Kidney stone prevention?

The more I research kidney stones, the more contradictory answers I receive. One site says avoid calcium. Another site says that dietary calcium is good because it binds with oxlate in the intestine and prevents the oxlate from being absorbed into the blood. One site says avoid high oxlate foods. Another site says that dietary oxlate makes little difference because 85-90% of urinary oxlate is produced when metabolozing other foods. One site says take vitamin C. Another site says that the metabolism of Vitamin C produces more urinary oxlate. One site says eat lots of leafy green vegetables. Another site says that leafy green vegetables are high in oxlate -- especially spinach. One site says that it is good to drink beer because it is a mild diuretic. Another site says that beer is high in oxlate and should be avoided. Yet another site says beer is low in oxlate. I am at the point where I cannot trust any advice I receive. Can anyone direct me to a reliable source -- ideally one that can explain some of these apparent contradictions?