# Module:TrainingPages

--The purpose of this module is to take a list of linked page, and use it to determine the next and previous page in the list as well as the total number of pages.  
local p = {}  
function anonymize(name)
return mw.ustring.gsub(name,"^"..mw.site.siteName,"Project") or name
end  
function out(name)
return mw.ustring.gsub(name,"^Project",mw.site.siteName) or name
end  
function keyize(pagename)
-- there was a complaint about "_" breaking things. Do all lookups with _ in place of any space.
-- also spaces in the index file (non-module) were causing trouble
pagename = mw.text.trim(pagename)
pagename = mw.ustring.gsub(pagename, " ", "_")
pagename = mw.uri.decode(pagename)
pagename = anonymize(pagename)
return pagename
end  
function p.main(,displacement,varstoreturn)
local parent=.getParent
local currentpage,indexmodule,defaultpage,noerr
---- args in the #invoke itself trump args in the parent
currentpage = .args.page and mw.text.trim(.args.page)
defaultpage = .args.defaultpage and mw.text.trim(.args.defaultpage)
indexmodule = .args.index and mw.text.trim(.args.index)
displacement = displacement or .args.displacement -- can be passed from the other function names at the end
noerr=.args.noerr -- used as boolean
anonymizereturn = .args.anonymize -- used as boolean
---- args in the parent come next
if parent then
currentpage=currentpage or (parent.args.page and mw.text.trim(parent.args.page))
indexmodule=indexmodule or (parent.args.index and mw.text.trim(parent.args.index)) -- index is a module return{'page1','page2', ...}
defaultpage=defaultpage or (parent.args.defaultpage and mw.text.trim(parent.args.defaultpage))
noerr=noerr or parent.args.noerr
anonymizereturn = anonymizereturn or parent.args.anonymize
end
---- default values if parameters aren't provided
defaultpage=defaultpage or "" -- don't know where to send people by default
if not(indexmodule) then
return "Module:TrainingPages error:no index parameter specified"
end
if not(currentpage) then
local pp=mw.title.getCurrentTitle
if not pp then
if noerr then
return "","",""
else return "Module:TrainingPages error:failed to access getCurrentTitle" -- this shouldn't happen anyway, I don't think....
end
end
currentpage=pp.fullText
end
currentpage=anonymize(currentpage) --- convert "Wikipedia:, "Meta:" etc. into "Project:
local index={}
if mw.ustring.sub(indexmodule,1,6)=="Module" then
---- get a table of the pages in order from indexmodule
index=mw.loadData(indexmodule)
else pp=mw.title.new(indexmodule)
if not pp then
if noerr then
return "","",""
else return "Module:TrainingPages error (*index* parameter): failed to access mw.title.new("..tostring(indexmodule)..") to load the index file",false,false,true
end
end
local textindex=pp.getContent(pp)
if not textindex then
if noerr then
return "","",""
else return "Module:TrainingPages error (*index* parameter):failed to access mw.title.new("..indexmodule.."):getContent to load the index data",false,false,true
end
end
prowl=mw.ustring.gmatch(textindex,"%[%[(.-)[%]|]") -- first half of any wikilink
index={}
repeat
link=prowl
if not(link) then break end
link = mw.text.trim(link)
if link~="" then table.insert(index,link) end
until false
end
displacement=displacement or 0 -- assume a null parameter is just display the same
---- set up the reverse lookup in lookup.
---- it would be faster to set this up in the indexmodule
---- but we don't want inconsistencies from user input!
local lookup={}
local i=0
repeat
i=i+1
local j=index[i]
if j then lookup[keyize(j)]=i else break end -- lookup["page name"] => page number
until false
--- get the page to return
local returnpage,currentpagenumber
if tonumber(currentpage) then
currentpagenumber=tonumber(currentpage)
returnpage=index[currentpagenumber+displacement] or defaultpage
else if (lookup[keyize(currentpage)]) then
currentpagenumber=lookup[keyize(currentpage)]
returnpage=index[currentpagenumber+displacement] or defaultpage
else returnpage=defaultpage
end
end
if anonymizereturn then
returnpage=anonymize(returnpage)
else
returnpage=out(returnpage)
end
if returnpage then returnpage = mw.text.trim(returnpage) end
if not(varstoreturn) then return tostring(returnpage) else return tostring(returnpage),currentpagenumber,#index end
end  
-- Return the next page in the index
-- Used like if on a page that is part of the index:
---
-- Used like this to find the next page after a specified page:
---  
function p.next_page
local returnpage,pagenumber,totalpages,errcode=p.main(,1,true)
return returnpage
end
p.next = p.next_page  
-- Same as above, but returns the previous page
function p.last_page
local returnpage,pagenumber,totalpages,errcode=p.main(,-1,true)
return returnpage
end
p.last = p.last_page  
function p.page_number
local returnpage,pagenumber,totalpages,errcode=p.main(,0,true)
if errcode then return returnpage else return pagenumber end
end
p.page = p.page_number  
function p.total_pages
local returnpage,pagenumber,totalpages,errcode=p.main(,0,true)
if errcode then return returnpage else return totalpages end
end
p.total = p.total_pages  
return p