/**
 * Copyright 2013 JogAmp Community. All rights reserved.
 *
 * This software is licensed under the GNU General Public License (GPL) Version 3.
 * 
 * The views and conclusions contained in the software and documentation are those of the
 * authors and should not be interpreted as representing official policies, either expressed
 * or implied, of JogAmp Community.
 */
package org.jogamp.jabot.util;

import java.util.Calendar;
import java.util.TimeZone;

public class TimeTool {
    public static String UTC_TZ = "UTC";
    public static String[] ZERO_TZs = { UTC_TZ, "GMT", "GMT0", "Zulu" };
    
    /** Returns closest to Zulu/UTC TimeZone w/ shortest ID */
    public static TimeZone getNearZuluTimeZone() {
        TimeZone tz = null;
        // Get preferred ..
        for(int i=0; null == tz && i<ZERO_TZs.length; i++) {
            tz = TimeZone.getTimeZone(ZERO_TZs[i]);
        }
        if(null == tz) {
            // Get shortest ..
            final String[] ids = TimeZone.getAvailableIDs(0);
            if( null != ids && ids.length > 0 ) {
                int min_len = Integer.MAX_VALUE;
                int min_idx = -1;
                for(int i=0; i<ids.length; i++) {
                    final int len = ids[i].length();
                    if( len < min_len ) { 
                        min_len = len;
                        min_idx = i;
                    }
                }
                tz = TimeZone.getTimeZone(ids[min_idx]);
            }
        }
        if(null == tz) {
            // last resort - default
            tz = TimeZone.getDefault();
        }
        return tz;        
    }
    
    /**
     * Returns timestamp of internal Calendar: YYYYMMDD HH:MM:SS
     * 
     * @param calendar Calendar providing current time
     * @param withHour if true includes daytime w/ or w/o spacing, otherwise just YYYYMMDD
     * @param withSpacing if true provides spacing, otherwise just  YYYYMMDDHHMMSS
     * @return
     */
    public static String getTimeStamp(final Calendar calendar, boolean withHour, boolean withSpacing) {
        final int year, month, day, hour, minute, seconds;
        {
            year = calendar.get(Calendar.YEAR);
            month = calendar.get(Calendar.MONTH) + 1; // Jan - 1
            day = calendar.get(Calendar.DAY_OF_MONTH);            
            hour = calendar.get(Calendar.HOUR_OF_DAY);
            minute = calendar.get(Calendar.MINUTE);
            seconds = calendar.get(Calendar.SECOND);
        }
        if( !withHour ) {
            return String.format("%04d%02d%02d", year, month, day);
        } else {
            if( !withSpacing ) {
                return String.format("%04d%02d%02d%02d%02d%02d",
                            year, month, day, hour, minute, seconds);                
            } else {
                return String.format("%04d%02d%02d %02d:%02d:%02d", year, month, day, hour, minute, seconds);
            }
        }
    }

}