-- Creates a slideshow gallery where the order is randomised. Intended for use on portal pages. local p = {} local excerptModule = require('Module:Excerpt/portals') local randomModule = require('Module:Random') local redirectModule = require('Module:Redirect')  function cleanupArgs(argsTable)  local cleanArgs = {}  for key, val in pairs(argsTable) do  if type(val) == 'string' then  val = val:match('^%s*(.-)%s*$')  if val ~= '' then  cleanArgs[key] = val  end  else  cleanArgs[key] = val  end  end  return cleanArgs end  function normaliseCssMeasurement(input)  local suffix = string.reverse(string.sub(string.reverse(input), 1, 2))  if ( suffix == 'px' ) or ( suffix == 'em' ) or ( string.sub(suffix, 2, 2) == '%' ) then  return input  else  return input .. 'px'  end end  function isDeclined(val)  if not val then return false end  local declinedWords = " decline declined exclude excluded false none not no n off omit omitted remove removed "  return string.find(declinedWords , ' '..val..' ', 1, true ) and true or false end  function makeOutput(galleryLines, maxWidth, containerClassName, nonRandom)  local randomiseArgs = { ['t'] = galleryLines }  local sortedLines = nonRandom and galleryLines or randomModule.main('array', randomiseArgs)  for i = 1, #sortedLines do  -- insert a switcher-label span just after the first pipe (which has already been escaped as {{!}} instead the | character)  sortedLines[i] = sortedLines[i]:gsub(  "%{%{%!%}%}",  '{{!}}<span class="switcher-label" style="display:none"><span class="randomSlideshow-sr-only">Image ' .. tostring(i) .. '</span></span>',  1)  end  local galleryContent = table.concat(sortedLines, '\n')  local output = '<div class="' .. containerClassName .. '" style="max-width:' .. normaliseCssMeasurement(maxWidth) .. '; margin:-4em auto;"><div class="nomobile"><!--intentionally empty on desktop, and is not present on mobile website (outside template namesapce)--></div>{{#tag:gallery|' .. galleryContent .. '|mode=slideshow|class=switcher-container}}</div>'  return output end  function makeGalleryLine(file, caption, credit)  local title = mw.title.new(file, "File" )  if not title  then  return "File:Blank.png{{!}}{{Error|File [[:File:" .. file .. "]] does not exist.}}"  end  local creditLine = ( credit and '<p><span style="font-size:88%">' .. credit .. '</span></p>' or '' )  return title.prefixedText .. '{{!}}' .. ( caption or '' ) .. creditLine end  function makeGalleryLinesTable(args)  local galleryLinesTable = {}  local i = 1  while args[i] do  table.insert(galleryLinesTable, makeGalleryLine(args[i], args[i+1], args['credit' .. (i+1)/2]))  i = i + 2  end  return galleryLinesTable end  function hasCaption(line)  local caption = mw.ustring.match(line, ".-{{!}}(.*)")  -- require caption to exist with more than 5 characters (avoids sizes etc being mistaken for captions)  return caption and #caption>5 and true or false end  function extractGalleryFiles(wikitext)  local gallery = mw.ustring.match(wikitext, '<gallery.->%s*(.-)%s*</gallery>')  if not gallery then  return false  end  gallery = mw.ustring.gsub(gallery, '|', '{{!}}')  return mw.text.split(gallery, '%c') end  function extractRegularFiles(wikitext)  local files = {}  local frame = mw.getCurrentFrame()  local expand = function(template)  return frame:preprocess(template)  end  for file in mw.ustring.gmatch(wikitext, '%b[]' ) do  -- remove keywords that don't work in galleries  file = mw.ustring.gsub(file, '|%s*thumb%s*([|%]])', '%1')  file = mw.ustring.gsub(file, '|%s*thumbnail%s*([|%]])', '%1')  file = mw.ustring.gsub(file, '|%s*border%s*([|%]])', '%1')  file = mw.ustring.gsub(file, '|%s*left%s*([|%]])', '%1')  file = mw.ustring.gsub(file, '|%s*right%s*([|%]])', '%1')  file = mw.ustring.gsub(file, '|%s*center%s*([|%]])', '%1')  file = mw.ustring.gsub(file, '|%s*centre%s*([|%]])', '%1')  file = mw.ustring.gsub(file, '|%s*baseline%s*([|%]])', '%1')  file = mw.ustring.gsub(file, '|%s*sub%s*([|%]])', '%1')  file = mw.ustring.gsub(file, '|%s*super%s*([|%]])', '%1')  file = mw.ustring.gsub(file, '|%s*top%s*([|%]])', '%1')  file = mw.ustring.gsub(file, '|%s*text%-top%s*([|%]])', '%1')  file = mw.ustring.gsub(file, '|%s*bottom%s*([|%]])', '%1')  file = mw.ustring.gsub(file, '|%s*text%-bottom%s*([|%]])', '%1')  file = mw.ustring.gsub(file, '|%s*framed?%s*([|%]])', '%1')  file = mw.ustring.gsub(file, '|%s*frameless%s*([|%]])', '%1')  file = mw.ustring.gsub(file, '|%s*upright%s*[0-9%.]*%s*([|%]])', '%1')  file = mw.ustring.gsub(file, '|%s*upright%s*=.-([|%]])', '%1')  file = mw.ustring.gsub(file, '|%s*link%s*=.-([|%]])', '%1')  -- remove spaces prior to captions (which cause pre-formatted text)  file = mw.ustring.gsub(file, '|%s*', '|')  -- remove sizes, which sometimes get mistaken for captions  file = mw.ustring.gsub(file, '|%s*%d*x?%d+%s*px%s*([|%]])', '%1')  -- expand templates  file = mw.ustring.gsub(file, '{%b{}}', expand)  -- remove loose closing braces which don't have matching opening braces  file = mw.ustring.gsub(file, '}}', '')  -- remove loose opening braces which don't have matching closing braces (and the subsequent content, which is probably just a template name)  file = mw.ustring.gsub(file, '{{.-([|%]])', '%1')  -- replace pipes and equals (which would otherwise break the {{#tag:}} syntax)  file = mw.ustring.gsub(file, '|%s*alt%s*=', '{{!}}alt=')  file = mw.ustring.gsub(file, '|', '{{!}}')  file = mw.ustring.gsub(file, '=', '{{=}}')  -- remove linebreaks  file = mw.ustring.gsub(file, '\n\n', '<br>')  file = mw.ustring.gsub(file, '\n', '')  -- remove surrounding square brackets  file = mw.ustring.gsub(file, '^%[%[', '')  file = mw.ustring.gsub(file, '%]%]$', '')  table.insert(files, file)  end  return files end  function makeTranscludedGalleryLinesTables(args)  local namespaceNumber = function(pagetitle)  local titleObject = mw.title.new(pagetitle)  return titleObject and titleObject.namespace  end  local lines = {}  local i = 1  while args[i] do  if namespaceNumber(args[i]) == 6 then -- file namespace  -- args[i] is either just the filename, or uses syntax File:Name.jpg##Caption##Credit  local parts = mw.text.split(args[i], '##%s*')  local filename = parts[1]  local caption = args['caption'..i] or parts[2] or false  local credit = args['credit'..i] or parts[3] or false  local line = makeGalleryLine(filename, caption, credit)  table.insert(lines, line)  else  local content, pagename = excerptModule.getContent(args[i])  if not pagename then  return error('Cannot read a valid page for "' .. args[i] .. '"', 0)  elseif not content then  return error('No content found on page "' .. args[i] .. '"', 0)  end  if args['section'..i] then  content = excerptModule.getSection(content, args['section'..i]) or ''  end  content = excerptModule.cleanupText(content, {keepSubsections=true}) -- true means keep subsections   local galleryFiles = extractGalleryFiles(content)  if galleryFiles then  for _, f in pairs(galleryFiles) do  if hasCaption(f) then  local filename = string.gsub(f, '{{!}}.*', '')  local isOkay = excerptModule.checkImage(filename)  if isOkay then  table.insert(lines, f.." (from '''[["..pagename.."]]''')")  end  end  end  end   local otherFiles = excerptModule.parse(content, {fileflags="1-100", filesOnly=true})  if otherFiles then  for _, f in pairs(extractRegularFiles(otherFiles)) do  if f and f ~= '' and mw.ustring.sub(f, 1, 5) == 'File:' and hasCaption(f) then  table.insert(lines, f.." (from '''[["..pagename.."]]''')")  end  end  end   end  i = i + 1  end  return ( #lines > 0 ) and lines or error('No images found') end  p._main = function(args, transclude, extraClassName)  if not args[1] then  return error(linked and 'No page specified' or 'No page specified', 0)  end  local lines = transclude and makeTranscludedGalleryLinesTables(args) or makeGalleryLinesTable(args)  local classNames = 'randomSlideshow-container'  if extraClassName then classNames = classNames .. ' ' .. extraClassName end  return makeOutput(lines, args.width or '100%', classNames, isDeclined(args.random)) end  p.main = function(frame)  local parent = frame.getParent(frame)  local parentArgs = parent.args  local args = cleanupArgs(parentArgs)  local output = p._main(args, false)  return frame:extensionTag{ name='templatestyles', args = { src='Module:Random slideshow/styles.css'} }  .. frame:preprocess(output) end  p.transclude = function(frame)  local parent = frame.getParent(frame)  local parentArgs = parent.args  local args = cleanupArgs(parentArgs)  local output = p._main(args, true)  return frame:extensionTag{ name='templatestyles', args = { src='Module:Random slideshow/styles.css'} }  .. frame:preprocess(output) end  return p