--[==[ 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 "A".

-- [[Module:Portal/images/b]]		- for portal names beginning with "B".

-- [[Module:Portal/images/c]]		- for portal names beginning with "C".

-- [[Module:Portal/images/d]]		- for portal names beginning with "D".

-- [[Module:Portal/images/e]]		- for portal names beginning with "E".

-- [[Module:Portal/images/f]]		- for portal names beginning with "F".

-- [[Module:Portal/images/g]]		- for portal names beginning with "G".

-- [[Module:Portal/images/h]]		- for portal names beginning with "H".

-- [[Module:Portal/images/i]]		- for portal names beginning with "I".

-- [[Module:Portal/images/j]]		- for portal names beginning with "J".

-- [[Module:Portal/images/k]]		- for portal names beginning with "K".

-- [[Module:Portal/images/l]]		- for portal names beginning with "L".

-- [[Module:Portal/images/m]]		- for portal names beginning with "M".

-- [[Module:Portal/images/n]]		- for portal names beginning with "N".

-- [[Module:Portal/images/o]]		- for portal names beginning with "O".

-- [[Module:Portal/images/p]]		- for portal names beginning with "P".

-- [[Module:Portal/images/q]]		- for portal names beginning with "Q".

-- [[Module:Portal/images/r]]		- for portal names beginning with "R".

-- [[Module:Portal/images/s]]		- for portal names beginning with "S".

-- [[Module:Portal/images/t]]		- for portal names beginning with "T".

-- [[Module:Portal/images/u]]		- for portal names beginning with "U".

-- [[Module:Portal/images/v]]		- for portal names beginning with "V".

-- [[Module:Portal/images/w]]		- for portal names beginning with "W".

-- [[Module:Portal/images/x]]		- for portal names beginning with "X".

-- [[Module:Portal/images/y]]		- for portal names beginning with "Y".

-- [[Module:Portal/images/z]]		- for portal names beginning with "Z".

-- [[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 = {}



-- determine whether we're being called from a sandbox

local isSandbox = mw.getCurrentFrame():getTitle():find('sandbox', 1, true)

local sandbox = isSandbox and '/sandbox' or ''



local function sandboxVersion(s)

	return isSandbox and s..'-sand' or s

end



local templatestyles = 'Module:Portal'..sandbox..'/styles.css'



local getArgs = require('Module:Arguments').getArgs

local yesno = require('Module:Yesno')



-- List of non-talk namespaces which should not be tracked (Talk pages are never tracked)

local badNamespaces = {'user','template','draft','wikipedia'}



-- Check whether to do tracking in this namespace

-- Returns true unless the page is one of the banned namespaces

local function checkTracking(title)

	local thisPage = title or mw.title.getCurrentTitle()

	if thisPage.isTalkPage then

		return false

	end

	local ns = thisPage.nsText:lower()

	for _, v in ipairs(badNamespaces) do

		if ns == v then

			return false

		end

	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 < 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 .. sandbox

	else

		imagePage = 'Module:Portal/images/other' .. sandbox

	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'..sandbox)

	for portal, aliases in pairs(aliasData) do

		for _, alias in ipairs(aliases) do

			if alias == s then

				return portal

			end

		end

	end

end



local defaultImage = 'Portal-puzzle.svg|link=|alt='



local function getImageName(s)

	-- Gets the image name for a given string.

	if type(s) ~= 'string' or #s < 1 then

		return defaultImage

	end

	s = mw.ustring.lower(s)

	return matchImagePage(s) or matchImagePage(getAlias(s)) or defaultImage

end

local function exists(title) 

	local success, exists = pcall(function() return title.exists end)

	-- If success = false, then we're out of expensive parser function calls and can't check whether it exists

	-- in that case, don't throw a Lua error

	return not success or exists

end



 -- Function to check argument portals for errors, generate tracking categories if needed

 --     Function first checks for too few/many portals provided

 --     Then checks the portal list to purge any portals that don't exist

 -- Arguments:

 --   portals: raw list of portals

 --   args.tracking: is tracking requested? (will not track on bad titles or namespaces)

 --   args.redlinks: should redlinks be displayed?

 --   args.minPortals: minimum number of portal arguments

 --   args.maxPortals: maximum number of portal arguments

 -- Returns:

 --   portals = list of portals, with redlinks purged (if args.redlinks=false)

 --   trackingCat = possible tracking category

 --   errorMsg = error message

function p._checkPortals(portals, args)

	local trackingCat = ''

	local errMsg = nil

	

	-- Tracking is on by default.

	-- It is disabled if any of the following is true

	-- 1/ the parameter "tracking" is set to 'no, 'n', or 'false'

	-- 2/ the current page fails the namespace or pagename tests 

	local trackingEnabled = args.tracking and checkTracking()

	

	args.minPortals = args.minPortals or 1

	args.maxPortals = args.maxPortals or -1

	-- check for too few portals

	if #portals < args.minPortals then

		errMsg = 'please specify at least '..args.minPortals..' portal'..(args.minPortals > 1 and 's' or '')

		trackingCat = (trackingEnabled and '[[Category:Portal templates with too few portals]]' or '')

		return portals, trackingCat, errMsg

	end

	-- check for too many portals

	if args.maxPortals >= 0 and #portals > args.maxPortals then

		errMsg = 'too many portals (maximum = '..args.maxPortals..')'

		trackingCat = (trackingEnabled and '[[Category:Portal templates with too many portals]]' or '')

		return portals, trackingCat, errMsg

	end

	if not args.redlinks or trackingEnabled then

		-- make new list of portals that exist

		local existingPortals = {}

		for _, portal in ipairs(portals) do

			local portalTitle = mw.title.new(portal,"Portal")

			-- if portal exists, put it into list

			if portalTitle and exists(portalTitle) then

				table.insert(existingPortals,portal)

			-- otherwise set tracking cat

			elseif trackingEnabled then

				trackingCat = "[[Category:Portal templates with redlinked portals]]"

			end

		end

		-- If redlinks is off, use portal list purged of redlinks

		portals = args.redlinks and portals or existingPortals

		-- if nothing left after purge, set tracking cat

		if #portals == 0 and trackingEnabled then

			trackingCat = trackingCat.."[[Category:Pages with empty portal template]]" 

		end

	end

	return portals, trackingCat, errMsg

end



local function portalBox(args)

	return mw.html.create('ul')

		:attr('role', 'navigation')

		:attr('aria-label', 'Portals')

		:addClass('noprint')

		:addClass(args.error and '' or sandboxVersion('portalbox'))

		:addClass(args.border and sandboxVersion('portalborder') or '')

		:addClass(sandboxVersion(args.left and 'portalleft' or 'portalright'))

		:css('margin', args.margin or nil)

		:newline()

end



local function fillBox(root, contents)

	for _, item in ipairs(contents) do

		local entry = root:tag('li')

		entry:addClass(sandboxVersion('portalbox-entry'))

		local image = entry:tag('span')

		image:addClass(sandboxVersion('portalbox-image'))

		image:wikitext(item1])

		local link = entry:tag('span')

		link:addClass(sandboxVersion('portalbox-link'))

		link:wikitext(item2])

	end

	return root

end



function p._portal(portals, args)

	-- This function builds the portal box used by the {{portal}} template.

	

	-- Normalize all arguments

	if args.redlinks == 'include' then args.redlinks = true end

	args.addBreak = args'break'

	for key, default in pairs({left=false,tracking=true,nominimum=false,

		                       redlinks=false,addBreak=false,border=true}) do

		if argskey == nil then argskey = default end

		argskey = yesno(argskey], default)

	end



	local root = portalBox(args)



	local trackingCat = ''

	local errMsg = nil

	args.minPortals = args.nominimum and 0 or 1

	args.maxPortals = -1

	portals, trackingCat, errMsg = p._checkPortals(portals, args)

	root:wikitext(trackingCat)

	-- if error message, put it in the box and return

	if errMsg then

		if args.border then -- suppress error message when border=no

			args.error = true  -- recreate box without fancy formatting

			root = portalBox(args)

			root:wikitext(trackingCat)

			local errTag = root:tag('strong')

			errTag:addClass('error')

			errTag:css('padding','0.2em')

			errTag:wikitext('Error: '..errMsg)

		end

		return tostring(root)

	end

	-- if no portals (and no error), just return tracking category

	if #portals == 0 then

		return trackingCat

	end



	local contents = {}

	-- Display the portals specified in the positional arguments.

	local defaultUsed = nil

	for _, portal in ipairs(portals) do

		local portalImage = getImageName(portal)

		if portalImage == defaultImage then

			defaultUsed = portal

		end

		local image = string.format('[[File:%s|32x28px|class=noviewer]]',

			portalImage)

		local link = string.format('[[Portal:%s|%s%sportal]]',

			portal, portal, args.addBreak and '<br />' or ' ')

		table.insert(contents, {image, link})

	end

	if defaultUsed and checkTracking() then

		local cat = string.format('[[Category:Portal templates with default image|%s]]',

			                      defaultUsed)

		root:wikitext(cat)

	end

	return tostring(fillBox(root, contents))

end



function p._demo(imageList, args)

	for key, default in pairs({left=false,border=true}) do

		if argskey == nil then argskey = default end

		argskey = yesno(argskey], default)

	end

	

	local root = portalBox(args)



	local contents = {}

	-- Display the portals specified in the positional arguments.

	for _, fn in ipairs(imageList) do

		local image = string.format('[[File:%s|32x28px|class=noviewer]]',fn)

		local link = string.format('[[:File:%s|%s]]',fn,fn)

		table.insert(contents,{image,link})

	end



	return tostring(fillBox(root,contents))

end



function p._image(portal,keep)

	-- Wrapper function to allow getImageName() to be accessed through #invoke.

	-- backward compatibility: if table passed, take first element

	if type(portal) == 'table' then

		portal = portal1

	end

	local name = getImageName(portal)

	-- If keep is yes (or equivalent), then allow all metadata (like image borders) to be returned

	local keepargs = yesno(keep)

	local args = mw.text.split(name, "|", true)

	local result = {args1]}  -- the filename always comes first

	local category = ''

	-- parse name, looking for category arguments

	for i = 2,#args do

		local m = mw.ustring.match(argsi],  "^%s*category%s*=")

		if keepargs or m then

			table.insert(result, argsi])

		end

	end

	-- reassemble arguments

	return table.concat(result,"|")

end





local function getAllImageTable()

	-- 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

		local imageTable = mw.loadData('Module:Portal/images/' .. subpage .. sandbox)

		for portal, image in pairs(imageTable) do

			local args = mw.text.split(image,"|")

			imagesportal = args1 -- just use image filename

		end

	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()

	portals = portals or {}

	for portal in pairs(getAllImageTable()) do

		table.insert(portals,lang:ucfirst(portal))

	end

	table.sort(portals)

	args.redlinks = args.redlinks or "yes"

	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 portal, image in pairs(getAllImageTable()) do

		if not existsimage then

			existsimage = portal

		else

			table.insert(dupes, string.format('The image "[[:File:%s|%s]]" is used for both portals "%s" and "%s".', image, image, existsimage], portal))

		end

	end

	if #dupes < 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

			namedArgsk = v

		end

	end

	table.sort(portals)

	for i, v in ipairs(portals) do

		portalsi = argsv

	end

	return portals, namedArgs

end



-- Entry point for sorting portals from other named arguments

function p._processPortalArgs(args)

	return processPortalArgs(args)

end



function p.image(frame)

	local origArgs = getArgs(frame)

	local portals, args = processPortalArgs(origArgs)

	return p._image(portals1],args.border)

end



function p.demo(frame)

	local args = getArgs(frame)

	local styles = frame:extensionTag{ name = 'templatestyles', args = { src = templatestyles} }

	return styles..p._demo(args,args)

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. 

		-- Also: trim whitespace and remove blank arguments

		local origArgs = getArgs(frame)

		-- create two tables to pass to func: an array of portal names, and a table of named arguments.

		local portals, args = processPortalArgs(origArgs)

		local results = ''

		if funcName == '_portal' or funcName == '_displayAll' then

			results = frame:extensionTag{ name = 'templatestyles', args = { src = templatestyles} }

		end

		return results .. pfuncName](portals, args) 

	end

end



for _, funcName in ipairs{'portal', 'imageDupes', 'displayAll'} do

	pfuncName = makeWrapper('_' .. funcName)

end



return p