package com.site.helper;

import java.util.ArrayList;
import java.util.List;

public class Splitters {
   public static StringSplitter by(char delimiter) {
      return new StringSplitter(delimiter);
   }

   public static StringSplitter by(String delimiter) {
      return new StringSplitter(delimiter);
   }

   public static class StringSplitter {
      private char m_charDelimiter;

      private String m_stringDelimiter;

      private boolean m_trimmed;

      private boolean m_noEmptyItem;

      StringSplitter(char delimiter) {
         m_charDelimiter = delimiter;
      }

      StringSplitter(String delimiter) {
         m_stringDelimiter = delimiter;
      }

      protected List<String> doCharSplit(String str, List<String> list) {
         char delimiter = m_charDelimiter;
         int len = str.length();
         StringBuilder sb = new StringBuilder(len);

         for (int i = 0; i < len + 1; i++) {
            char ch = i == len ? delimiter : str.charAt(i);

            if (ch == delimiter) {
               String item = sb.toString();

               sb.setLength(0);

               if (m_trimmed) {
                  item = item.trim();
               }

               if (m_noEmptyItem && item.length() == 0) {
                  continue;
               }

               list.add(item);
            } else {
               sb.append(ch);
            }
         }

         return list;
      }

      protected List<String> doStringSplit(String source, List<String> list) {
         String delimiter = m_stringDelimiter;
         int len = delimiter.length();
         int offset = 0;
         int index = source.indexOf(delimiter, offset);

         while (true) {
            String part;

            if (index == -1) { // last part
               part = source.substring(offset);
            } else {
               part = source.substring(offset, index);
            }

            if (m_trimmed) {
               part = part.trim();
            }

            if (!m_noEmptyItem || part.length() > 0) {
               list.add(part);
            }

            if (index == -1) { // last part
               break;
            } else {
               offset = index + len;
               index = source.indexOf(delimiter, offset);
            }
         }

         return list;
      }

      public StringSplitter noEmptyItem() {
         m_noEmptyItem = true;
         return this;
      }

      public List<String> split(String str) {
         return split(str, new ArrayList<String>());
      }

      public List<String> split(String str, List<String> list) {
         if (str == null) {
            return null;
         }

         if (m_charDelimiter > 0) {
            return doCharSplit(str, list);
         } else if (m_stringDelimiter != null) {
            return doStringSplit(str, list);
         }

         throw new UnsupportedOperationException();
      }

      public StringSplitter trim() {
         m_trimmed = true;
         return this;
      }
   }
}