// Formatter.java
// -----------------------
// part of YACY
// (C) by Michael Peter Christen; mc@yacy.net
// first published on http://www.anomic.de
// Frankfurt, Germany, 2004
//
// (C) 2007 Bjoern 'Fuchs' Krombholz; fox.box@gmail.com
//
// $LastChangedDate$
// $LastChangedRevision$
// $LastChangedBy$
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

package net.yacy.kelondro.util;

import java.text.DecimalFormat;
import java.text.DecimalFormatSymbols;
import java.text.NumberFormat;
import java.util.Locale;

/**
 * This class provides simple Formatters to unify YaCy's output
 * formattings.
 *
 * At the moment yFormatter can be used to format numbers according
 * to the locale set for YaCy.
 */
public final class Formatter {

    // default formatter
    private static Locale locale = new Locale("en");
    /**
     * use ThreadLocal to generate new formatter for each Thread since NumberFormat is not synchronized
     */
    private static final ThreadLocal <NumberFormat> numForm =
        new ThreadLocal <NumberFormat>() {
          @Override protected NumberFormat initialValue() {
              NumberFormat n = locale == null ? new DecimalFormat("####.##", new DecimalFormatSymbols(Locale.ENGLISH)) : NumberFormat.getInstance(locale);
              n.setGroupingUsed(true);          // always group int digits
              n.setParseIntegerOnly(false);     // allow int/double/float
              n.setMaximumFractionDigits(2);    // 2 decimal digits for float/double
              return n;
          }
      };
      private static final ThreadLocal <NumberFormat> cleanNumForm =
          new ThreadLocal <NumberFormat>() {
            @Override protected NumberFormat initialValue() {
                NumberFormat n = new DecimalFormat("####.##", new DecimalFormatSymbols(Locale.ENGLISH));
                return n;
            }
        };


    /**
     * @param locale the {@link Locale} to set or <code>null</code> to set the special
     * empty locale to create unformatted numbers
     */
    private static void setLocale(final Locale l) {
        locale = l;
    }

    /**
     * @param lang an ISO 639 language code which is used to generate a {@link Locale}
     */
    public static void setLocale(final String lang) {
        final String l = (lang.equalsIgnoreCase("default") ? "en" : lang.toLowerCase());
        setLocale(l.equals("none") ? null : new Locale(l));
    }


    public static String number(final double d, final boolean localized) {
        return (localized ? numForm.get().format(d) : cleanNumForm.get().format(d));
    }

    private static String number(final double d) {
        return numForm.get().format(d);
    }

    public static String number(final long l, final boolean localized) {
        return (localized ? numForm.get().format(l) : cleanNumForm.get().format(l));
    }

    public static String number(final long l) {
        return numForm.get().format(l);
    }

    /**
     * Method formats String representation of numbers according to the formatting
     * rules for numbers defined by this class. This method is probably only useful
     * for "numbers" read from property files.
     * @param s string to parse into a number and reformat
     * @return the formatted number as a String or "-" in case of a parsing error
     */
    public static String number(final String s) {
        String ret = null;
        try {
            if (s.indexOf('.') == -1) {
                ret = number(Long.parseLong(s));
            } else {
                ret = number(Float.parseFloat(s));
            }
        } catch (final NumberFormatException e) { /* empty */ }

        return (ret == null ? "-" : ret);
    }


    /**
     * Formats a number if it are bytes to greatest unit (1024 based)
     * @param byteCount
     * @return formatted String with unit
     */
    public static String bytesToString(final long byteCount) {
        try {
            final StringBuilder byteString = new StringBuilder();

            if (byteCount > 1073741824) {
                byteString.append(number((double)byteCount / (double)1073741824 )).append(" GB");
            } else if (byteCount > 1048576) {
                byteString.append(number((double)byteCount / (double)1048576)).append(" MB");
            } else if (byteCount > 1024) {
                byteString.append(number((double)byteCount / (double)1024)).append(" KB");
            } else {
                byteString.append(Long.toString(byteCount)).append(" Bytes");
            }

            return byteString.toString();
        } catch (final Exception e) {
            return "unknown";
        }
    }
}