/* $RCSfile$
 * $Author: hansonr $
 * $Date: 2007-04-26 16:57:51 -0500 (Thu, 26 Apr 2007) $
 * $Revision: 7502 $
 *
 * Some portions of this file have been modified by Robert Hanson hansonr.at.stolaf.edu 2012-2017
 * for use in SwingJS via transpilation into JavaScript using Java2Script.
 *
 * Copyright (C) 2005  The Jmol Development Team
 *
 * Contact: jmol-developers@lists.sf.net
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library 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
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 */

package javajs.util;

/**
 * created to remove ambiguities and make a simpler DecimalFormat
 */
public class DF {

  private final static String[] formattingStrings = { 
      "0", "0.0", "0.00",
      "0.000", "0.0000", "0.00000", 
      "0.000000", "0.0000000", "0.00000000",
      "0.000000000", "0.0000000000", "0.00000000000",  "0.000000000000", };
  private final static String zeros = "0000000000000000000000000000000000000000";

  private final static double[] formatAdds = { 
      0.5, 0.05, 0.005, 
      0.0005, 0.00005, 0.000005,
      0.0000005, 0.00000005, 0.000000005, 
      0.0000000005, 0.00000000005 , 0.000000000005 , 0.0000000000005 };

  private final static Boolean[] useNumberLocalization = new Boolean[] { Boolean.TRUE };

  public static void setUseNumberLocalization(boolean TF) {
    useNumberLocalization[0] = (TF ? Boolean.TRUE : Boolean.FALSE);
  }

  public static String formatDecimalDbl(double value, int decimalDigits) {
    if (decimalDigits == Integer.MAX_VALUE 
        || value == Double.NEGATIVE_INFINITY
        || value == Double.POSITIVE_INFINITY 
        || Double.isNaN(value))
      return "" + value;
    return DF.formatDecimal(value, decimalDigits);
  }

  /**
   * a simple alternative to DecimalFormat (which Java2Script does not have
   * and which is quite too complex for our use here.)
   * 
   * @param value
   * @param decimalDigits
   * @return formatted decimal
   */
  public static String formatDecimal(double value, int decimalDigits) {
    if (value == Double.NEGATIVE_INFINITY || value == Double.POSITIVE_INFINITY || Double.isNaN(value))
      return "" + value;
    if (decimalDigits == Integer.MAX_VALUE)
      return "" + (float) value;
    boolean isNeg = (value < 0);
    if (isNeg)
      value = -value;
    int n;
    if (decimalDigits < 0) {
      decimalDigits = -decimalDigits;
      if (decimalDigits > formattingStrings.length)
        decimalDigits = formattingStrings.length;
      if (value == 0)
        return formattingStrings[decimalDigits - 1] + "E+0";
      //scientific notation
      n = 0;
      double d;
      if (Math.abs(value) < 1) {
        n = 100;
        d = value * 1e-100;
      } else {
        n = -100;
        d = value * 1e100;
      }
      String s = ("" + d).toUpperCase();
      int i1 = s.indexOf("E");
      String sf;
      if (i1 < 0) {
        sf = "" + value;
      } else {
        n = PT.parseInt(s.substring(i1 + (s.indexOf("E+") == i1 ? 2 : 1))) + n;
        double f = PT.parseFloat(s.substring(0, i1));
        sf = formatDecimal(f, decimalDigits - 1);
        if (sf.startsWith("10.")) {
          sf = formatDecimal(1, decimalDigits - 1);
          n++;
        }
      }
      return (isNeg ? "-" : "") + sf + "E" + (n >= 0 ? "+" : "") + n;
    }

    if (decimalDigits >= formattingStrings.length)
      decimalDigits = formattingStrings.length - 1;
    String s1 = ("" + value).toUpperCase();
    int pt = s1.indexOf(".");
    if (pt < 0) // specifically JavaScript "-2" not "-2.0"
      return (isNeg ? "-" : "") + s1 + formattingStrings[decimalDigits].substring(1);
    int pt1 = s1.indexOf("E-");
    if (pt1 > 0) {
      n = PT.parseInt(s1.substring(pt1 + 1));
      // 3.567E-2
      // 0.03567
      // -0.0001
      s1 = "0." + zeros.substring(0, -n - 1) + s1.substring(0, 1) + s1.substring(2, pt1);
      pt = 1;
    }

    pt1 = s1.indexOf("E");
    // 3.5678E+3
    // 3567.800000000
    // 1.234E10 %3.8f -> 12340000000.00000000
    if (pt1 > 0) {
      n = PT.parseInt(s1.substring(pt1 + 1));
      s1 = s1.substring(0, 1) + s1.substring(2, pt1) + zeros;
      s1 = s1.substring(0, n + 1) + "." + s1.substring(n + 1);
      pt = s1.indexOf(".");
    }
    // "234.345667  len == 10; pt = 3
    // "  0.0 "  decimalDigits = 1

    int len = s1.length();
    int pt2 = decimalDigits + pt + 1;
    if (pt2 < len && s1.charAt(pt2) >= '5') {
      return formatDecimal((isNeg ? -1 : 1) * (value + formatAdds[decimalDigits]), decimalDigits);
    }

    String s0 = s1.substring(0, (decimalDigits == 0 ? pt
        : ++pt));
    SB sb = SB.newS(s0);
    if (isNeg && s0.equals("0.") && decimalDigits + 2 <= len && s1.substring(2, 2 + decimalDigits).equals(zeros.substring(0, decimalDigits)))
      isNeg = false;
    for (int i = 0; i < decimalDigits; i++, pt++) {
      if (pt < len)
        sb.appendC(s1.charAt(pt));
      else
        sb.appendC('0');
    }
    s1 = (isNeg ? "-" : "") + sb;
    return (Boolean.TRUE.equals(useNumberLocalization[0]) ? s1 : s1.replace(',',
        '.'));
  }

  /**
   * an alternative to DecimalFormat "0.#"
   * 
   * @param x
   * @param precision
   * @return  formatted number 
   */
  public static String formatDecimalTrimmed(double x, int precision) {
    String str = formatDecimalDbl(x, precision);
    int m = str.length() - 1;
    char zero = '0';
    while (m >= 0 && str.charAt(m) == zero)
      m--;
    return str.substring(0, m + 1); // 0.##...
  }

  /**
   * an alternative to DecimalFormat "0.0"
   * 
   * @param x
   * @param precision
   * @return  formatted number 
   */
  public static String formatDecimalTrimmed0(double x, int precision) {
    String str = DF.formatDecimalDbl(x, precision);
    int m = str.length() - 1;
    int pt = str.indexOf(".") + 1;
    while (m > pt && str.charAt(m) == '0')
      m--;
    return str.substring(0, m + 1); // 0.0##...
  }

}