/*
    * Copyright 2015 The Netty Project
    *
    * The Netty Project 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:
    *
    *   https://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 io.netty5.handler.codec.http.cookie;
  
  import io.netty5.handler.codec.http.HttpConstants;
  
  import java.util.BitSet;
  
  final class CookieUtil {
  
      private static final BitSet VALID_COOKIE_NAME_OCTETS = validCookieNameOctets();
  
      private static final BitSet VALID_COOKIE_VALUE_OCTETS = validCookieValueOctets();
  
      private static final BitSet VALID_COOKIE_ATTRIBUTE_VALUE_OCTETS = validCookieAttributeValueOctets();
  
      // token = 1*<any CHAR except CTLs or separators>
      // separators = "(" | ")" | "<" | ">" | "@"
      // | "," | ";" | ":" | "\" | <">
      // | "/" | "[" | "]" | "?" | "="
      // | "{" | "}" | SP | HT
      private static BitSet validCookieNameOctets() {
          BitSet bits = new BitSet();
          for (int i = 32; i < 127; i++) {
              bits.set(i);
          }
          int[] separators = new int[]
                  { '(', ')', '<', '>', '@', ',', ';', ':', '\\', '"', '/', '[', ']', '?', '=', '{', '}', ' ', '\t' };
          for (int separator : separators) {
              bits.set(separator, false);
          }
          return bits;
      }
  
      // cookie-octet = %x21 / %x23-2B / %x2D-3A / %x3C-5B / %x5D-7E
      // US-ASCII characters excluding CTLs, whitespace, DQUOTE, comma, semicolon, and backslash
      private static BitSet validCookieValueOctets() {
          BitSet bits = new BitSet();
          bits.set(0x21);
          for (int i = 0x23; i <= 0x2B; i++) {
              bits.set(i);
          }
          for (int i = 0x2D; i <= 0x3A; i++) {
              bits.set(i);
          }
          for (int i = 0x3C; i <= 0x5B; i++) {
              bits.set(i);
          }
          for (int i = 0x5D; i <= 0x7E; i++) {
              bits.set(i);
          }
          return bits;
      }
  
      // path-value        = <any CHAR except CTLs or ";">
      private static BitSet validCookieAttributeValueOctets() {
          BitSet bits = new BitSet();
          for (int i = 32; i < 127; i++) {
              bits.set(i);
          }
          bits.set(';', false);
          return bits;
      }
  
      /**
       * @param buf a buffer where some cookies were maybe encoded
       * @return the buffer String without the trailing separator, or null if no cookie was appended.
       */
      static String stripTrailingSeparatorOrNull(StringBuilder buf) {
          return buf.length() == 0 ? null : stripTrailingSeparator(buf);
      }
  
      static String stripTrailingSeparator(StringBuilder buf) {
          if (buf.length() > 0) {
              buf.setLength(buf.length() - 2);
          }
          return buf.toString();
      }
  
      static void add(StringBuilder sb, String name, long val) {
          sb.append(name);
          sb.append('=');
          sb.append(val);
          sb.append(';');
          sb.append(HttpConstants.SP_CHAR);
      }
 
     static void add(StringBuilder sb, String name, String val) {
         sb.append(name);
         sb.append('=');
         sb.append(val);
         sb.append(';');
         sb.append(HttpConstants.SP_CHAR);
     }
 
     static void add(StringBuilder sb, String name) {
         sb.append(name);
         sb.append(';');
         sb.append(HttpConstants.SP_CHAR);
     }
 
     static void addQuoted(StringBuilder sb, String name, String val) {
         if (val == null) {
             val = "";
         }
 
         sb.append(name);
         sb.append('=');
         sb.append('"');
         sb.append(val);
         sb.append('"');
         sb.append(';');
         sb.append(HttpConstants.SP_CHAR);
     }
 
     static int firstInvalidCookieNameOctet(CharSequence cs) {
         return firstInvalidOctet(cs, VALID_COOKIE_NAME_OCTETS);
     }
 
     static int firstInvalidCookieValueOctet(CharSequence cs) {
         return firstInvalidOctet(cs, VALID_COOKIE_VALUE_OCTETS);
     }
 
     static int firstInvalidOctet(CharSequence cs, BitSet bits) {
         for (int i = 0; i < cs.length(); i++) {
             char c = cs.charAt(i);
             if (!bits.get(c)) {
                 return i;
             }
         }
         return -1;
     }
 
     static CharSequence unwrapValue(CharSequence cs) {
         final int len = cs.length();
         if (len > 0 && cs.charAt(0) == '"') {
             if (len >= 2 && cs.charAt(len - 1) == '"') {
                 // properly balanced
                 return len == 2 ? "" : cs.subSequence(1, len - 1);
             } else {
                 return null;
             }
         }
         return cs;
     }
 
     static String validateAttributeValue(String name, String value) {
         if (value == null) {
             return null;
         }
         value = value.trim();
         if (value.isEmpty()) {
             return null;
         }
         int i = firstInvalidOctet(value, VALID_COOKIE_ATTRIBUTE_VALUE_OCTETS);
         if (i != -1) {
             throw new IllegalArgumentException(name + " contains the prohibited characters: " + value.charAt(i));
         }
         return value;
     }
 
     private CookieUtil() {
         // Unused
     }
 }