/*
 * Jalview - A Sequence Alignment Editor and Viewer (Version 2.9.0b1)
 * Copyright (C) 2015 The Jalview Authors
 * 
 * This file is part of Jalview.
 * 
 * Jalview 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 3
 * of the License, or (at your option) any later version.
 *  
 * Jalview 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 Jalview.  If not, see <http://www.gnu.org/licenses/>.
 * The Jalview Authors are detailed in the 'AUTHORS' file.
 */
package jalview.util;

import java.util.ArrayList;
import java.util.List;
import java.util.regex.Pattern;

public class StringUtils
{
  private static final Pattern DELIMITERS_PATTERN = Pattern
          .compile(".*='[^']*(?!')");

  private static final boolean DEBUG = false;

  /**
   * Returns a new character array, after inserting characters into the given
   * character array.
   * 
   * @param in
   *          the character array to insert into
   * @param position
   *          the 0-based position for insertion
   * @param count
   *          the number of characters to insert
   * @param ch
   *          the character to insert
   */
  public static final char[] insertCharAt(char[] in, int position,
          int count, char ch)
  {
    char[] tmp = new char[in.length + count];

    if (position >= in.length)
    {
      System.arraycopy(in, 0, tmp, 0, in.length);
      position = in.length;
    }
    else
    {
      System.arraycopy(in, 0, tmp, 0, position);
    }

    int index = position;
    while (count > 0)
    {
      tmp[index++] = ch;
      count--;
    }

    if (position < in.length)
    {
      System.arraycopy(in, position, tmp, index, in.length - position);
    }

    return tmp;
  }

  /**
   * Delete
   * 
   * @param in
   * @param from
   * @param to
   * @return
   */
  public static final char[] deleteChars(char[] in, int from, int to)
  {
    if (from >= in.length || from < 0)
    {
      return in;
    }

    char[] tmp;

    if (to >= in.length)
    {
      tmp = new char[from];
      System.arraycopy(in, 0, tmp, 0, from);
      to = in.length;
    }
    else
    {
      tmp = new char[in.length - to + from];
      System.arraycopy(in, 0, tmp, 0, from);
      System.arraycopy(in, to, tmp, from, in.length - to);
    }
    return tmp;
  }

  /**
   * Returns the last part of 'input' after the last occurrence of 'token'. For
   * example to extract only the filename from a full path or URL.
   * 
   * @param input
   * @param token
   *          a delimiter which must be in regular expression format
   * @return
   */
  public static String getLastToken(String input, String token)
  {
    if (input == null)
    {
      return null;
    }
    if (token == null)
    {
      return input;
    }
    String[] st = input.split(token);
    return st[st.length - 1];
  }

  /**
   * Parses the input string into components separated by the delimiter. Unlike
   * String.split(), this method will ignore occurrences of the delimiter which
   * are nested within single quotes in name-value pair values, e.g. a='b,c'.
   * 
   * @param input
   * @param delimiter
   * @return elements separated by separator
   */
  public static String[] separatorListToArray(String input, String delimiter)
  {
    int seplen = delimiter.length();
    if (input == null || input.equals("") || input.equals(delimiter))
    {
      return null;
    }
    List<String> jv = new ArrayList<String>();
    int cp = 0, pos, escape;
    boolean wasescaped = false, wasquoted = false;
    String lstitem = null;
    while ((pos = input.indexOf(delimiter, cp)) >= cp)
    {
      escape = (pos > 0 && input.charAt(pos - 1) == '\\') ? -1 : 0;
      if (wasescaped || wasquoted)
      {
        // append to previous pos
        jv.set(jv.size() - 1,
                lstitem = lstitem + delimiter
                        + input.substring(cp, pos + escape));
      }
      else
      {
        jv.add(lstitem = input.substring(cp, pos + escape));
      }
      cp = pos + seplen;
      wasescaped = escape == -1;
      // last separator may be in an unmatched quote
      wasquoted = DELIMITERS_PATTERN.matcher(lstitem).matches();
    }
    if (cp < input.length())
    {
      String c = input.substring(cp);
      if (wasescaped || wasquoted)
      {
        // append final separator
        jv.set(jv.size() - 1, lstitem + delimiter + c);
      }
      else
      {
        if (!c.equals(delimiter))
        {
          jv.add(c);
        }
      }
    }
    if (jv.size() > 0)
    {
      String[] v = jv.toArray(new String[jv.size()]);
      jv.clear();
      if (DEBUG)
      {
        System.err.println("Array from '" + delimiter
                + "' separated List:\n" + v.length);
        for (int i = 0; i < v.length; i++)
        {
          System.err.println("item " + i + " '" + v[i] + "'");
        }
      }
      return v;
    }
    if (DEBUG)
    {
      System.err.println("Empty Array from '" + delimiter
              + "' separated List");
    }
    return null;
  }

  /**
   * Returns a string which contains the list elements delimited by the
   * separator. Null items are ignored. If the input is null or has length zero,
   * a single delimiter is returned.
   * 
   * @param list
   * @param separator
   * @return concatenated string
   */
  public static String arrayToSeparatorList(String[] list, String separator)
  {
    StringBuffer v = new StringBuffer();
    if (list != null && list.length > 0)
    {
      for (int i = 0, iSize = list.length; i < iSize; i++)
      {
        if (list[i] != null)
        {
          if (v.length() > 0)
          {
            v.append(separator);
          }
          // TODO - escape any separator values in list[i]
          v.append(list[i]);
        }
      }
      if (DEBUG)
      {
        System.err.println("Returning '" + separator
                + "' separated List:\n");
        System.err.println(v);
      }
      return v.toString();
    }
    if (DEBUG)
    {
      System.err.println("Returning empty '" + separator
              + "' separated List\n");
    }
    return "" + separator;
  }
}