Color Changing Moving Average

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


//@version=5
indicator(title="Color Changing Moving Average", shorttitle="Colored MA", overlay=true)

// @keywords: moving-average, simple-moving-average, exponential-moving-average, ema-sma-toggle, ma-slope, slope-angle, atr-normalized-angle, trend-direction, bullish-trend, bearish-trend, neutral-trend, trend-reversal, trend-alerts, bull-bear-alerts, angle-lookback, atr-period, custom-ma-length, price-source-input, angle-based-ma, dual-trend-plot

//inputs
i_lookback   = input.int(2,     "Angle Period", minval = 1)
i_atrPeriod  = input.int(10,    "ATR Period",  minval = 1)
i_angleLevel = input.int(6,     "Angle Level",  minval = 1)

len = input.int(21, minval=1, title="Length")
src = input.source(close, title="Source")
offset = 0
type=input.bool(true, "Use EMA? (Off=SMA)")

out=type? ta.ema(src, len) : ta.sma(src, len)

//color change
f_angle(_src, _lookback, _atrPeriod) =>
    rad2degree = 180 / 3.141592653589793238462643  //pi 
    ang = rad2degree * math.atan((_src[0] - _src[_lookback]) / ta.atr(_atrPeriod)/_lookback)
    ang

f_ma(type, _src, _len) =>
    float result = 0
    if type=="SMA" // Simple
        result := ta.sma(_src, _len)
    if type=="EMA" // Exponential
        result := ta.ema(_src, _len)

    result

_ma_type = type ? "EMA" : "SMA"
_ma    = f_ma(_ma_type, src, len)
_angle = f_angle(_ma, i_lookback, i_atrPeriod)
color_H = _angle > 0 ? color.lime : _angle < 0 ? color.red : color.gray

//trend color change
colsh= _angle>0 ? #00ff00 : na
colsh2= _angle<0? #ff0000 : na

//no trend color change
colsh3= _angle==0 ? #9598a1 : na
colsh4= _angle==0 ? #9598a1 : na

//plots
// //trend line plot
plot(out, color=colsh, linewidth=3, offset=offset)
plot(out, color=colsh2, linewidth=3, offset=offset)


alertcondition(_angle>0 and _angle[1]<0, "Now Bull Color", "Now Bull Color")
alertcondition(_angle<0 and _angle[1]>0, "Now Bear Color", "Now Bear Color")
alertcondition( (_angle<0 and _angle[1]>0) or (_angle>0 and _angle[1]<0), "ANY Color Change", "ANY Color Change")