/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
    * with the License.  You may obtain a copy of the License at
    *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  package org.apache.shiro.lang.util;
  
  import java.text.ParseException;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.LinkedHashSet;
  import java.util.List;
  import java.util.Set;
  import java.util.StringTokenizer;
  
  
  /**
   * <p>Simple utility class for String operations useful across the framework.
   * <p/>
   * <p>Some methods in this class were copied from the Spring Framework so we didn't have to re-invent the wheel,
   * and in these cases, we have retained all license, copyright and author information.
   *
   * @since 0.9
   */
  @SuppressWarnings("checkstyle:CyclomaticComplexity")
  public final class StringUtils {
  
      /**
       * Constant representing the empty string, equal to &quot;&quot;
       */
      public static final String EMPTY_STRING = "";
  
      /**
       * Constant representing the default delimiter character (comma), equal to <code>','</code>
       */
      public static final char DEFAULT_DELIMITER_CHAR = ',';
  
      /**
       * Constant representing the default quote character (double quote), equal to '&quot;'</code>
       */
      public static final char DEFAULT_QUOTE_CHAR = '"';
  
      private StringUtils() {
      }
  
      /**
       * Check whether the given String has actual text.
       * More specifically, returns <code>true</code> if the string not <code>null</code>,
       * its length is greater than 0, and it contains at least one non-whitespace character.
       * <p/>
       * <code>StringUtils.hasText(null) == false<br/>
       * StringUtils.hasText("") == false<br/>
       * StringUtils.hasText(" ") == false<br/>
       * StringUtils.hasText("12345") == true<br/>
       * StringUtils.hasText(" 12345 ") == true</code>
       * <p/>
       * <p>Copied from the Spring Framework while retaining all license, copyright and author information.
       *
       * @param str the String to check (may be <code>null</code>)
       * @return <code>true</code> if the String is not <code>null</code>, its length is
       * greater than 0, and it does not contain whitespace only
       * @see java.lang.Character#isWhitespace
       */
      public static boolean hasText(String str) {
          if (!hasLength(str)) {
              return false;
          }
          int strLen = str.length();
          for (int i = 0; i < strLen; i++) {
              if (!Character.isWhitespace(str.charAt(i))) {
                  return true;
              }
          }
          return false;
      }
  
      /**
       * Check that the given String is neither <code>null</code> nor of length 0.
       * Note: Will return <code>true</code> for a String that purely consists of whitespace.
       * <p/>
       * <code>StringUtils.hasLength(null) == false<br/>
       * StringUtils.hasLength("") == false<br/>
       * StringUtils.hasLength(" ") == true<br/>
       * StringUtils.hasLength("Hello") == true</code>
      * <p/>
      * Copied from the Spring Framework while retaining all license, copyright and author information.
      *
      * @param str the String to check (may be <code>null</code>)
      * @return <code>true</code> if the String is not null and has length
      * @see #hasText(String)
      */
     public static boolean hasLength(String str) {
         return (str != null && str.length() > 0);
     }
 
 
     /**
      * Test if the given String starts with the specified prefix,
      * ignoring upper/lower case.
      * <p/>
      * <p>Copied from the Spring Framework while retaining all license, copyright and author information.
      *
      * @param str    the String to check
      * @param prefix the prefix to look for
      * @return <code>true</code> starts with the specified prefix (ignoring case), <code>false</code> if it does not.
      * @see java.lang.String#startsWith
      */
     public static boolean startsWithIgnoreCase(String str, String prefix) {
         if (str == null || prefix == null) {
             return false;
         }
         if (str.startsWith(prefix)) {
             return true;
         }
         if (str.length() < prefix.length()) {
             return false;
         }
         String lcStr = str.substring(0, prefix.length()).toLowerCase();
         String lcPrefix = prefix.toLowerCase();
         return lcStr.equals(lcPrefix);
     }
 
     /**
      * Returns a 'cleaned' representation of the specified argument.  'Cleaned' is defined as the following:
      * <p/>
      * <ol>
      * <li>If the specified <code>String</code> is <code>null</code>, return <code>null</code></li>
      * <li>If not <code>null</code>, {@link String#trim() trim()} it.</li>
      * <li>If the trimmed string is equal to the empty String (i.e. &quot;&quot;), return <code>null</code></li>
      * <li>If the trimmed string is not the empty string, return the trimmed version</li>.
      * </ol>
      * <p/>
      * Therefore this method always ensures that any given string has trimmed text, and if it doesn't, <code>null</code>
      * is returned.
      *
      * @param in the input String to clean.
      * @return a populated-but-trimmed String or <code>null</code> otherwise
      */
     public static String clean(String in) {
         String out = in;
 
         if (in != null) {
             out = in.trim();
             if (out.equals(EMPTY_STRING)) {
                 out = null;
             }
         }
 
         return out;
     }
 
     /**
      * Returns the specified array as a comma-delimited (',') string.
      *
      * @param array the array whose contents will be converted to a string.
      * @return the array's contents as a comma-delimited (',') string.
      * @since 1.0
      */
     public static String toString(Object[] array) {
         return toDelimitedString(array, ",");
     }
 
     /**
      * Returns the array's contents as a string, with each element delimited by the specified
      * {@code delimiter} argument.  Useful for {@code toString()} implementations and log messages.
      *
      * @param array     the array whose contents will be converted to a string
      * @param delimiter the delimiter to use between each element
      * @return a single string, delimited by the specified {@code delimiter}.
      * @since 1.0
      */
     public static String toDelimitedString(Object[] array, String delimiter) {
         if (array == null || array.length == 0) {
             return EMPTY_STRING;
         }
         StringBuilder sb = new StringBuilder();
         for (int i = 0; i < array.length; i++) {
             if (i > 0) {
                 sb.append(delimiter);
             }
             sb.append(array[i]);
         }
         return sb.toString();
     }
 
     /**
      * Returns the collection's contents as a string, with each element delimited by the specified
      * {@code delimiter} argument.  Useful for {@code toString()} implementations and log messages.
      *
      * @param c         the collection whose contents will be converted to a string
      * @param delimiter the delimiter to use between each element
      * @return a single string, delimited by the specified {@code delimiter}.
      * @since 1.2
      */
     public static String toDelimitedString(Collection c, String delimiter) {
         if (c == null || c.isEmpty()) {
             return EMPTY_STRING;
         }
         return join(c.iterator(), delimiter);
     }
 
     /**
      * Tokenize the given String into a String array via a StringTokenizer.
      * Trims tokens and omits empty tokens.
      * <p>The given delimiters string is supposed to consist of any number of
      * delimiter characters. Each of those characters can be used to separate
      * tokens. A delimiter is always a single character; for multi-character
      * delimiters, consider using <code>delimitedListToStringArray</code>
      * <p/>
      * <p>Copied from the Spring Framework while retaining all license, copyright and author information.
      *
      * @param str        the String to tokenize
      * @param delimiters the delimiter characters, assembled as String
      *                   (each of those characters is individually considered as delimiter).
      * @return an array of the tokens
      * @see java.util.StringTokenizer
      * @see java.lang.String#trim()
      */
     public static String[] tokenizeToStringArray(String str, String delimiters) {
         return tokenizeToStringArray(str, delimiters, true, true);
     }
 
     /**
      * Tokenize the given String into a String array via a StringTokenizer.
      * <p>The given delimiters string is supposed to consist of any number of
      * delimiter characters. Each of those characters can be used to separate
      * tokens. A delimiter is always a single character; for multi-character
      * delimiters, consider using <code>delimitedListToStringArray</code>
      * <p/>
      * <p>Copied from the Spring Framework while retaining all license, copyright and author information.
      *
      * @param str               the String to tokenize
      * @param delimiters        the delimiter characters, assembled as String
      *                          (each of those characters is individually considered as delimiter)
      * @param trimTokens        trim the tokens via String's <code>trim</code>
      * @param ignoreEmptyTokens omit empty tokens from the result array
      *                          (only applies to tokens that are empty after trimming; StringTokenizer
      *                          will not consider subsequent delimiters as token in the first place).
      * @return an array of the tokens (<code>null</code> if the input String
      * was <code>null</code>)
      * @see java.util.StringTokenizer
      * @see java.lang.String#trim()
      */
     @SuppressWarnings({"unchecked"})
     public static String[] tokenizeToStringArray(
             String str, String delimiters, boolean trimTokens, boolean ignoreEmptyTokens) {
 
         if (str == null) {
             return null;
         }
         StringTokenizer st = new StringTokenizer(str, delimiters);
         List tokens = new ArrayList();
         while (st.hasMoreTokens()) {
             String token = st.nextToken();
             if (trimTokens) {
                 token = token.trim();
             }
             if (!ignoreEmptyTokens || token.length() > 0) {
                 tokens.add(token);
             }
         }
         return toStringArray(tokens);
     }
 
     /**
      * Copy the given Collection into a String array.
      * The Collection must contain String elements only.
      * <p/>
      * <p>Copied from the Spring Framework while retaining all license, copyright and author information.
      *
      * @param collection the Collection to copy
      * @return the String array (<code>null</code> if the passed-in
      * Collection was <code>null</code>)
      */
     @SuppressWarnings({"unchecked"})
     public static String[] toStringArray(Collection collection) {
         if (collection == null) {
             return null;
         }
         return (String[]) collection.toArray(new String[collection.size()]);
     }
 
     public static String[] splitKeyValue(String aLine) throws ParseException {
         String line = clean(aLine);
         if (line == null) {
             return null;
         }
         String[] split = line.split(" ", 2);
         if (split.length != 2) {
             //fallback to checking for an equals sign
             split = line.split("=", 2);
             if (split.length != 2) {
                 String msg = "Unable to determine Key/Value pair from line [" + line + "].  There is no space from "
                         + "which the split location could be determined.";
                 throw new ParseException(msg, 0);
             }
 
         }
 
         split[0] = clean(split[0]);
         split[1] = clean(split[1]);
         if (split[1].startsWith("=")) {
             //they used spaces followed by an equals followed by zero or more spaces to split the key/value pair, so
             //remove the equals sign to result in only the key and values in the
             split[1] = clean(split[1].substring(1));
         }
 
         if (split[0] == null) {
             String msg = "No valid key could be found in line [" + line + "] to form a key/value pair.";
             throw new ParseException(msg, 0);
         }
         if (split[1] == null) {
             String msg = "No corresponding value could be found in line [" + line + "] for key [" + split[0] + "]";
             throw new ParseException(msg, 0);
         }
 
         return split;
     }
 
     /**
      * Splits a string using the {@link #DEFAULT_DELIMITER_CHAR} (which is {@value #DEFAULT_DELIMITER_CHAR}).
      * This method also recognizes quoting using the {@link #DEFAULT_QUOTE_CHAR}
      * (which is {@value #DEFAULT_QUOTE_CHAR}), but does not retain them.
      *
      * <p>This is equivalent of calling {@link #split(String, char, char, char, boolean, boolean)} with
      * {@code line, DEFAULT_DELIMITER_CHAR, DEFAULT_QUOTE_CHAR, DEFAULT_QUOTE_CHAR, false, true}.</p>
      *
      * @param line the line to split using the {@link #DEFAULT_DELIMITER_CHAR}.
      * @return the split line, split tokens do not contain quotes and are trimmed.
      * @see #split(String, char, char, char, boolean, boolean)
      */
     public static String[] split(String line) {
         return split(line, DEFAULT_DELIMITER_CHAR);
     }
 
     public static String[] split(String line, char delimiter) {
         return split(line, delimiter, DEFAULT_QUOTE_CHAR);
     }
 
     public static String[] split(String line, char delimiter, char quoteChar) {
         return split(line, delimiter, quoteChar, quoteChar);
     }
 
     public static String[] split(String line, char delimiter, char beginQuoteChar, char endQuoteChar) {
         return split(line, delimiter, beginQuoteChar, endQuoteChar, false, true);
     }
 
     /**
      * Splits the specified delimited String into tokens, supporting quoted tokens so that quoted strings themselves
      * won't be tokenized.
      * <p/>
      * This method's implementation is very loosely based (with significant modifications) on
      * <a href="http://blogs.bytecode.com.au/glen">Glen Smith</a>'s open-source
      * <a href="http://opencsv.svn.sourceforge.net/viewvc/opencsv/trunk/src/au/com/bytecode/opencsv/CSVReader.java
      * ?&view=markup">CSVReader.java</a>
      * file.
      * <p/>
      * That file is Apache 2.0 licensed as well, making Glen's code a great starting point for us to modify to
      * our needs.
      *
      * @param aLine          the String to parse
      * @param delimiter      the delimiter by which the <tt>line</tt> argument is to be split
      * @param beginQuoteChar the character signifying the start of quoted text (so the quoted text will not be split)
      * @param endQuoteChar   the character signifying the end of quoted text
      * @param retainQuotes   if the quotes themselves should be retained when constructing the corresponding token
      * @param trimTokens     if leading and trailing whitespace should be trimmed from discovered tokens.
      * @return the tokens discovered from parsing the given delimited <tt>line</tt>.
      */
     public static String[] split(String aLine, char delimiter, char beginQuoteChar, char endQuoteChar,
                                  boolean retainQuotes, boolean trimTokens) {
         String line = clean(aLine);
         if (line == null) {
             return null;
         }
 
         List<String> tokens = new ArrayList<String>();
         StringBuilder sb = new StringBuilder();
         boolean inQuotes = false;
 
         for (int i = 0; i < line.length(); i++) {
 
             char c = line.charAt(i);
             if (c == beginQuoteChar) {
                 // this gets complex... the quote may end a quoted block, or escape another quote.
                 // do a 1-char lookahead:
                 // we are in quotes, therefore there can be escaped quotes in here.
                 if (inQuotes
                         // there is indeed another character to check.
                         && line.length() > (i + 1)
                         // ..and that char. is a quote also.
                         && line.charAt(i + 1) == beginQuoteChar) {
                     // we have two quote chars in a row == one quote char, so consume them both and
                     // put one on the token. we do *not* exit the quoted text.
                     sb.append(line.charAt(i + 1));
                     i++;
                 } else {
                     inQuotes = !inQuotes;
                     if (retainQuotes) {
                         sb.append(c);
                     }
                 }
             } else if (c == endQuoteChar) {
                 inQuotes = !inQuotes;
                 if (retainQuotes) {
                     sb.append(c);
                 }
             } else if (c == delimiter && !inQuotes) {
                 String s = sb.toString();
                 if (trimTokens) {
                     s = s.trim();
                 }
                 tokens.add(s);
                 // start work on next token
                 sb = new StringBuilder();
             } else {
                 sb.append(c);
             }
         }
         String s = sb.toString();
         if (trimTokens) {
             s = s.trim();
         }
         tokens.add(s);
         return tokens.toArray(new String[tokens.size()]);
     }
 
     /**
      * Joins the elements of the provided {@code Iterator} into
      * a single String containing the provided elements.</p>
      * <p/>
      * No delimiter is added before or after the list.
      * A {@code null} separator is the same as an empty String ("").</p>
      * <p/>
      * Copied from Commons Lang, version 3 (r1138702).</p>
      *
      * @param iterator  the {@code Iterator} of values to join together, may be null
      * @param separator the separator character to use, null treated as ""
      * @return the joined String, {@code null} if null iterator input
      * @since 1.2
      */
     public static String join(Iterator<?> iterator, String separator) {
         final String empty = "";
 
         // handle null, zero and one elements before building a buffer
         if (iterator == null) {
             return null;
         }
         if (!iterator.hasNext()) {
             return empty;
         }
         Object first = iterator.next();
         if (!iterator.hasNext()) {
             return first == null ? empty : first.toString();
         }
 
         // two or more elements
         // Java default is 16, probably too small
         @SuppressWarnings("checkstyle:MagicNumber")
         StringBuilder buf = new StringBuilder(256);
         if (first != null) {
             buf.append(first);
         }
 
         while (iterator.hasNext()) {
             if (separator != null) {
                 buf.append(separator);
             }
             Object obj = iterator.next();
             if (obj != null) {
                 buf.append(obj);
             }
         }
         return buf.toString();
     }
 
     /**
      * Splits the {@code delimited} string (delimited by the specified {@code separator} character) and returns the
      * delimited values as a {@code Set}.
      * <p/>
      * If either argument is {@code null}, this method returns {@code null}.
      *
      * @param delimited the string to split
      * @param separator the character that delineates individual tokens to split
      * @return the delimited values as a {@code Set}.
      * @since 1.2
      */
     public static Set<String> splitToSet(String delimited, String separator) {
         if (delimited == null || separator == null) {
             return null;
         }
         String[] split = split(delimited, separator.charAt(0));
         return asSet(split);
     }
 
     /**
      * Returns the input argument, but ensures the first character is capitalized (if possible).
      *
      * @param in the string to uppercase the first character.
      * @return the input argument, but with the first character capitalized (if possible).
      * @since 1.2
      */
     public static String uppercaseFirstChar(String in) {
         if (in == null || in.length() == 0) {
             return in;
         }
         int length = in.length();
         StringBuilder sb = new StringBuilder(length);
 
         sb.append(Character.toUpperCase(in.charAt(0)));
         if (length > 1) {
             String remaining = in.substring(1);
             sb.append(remaining);
         }
         return sb.toString();
     }
 
     //////////////////////////
     // From CollectionUtils //
     //////////////////////////
     // CollectionUtils cannot be removed from shiro-core until 2.0 as it has a dependency on PrincipalCollection
 
 
     @SafeVarargs
     private static <E> Set<E> asSet(E... elements) {
         if (elements == null || elements.length == 0) {
             return Collections.emptySet();
         }
 
         if (elements.length == 1) {
             return Collections.singleton(elements[0]);
         }
 
         LinkedHashSet<E> set = new LinkedHashSet<E>(elements.length * 4 / 3 + 1);
         Collections.addAll(set, elements);
         return set;
     }
 
 }