require('Module:No globals')  
-- Module to find commons galleries and categories based on wikidata entries
local getArgs = require('Module:Arguments').getArgs
local yesNo = require('Module:Yesno')
local generateWarning = require('Module:If preview')._warning
local p = {}  
-- Check if string is a valid QID
-- Argument: QID to check
-- Returns: valid (bool)
local function _validQID(qid)
return qid and mw.ustring.find(qid,"^[Qq]%d+$")
end  
-- Check if string is a valid wikidata property string
-- Argument: property string to check
-- Returns: valid (bool)
local function _validProp(prop)
return prop and mw.ustring.find(prop,"^[Pp]%d+$")
end  
local function _lcfirst(s)
return mw.ustring.lower(mw.ustring.sub(s,1,1))..mw.ustring.sub(s,2)
end  
-- Format displayed linktext
-- Arguments:
-- s = string to display
-- formatting = formatting table:
-- formatting.linktext = if defined, override s
-- formatting.lcfirst = lower case the first letter in display
-- formatting.bold = whether to bold the display
-- formatting.italic = whether to italicize the display
-- formatting.nowrap = set nowrapping
-- Returns:
-- formatted string
local function _formatResult(s, formatting)
local resultVal = formatting.linktext or s
if formatting.lcfirst then
resultVal = _lcfirst(resultVal)
end
local
if formatting.italic then end
if formatting.bold then style = style.."font-weight:bold; " end
if formatting.nowrap then style = style.."white-space:nowrap; " end
if style ~= "" then
resultVal = '<span>'..resultVal..'</span>'
end
return resultVal
end  
-- Get title, namespace, and QID for current page
-- Arguments:
-- qid = testing only: get title of alternative page with QID=qid
-- nsQid = whether to return the ns of the qid page or current
-- Returns:
-- title, namespace (string), qid of current page (or test page)
local function _getTitleQID(qid,nsQid)
local titleObject = mw.title.getCurrentTitle
-- look up qid for current page (if not testing)
local nsText = mw.ustring.gsub(titleObject.nsText,"_"," ")
if not _validQID(qid) then
qid = mw.wikibase.getEntityIdForCurrentPage
return titleObject.text, nsText, qid
end
-- testing-only path: given a qid, determine title
-- always use namespace from current page (to suppress tracking cat)
qid = qid:upper
local title = mw.wikibase.getSitelink(qid) or ""
-- strip any namespace from sitelink
local firstColon = mw.ustring.find(title,':',1,true)
local qidNsText = ""
if firstColon then
qidNsText = mw.ustring.sub(title,1,firstColon-1)
title = mw.ustring.sub(title,firstColon+1)
end
if nsQid then
return title, qidNsText, qid
end
return title, nsText, 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)
if not _validQID(qid) then
return nil, true, nil
end
qid = qid:upper
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 _validQID(qid) or not _validProp(property) then
return nil
end
qid = qid:upper
property = property:upper
-- 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)
if not _validQID(qid) then
return nil, true, nil
end
qid = qid:upper
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
-- 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
qid = nil
else
categoryLink = fallback
end
end
-- P373 is the "commons category" property for this article. This is
-- a low-quality field, so should only be used as a last resort.
if categoryLink == nil and _validQID(qid) then
local P373 = mw.wikibase.getBestStatements(qid, "P373")[1]
if P373 and P373.mainsnak.datavalue then
categoryLink = P373.mainsnak.datavalue.value
consistent = true -- P373 is never used if anything else is available
end
end
return categoryLink, consistent, commonsSitelink
end  
-- Does the article have a Commons gallery, and is it consistent?
-- Arguments:
-- qid = QID to lookup in wikidata (for testing only)
-- Returns:
-- filename at Commons, bool: is wikidata consistent for this article?
function p._hasGalleryConsistent(qid)
local wp_title, wp_ns
wp_title, wp_ns, qid = _getTitleQID(qid)
return _lookupGallery(qid,true)
end  
-- Does the article have a corresponding Commons gallery?
-- Arguments:
-- qid = QID to lookup in wikidata (for testing only)
-- Returns:
-- filename at Commons if so, false if not
function p._hasGallery(qid)
local galleryLink, consistent = p._hasGalleryConsistent(qid)
return consistent and galleryLink
end  
-- Does the article have a Commons category? Is wikidata consistent for that?
-- Arguments:
-- qid = QID to lookup in wikidata (for testing only)
-- prefix = whether to add "Category:" to return string (default true)
-- Returns:
-- filename at Commons, bool: consistent
function p._hasCategoryConsistent(qid,prefix)
if prefix == nil then
prefix = true
end
local wp_title, wp_ns
wp_title, wp_ns, qid = _getTitleQID(qid)
local categoryLink, consistent = _lookupCategory(qid,true)
if categoryLink and prefix then
categoryLink = "Category:"..categoryLink
end
return categoryLink, consistent
end  
-- Does the article have a corresponding Commons category?
-- Arguments: