package util;

import java.text.ParseException;
import java.text.SimpleDateFormat;

public class FormatHelper {

	private static final SimpleDateFormat in = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
	private static final SimpleDateFormat out = new SimpleDateFormat("dd.MM.yyyy HH:mm:ss");

	/**
	 * Convert mysql date/time format to human readable (German) format.
	 * If the given date is not parsable, "<invalid>" will be returned.
	 * 
	 * @param dateTime yyyy-MM-dd HH:mm:ss
	 * @return dd.MM.yy HH:mm
	 */
	public static String mysqlDateToGerman(String dateTime) {
		try {
			return out.format(in.parse(dateTime));
		} catch (ParseException e) {
			return "<invalid>";
		}
	}

	public static String byteToGigabyte(long bytes, boolean si) {
		int unit = si ? 1000 : 1024;
		if (bytes < unit)
			return bytes + " B";
		int exp = (int) (Math.log(bytes) / Math.log(unit));
		String pre = (si ? "kMGTPE" : "KMGTPE").charAt(exp - 1) + (si ? "" : "i");
		return String.format("%.1f %sB", bytes / Math.pow(unit, exp), pre);
	}

}