Módulo:ResolveEntityId

local p = {}

function p._entityid(_,id,alt)
    -- backwards compatibility for deprecated _entityid function
    return p._id(id,alt)
end

function p._id(id,alt)
    if type(id) == 'string' then
        id = mw.ustring.upper(mw.ustring.sub(id,1,1))..mw.ustring.sub(id,2)
        if mw.ustring.match(id,'^Q%d+$') then
            -- id is in the proper format for a Wikidata entity
            if mw.wikibase.isValidEntityId(id) then
                -- id is valid
                id = mw.wikibase.getEntity(id)
                if id then
                    -- entity exists
                    return id.id
                end
            end
        else
            id = mw.wikibase.getEntityIdForTitle(id)
            if id then
                -- id is a title that matches a Wikidata entity
                local instanceOf = mw.wikibase.getBestStatements(id, 'P31')[1] --instance of
                if instanceOf and instanceOf.mainsnak.datavalue.value.id ~= 'Q4167410' then
                    -- not disambiguation
                    return mw.wikibase.getEntity(id).id
                elseif instanceOf == nil then
                    -- id is a title, but is missing an instance-of value
                    return mw.wikibase.getEntity(id).id
                end
            end
        end
    end
    return alt or nil
end

function p.entityid(frame)
    return p._id(frame.args[1], frame.args[2])
end

return p