package eu.smartlm.abs.portal.data.aggregation;

import java.util.Calendar;
import java.util.Date;

/**
 * Performs different time calculations with the dates of the Usage Records
 * @author David García Pérez - CESGA
 */
public class TimeCalculation {

	/**
	 * This class performs a time difference between two formated dates, if the dates are wrongly formated, it returns -1
	 * @param formatedDate1 On of the dates to be used in the calculation
	 * @param formatedDate2 The other date to be used in the calculation
	 * @return returns the difference in miliseconds between formatedDate1 and formatedDate2, if they are wrongly formated it returns -1
	 */
	public static long timeDifferenceInMiliSeconds(Calendar calendar1, Calendar calendar2) {
		    
		Date date1 = calendar1.getTime();
		Date date2 = calendar2.getTime();

		//Calculating the difference
		if(date1.after(date2)) 
			return date1.getTime() - date2.getTime();
		else
			return date2.getTime() - date1.getTime();
	}

	/**
	 * This method performs the time difference between two UsageRecord dates in hours
	 * @param formatedDate1 formated usage record date to use in the calculation
	 * @param formatedDate2 formated usage record date to use in the calculation
	 * @return the difference in hours between formatedDate1 and formatedDate2, -1 if one or both dates are wrongly formatted
	 */
	public static double timeDifferenceInHours(Calendar date1, Calendar date2) {
		
		long differenceInMiliSeconds = timeDifferenceInMiliSeconds(date1, date2);
		
		if(differenceInMiliSeconds != -1)
			return ((double) differenceInMiliSeconds) / (1000.0 * 60.0 * 60.0);
		else
			return -1.0;
	}

}