Permanent residents of the United States do not require a visa to visit or transit through Canada. You will require eTA, however:
Who needs an eTA to travel to Canada?
There are four types of travellers:
Travellers who need an eTA:
Lawful permanent residents of the U.S. need an eTA to fly to or transit through a Canadian ...
If you don't leave the airport then you do not need a visa.
If you plan to leave the airport you will need to apply for an eVisa from the Turkish government from : evisa.gov.tr as they no longer provide visas upon arrival.