Converting a study into a strategy on pinescript

Im trying to build a strategy with an indicator from lazy bear on pinescript. The code looks like this:

//@version=5

strategy(title='Volume Flow Indicator [LazyBear]', shorttitle='VFI_LB', overlay = true)

length = input(130, title='VFI length')
coef = input(0.2)
vcoef = input(2.5, title='Max. vol. cutoff')
signalLength = input(5)
smoothVFI = input(false)

if ta.sma(x, y) >= smoothVFI
    ta.sma(x, y)
else 
    X
   // sma_1 = ta.sma(x, y)
   // smoothVFI ? sma_1 : x

typical = hlc3
inter = math.log(typical) - math.log(typical[1])
vinter = ta.stdev(inter, 30)
cutoff = coef * vinter * close
vave = ta.sma(volume, length)[1]
vmax = vave * vcoef
vc = if volume < vmax
    volume
else
    vmax  //min( volume, vmax )

mf = typical - typical[1]

vcp = if mf > cutoff
    vc
if mf < -cutoff
    vc * -1
else
    0

vfi = ta.sma(math.sum(vcp, length) / vave, 3)
vfima = ta.ema(vfi, signalLength)
d = vfi - vfima

plot(0, color=color.new(color.gray, 0), style=plot.style_cross)
showHisto = input(false)
plot(showHisto ? d : na, style=plot.style_histogram, color=color.new(color.gray, 50), linewidth=3)
plot(vfima, title='EMA of vfi', color=color.new(color.orange, 0))
plot(vfi, title='vfi', color=color.new(color.green, 0), linewidth=2)

These are my current mistakes and I do not know how to fix them.
Fehler in 11:11 Undeclared identifier 'x'
Fehler in 11:14 Undeclared identifier 'y'
Fehler in 14:5 Undeclared identifier 'X'
Fehler in 11:20 Cannot call 'operator >=' with argument 'expr1'='smoothVFI'. An argument of 'input bool' type was used but a 'simple float' is expected.

My idea is that I just want to do some backtesting on how it works to simply enter a long trade when the vfi crosses the zero above. Its not a standalone idea, I just want to implement that indicator into other strategies Im currently trading. Does anybody know how to fix these errors? Thanks for the help!

Below line in the original code is actually a function and not a call to ta.sma() (in v5).

ma(x,y) => smoothVFI ? sma(x,y) : x

So, you should write this also as a function.

Below code is the correct way of upgrading this code to v5:

//@version=5
indicator(title = "Volume Flow Indicator [LazyBear]", shorttitle="VFI_LB")

length = input(130, title="VFI length")
coef = input(0.2)
vcoef = input(2.5, title="Max. vol. cutoff")
signalLength=input(5)
smoothVFI=input.bool(false)

ma(x,y) => smoothVFI ? ta.sma(x,y) : x

typical=hlc3
inter = math.log( typical ) - math.log( typical[1] )
vinter = ta.stdev(inter, 30 )
cutoff = coef * vinter * close
vave = ta.sma( volume, length )[1]
vmax = vave * vcoef

vc = if (volume < vmax)
    volume
else
    vmax //min( volume, vmax )

mf = typical - typical[1]

vcp = if (mf > cutoff)
    vc
else
    if (mf < -cutoff)
        -vc
    else
        0

vfi = ma(math.sum( vcp , length )/vave, 3)
vfima=ta.ema( vfi, signalLength )
d=vfi-vfima

plot(0, color=color.gray, style=plot.style_circles)
showHisto=input.bool(false)
plot(showHisto ? d : na, style=plot.style_histogram, color=color.new(color.gray, 50), linewidth=3)
plot( vfima , title="EMA of vfi", color=color.orange)
plot( vfi, title="vfi", color=color.green,linewidth=2)