Module:Random slideshow

 -- Creates a slideshow gallery where the order is randomised. Intended for use on portal pages.
 localp={}
 localexcerptModule=require('Module:Excerpt/portals')
 localrandomModule=require('Module:Random')

 functioncleanupArgs(argsTable)
 localcleanArgs={}
 forkey,valinpairs(argsTable)do
 iftype(val)=='string'then
 val=val:match('^%s*(.-)%s*$')
 ifval~=''then
 cleanArgs[key]=val
 end
 else
 cleanArgs[key]=val
 end
 end
 returncleanArgs
 end

 functionnormaliseCssMeasurement(input)
 localsuffix=string.reverse(string.sub(string.reverse(input),1,2))
 if(suffix=='px')or(suffix=='em')or(string.sub(suffix,2,2)=='%')then
 returninput
 else
 returninput..'px'
 end
 end

 functionisDeclined(val)
 ifnotvalthenreturnfalseend
 localdeclinedWords=" decline declined exclude excluded false none not no n off omit omitted remove removed "
 returnstring.find(declinedWords,' '..val..' ',1,true)andtrueorfalse
 end

 functionmakeOutput(galleryLines,maxWidth,containerClassName,nonRandom)
 localrandomiseArgs={['t']=galleryLines}
 localsortedLines=nonRandomandgalleryLinesorrandomModule.main('array',randomiseArgs)
 fori=1,#sortedLinesdo
 -- insert a switcher-label span just after the first pipe, which should ideally be the caption
 sortedLines[i]=sortedLines[i]:gsub(
 "|",
 '|<span class="switcher-label" style="display:none"><span class="randomSlideshow-sr-only">Image '..tostring(i)..'</span></span>',
 1)
 end
 localgalleryContent=table.concat(sortedLines,'\n')
 localoutput='<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>'
 ..mw.getCurrentFrame():extensionTag({name="gallery",content=galleryContent,args={mode="slideshow",class="switcher-container"}})..'</div>'
 returnoutput
 end

 functionmakeGalleryLine(file,caption,credit)
 localtitle=mw.title.new(file,"File")
 ifnottitle
 then
 return"File:Blank.png|{{Error|File [[:File:"..file.."]] does not exist.}}"
 end
 localcreditLine=(creditand'<p><span style="font-size:88%">'..credit..'</span></p>'or'')
 returntitle.prefixedText..'|'..(captionor'')..creditLine
 end

 functionmakeGalleryLinesTable(args)
 localgalleryLinesTable={}
 locali=1
 whileargs[i]do
 table.insert(galleryLinesTable,makeGalleryLine(args[i],args[i+1],args['credit'..(i+1)/2]))
 i=i+2
 end
 returngalleryLinesTable
 end

 functionhasCaption(line)
 localcaption=mw.ustring.match(line,".-|(.*)")
 -- require caption to exist with more than 5 characters (avoids sizes etc being mistaken for captions)
 returncaptionand#caption>5andtrueorfalse
 end

 functionextractGalleryFiles(wikitext)
 localgallery=mw.ustring.match(wikitext,'<gallery.->%s*(.-)%s*</gallery>')
 ifnotgallerythen
 returnfalse
 end
 returnmw.text.split(gallery,'%c')
 end

 functionextractRegularFiles(wikitext)
 localfiles={}
 localframe=mw.getCurrentFrame()
 localexpand=function(template)
 returnframe:preprocess(template)
 end
 forfileinmw.ustring.gmatch(wikitext,'%b[]')do
 -- remove keywords that don't work in galleries
 file=mw.ustring.gsub(file,'|%s*baseline%s*([|%]])','%1')
 file=mw.ustring.gsub(file,'|%s*border%s*([|%]])','%1')
 file=mw.ustring.gsub(file,'|%s*bottom%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*class%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*lang%s*=.-([|%]])','%1')
 file=mw.ustring.gsub(file,'|%s*left%s*([|%]])','%1')
 file=mw.ustring.gsub(file,'|%s*link%s*=.-([|%]])','%1')
 file=mw.ustring.gsub(file,'|%s*none%s*([|%]])','%1')
 file=mw.ustring.gsub(file,'|%s*right%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*text%-bottom%s*([|%]])','%1')
 file=mw.ustring.gsub(file,'|%s*text%-top%s*([|%]])','%1')
 file=mw.ustring.gsub(file,'|%s*thumb%s*([|%]])','%1')
 file=mw.ustring.gsub(file,'|%s*thumbnail%s*([|%]])','%1')
 file=mw.ustring.gsub(file,'|%s*top%s*([|%]])','%1')
 file=mw.ustring.gsub(file,'|%s*upright%s*[0-9%.]*%s*([|%]])','%1')
 file=mw.ustring.gsub(file,'|%s*upright%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')
 -- 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
 returnfiles
 end

 --Central function for fixing issues that could occur in both gallery-fetched and file-fetched files
 localfunctiondoubleCheck(file)
 -- disable pipes in wikilinks
 file=file:gsub(
 "%[%[([^%]]-)|(.-)]]",
 "[[%1__PIPE__%2]]")
 -- move any alt parameter to the end to avoid putting the switcher in too early and causing a linter error
 file=file:gsub(
 "^(.+)(|alt=[^|]*)(.*)$",
 "%1%3%2")
 -- bring back pipes in wikilinks
 file=file:gsub(
 "%[%[(.-)__PIPE__(.-)]]",
 "[[%1|%2]]")
 returnfile
 end

 functionmakeTranscludedGalleryLinesTables(args)
 localnamespaceNumber=function(pagetitle)
 localtitleObject=mw.title.new(pagetitle)
 returntitleObjectandtitleObject.namespace
 end
 locallines={}
 locali=1
 whileargs[i]do
 ifnamespaceNumber(args[i])==6then-- file namespace
 -- args[i] is either just the filename, or uses syntax File:Name.jpg##Caption##Credit
 localparts=mw.text.split(args[i],'##%s*')
 localfilename=parts[1]
 localcaption=args['caption'..i]orparts[2]orfalse
 localcredit=args['credit'..i]orparts[3]orfalse
 localline=makeGalleryLine(filename,caption,credit)
 table.insert(lines,line)
 else
 localcontent,pagename=excerptModule.getContent(args[i])
 ifnotpagenamethen
 returnerror('Cannot read a valid page for "'..args[i]..'"',0)
 elseifnotcontentthen
 returnerror('No content found on page "'..args[i]..'"',0)
 end
 ifargs['section'..i]then
 content=excerptModule.getSection(content,args['section'..i])or''
 end
 content=excerptModule.cleanupText(content,{keepSubsections=true,ignoreOnlyincludes=true})-- true means keep subsections

 localgalleryFiles=extractGalleryFiles(content)
 ifgalleryFilesthen
 for_,finpairs(galleryFiles)do
 ifhasCaption(f)then
 localfilename=string.gsub(f,'|.*','')
 localisOkay=excerptModule.checkImage(filename)
 ifisOkaythen
 table.insert(lines,doubleCheck(f.." (from '''[["..pagename.."]]''')"))
 end
 end
 end
 end

 localotherFiles=excerptModule.parse(content,{fileflags="1-100",filesOnly=true})
 ifotherFilesthen
 for_,finpairs(extractRegularFiles(otherFiles))do
 iffandf~=''andmw.ustring.sub(f,1,5)=='File:'andhasCaption(f)then
 table.insert(lines,doubleCheck(f.." (from '''[["..pagename.."]]''')"))
 end
 end
 end

 end
 i=i+1
 end
 return(#lines>0)andlinesorerror('No images found')
 end

 p._main=function(args,transclude,extraClassName)
 ifnotargs[1]then
 returnerror(linkedand'No page specified'or'No page specified',0)
 end
 locallines=transcludeandmakeTranscludedGalleryLinesTables(args)ormakeGalleryLinesTable(args)
 localclassNames='randomSlideshow-container'
 ifextraClassNamethenclassNames=classNames..' '..extraClassNameend
 returnmakeOutput(lines,args.widthor'100%',classNames,isDeclined(args.random))
 end

 p.main=function(frame)
 localparent=frame.getParent(frame)
 localparentArgs=parent.args
 localargs=cleanupArgs(parentArgs)
 localoutput=p._main(args,false)
 returnframe:extensionTag{name='templatestyles',args={src='Module:Random slideshow/styles.css'}}
 ..frame:preprocess(output)
 end

 p.transclude=function(frame)
 localparent=frame.getParent(frame)
 localparentArgs=parent.args
 localargs=cleanupArgs(parentArgs)
 localoutput=p._main(args,true)
 returnframe:extensionTag{name='templatestyles',args={src='Module:Random slideshow/styles.css'}}
 ..frame:preprocess(output)
 end

 returnp