Engulfing Look-back Alert

This script is an extension of the classical engulf pattern with added rules and user defined features.

Engulfing Candle Definition:
- Bullish Engulfing: Trade BELOW the prior candle's LOW and CLOSE ABOVE the prior candle's HIGH. Previous candle can be an up (bullish) or a down (bearish) candle
- Bearish Engulfing: Trade ABOVE the prior candle’s HIGH and CLOSE BELOW the prior candle’s LOW. Previous candle can be an up (bullish) or a down (bearish) candle

Features:
- Set the look-back period for engulfing candle high and low -> default = 1; e.g. Did the bullish eng candle trade below the lows of the last 3 candles and trade above the highs of the last 4 candles? Set the input values accordingly
- Choose time frame(s) engulfing candle is to be displayed on -> default = M/W/D/4H/1H/15M
- Ability to enable Alerts (includes time frame alert was triggered on): IMPORTANT - when setting alerts ensure to choose "ONCE PER BAR"; otherwise alerts will NOT trigger as intended
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Notes de version:

New features added:
- Multi-hour and multi-minute support
- Compare candle shadows -> Bullish Engulf: upper shadow can be bigger or smaller than lower by x%. Vice versa for Bearish Engulf
- Compare candle size relative to the previous x candles based on candle body and/or shadows
- Compare candle look back period based on candle close or candle shadow