On Neck - Bearish

//@version=5
indicator("On Neck - Bearish", shorttitle = "On Neck - Bear", overlay=true)

C_DownTrend = true
C_UpTrend = true
var trendRule1 = "SMA50"
var trendRule2 = "SMA50, SMA200"
var trendRule = input.string(trendRule1, "Detect Trend Based On", options=[trendRule1, trendRule2, "No detection"])

if trendRule == trendRule1
    priceAvg = ta.sma(close, 50)
    C_DownTrend := close < priceAvg
    C_UpTrend := close > priceAvg

if trendRule == trendRule2
    sma200 = ta.sma(close, 200)
    sma50 = ta.sma(close, 50)
    C_DownTrend := close < sma50 and sma50 < sma200
    C_UpTrend := close > sma50 and sma50 > sma200
C_Len = 14 // ta.ema depth for bodyAvg
C_ShadowPercent = 5.0 // size of shadows
C_ShadowEqualsPercent = 100.0
C_DojiBodyPercent = 5.0
C_Factor = 2.0 // shows the number of times the shadow dominates the candlestick body

C_BodyHi = math.max(close, open)
C_BodyLo = math.min(close, open)
C_Body = C_BodyHi - C_BodyLo
C_BodyAvg = ta.ema(C_Body, C_Len)
C_SmallBody = C_Body < C_BodyAvg
C_LongBody = C_Body > C_BodyAvg
C_UpShadow = high - C_BodyHi
C_DnShadow = C_BodyLo - low
C_HasUpShadow = C_UpShadow > C_ShadowPercent / 100 * C_Body
C_HasDnShadow = C_DnShadow > C_ShadowPercent / 100 * C_Body
C_WhiteBody = open < close
C_BlackBody = open > close
C_Range = high-low
C_IsInsideBar = C_BodyHi[1] > C_BodyHi and C_BodyLo[1] < C_BodyLo
C_BodyMiddle = C_Body / 2 + C_BodyLo
C_ShadowEquals = C_UpShadow == C_DnShadow or (math.abs(C_UpShadow - C_DnShadow) / C_DnShadow * 100) < C_ShadowEqualsPercent and (math.abs(C_DnShadow - C_UpShadow) / C_UpShadow * 100) < C_ShadowEqualsPercent
C_IsDojiBody = C_Range > 0 and C_Body <= C_Range * C_DojiBodyPercent / 100
C_Doji = C_IsDojiBody and C_ShadowEquals

patternLabelPosLow = low - (ta.atr(30) * 0.6)
patternLabelPosHigh = high + (ta.atr(30) * 0.6)

label_color_bearish = input(color.red, "Label Color Bearish")
C_OnNeckBearishNumberOfCandles = 2
C_OnNeckBearish = false
if C_DownTrend and C_BlackBody[1] and C_LongBody[1] and C_WhiteBody and open < close[1] and C_SmallBody and C_Range!=0 and math.abs(close-low[1])<=C_BodyAvg*0.05
    C_OnNeckBearish := true
alertcondition(C_OnNeckBearish, title = "New pattern detected", message = "New On Neck – Bearish pattern detected")
if C_OnNeckBearish
    var ttBearishOnNeck = "On Neck\nOn Neck is a two-line continuation pattern found in a downtrend. The first candle is long and red, the second candle is short and has a green body. The closing price of the second candle is close or equal to the first candle's low price. The pattern hints at a continuation of a downtrend, and penetrating the low of the green candlestick is sometimes considered a confirmation. "
    label.new(bar_index, patternLabelPosHigh, text="ON", style=label.style_label_down, color = label_color_bearish, textcolor=color.white, tooltip = ttBearishOnNeck)
bgcolor(ta.highest(C_OnNeckBearish?1:0, C_OnNeckBearishNumberOfCandles)!=0 ? color.new(color.red, 90) : na, offset=-(C_OnNeckBearishNumberOfCandles-1))