SupportResitanceAndTrend

// This source code is subject to the terms of the Mozilla Public License 2.0 at https://mozilla.org/MPL/2.0/
// © Electrified (electrifiedtrading)

// @version=5
// @description Contains utilities for finding key levels of support, resistance and direction of trend.
library("SupportResitanceAndTrend", true)
import Electrified/MovingAverages/2 as ma

// @function A more flexible version of SuperTrend that allows for supplying the series used and sensitivity adjustment by confirming close bars.
// @param multiple The multiple to apply to the average true range.
// @param h The high values.
// @param l The low values.
// @param atr The average true range values.
// @param closeBars The number of bars to confirm a change in trend.
// @returns [trend, up, dn, unconfirmed, warn, reversal]
export superTrendPlus(
  simple float multiple,
  series float h,
  series float l,
  series float atr,
  simple int closeBars = 0) =>
    up = l-(multiple*atr)
    up1 = nz(up[1], up)
    up := l[1] > up1 ? math.max(up, up1) : up
    dn = h+(multiple*atr)
    dn1 = nz(dn[1], dn)
    dn := h[1] < dn1 ? math.min(dn, dn1) : dn

    var lastU = up1
    var lastD = dn1
    var trend = 0
    var confirmation = 0
    var unconfirmed = 0

    // cover gap cases
    if(trend != +1 and l > lastD)
        trend := +1
    else if(trend != -1 and h < lastU)
        trend := -1

    // confirmed cases
    else if(trend != +1 and h > lastD)
        unconfirmed += 1
        if(confirmation<closeBars and close[1]>lastD)
            confirmation += 1
        if(confirmation>=closeBars)
            trend := +1
    else if(trend != -1 and l < lastU)
        unconfirmed += 1
        if(confirmation<closeBars and close[1]<lastU)
            confirmation += 1
        if(confirmation>=closeBars)
            trend := -1

    if(trend[1]!=trend)
        lastU := up1
        lastD := dn1
        confirmation := 0
        unconfirmed := 0
    else
        lastU := trend==+1 ? math.max(lastU, up1) : up1
        lastD := trend==-1 ? math.min(lastD, dn1) : dn1
        // Trend is clearly continuing?  Reset confirmation.
        if(trend==+1 and dn1>dn1[1] or trend==-1 and up1<up1[1])
            confirmation := 0
            unconfirmed := 0

    [trend, lastU, lastD, unconfirmed, unconfirmed[1]==0 and unconfirmed > 0, trend != trend[1]]
///

// @function superTrendPlus with simplified parameters.
// @param multiple The multiple to apply to the average true range.
// @param period The number of bars to measure.
// @param mode The type of moving average to use with the true range.
// @param closeBars The number of bars to confirm a change in trend.
// @returns [trend, up, dn, unconfirmed, warn, reversal]
export superTrend(
  simple float multiple,
  simple int period,
  simple string mode = "WMA",
  simple int closeBars = 0) =>
    superTrendPlus(multiple, high, low, ma.getMA(mode, period, ta.tr), closeBars)
///

// @function Identifies support and resistance levels by when a stochastic RSI reverses.
// @returns [trend, up, dn, unconfirmed, warn, reversal]
export stochSR(
  simple int smoothK,
  simple int smoothD,
  simple int lengthRSI,
  simple int lengthStoch,
  series float src = hlc3,
  simple float lowerBand = 20,
  simple float upperBand = 80,
  simple float lowerReversal = 20,
  simple float upperReversal = 80) =>
    rsi1 = ta.rsi(src, lengthRSI)
    stoch = ta.stoch(rsi1, rsi1, rsi1, lengthStoch)
    k = ta.wma(stoch, smoothK)
    d = ta.sma(k, smoothD)
    k_c = ta.change(k)
    d_c = ta.change(d)
    kd = k - d

    var hi = high
    var lo = low
    var phi = high
    var plo = low
    var state = 0

    if(d<lowerBand)
        phi := high
    if(d>upperBand)
        plo := low

    if(high>phi)
        phi := high
    if(low<plo)
        plo := low

    if(state!=-1 and d<lowerBand)
        state := -1
    else if(state!=+1 and d>upperBand)
        state := +1

    if(hi>phi and state==+1 and k<d and k<lowerReversal)
        hi := phi
    if(lo<plo and state==-1 and k>d and k>upperReversal)
        lo := plo

    if(high>hi)
        hi := high
    if(low<lo)
        lo := low

    [lo, hi]
///