How can I add a simple function to a pine script code

I need help in adding this function as I am still at the beginning with pine script.
This indicator looks for fair gap value but it gives to many gaps so I want to limit those gaps by looking for a specific candle pattern, for example...I want the indicator to show me only gaps from green candle, red candle, red candle...or red candle, red candle, red candle...i want to backtest only for a specific candle patter so that s why it needs this feature.

Thanks in advance, here is the code.

//@version=5
indicator("Fair Value Gap", overlay = true, max_boxes_count = 500, max_lines_count = 500, max_labels_count = 500)
// ———————————————————— Inputs {
// Standard practice declared input variables with i_ easier to identify
i_tf = input.timeframe("D", "MTF Timeframe", group = "MTF Settings")
i_mtf = input.string(defval = "Current TF",group = "MTF Settings", title = "MTF Options", options = ["Current TF", "Current + HTF", "HTF"])
i_tfos = input.int(defval = 10,title = "Offset", minval = 0, maxval = 500 ,group = "MTF Settings", inline = "OS")
i_mtfos = input.int(defval = 20,title = "MTF Offset", minval = 0, maxval = 500 ,group = "MTF Settings", inline = "OS")
i_fillByMid = input.bool(false, "MidPoint Fill",group = "General Settings", tooltip = "When enabled FVG is filled when midpoint is tested")
i_deleteonfill = input.bool(true, "Delete Old On Fill",group = "General Settings")
i_labeltf = input.bool(true,"Label FVG Timeframe",group = "General Settings")
i_bullishfvgcolor = input.color(color.new(color.green,90), "Bullish FVG", group = "Coloring", inline = "BLFVG")
i_mtfbullishfvgcolor = input.color(color.new(color.lime,80), "MTF Bullish FVG", group = "Coloring", inline = "BLFVG")
i_bearishfvgcolor = input.color(color.new(color.red,90), "Bearish FVG", group = "Coloring", inline = "BRFVG")
i_mtfbearishfvgcolor = input.color(color.new(color.maroon,80), "MTF Bearish FVG", group = "Coloring", inline = "BRFVG")
i_midPointColor = input.color(color.new(color.white,85), "MidPoint Color", group = "Coloring")
i_textColor = input.color(color.white, "Text Color", group = "Coloring")
// }
// ———————————————————— Global data {
//Using current bar data for HTF highs and lows instead of security to prevent future leaking
var htfH = open
var htfL = open
if close > htfH 
htfH:= close
if close < htfL
htfL := close
//Security Data, used for HTF Bar Data reference
sClose = request.security(syminfo.tickerid, i_tf, close[1], barmerge.gaps_off, barmerge.lookahead_on)
sHighP2 = request.security(syminfo.tickerid, i_tf, high[2], barmerge.gaps_off, barmerge.lookahead_on)
sLowP2 = request.security(syminfo.tickerid, i_tf, low[2], barmerge.gaps_off, barmerge.lookahead_on)
sOpen = request.security(syminfo.tickerid, i_tf, open[1], barmerge.gaps_off, barmerge.lookahead_on)
sBar = request.security(syminfo.tickerid, i_tf, bar_index, barmerge.gaps_off, barmerge.lookahead_on)
// }
//var keyword can be used to hold data in memory, with pinescript all data is lost including variables unless the var keyword is used to preserve this data
var bullishgapholder = array.new_box(0)
var bearishgapholder = array.new_box(0)
var bullishmidholder = array.new_line(0)
var bearishmidholder = array.new_line(0)
var bullishlabelholder = array.new_label(0)
var bearishlabelholder = array.new_label(0)
var transparentcolor = color.new(color.white,100)
// ———————————————————— Functions {
//function paramaters best declared with '_' this helps defer from variables in the function scope declaration and elsewhere e.g. close => _close
f_gapCreation(_upperlimit,_lowerlimit,_midlimit,_bar,_boxholder,_midholder,_labelholder,_boxcolor,_mtfboxcolor, _htf)=>
timeholder = str.tostring(i_tf)
offset = i_mtfos
boxbgcolor = _mtfboxcolor
if _htf == false
timeholder := str.tostring(timeframe.period)
offset := i_tfos
boxbgcolor := _boxcolor
array.push(_boxholder,box.new(_bar,_upperlimit,_bar+1,_lowerlimit,border_color=transparentcolor,bgcolor = boxbgcolor, extend = extend.right))
if i_fillByMid 
array.push(_midholder,line.new(_bar,_midlimit,_bar+1,_midlimit,color = i_midPointColor, extend = extend.right))
if i_labeltf
array.push(_labelholder,label.new(_bar+ offset,_midlimit * 0.999, text = timeholder + " FVG", style =label.style_none, size = size.normal, textcolor = i_textColor))
//checks for gap between current candle and 2 previous candle e.g. low of current candle and high of the candle before last, this is the fair value gap.
f_gapLogic(_close,_high,_highp2,_low,_lowp2,_open,_bar,_htf)=>
if _open > _close
if _high - _lowp2 < 0
upperlimit = _close - (_close - _lowp2 )
lowerlimit = _close - (_close-_high)
midlimit = (upperlimit + lowerlimit) / 2
f_gapCreation(upperlimit,lowerlimit,midlimit,_bar,bullishgapholder,bullishmidholder,bullishlabelholder,i_bullishfvgcolor,i_mtfbullishfvgcolor,_htf)
else
if _low - _highp2 > 0 
upperlimit = _close - (_close-_low)
lowerlimit = _close- (_close - _highp2),
midlimit = (upperlimit + lowerlimit) / 2
f_gapCreation(upperlimit,lowerlimit,midlimit,_bar,bearishgapholder,bearishmidholder,bearishlabelholder,i_bearishfvgcolor,i_mtfbearishfvgcolor,_htf)
//Used to remove the gap from its relevant array as a result of it being filled.
f_gapDeletion(_currentgap,_i,_boxholder,_midholder,_labelholder)=>
array.remove(_boxholder,_i)
if i_fillByMid
currentmid=array.get(_midholder,_i)
array.remove(_midholder,_i)
if i_deleteonfill
line.delete(currentmid)
else
line.set_extend(currentmid, extend.none)
line.set_x2(currentmid,bar_index)
if i_deleteonfill
box.delete(_currentgap)
else
box.set_extend(_currentgap,extend.none)
box.set_right(_currentgap,bar_index)
if i_labeltf
currentlabel=array.get(_labelholder,_i)
array.remove(_labelholder,_i)
if i_deleteonfill
label.delete(currentlabel)
//checks if gap has been filled either by 0.5 fill (i_fillByMid) or SHRINKS the gap to reflect the true value gap left.
f_gapCheck(_high,_low)=>
if array.size(bullishgapholder) > 0
for i = array.size(bullishgapholder)-1 to 0
currentgap = array.get(bullishgapholder,i)
currenttop = box.get_top(currentgap)
if i_fillByMid 
currentmid = array.get(bullishmidholder,i)
currenttop := line.get_y1(currentmid)
if _high >= currenttop
f_gapDeletion(currentgap,i,bullishgapholder,bullishmidholder,bullishlabelholder)
if _high > box.get_bottom(currentgap) and _high < box.get_top(currentgap)
box.set_bottom(currentgap,_high)
if array.size(bearishgapholder) > 0
for i = array.size(bearishgapholder)-1 to 0
currentgap = array.get(bearishgapholder,i)
currentbottom = box.get_bottom(currentgap)
if i_fillByMid 
currentmid = array.get(bearishmidholder,i)
currentbottom := line.get_y1(currentmid)           
if _low <= currentbottom
f_gapDeletion(currentgap,i,bearishgapholder,bearishmidholder,bearishlabelholder)
if _low < box.get_top(currentgap) and _low > box.get_bottom(currentgap)
box.set_top(currentgap,_low)      
// pine provided function to determine a new bar
is_newbar(res) =>
t = time(res)
not na(t) and (na(t[1]) or t > t[1])
if is_newbar(i_tf)
htfH := open
htfL := open
// }
// User Input, allow MTF data calculations
if is_newbar(i_tf) and (i_mtf == "Current + HTF" or i_mtf == "HTF")
f_gapLogic(sClose,htfH,sHighP2,htfL,sLowP2,sOpen,bar_index,true)
// Use current Timeframe data to provide gap logic
if (i_mtf == "Current + HTF" or i_mtf == "Current TF")
f_gapLogic(close[1],high,high[2],low,low[2],open[1],bar_index,false) 
f_gapCheck(high,low)

I have tried to look for some tutorials on how to do it but all attempts failed because it s a bit too complex for my knowledge.

In the script below I added filter just by 3 green candles or 3 red candles and only for the chart timeframe.

You can find code for more patterns, e.g., in this great script: enter link description here

//@version=5
indicator("Fair Value Gap", overlay = true, max_boxes_count = 500, max_lines_count = 500, max_labels_count = 500)
// ———————————————————— Inputs {
// Standard practice declared input variables with i_ easier to identify
i_tf = input.timeframe("D", "MTF Timeframe", group = "MTF Settings")
i_mtf = input.string(defval = "Current TF",group = "MTF Settings", title = "MTF Options", options = ["Current TF", "Current + HTF", "HTF"])
i_tfos = input.int(defval = 10,title = "Offset", minval = 0, maxval = 500 ,group = "MTF Settings", inline = "OS")
i_mtfos = input.int(defval = 20,title = "MTF Offset", minval = 0, maxval = 500 ,group = "MTF Settings", inline = "OS")
i_fillByMid = input.bool(false, "MidPoint Fill",group = "General Settings", tooltip = "When enabled FVG is filled when midpoint is tested")
i_deleteonfill = input.bool(true, "Delete Old On Fill",group = "General Settings")
i_labeltf = input.bool(true,"Label FVG Timeframe",group = "General Settings")
i_candlePattern = input.string(group = "Filter by candle patterns", defval = "None", title = "Filter by candle pattern", options = ["None", "cpGgg", "cpRrr"])
i_bullishfvgcolor = input.color(color.new(color.green,90), "Bullish FVG", group = "Coloring", inline = "BLFVG")
i_mtfbullishfvgcolor = input.color(color.new(color.lime,80), "MTF Bullish FVG", group = "Coloring", inline = "BLFVG")
i_bearishfvgcolor = input.color(color.new(color.red,90), "Bearish FVG", group = "Coloring", inline = "BRFVG")
i_mtfbearishfvgcolor = input.color(color.new(color.maroon,80), "MTF Bearish FVG", group = "Coloring", inline = "BRFVG")
i_midPointColor = input.color(color.new(color.white,85), "MidPoint Color", group = "Coloring")
i_textColor = input.color(color.white, "Text Color", group = "Coloring")
// }
// ———————————————————— Global data {
//Using current bar data for HTF highs and lows instead of security to prevent future leaking
var htfH = open
var htfL = open
if close > htfH 
htfH:= close
if close < htfL
htfL := close
//Security Data, used for HTF Bar Data reference
sClose = request.security(syminfo.tickerid, i_tf, close[1], barmerge.gaps_off, barmerge.lookahead_on)
sHighP2 = request.security(syminfo.tickerid, i_tf, high[2], barmerge.gaps_off, barmerge.lookahead_on)
sLowP2 = request.security(syminfo.tickerid, i_tf, low[2], barmerge.gaps_off, barmerge.lookahead_on)
sOpen = request.security(syminfo.tickerid, i_tf, open[1], barmerge.gaps_off, barmerge.lookahead_on)
sBar = request.security(syminfo.tickerid, i_tf, bar_index, barmerge.gaps_off, barmerge.lookahead_on)
// }
//var keyword can be used to hold data in memory, with pinescript all data is lost including variables unless the var keyword is used to preserve this data
var bullishgapholder = array.new_box(0)
var bearishgapholder = array.new_box(0)
var bullishmidholder = array.new_line(0)
var bearishmidholder = array.new_line(0)
var bullishlabelholder = array.new_label(0)
var bearishlabelholder = array.new_label(0)
var transparentcolor = color.new(color.white,100)
// ———————————————————— Candle patterns {
cpRrr = close < open and close[1] < open[1] and close[2] < open[2]
cpGgg = close > open and close[1] > open[1] and close[2] > open[2]
cpFilter = switch i_candlePattern
"cpGgg" => cpGgg
"cpRrr" => cpRrr
=> true
// END OF candle patterns }
// ———————————————————— Functions {
//function paramaters best declared with '_' this helps defer from variables in the function scope declaration and elsewhere e.g. close => _close
f_gapCreation(_upperlimit,_lowerlimit,_midlimit,_bar,_boxholder,_midholder,_labelholder,_boxcolor,_mtfboxcolor, _htf)=>
timeholder = str.tostring(i_tf)
offset = i_mtfos
boxbgcolor = _mtfboxcolor
if _htf == false
timeholder := str.tostring(timeframe.period)
offset := i_tfos
boxbgcolor := _boxcolor
array.push(_boxholder,box.new(_bar,_upperlimit,_bar+1,_lowerlimit,border_color=transparentcolor,bgcolor = boxbgcolor, extend = extend.right))
if i_fillByMid 
array.push(_midholder,line.new(_bar,_midlimit,_bar+1,_midlimit,color = i_midPointColor, extend = extend.right))
if i_labeltf
array.push(_labelholder,label.new(_bar+ offset,_midlimit * 0.999, text = timeholder + " FVG", style =label.style_none, size = size.normal, textcolor = i_textColor))
//checks for gap between current candle and 2 previous candle e.g. low of current candle and high of the candle before last, this is the fair value gap.
f_gapLogic(_close,_high,_highp2,_low,_lowp2,_open,_bar,_htf)=>
if _open > _close
if _high - _lowp2 < 0
upperlimit = _close - (_close - _lowp2 )
lowerlimit = _close - (_close-_high)
midlimit = (upperlimit + lowerlimit) / 2
f_gapCreation(upperlimit,lowerlimit,midlimit,_bar,bullishgapholder,bullishmidholder,bullishlabelholder,i_bullishfvgcolor,i_mtfbullishfvgcolor,_htf)
else
if _low - _highp2 > 0 
upperlimit = _close - (_close-_low)
lowerlimit = _close- (_close - _highp2),
midlimit = (upperlimit + lowerlimit) / 2
f_gapCreation(upperlimit,lowerlimit,midlimit,_bar,bearishgapholder,bearishmidholder,bearishlabelholder,i_bearishfvgcolor,i_mtfbearishfvgcolor,_htf)
//Used to remove the gap from its relevant array as a result of it being filled.
f_gapDeletion(_currentgap,_i,_boxholder,_midholder,_labelholder)=>
array.remove(_boxholder,_i)
if i_fillByMid
currentmid=array.get(_midholder,_i)
array.remove(_midholder,_i)
if i_deleteonfill
line.delete(currentmid)
else
line.set_extend(currentmid, extend.none)
line.set_x2(currentmid,bar_index)
if i_deleteonfill
box.delete(_currentgap)
else
box.set_extend(_currentgap,extend.none)
box.set_right(_currentgap,bar_index)
if i_labeltf
currentlabel=array.get(_labelholder,_i)
array.remove(_labelholder,_i)
if i_deleteonfill
label.delete(currentlabel)
//checks if gap has been filled either by 0.5 fill (i_fillByMid) or SHRINKS the gap to reflect the true value gap left.
f_gapCheck(_high,_low)=>
if array.size(bullishgapholder) > 0
for i = array.size(bullishgapholder)-1 to 0
currentgap = array.get(bullishgapholder,i)
currenttop = box.get_top(currentgap)
if i_fillByMid 
currentmid = array.get(bullishmidholder,i)
currenttop := line.get_y1(currentmid)
if _high >= currenttop
f_gapDeletion(currentgap,i,bullishgapholder,bullishmidholder,bullishlabelholder)
if _high > box.get_bottom(currentgap) and _high < box.get_top(currentgap)
box.set_bottom(currentgap,_high)
if array.size(bearishgapholder) > 0
for i = array.size(bearishgapholder)-1 to 0
currentgap = array.get(bearishgapholder,i)
currentbottom = box.get_bottom(currentgap)
if i_fillByMid 
currentmid = array.get(bearishmidholder,i)
currentbottom := line.get_y1(currentmid)           
if _low <= currentbottom
f_gapDeletion(currentgap,i,bearishgapholder,bearishmidholder,bearishlabelholder)
if _low < box.get_top(currentgap) and _low > box.get_bottom(currentgap)
box.set_top(currentgap,_low)      
// pine provided function to determine a new bar
is_newbar(res) =>
t = time(res)
not na(t) and (na(t[1]) or t > t[1])
if is_newbar(i_tf)
htfH := open
htfL := open
// }
// User Input, allow MTF data calculations
if is_newbar(i_tf) and (i_mtf == "Current + HTF" or i_mtf == "HTF") 
f_gapLogic(sClose,htfH,sHighP2,htfL,sLowP2,sOpen,bar_index,true)
// Use current Timeframe data to provide gap logic
if (i_mtf == "Current + HTF" or i_mtf == "Current TF") and cpFilter
f_gapLogic(close[1],high,high[2],low,low[2],open[1],bar_index,false) 
f_gapCheck(high,low)