the portals in the order
 	-- they were passed to the template, but we also want to be able to deal with positional arguments passed explicitly, for example
 	-- {{portal|2=Politics}}. The behaviour of ipairs is undefined if nil values are present, so we need to make sure they are all removed.
 	args = type(args) == 'table' and args or {}
 	local portals = {}
 	local namedArgs = {}
 	for k, v in pairs(args) do
 		if type(k) == 'number' and type(v) == 'string' then -- Make sure we have no non-string portal names.
 			table.insert(portals, k)
 		elseif type(k) ~= 'number' then
 			namedArgs[k] = v
 		end
 	end
 	table.sort(portals)
 	for i, v in ipairs(portals) do
 		portals[i] = args[v]
 	end
 	return portals, namedArgs
 end
 
 local function makeWrapper(funcName)
 	-- Processes external arguments and sends them to the other functions.
 	return function (frame)
 		-- If called via #invoke, use the args passed into the invoking
 		-- template, or the args passed to #invoke if any exist. Otherwise
 		-- assume args are being passed directly in from the debug console
 		-- or from another Lua module.
 		local origArgs
 		if type(frame.getParent) == 'function' then
 			origArgs = frame:getParent().args
 			for k, v in pairs(frame.args) do
 				origArgs = frame.args
 				break
 			end
 		else
 			origArgs = frame
 		end
 		-- Trim whitespace and remove blank arguments.
 		local args = {}
 		for k, v in pairs(origArgs) do
 			if type(v) == 'string' then
 				v = mw.text.trim(v)
 			end
 			if v ~= '' then
 				args[k] = v
 			end
 		end
 		
 		local results = ''
 		if funcName == '_portal' or funcName == '_displayAll' then
 			results = frame:extensionTag{ name = 'templatestyles', args = { src = templatestyles} }
 		end
 		return results .. p[funcName](processPortalArgs(args)) -- passes two tables to func: an array of portal names, and a table of named arguments.
 	end
 end
 
 for _, funcName in ipairs{'portal', 'image', 'imageDupes', 'displayAll'} do
 	p[funcName] = makeWrapper('_' .. funcName)
 end