/*
    * ====================================================================
    *
    *  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.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   */
  
  package org.apache.http.client.utils;
  
  import java.net.URI;
  import java.net.URISyntaxException;
  import java.nio.charset.Charset;
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  
  import org.apache.http.Consts;
  import org.apache.http.NameValuePair;
  import org.apache.http.annotation.NotThreadSafe;
  import org.apache.http.conn.util.InetAddressUtils;
  import org.apache.http.message.BasicNameValuePair;
  
  /**
   * {@link URI} builder for HTTP requests.
   *
   * @since 4.2
   */
  @NotThreadSafe
  public class URIBuilder {
  
      private String scheme;
      private String encodedSchemeSpecificPart;
      private String encodedAuthority;
      private String userInfo;
      private String encodedUserInfo;
      private String host;
      private int port;
      private String path;
      private String encodedPath;
      private String encodedQuery;
      private List<NameValuePair> queryParams;
      private String fragment;
      private String encodedFragment;
  
      /**
       * Constructs an empty instance.
       */
      public URIBuilder() {
          super();
          this.port = -1;
      }
  
      /**
       * Construct an instance from the string which must be a valid URI.
       * 
       * @param string a valid URI in string form
       * @throws URISyntaxException if the input is not a valid URI
       */
      public URIBuilder(final String string) throws URISyntaxException {
          super();
          digestURI(new URI(string));
      }
  
      /**
       * Construct an instance from the provided URI.
       * @param uri
       */
      public URIBuilder(final URI uri) {
          super();
          digestURI(uri);
      }
  
      private List <NameValuePair> parseQuery(final String query, final Charset charset) {
          if (query != null && query.length() > 0) {
              return URLEncodedUtils.parse(query, charset);
          }
          return null;
      }
  
      /**
      * Builds a {@link URI} instance.
      */
     public URI build() throws URISyntaxException {
         return new URI(buildString());
     }
     
     private String buildString() {
         StringBuilder sb = new StringBuilder();
         if (this.scheme != null) {
             sb.append(this.scheme).append(':');
         }
         if (this.encodedSchemeSpecificPart != null) {
             sb.append(this.encodedSchemeSpecificPart);
         } else {
             if (this.encodedAuthority != null) {
                 sb.append("//").append(this.encodedAuthority);
             } else if (this.host != null) {
                 sb.append("//");
                 if (this.encodedUserInfo != null) {
                     sb.append(this.encodedUserInfo).append("@");
                 } else if (this.userInfo != null) {
                     sb.append(encodeUserInfo(this.userInfo)).append("@");
                 }
                 if (InetAddressUtils.isIPv6Address(this.host)) {
                     sb.append("[").append(this.host).append("]");
                 } else {
                     sb.append(this.host);
                 }
                 if (this.port >= 0) {
                     sb.append(":").append(this.port);
                 }
             }
             if (this.encodedPath != null) {
                 sb.append(normalizePath(this.encodedPath));
             } else if (this.path != null) {
                 sb.append(encodePath(normalizePath(this.path)));
             }
             if (this.encodedQuery != null) {
                 sb.append("?").append(this.encodedQuery);
             } else if (this.queryParams != null) {
                 sb.append("?").append(encodeQuery(this.queryParams));
             }
         }
         if (this.encodedFragment != null) {
             sb.append("#").append(this.encodedFragment);
         } else if (this.fragment != null) {
             sb.append("#").append(encodeFragment(this.fragment));
         }
         return sb.toString();
     }
 
     private void digestURI(final URI uri) {
         this.scheme = uri.getScheme();
         this.encodedSchemeSpecificPart = uri.getRawSchemeSpecificPart();
         this.encodedAuthority = uri.getRawAuthority();
         this.host = uri.getHost();
         this.port = uri.getPort();
         this.encodedUserInfo = uri.getRawUserInfo();
         this.userInfo = uri.getUserInfo();
         this.encodedPath = uri.getRawPath();
         this.path = uri.getPath();
         this.encodedQuery = uri.getRawQuery();
         this.queryParams = parseQuery(uri.getRawQuery(), Consts.UTF_8);
         this.encodedFragment = uri.getRawFragment();
         this.fragment = uri.getFragment();
     }
 
     private String encodeUserInfo(final String userInfo) {
         return URLEncodedUtils.encUserInfo(userInfo, Consts.UTF_8);
     }
 
     private String encodePath(final String path) {
         return URLEncodedUtils.encPath(path, Consts.UTF_8);
     }
 
     private String encodeQuery(final List<NameValuePair> params) {
         return URLEncodedUtils.format(params, Consts.UTF_8);
     }
 
     private String encodeFragment(final String fragment) {
         return URLEncodedUtils.encFragment(fragment, Consts.UTF_8);
     }
 
     /**
      * Sets URI scheme.
      */
     public URIBuilder setScheme(final String scheme) {
         this.scheme = scheme;
         return this;
     }
 
     /**
      * Sets URI user info. The value is expected to be unescaped and may contain non ASCII
      * characters.
      */
     public URIBuilder setUserInfo(final String userInfo) {
         this.userInfo = userInfo;
         this.encodedSchemeSpecificPart = null;
         this.encodedAuthority = null;
         this.encodedUserInfo = null;
         return this;
     }
 
     /**
      * Sets URI user info as a combination of username and password. These values are expected to
      * be unescaped and may contain non ASCII characters.
      */
     public URIBuilder setUserInfo(final String username, final String password) {
         return setUserInfo(username + ':' + password);
     }
 
     /**
      * Sets URI host.
      */
     public URIBuilder setHost(final String host) {
         this.host = host;
         this.encodedSchemeSpecificPart = null;
         this.encodedAuthority = null;
         return this;
     }
 
     /**
      * Sets URI port.
      */
     public URIBuilder setPort(final int port) {
         this.port = port < 0 ? -1 : port;
         this.encodedSchemeSpecificPart = null;
         this.encodedAuthority = null;
         return this;
     }
 
     /**
      * Sets URI path. The value is expected to be unescaped and may contain non ASCII characters.
      */
     public URIBuilder setPath(final String path) {
         this.path = path;
         this.encodedSchemeSpecificPart = null;
         this.encodedPath = null;
         return this;
     }
 
     /**
      * Removes URI query.
      */
     public URIBuilder removeQuery() {
         this.queryParams = null;
         this.encodedQuery = null;
         this.encodedSchemeSpecificPart = null;
         return this;
     }
 
     /**
      * Sets URI query.
      * <p>
      * The value is expected to be encoded form data.
      */
     public URIBuilder setQuery(final String query) {
         this.queryParams = parseQuery(query, Consts.UTF_8);
         this.encodedQuery = null;
         this.encodedSchemeSpecificPart = null;
         return this;
     }
 
     /**
      * Adds parameter to URI query. The parameter name and value are expected to be unescaped
      * and may contain non ASCII characters.
      */
     public URIBuilder addParameter(final String param, final String value) {
         if (this.queryParams == null) {
             this.queryParams = new ArrayList<NameValuePair>();
         }
         this.queryParams.add(new BasicNameValuePair(param, value));
         this.encodedQuery = null;
         this.encodedSchemeSpecificPart = null;
         return this;
     }
 
     /**
      * Sets parameter of URI query overriding existing value if set. The parameter name and value
      * are expected to be unescaped and may contain non ASCII characters.
      */
     public URIBuilder setParameter(final String param, final String value) {
         if (this.queryParams == null) {
             this.queryParams = new ArrayList<NameValuePair>();
         }
         if (!this.queryParams.isEmpty()) {
             for (Iterator<NameValuePair> it = this.queryParams.iterator(); it.hasNext(); ) {
                 NameValuePair nvp = it.next();
                 if (nvp.getName().equals(param)) {
                     it.remove();
                 }
             }
         }
         this.queryParams.add(new BasicNameValuePair(param, value));
         this.encodedQuery = null;
         this.encodedSchemeSpecificPart = null;
         return this;
     }
 
     /**
      * Sets URI fragment. The value is expected to be unescaped and may contain non ASCII
      * characters.
      */
     public URIBuilder setFragment(final String fragment) {
         this.fragment = fragment;
         this.encodedFragment = null;
         return this;
     }
 
     public String getScheme() {
         return this.scheme;
     }
 
     public String getUserInfo() {
         return this.userInfo;
     }
 
     public String getHost() {
         return this.host;
     }
 
     public int getPort() {
         return this.port;
     }
 
     public String getPath() {
         return this.path;
     }
 
     public List<NameValuePair> getQueryParams() {
         if (this.queryParams != null) {
             return new ArrayList<NameValuePair>(this.queryParams);
         } else {
             return new ArrayList<NameValuePair>();
         }
     }
 
     public String getFragment() {
         return this.fragment;
     }
 
     @Override
     public String toString() {
         return buildString();
     }
 
     private static String normalizePath(String path) {
         if (path == null) {
             return null;
         }
         int n = 0;
         for (; n < path.length(); n++) {
             if (path.charAt(n) != '/') {
                 break;
             }
         }
         if (n > 1) {
             path = path.substring(n - 1);
         }
         return path;
     }
 
 }