/*
 * Copyright 2010-2020 Alfresco Software, Ltd.
 *
 * 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.activiti.engine.impl.util.json;

/*
 Copyright (c) 2002 JSON.org

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:

 The above copyright notice and this permission notice shall be included in all
 copies or substantial portions of the Software.

 The Software shall be used for Good, not Evil.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 */

/**
 * Convert a web browser cookie specification to a JSONObject and back. JSON and Cookies are both notations for name/value pairs.
 *

 * @version 2008-09-18
 */
public class Cookie {

  /**
   * Produce a copy of a string in which the characters '+', '%', '=', ';' and control characters are replaced with "%hh". This is a gentle form of URL encoding, attempting to cause as little
   * distortion to the string as possible. The characters '=' and ';' are meta characters in cookies. By convention, they are escaped using the URL-encoding. This is only a convention, not a standard.
   * Often, cookies are expected to have encoded values. We encode '=' and ';' because we must. We encode '%' and '+' because they are meta characters in URL encoding.
   *
   * @param string
   *          The source string.
   * @return The escaped result.
   */
  public static String escape(String string) {
    char c;
    String s = string.trim();
    StringBuilder sb = new StringBuilder();
    int len = s.length();
    for (int i = 0; i < len; i += 1) {
      c = s.charAt(i);
      if (c < ' ' || c == '+' || c == '%' || c == '=' || c == ';') {
        sb.append('%');
        sb.append(Character.forDigit((char) ((c >>> 4) & 0x0f), 16));
        sb.append(Character.forDigit((char) (c & 0x0f), 16));
      } else {
        sb.append(c);
      }
    }
    return sb.toString();
  }

  /**
   * Convert a cookie specification string into a JSONObject. The string will contain a name value pair separated by '='. The name and the value will be unescaped, possibly converting '+' and '%'
   * sequences. The cookie properties may follow, separated by ';', also represented as name=value (except the secure property, which does not have a value). The name will be stored under the key
   * "name", and the value will be stored under the key "value". This method does not do checking or validation of the parameters. It only converts the cookie string into a JSONObject.
   *
   * @param string
   *          The cookie specification string.
   * @return A JSONObject containing "name", "value", and possibly other members.
   * @throws JSONException
   */
  public static JSONObject toJSONObject(String string) throws JSONException {
    String n;
    JSONObject o = new JSONObject();
    Object v;
    JSONTokener x = new JSONTokener(string);
    o.put("name", x.nextTo('='));
    x.next('=');
    o.put("value", x.nextTo(';'));
    x.next();
    while (x.more()) {
      n = unescape(x.nextTo("=;"));
      if (x.next() != '=') {
        if (n.equals("secure")) {
          v = Boolean.TRUE;
        } else {
          throw x.syntaxError("Missing '=' in cookie parameter.");
        }
      } else {
        v = unescape(x.nextTo(';'));
        x.next();
      }
      o.put(n, v);
    }
    return o;
  }

  /**
   * Convert a JSONObject into a cookie specification string. The JSONObject must contain "name" and "value" members. If the JSONObject contains "expires", "domain", "path", or "secure" members, they
   * will be appended to the cookie specification string. All other members are ignored.
   *
   * @param o
   *          A JSONObject
   * @return A cookie specification string
   * @throws JSONException
   */
  public static String toString(JSONObject o) throws JSONException {
    StringBuilder sb = new StringBuilder();

    sb.append(escape(o.getString("name")));
    sb.append("=");
    sb.append(escape(o.getString("value")));
    if (o.has("expires")) {
      sb.append(";expires=");
      sb.append(o.getString("expires"));
    }
    if (o.has("domain")) {
      sb.append(";domain=");
      sb.append(escape(o.getString("domain")));
    }
    if (o.has("path")) {
      sb.append(";path=");
      sb.append(escape(o.getString("path")));
    }
    if (o.optBoolean("secure")) {
      sb.append(";secure");
    }
    return sb.toString();
  }

  /**
   * Convert <code>%</code><i>hh</i> sequences to single characters, and convert plus to space.
   *
   * @param s
   *          A string that may contain <code>+</code> &nbsp;<small>(plus)</small> and <code>%</code><i>hh</i> sequences.
   * @return The unescaped string.
   */
  public static String unescape(String s) {
    int len = s.length();
    StringBuilder b = new StringBuilder();
    for (int i = 0; i < len; ++i) {
      char c = s.charAt(i);
      if (c == '+') {
        c = ' ';
      } else if (c == '%' && i + 2 < len) {
        int d = JSONTokener.dehexchar(s.charAt(i + 1));
        int e = JSONTokener.dehexchar(s.charAt(i + 2));
        if (d >= 0 && e >= 0) {
          c = (char) (d * 16 + e);
          i += 2;
        }
      }
      b.append(c);
    }
    return b.toString();
  }
}
