Create a simple function that return yesterday date, if yesterday is a sunday, return the date of Friday,

Hello !

I use an Anchored VWAP indicator to check the direction of the market and place order using an EA.

Before market opening, I need to have the VWAP anchored the day before.

So I need a function that return date and time of the market opening for the indicator.
In my EA, I have this :

input int marketOpenHour            = 14;

input int marketOpenMinute          = 30;



string DateVWAP = TimeToStr(TimeCurrent(),TIME_DATE); //"yyyy.mm.dd";

datetime VWAPDateTime = StrToTime(StringConcatenate( DateVWAP , " " , marketOpenHour, ":" , marketOpenMinute));

The problem, is if the time is 11:00, the result will be in the future and the indicator will not work at all ... 

I need this to be modified that way :

Before market open at 14:30, we need to have DateVWAP returning the day before (yesterday), but if the day before is a Sunday, return the date of 3 days before.

Examples :

The EA is started Tuesday 2019.10.01 15:00 => the function return 2019.10.01 14:30
The EA is started Tuesday 2019.10.01 12:00 => the function return 2019.09.30 14:30

The EA is started Monday 2019.09.30 16:00 => the function return 2019.09.30 14:30

The EA is started Monday 2019.09.30 08:00 => the function return 2019.09.27 14:30