input alertPeriodStart = 930;
input alertPeriodEnd = 1130;
input alertOnBreak = yes;
input alertOnPullBack = yes;
input numberOfDays = 0;
input numberOfYears = 0;
input aggregationPeriod = AggregationPeriod.DAY;
input showOnlyLastPeriod = yes;



def okToPlot = GetLastDay() - numberOfDays <= GetDay() and GetLastYear() - numberOfYears <= GetYear() ;
def startCounter =  SecondsFromTime(alertPeriodStart);
def endCounter = SecondsTillTime(alertPeriodEnd);
def alertPeriod = if startCounter >= 0 and endCounter >= 0 then 1 else 0;
def regularSessionHours = RegularTradingStart(GetYYYYMMDD()) <= GetTime();
def extendedSessionHours = RegularTradingStart(GetYYYYMMDD()) >= GetTime();
def extendedSessionStart = regularSessionHours[1] and extendedSessionHours;
def regularSessionStart = extendedSessionHours[1] and regularSessionHours;
def extendedSessionHigh = CompoundValue(1, if extendedSessionStart then high else if extendedSessionHours then Max(high, extendedSessionHigh[1]) else extendedSessionHigh[1], 0);
def extendedSessionLow = CompoundValue(1, if extendedSessionStart then low else if extendedSessionHours then Min(low, extendedSessionLow[1]) else extendedSessionLow[1], 0);
def regularSessionHigh = CompoundValue(1, if regularSessionStart then high else if regularSessionHours then Max(high, regularSessionHigh[1]) else regularSessionHigh[1], 0);
def regularSessionLow = CompoundValue(1, if regularSessionStart then low else if regularSessionHours then Min(low, regularSessionLow[1]) else regularSessionLow[1], 0);


def prevPrice = open(period = aggregationPeriod)[-1];
def price = open(period = aggregationPeriod);

#---------- Highlight the alert period
AddCloud(if okToPlot and alertPeriod then Double.POSITIVE_INFINITY else Double.NaN, if okToPlot and alertPeriod then Double.NEGATIVE_INFINITY else Double.NaN, Color.light_GRAY,  Color.BLACK);
#---------- Plot the overnight high/low during regular market hours
plot overnightHigh = if okToPlot and regularSessionHours then extendedSessionHigh else Double.NaN;
overnightHigh.SetDefaultColor(Color.DARK_GREEN);
overnightHigh.SetLineWeight(2);
plot overnightLow = if okToPlot and regularSessionHours then extendedSessionLow else Double.NaN;
overnightLow.SetDefaultColor(Color.DARK_RED);
overnightLow.SetLineWeight(2);

plot DailyOpen = if showOnlyLastPeriod and !IsNaN(prevPrice) then Double.NaN else price;
DailyOpen.SetDefaultColor(Color.DARK_GREEN);
Dailyopen.SetLineWeight(2);


def breakOfHigh = if regularSessionStart then low < extendedSessionHigh and high > extendedSessionHigh else extendedSessionHigh[1] > regularSessionHigh[1] and regularSessionHigh > extendedSessionHigh;


def pullbackToHigh = low[1] > extendedSessionHigh[1] and low < extendedSessionHigh;
def pullbackToLow = high[1] < extendedSessionLow[1] and high > extendedSessionLow;




def breakOfLow = if regularSessionStart then high > extendedSessionLow and low < extendedSessionLow else extendedSessionLow[1] < regularSessionLow[1] and regularSessionLow < extendedSessionLow;

#---------- Throw some alerts in here
Alert(alertOnBreak and alertPeriod and breakOfHigh, "Break Above Overnight High", Alert.BAR, Sound.RING);