/**
    * Copyright 2010-2013 The Kuali Foundation
    *
    * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
    *
   * 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.kuali.common.util;
  
  import java.io.UnsupportedEncodingException;
  import java.util.List;
  
  import org.apache.commons.lang3.StringUtils;
  
  /**
   * Operations on <code>String</code> that are <code>null</code> safe
   */
  public class Str {
  
  	public static final String EMPTY_STRING = "";
  	public static final String UTF8 = "UTF-8";
  	public static final String COMMA = ",";
  	public static final String SPACE = " ";
  	public static final String CR = "\r";
  	public static final String LF = "\n";
  	public static final String DOT = ".";
  	public static final String FORWARD_SLASH = "/";
  	public static final char DOUBLE_QUOTE = '"';
  	public static final String CDATA_PREFIX = "<![CDATA[";
  	public static final String CDATA_SUFFIX = "]]>";
  
  	/**
  	 * Turn the string into CDATA - http://en.wikipedia.org/wiki/CDATA
  	 */
  	public static final String cdata(String s) {
  		if (s == null) {
  			return null;
  		} else {
  			return CDATA_PREFIX + s + CDATA_SUFFIX;
  		}
  	}
  
  	/**
  	 * If <code>s</code> ends with <code>suffix</code>, remove it
  	 */
  	public static final String removeSuffix(String s, String suffix) {
  		if (StringUtils.endsWith(s, suffix)) {
  			int end = StringUtils.length(s) - StringUtils.length(suffix);
  			return StringUtils.substring(s, 0, end);
  		} else {
  			return s;
  		}
  	}
  
  	/**
  	 * If s is null return "" otherwise return s
  	 */
  	public static final String toEmpty(String s) {
  		if (s == null) {
  			return "";
  		} else {
  			return s;
  		}
  	}
  
  	public static final String getString(byte[] bytes, String encoding) {
  		if (bytes == null) {
  			return null;
  		}
  		if (encoding == null) {
  			return new String(bytes);
  		}
  		try {
  			return new String(bytes, encoding);
  		} catch (UnsupportedEncodingException e) {
  			throw new IllegalArgumentException(e);
  		}
  	}
  
  	public static final byte[] getUTF8Bytes(String s) {
  		if (s == null) {
  			return null;
  		} else {
  			return getBytes(s, UTF8);
  		}
  	}
  
  	public static final byte[] getBytes(String s, String encoding) {
  		if (s == null) {
  			return null;
  		}
 		if (encoding == null) {
 			return s.getBytes();
 		}
 		try {
 			return s.getBytes(encoding);
 		} catch (UnsupportedEncodingException e) {
 			throw new IllegalArgumentException(e);
 		}
 	}
 
 	public static final boolean contains(List<String> tokens, String value, boolean caseSensitive) {
 		for (String token : tokens) {
 			if (equals(token, value, caseSensitive)) {
 				return true;
 			}
 		}
 		return false;
 	}
 
 	public static final boolean equals(String s1, String s2, boolean caseSensitive) {
 		if (caseSensitive) {
 			return StringUtils.equals(s1, s2);
 		} else {
 			return StringUtils.equalsIgnoreCase(s1, s2);
 		}
 	}
 
 	/**
 	 * Combine <code>tokens</code> into a <code>String</code>
 	 */
 	public static final String toString(String[] tokens) {
 		if (tokens == null) {
 			return null;
 		}
 		StringBuilder sb = new StringBuilder();
 		for (String token : tokens) {
 			sb.append(token);
 		}
 		return sb.toString();
 	}
 
 	/**
 	 * Convert dots to forward slashes and trim.
 	 */
 	public static final String getPath(String s) {
 		return StringUtils.trim(StringUtils.replace(s, DOT, FORWARD_SLASH));
 	}
 
 	/**
 	 * Surround the string with double quotes.
 	 */
 	public static final String quote(String s) {
 		return s == null ? null : DOUBLE_QUOTE + s + DOUBLE_QUOTE;
 	}
 
 	/**
 	 * Split comma separated values into tokens, optionally trimming the tokens.
 	 */
 	public static final String[] splitCSV(String csv, boolean trim) {
 		return split(csv, COMMA, trim);
 	}
 
 	/**
 	 * Split comma separated values into tokens, trimming as we go.
 	 */
 	public static final String[] splitAndTrimCSV(String csv) {
 		return splitCSV(csv, true);
 	}
 
 	/**
 	 * Split the string into tokens using the indicated separator, trimming as we go.
 	 */
 	public static final String[] splitAndTrim(String s, String separatorChars) {
 		return split(s, separatorChars, true);
 	}
 
 	/**
 	 * Split the string into tokens using the indicated separator chars, optionally trimming the tokens.
 	 */
 	public static final String[] split(String s, String separatorChars, boolean trim) {
 		String[] tokens = StringUtils.split(s, separatorChars);
 		if (tokens == null) {
 			return null;
 		}
 		for (int i = 0; i < tokens.length; i++) {
 			tokens[i] = trim ? StringUtils.trim(tokens[i]) : tokens[i];
 		}
 		return tokens;
 	}
 
 	/**
 	 * Replace carriage returns and linefeeds with a space
 	 */
 	public static final String flatten(String s) {
 		return flatten(s, SPACE, SPACE);
 	}
 
 	/**
 	 * Replace carriage returns with <code>cr</code> and linefeeds with <code>lf</code>.
 	 */
 	public static final String flatten(String s, String cr, String lf) {
 		return StringUtils.replace(StringUtils.replace(s, CR, cr), LF, lf);
 	}
 }