Module:WikidataCheckYear

local p = {}
 
function p.wikidatacheckyear(frame)
    local pframe = frame:getParent()
    local config = frame.args -- the arguments passed BY the template, in the wikitext of the template itself
    local args = pframe.args -- the arguments passed TO the template, in the wikitext that transcludes the template
 
    local property = config.property
    local value = config.value
    local catbase = config.category
    local namespaces = config.namespaces
    local ok = false -- one-way flag to check if we're in a good namespace
    local ns = mw.title.getCurrentTitle().namespace
    for v in mw.text.gsplit( namespaces, ",", true) do
        if tonumber(v) == ns then
            ok = true
        end
    end
    if not ok then -- not in one of the approved namespaces
        return ""
    end
    local entity = mw.wikibase.getEntityObject()
    if not entity then -- no Wikidata item
        return "[[Category:" .. catbase .. " not in Wikidata]]"
    end
    local claims = entity.claims or {}
    local hasProp = claims[property]
    if not hasProp then -- no claim of that property
        return "[[Category:" .. catbase .. " not in Wikidata]]" -- bad. Bot needs to add the property
    end
    if not hasProp[1].mainsnak.datavalue == nil then
    	local propValue = hasProp[1].mainsnak.datavalue.value.time -- This should eventually iterate over all possible values?
	    if string.sub(propValue, 2, 5) == value then
	        return "[[Category:" .. catbase .. " same as Wikidata]]" -- yay!
	    else
	        return "[[Category:" .. catbase .. " different from Wikidata]]" -- needs human review :(
	    end
	end
end
 
return p