/*
    * Copyright (c) 2002-2026 Gargoyle Software Inc.
    *
    * 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
    * 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 org.htmlunit.css;
  
  import java.io.Serializable;
  import java.util.concurrent.atomic.AtomicLong;
  
  import org.htmlunit.cssparser.parser.selector.SelectorSpecificity;
  
  /**
   * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
   *
   * Contains information about a single style element, including its name, its value, and an index which
   * can be compared against other indices in order to determine precedence.
   *
   * @author Mike Bowler
   * @author Christian Sell
   * @author Daniel Gredler
   * @author Chris Erskine
   * @author Ahmed Ashour
   * @author Rodney Gitzel
   * @author Sudhan Moghe
   * @author Ronald Brill
   * @author Frank Danek
   */
  public class StyleElement implements Serializable {
      /** CSS important property constant. */
      public static final String PRIORITY_IMPORTANT = "important";
  
      /** The current style element index. */
      private static final AtomicLong ELEMENT_INDEX = new AtomicLong();
  
      private final String name_;
      private final String value_;
      private final String priority_;
      private final long index_;
      private final SelectorSpecificity specificity_;
  
      /**
       * Creates a new instance.
       * @param name the style element's name
       * @param value the style element's value
       * @param priority the style element's priority like "important"
       * @param specificity the specificity of the rule providing this style information
       * @param index the style element's index
       */
      public StyleElement(final String name, final String value, final String priority,
              final SelectorSpecificity specificity, final long index) {
          name_ = name;
          value_ = value;
          priority_ = priority;
          specificity_ = specificity;
          index_ = index;
      }
  
      /**
       * Creates a new instance.
       * @param name the style element's name
       * @param value the style element's value
       * @param priority the style element's priority like "important"
       * @param specificity the specificity of the rule providing this style information
       */
      public StyleElement(final String name, final String value, final String priority,
              final SelectorSpecificity specificity) {
          this(name, value, priority, specificity, ELEMENT_INDEX.incrementAndGet());
      }
  
      /**
       * Returns the style element's name.
       * @return the style element's name
       */
      public String getName() {
          return name_;
      }
  
      /**
       * Returns the style element's value.
       * @return the style element's value
       */
      public String getValue() {
          return value_;
      }
  
      /**
       * Returns the style element's priority.
       * @return the style element's priority
       */
     public String getPriority() {
         return priority_;
     }
 
     /**
      * Return true if priority is 'important'.
      *
      * @return true if priority is 'important'
      */
     public boolean isImportant() {
         return PRIORITY_IMPORTANT.equals(getPriority());
     }
 
     /**
      * Returns the specificity of the rule specifying this element.
      * @return the specificity
      */
     public SelectorSpecificity getSpecificity() {
         return specificity_;
     }
 
     /**
      * Returns the style element's index.
      * @return the style element's index
      */
     public long getIndex() {
         return index_;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public String toString() {
         return "[" + index_ + "]" + name_  + "=" + value_;
     }
 
     /**
      * This takes only the importance, the specificity and the index into account.
      * The name and value properties are ignored.
      *
      * @param first the {@link StyleElement} to compare
      * @param second the {@link StyleElement} to compare with
      * @return a negative integer, zero, or a positive integer as this object
      *         is less than, equal to, or greater than the specified object.
      */
     public static int compareToByImportanceAndSpecificity(final StyleElement first, final StyleElement second) {
         if (first == null) {
             return second == null ? 0 : -1;
         }
 
         if (second == null) {
             return 1;
         }
 
         if (first == second) {
             return 0;
         }
 
         if (first.isImportant()) {
             if (!second.isImportant()) {
                 return 1;
             }
         }
         else {
             if (second.isImportant()) {
                 return -1;
             }
         }
 
         final int comp = first.getSpecificity().compareTo(second.getSpecificity());
         if (comp == 0) {
             return Long.compare(first.getIndex(), second.getIndex());
         }
         return comp;
     }
 }