Putin is good at playing a weak hand & good at taking advantage of any situation that comes his way that helps his objectives of weakening the West, sowing discord & ideally breaking up NATO & the EU & reestablishing Russian regional Hegemony* & Turkey is a gift that pushes all of these buttons which as usual Putin is playing very well, so it keeps on giving.
Turkish President Erdogan as Europe's newest Poundland dictator also has a weak hand, which he is playing generally very badly, with the exception of Trump where he has sussed flattery gets you everywhere with him. The economy being Turkey's achilles heel, after all what is the point of installing yourself as a dictator if you & your ruling cabal can't enrich themselves at the expense of the hardworking people, by helping yourself to any wealth you fancy?
The end result is that their currency has been in freefall & Erdogan has just sacked the caperable, but can't produce miracles head of their state bank which has made things worse, so the economy is one to watch. As an aside Erdogan recently lost the local Istanbul elections & taking a leaf out of the EU's election playbook of keep voting until you vote the right way, so the second election meant he lost by even bigger margins.

Best of 3,5,7... in UK EURef2 anybody.

Coming back to the F35 v S400, where the US is cancelling delivery of the F35s to Turkey. This is the correct decision where Russian technicians 'training' Turkish operators would have full access to the F35's radar, IR & electromagnetic emissions profiles, why gift this when they will have to work of getting them through 'provocative' combat training missions, the same way as everybody else does against everybody else. This is particularly important with the S400 system with its multiple band radars and IR spectrum sensors where they try to detect & defeat stealth aircraft.
Turkey as a major F35 partner makes over 900 parts, with these now having to be sourced from new suppliers is adding $$$m to the overall production costs, plus a 100 aircraft shorter production run will also do the same. How hardball Trump plays with Turkey in terms of sanctions who knows, including I suspect Trump himself? If this hots up with severe sanctions, including cutting them off from the SWIFT banking system, good luck to all those Tourists in Turkey caught up in this in trying to get home & your value as a Western hostage.
Personally, I would risk booking a holiday there until we see what happens.
*Putin's Master Plan by US political strategists Douglas E. Schoen & Evan Roth Smith