In order to code your request, please help us to define:

1. Stock which was uptrending
2. swing low to swing high point (how to find these points?)

1/ counting how many times the MA50 had been above the MA200 is a common and simple rule to determine an uptrend. How course, you’ll have to determine a threshold for the count value to confirm the trend.

2/ storing the lowest low value while MA50 is below MA200 and the highest high while it is above could be a good idea.

Let me know your thinking about these 2 proposals.

This first rough version is a first try and does not find the good LL and HH:

uptrendThreshold = 20 //periods

//indis
ma200=average[200]
ma50=average[50]

//reset highest high and lowest low
if ma50 crosses under ma200 then 
ll=low
endif
if ma50 crosses over ma200 then
hh=0
endif

//compute hh and ll
hh=max(hh,high)
ll=min(ll,low)

//confirmed uptrend
uptrend = summation[uptrendThreshold](ma50>ma200)=uptrendThreshold

//retracement 61.8
percent = (close-ll)/(hh-ll)
retrace = percent>=0.55 and percent<=0.65 

//global test
test = uptrend and retrace and ll>0 and hh>0

screener[test](percent)

My proposal for point 2 was not a good idea since moving average are obviously suffering from lag the saved LL and HH are not the ones we are looking for. I let you doing some tests and try to find a better way to find them 🙂

I still did not add any condition on the price bouncing on MA200.