Editing Module:Sandbox/Hike395/CommonsLink2

-- Module to find commons galleries and categories based on wikidata entries
local getArgs = require('Module:Arguments').getArgs
local p = {}

local function _getTitleQID(qid)
	local titleObject = mw.title.getCurrentTitle()
	qid = (qid or ""):upper()
	-- look up qid for current page (if not testing)
	if qid == "" then
		qid = mw.wikibase.getEntityIdForCurrentPage()
		return titleObject.text, titleObject.namespace, qid
	end
	-- testing-only path: given a qid, determine title
	-- use namespace from current page (to suppress tracking cat)
	local title = mw.wikibase.sitelink(qid)
	-- string any namespace from sitelink
	local firstColon = mw.ustring.find(title,':',1,true)
	if firstColon then
		title = mw.ustring.sub(title,firstColon+1)
	end
	return title, titleObject.namespace, qid
end

-- Lookup Commons gallery in Wikidata
-- Arguments:
--   qid = QID of current article
--   fetch = whether to lookup Commons sitelink (bool)
--   commonsSitelink = default value for Commons sitelink
-- Returns:
--   categoryLink = name of Commons category, nil if nothing is found
--   consistent = multiple wikidata fields are examined: are they consistent?
--   commonsSitelink = commons sitelink for current article
local function _lookupGallery(qid,fetch,commonsSitelink)
	local galleryLink = nil
	local consistent = true
	-- look up commons sitelink for article, use if not category
	if fetch then
		commonsSitelink = mw.wikibase.getSitelink(qid,"commonswiki") or commonsSitelink
	end
	if commonsSitelink and mw.ustring.sub(commonsSitelink,1,9) ~= "Category:" then
		galleryLink = commonsSitelink
	end
	-- P935 is the "commons gallery" property for this article
	local P935 = mw.wikibase.getBestStatements(qid, "P935")[1]
	if P935 and P935.mainsnak.datavalue then
		local gallery = P935.mainsnak.datavalue.value
		if galleryLink and galleryLink ~= gallery then
			consistent = false
		else
			galleryLink = gallery
		end
	end
	return galleryLink, consistent, commonsSitelink
end

-- Find fallback category by looking up Commons sitelink of different page
-- Arguments:
--    qid = QID for current article
--    property = property that refers to other article whose sitelink to return
-- Returns: either category-stripped name of article, or nil
local function _lookupFallback(qid,property)
	if not qid then
		return nil
	end
	-- If property exists on current article, get value (other article qid)
	local value = mw.wikibase.getBestStatements(qid, property)[1]
	if value and value.mainsnak.datavalue and value.mainsnak.datavalue.value.id then
		-- Look up Commons sitelink of other article
		local sitelink = mw.wikibase.getSitelink(value.mainsnak.datavalue.value.id,"commonswiki")
		-- Check to see if it starts with "Category:". If so, strip it and return
		if sitelink and mw.ustring.sub(sitelink,1,9) == "Category:" then
			return mw.ustring.sub(sitelink,10)
		end
	end
	return nil
end

-- Find Commons category by looking in wikidata
-- Arguments:
--   qid = QID of current article
--   fetch = whether to lookup Commons sitelink (bool)
--   commonsSitelink = default value for Commons sitelink
-- Returns:
--   categoryLink = name of Commons category, nil if nothing is found
--   consistent = multiple wikidata fields are examined: are they consistent?
--   commonsSitelink = commons sitelink for current article
local function _lookupCategory(qid, fetch, commonsSitelink)
	local categoryLink = nil
	local consistent = true
	-- look up commons sitelink for article, use if starts with "Category:"
	if fetch then
		commonsSitelink = mw.wikibase.getSitelink(qid,"commonswiki") or commonsSitelink
	end
	if commonsSitelink and mw.ustring.sub(commonsSitelink,1,9) == "Category:" then
		categoryLink = mw.ustring.sub(commonsSitelink,10)
	end
	-- P373 is the "commons category" property for this article
	local P373 = mw.wikibase.getBestStatements(qid, "P373")[1]
	if P373 and P373.mainsnak.datavalue then
		P373 = P373.mainsnak.datavalue.value
		if categoryLink and categoryLink ~= P373 then
			consistent = false
			qid = nil  -- stop searching on inconsistent data
		else
			categoryLink = P373
		end
	end
	-- P910 is the "topic's main category". Look for commons sitelink there
	local fallback = _lookupFallback(qid,"P910")
	if fallback then
		if categoryLink and categoryLink ~= fallback then
			consistent = false
			qid = nil
		else
			categoryLink = fallback
		end
	end
	-- P1754 is the "list's main category". Look for commons sitelink there
	fallback = _lookupFallback(qid,"P1754")
	if fallback then
		if categoryLink and categoryLink ~= fallback then
			consistent = false
		else
			categoryLink = fallback
		end
	end
	return categoryLink, consistent, commonsSitelink
end


-- Create Commons gallery link corresponding to current article
-- Arguments:
--   default = use as Commons link, don't access wikidata
--   linktext = text to display in link
--   search = string to search for
--   qid = QID to lookup in wikidata (for testing only)
-- Returns:
--   formatted wikilink to Commons gallery
function p._getGallery(default,linktext,search,qid)
	if default then
		return "[[Commons:"..default.."|"..(linktext or default).."]]"
	end
	if search then
		return "[[Commons:Special:Search/"..search.."|"..(linktext or search).."]]"
	end
	local title, ns
	title, ns, qid = _getTitleQID(qid)
	-- construct default result (which searches for title)
	local searchResult = "[[Commons:Special:Search/"..title.."|"..(linktext or title).."]]"
	if qid then
		local galleryLink, consistent = _lookupGallery(qid,true)
		-- use wikidata if either sitelink or P935 exist, and they both agree
		if galleryLink and consistent then
			return "[[Commons:"..galleryLink.."|"..(linktext or galleryLink).."]]"
		end
		-- if not consistent, fall back to search and add to tracking cat
		if not consistent and ns == 0 then
			searchResult = searchResult.."[[Category:Inconsistent wikidata for Commons gallery]]"
		end
	end
	return searchResult
end

-- Create Commons category link corresponding to current article
-- Arguments:
--   default = use as Commons category link, don't access wikidata
--   linktext = text to display in link
--   search = string to search for
--   qid = QID to lookup in wikidata (for testing only)
-- Returns:
--   formatted wikilink to Commons gallery
function p._getCategory(default,linktext,search,qid)
	if default then
		return "[[Commons:Category:"..default.."|"..(linktext or default).."]]"
	end
	if search then
		return "[[Commons:Special:Search/Category:"..search.."|"..(linktext or search).."]]"
	end
    local title, ns
    title, ns, qid = _getTitleQID(qid)
	-- construct default result (which searches for title in Category space)
	local searchResult = "[[Commons:Special:Search/Category:"..title.."|"..(linktext or title).."]]"
	if qid then
		local categoryLink, consistent = _lookupCategory(qid,true)
		-- if any of sitelink category, P373, and P910/P1754 commons sitelinks exist,
		-- use it. But don't use if they don't agree with each other
		if categoryLink and consistent then
			return "[[Commons:Category:"..categoryLink.."|"..(linktext or categoryLink).."]]"
		end
		-- if not consistent, fall back to search, but add tracking category
		if not consistent and ns == 0 then
			searchResult = searchResult.."[[Category:Inconsistent wikidata for Commons category]]"
		end
	end
	return searchResult
end


-- Returns "best" Commons link: first look for gallery, then try category
-- Arguments:
--   default = use as Commons link, don't access wikidata
--   linktext = text to display in link
--   search = string to search for
--   qid = QID to lookup in wikidata (for testing only)
-- Returns:
--   formatted wikilink to Commons "best" landing page
function p._getGalleryOrCategory(default,linktext,search,qid)
	if default then
		return "[[Commons:"..default.."|"..(linktext or default).."]]"
	end
	if search then
		return "[[Commons:Special:Search/"..search.."|"..(linktext or search).."]]"
	end
	local title, ns
	title, ns, qid = _getTitleQID(qid)
	-- construct default result (which searches for title)
	local searchResult = "[[Commons:Special:Search/"..title.."|"..(linktext or title).."]]"
	local trackingCats = ""
	if qid then
		local galleryLink, consistent, commonsSitelink = _lookupGallery(qid,true)
		-- use wikidata if either sitelink or P935 exist, and they both agree
		if galleryLink and consistent then
			return "[[Commons:"..galleryLink.."|"..(linktext or galleryLink).."]]"
		end
		if not consistent and ns == 0 then
			trackingCats = "[[Category:Inconsistent wikidata for Commons gallery]]"
		end
		-- if gallery is not good, fall back looking for category
		local categoryLink
		categoryLink, consistent = _lookupCategory(qid,false,commonsSitelink)
		if categoryLink and consistent then
			return "[[Commons:Category:"..categoryLink.."|"..(linktext or categoryLink).."]]"..trackingCats
		end
		if not consistent and ns == 0 then
			trackingCats = trackingCats.."[[Category:Inconsistent wikidata for Commons category]]"
		end
	end
	return searchResult..trackingCats
end


-- Testing-only entry point for _getTitleQID
function p.getTitleQID(frame)
	local args = getArgs(frame,{frameOnly=true,parentOnly=false,parentFirst=false})
	local text, ns, qid = _getTitleQID(args[1])
	return text..","..ns..","..(qid or "nil")
end

-- Testing-only entry point for _lookupFallback
function p.lookupFallback(frame)
	local args = getArgs(frame,{frameOnly=true,parentOnly=false,parentFirst=false})
	local fallback = _lookupFallback(args[1],args[2])
	return fallback or "nil"
end

-- Find the Commons gallery page associated with article
function p.getGallery(frame)
	local args = getArgs(frame,{frameOnly=true,parentOnly=false,parentFirst=false})
	return p._getGallery(args[1],args.linktext,args.search,args.qid)
end

-- Find the Commons category page associated with article
function p.getCategory(frame)
	local args = getArgs(frame,{frameOnly=true,parentOnly=false,parentFirst=false})
	return p._getCategory(args[1],args.linktext,args.search,args.qid)
end

function p.getGalleryOrCategory(frame)
	local args = getArgs(frame,{frameOnly=true,parentOnly=false,parentFirst=false})
	return p._getGalleryOrCategory(args[1],args.linktext,args.search,args.qid)
end


return p