Some people have been upgraded to long haul, it's impossible to say. You may very well be stuck on the short haul depending on future needs.
Regarding a contract's permanency, I can tell you this, it's worth less than the paper it is written on.
If they do not want you, they will simply not renew your working permit among other tricks commonly used in Turkey. Forget about appealing, courts, rights and similiar stuff. Failing inconvenient people in the simulator is very common as well. If they decide to bend you over they will and as a foreigner this will be the cause several times during your stay, wich is why you have to go in with open eyes and not expect to much and not plan far too much ahead.