/**
    *
    * Copyright (C) 2011 Cloud Conscious, LLC. <info@cloudconscious.com>
    *
    * ====================================================================
    * Licensed 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.jclouds.util;
  
  import static com.google.common.base.Preconditions.checkNotNull;
  import static com.google.common.io.ByteStreams.toByteArray;
  import static com.google.common.io.Closeables.closeQuietly;
  import static org.jclouds.util.Patterns.CHAR_TO_ENCODED_PATTERN;
  import static org.jclouds.util.Patterns.CHAR_TO_PATTERN;
  import static org.jclouds.util.Patterns.PLUS_PATTERN;
  import static org.jclouds.util.Patterns.STAR_PATTERN;
  import static org.jclouds.util.Patterns.TOKEN_TO_PATTERN;
  import static org.jclouds.util.Patterns.URL_ENCODED_PATTERN;
  import static org.jclouds.util.Patterns._7E_PATTERN;
  
  import java.io.ByteArrayInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.UnsupportedEncodingException;
  import java.net.URLDecoder;
  import java.net.URLEncoder;
  import java.util.Map;
  import java.util.Map.Entry;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import javax.annotation.Resource;
  
  import org.jclouds.logging.Logger;
  
  import com.google.common.base.Charsets;
  
  /**
   * 
   * 
   * @author Adrian Cole
   */
  public class Strings2 {
  
     /**
      * Web browsers do not always handle '+' characters well, use the well-supported '%20' instead.
      */
     public static String urlEncode(String in, char... skipEncode) {
        if (isUrlEncoded(in))
           return in;
        try {
           String returnVal = URLEncoder.encode(in, "UTF-8");
           returnVal = Strings2.replaceAll(returnVal, '+', PLUS_PATTERN, "%20");
           returnVal = Strings2.replaceAll(returnVal, '*', STAR_PATTERN, "%2A");
           returnVal = Strings2.replaceAll(returnVal, _7E_PATTERN, "~");
           for (char c : skipEncode) {
              returnVal = Strings2.replaceAll(returnVal, CHAR_TO_ENCODED_PATTERN.get(c), c + "");
           }
           return returnVal;
        } catch (UnsupportedEncodingException e) {
           throw new IllegalStateException("Bad encoding on input: " + in, e);
        }
     }
  
     public static boolean isUrlEncoded(String in) {
        return URL_ENCODED_PATTERN.matcher(in).matches();
     }
  
     public static String urlDecode(String in) {
        try {
           return URLDecoder.decode(in, "UTF-8");
        } catch (UnsupportedEncodingException e) {
           throw new IllegalStateException("Bad encoding on input: " + in, e);
        }
     }
  
     public static String replaceTokens(String value, Iterable<Entry<String, String>> tokenValues) {
        for (Entry<String, String> tokenValue : tokenValues) {
           value = Strings2.replaceAll(value, TOKEN_TO_PATTERN.get(tokenValue.getKey()), tokenValue.getValue());
        }
        return value;
     }
  
     public static String replaceAll(String returnVal, Pattern pattern, String replace) {
        Matcher m = pattern.matcher(returnVal);
        returnVal = m.replaceAll(replace);
        return returnVal;
     }
 
    public static String replaceAll(String input, char ifMatch, Pattern pattern, String replacement) {
       if (input.indexOf(ifMatch) != -1) {
          input = pattern.matcher(input).replaceAll(replacement);
       }
       return input;
    }
 
    public static String replaceAll(String input, char match, String replacement) {
       if (input.indexOf(match) != -1) {
          input = CHAR_TO_PATTERN.get(match).matcher(input).replaceAll(replacement);
       }
       return input;
    }
 
    public static final String UTF8_ENCODING = "UTF-8";
 
    public static String toStringAndClose(InputStream input) throws IOException {
       checkNotNull(input, "input");
       try {
          return new String(toByteArray(input), Charsets.UTF_8);
       } catch (IOException e) {
          logger.warn(e, "Failed to read from stream");
          return null;
       } catch (NullPointerException e) {
          return null;
       } finally {
          closeQuietly(input);
       }
    }
 
    public static InputStream toInputStream(String in) {
       return new ByteArrayInputStream(in.getBytes(Charsets.UTF_8));
    }
 
    /**
     * Encode the given string with the given encoding, if possible. If the encoding fails with
     * {@link UnsupportedEncodingException}, log a warning and fall back to the system's default
     * encoding.
     * 
     * @param str
     *           what to encode
     * @param charsetName
     *           the name of a supported {@link java.nio.charset.Charset </code>charset<code>}
     * @return properly encoded String.
     */
    public static byte[] encodeString(String str, String charsetName) {
       try {
          return str.getBytes(charsetName);
       } catch (UnsupportedEncodingException e) {
          logger.warn(e, "Failed to encode string to bytes with encoding " + charsetName
                + ". Falling back to system's default encoding");
          return str.getBytes();
       }
    }
 
    @Resource
    private static Logger logger = Logger.NULL;
 
    /**
     * Encode the given string with the UTF-8 encoding, the sane default. In the very unlikely event
     * the encoding fails with {@link UnsupportedEncodingException}, log a warning and fall back to
     * the system's default encoding.
     * 
     * @param str
     *           what to encode
     * @return properly encoded String.
     */
    public static byte[] encodeString(String str) {
       return encodeString(str, UTF8_ENCODING);
    }
 
    /**
     * replaces tokens that are expressed as <code>{token}</code>
     * 
     * <p/>
     * ex. if input is "hello {where}"<br/>
     * and replacements is "where" -> "world" <br/>
     * then replaceTokens returns "hello world"
     * 
     * @param input
     *           source to replace
     * @param replacements
     *           token/value pairs
     */
    public static String replaceTokens(String input, Map<String, String> replacements) {
       Matcher matcher = Patterns.TOKEN_PATTERN.matcher(input);
       StringBuilder builder = new StringBuilder();
       int i = 0;
       while (matcher.find()) {
          String replacement = replacements.get(matcher.group(1));
          builder.append(input.substring(i, matcher.start()));
          if (replacement == null)
             builder.append(matcher.group(0));
          else
             builder.append(replacement);
          i = matcher.end();
       }
       builder.append(input.substring(i, input.length()));
       return builder.toString();
    }
 
 }