Who should take the hit in Detroit's bankruptcy?

The city has declared bankruptcy and all of the current debt holders are going to take a haircut. Bond holders will not get all of their money, vendors will lose some money, and pensioners will lose money as well. Let's assume that the federal gov't isn't legally obligated to cover the pensions (I know the PBGC covers pensions for liquidated private companies, but I don't know about reorganized cities). How much of the pain should go to bondholders (who have known about Detroit's finances for at least a decade)? How much pain should go to vendors (the same about the finances)? How much should go to the pensioners (the cause of most of the debt and the people who elected leaders unwilling to tackle the foreseeable problems for over a decade)?