what's wrong in here?

[damsiboko]

//!!! I must define all input properties here, because they are not automatically defined.
	// This function is not global prototype, one new function is created for each case. This is because % iCustom % must be unique
	
	string symbol = Symbol;
	ENUM_TIMEFRAMES timeframe = Period;
	int buffer    = 1;
	int shift     = Shift + FXD_MORE_SHIFT;
	
	double retval = EMPTY_VALUE;
	int i;
	double ival;
	
	if (ModeOutput == "id")
	{
		retval = iCustom(symbol, timeframe, "ccf1p-value" , buffer, shift);
		
	}
	else if (ModeOutput == "time")
	{
		datetime time;
		
		if (0 && StringFind(TimeStamp, ":") == -1)
		{	
			time = (datetime)StringToInteger(TimeStamp); // hangs in MQL4!!!
		}
		else
		{
			time = StringToTime(TimeStamp);
		}
		
		shift = iCandleID(symbol, timeframe, time);
		retval = iCustom(symbol, timeframe, "ccf1p-value" , buffer, shift);
	}
	else if (ModeOutput == "visible" || ModeOutput == "id_by_visible")
	{
		if (VisibleLimit == 0) {VisibleLimit = iBars(symbol, timeframe);}
		
		int vid = 0;
		
		for (i = shift; i <= VisibleLimit; i++)
		{
			ival = iCustom(symbol, timeframe, "ccf1p-value" , buffer, shift + i);
			
			if (ival == EMPTY_VALUE || ival == 0) {continue;}
			if (vid >= VisibleID) {
				if (ModeOutput == "visible") {retval = ival;}
				else {retval = i;}
				break;	
			}
				
			vid++;
		}
	}
	else if (ModeOutput == "range")
	{
		int cstart = RangeCandleStart;
		int cend   = RangeCandleEnd;
		//string RangeValue = RangeValue;
		
		// reverse values, if needed
		if (RangeCandleStart > RangeCandleEnd) {
			int ctmp = RangeCandleEnd;
			RangeCandleEnd = RangeCandleStart;
			RangeCandleStart = ctmp;
		}
	
		if (RangeValue == "max")
		{
			retval = -EMPTY_VALUE;
			
			for (i = RangeCandleStart; i <= RangeCandleEnd; i++)
			{
				ival = iCustom(symbol, timeframe, "ccf1p-value" , buffer, shift + i);
				if (ival == EMPTY_VALUE || ival == 0) {continue;}
				if (ival > retval) {retval = ival;}
			}
			
			if (retval == -EMPTY_VALUE) {retval = EMPTY_VALUE;}
		}
		else if (RangeValue == "min")
		{
			retval = EMPTY_VALUE;
			
			for (i = RangeCandleStart; i <= RangeCandleEnd; i++)
			{
				ival = iCustom(symbol, timeframe, "ccf1p-value" , buffer, shift + i);
				if (ival == EMPTY_VALUE || ival == 0) {continue;}
				if (ival < retval) {retval = ival;}
			}
		}
	}
	else if (ModeOutput == "range_time")
	{
		datetime offset = 0;
		if (RangeTimeSource == "gmt") {offset = (int)(TimeCurrent() - TimeLocal() + TimeGMTOffset());}
		else if (RangeTimeSource == "server") {offset = (int)(TimeCurrent() - TimeLocal());}
		
		datetime time1 = StringToTime(RangeTimeStart)-(datetime)(86400*RangeDayOffset) + offset;
		datetime time2 = StringToTime(RangeTimeEnd)-(datetime)(86400*RangeDayOffset) + offset;
		
		int x1 = iBarShift(symbol, timeframe, time1, false);
		int x2 = iBarShift(symbol, timeframe, time2, false);
		if (x1<x2) {x1=iBarShift(symbol,timeframe,(time1-86400),false);}
		
		if (RangeValue == "max")
		{
			retval = -EMPTY_VALUE;
			
			for (i=x2; i<=x1; i++)
			{
				ival = iCustom(symbol, timeframe, "ccf1p-value" , buffer, shift + i);
				if (ival == EMPTY_VALUE || ival == 0) {continue;}
				if (ival > retval) {retval = ival;}
			}
			
			if (retval == -EMPTY_VALUE) {retval = EMPTY_VALUE;}
		}
		else if (RangeValue == "min")
		{
			retval = EMPTY_VALUE;
			
			for (i=x2; i<=x1; i++)
			{
				ival = iCustom(symbol, timeframe, "ccf1p-value" , buffer, shift + i);
				if (ival == EMPTY_VALUE || ival == 0) {continue;}
				if (ival < retval) {retval = ival;}
			}
		}
	}
	
	return (retval);
}

[fxDreema]

If you are asking about the comments on the top, I probably placed them for the future me, for me to know what is going on If I touch this code in the future.