/*
    * 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.javascript.host.dom;
  
  import java.util.List;
  
  import org.htmlunit.html.DomAttr;
  import org.htmlunit.html.DomNode;
  import org.htmlunit.javascript.HtmlUnitScriptable;
  import org.htmlunit.javascript.JavaScriptEngine;
  import org.htmlunit.javascript.configuration.JsxClass;
  import org.htmlunit.javascript.configuration.JsxConstant;
  import org.htmlunit.javascript.configuration.JsxConstructor;
  import org.htmlunit.javascript.configuration.JsxFunction;
  import org.htmlunit.javascript.configuration.JsxGetter;
  
  /**
   * A JavaScript object for {@code XPathResult}.
   *
   * @author Ahmed Ashour
   * @author Chuck Dumont
   * @author Ronald Brill
   */
  @JsxClass
  public class XPathResult extends HtmlUnitScriptable {
  
      /**
       * This code does not represent a specific type.
       * An evaluation of an XPath expression will never produce this type. If this type is requested,
       * then the evaluation returns whatever type naturally results from evaluation of the expression.
       */
      @JsxConstant
      public static final int ANY_TYPE = 0;
  
      /**
       * The result is a number.
       */
      @JsxConstant
      public static final int NUMBER_TYPE = 1;
  
      /**
       * The result is a string.
       */
      @JsxConstant
      public static final int STRING_TYPE = 2;
  
      /**
       * The result is a boolean.
       */
      @JsxConstant
      public static final int BOOLEAN_TYPE = 3;
  
      /**
       * The result is a node set that will be accessed iteratively, which may not produce nodes in a particular order.
       * This is the default type returned if the result is a node set and {@link #ANY_TYPE} is requested.
       */
      @JsxConstant
      public static final int UNORDERED_NODE_ITERATOR_TYPE = 4;
  
      /**
       * The result is a node set that will be accessed iteratively, which will produce document-ordered nodes.
       */
      @JsxConstant
      public static final int ORDERED_NODE_ITERATOR_TYPE = 5;
  
      /**
       * The result is a node set that will be accessed as a snapshot list of nodes
       * that may not be in a particular order.
       */
      @JsxConstant
      public static final int UNORDERED_NODE_SNAPSHOT_TYPE = 6;
  
      /**
       * The result is a node set that will be accessed as a snapshot list of nodes
       * that will be in original document order.
       */
      @JsxConstant
      public static final int ORDERED_NODE_SNAPSHOT_TYPE = 7;
  
      /**
       * The result is a node set and will be accessed as a single node, which may be null if the node set is empty.
       * If there is more than one node in the actual result,
       * the single node returned might not be the first in document order.
       */
      @JsxConstant
      public static final int ANY_UNORDERED_NODE_TYPE = 8;
  
     /**
      * The result is a node set and will be accessed as a single node, which may be null if the node set is empty.
      * If there are more than one node in the actual result,
      * the single node returned will be the first in document order.
      */
     @JsxConstant
     public static final int FIRST_ORDERED_NODE_TYPE = 9;
 
     private List<?> result_;
     private int resultType_;
 
     /**
      * The index of the next result.
      */
     private int iteratorIndex_;
 
     /**
      * Creates an instance.
      */
     @JsxConstructor
     public void jsConstructor() {
         throw JavaScriptEngine.typeErrorIllegalConstructor();
     }
 
     /**
      * Initializes this XPath result.
      *
      * @param result the evaluation result
      * @param type the requested result type; if a specific type is specified,
      *        the result will be returned as the corresponding type
      */
     void init(final List<?> result, final int type) {
         result_ = result;
         resultType_ = type;
 
         if (type == ANY_TYPE) {
             resultType_ = UNORDERED_NODE_ITERATOR_TYPE;
 
             if (result_.size() == 1) {
                 final Object o = result_.get(0);
                 if (o instanceof Number) {
                     resultType_ = NUMBER_TYPE;
                 }
                 else if (o instanceof String) {
                     resultType_ = STRING_TYPE;
                 }
                 else if (o instanceof Boolean) {
                     resultType_ = BOOLEAN_TYPE;
                 }
             }
         }
 
         iteratorIndex_ = 0;
     }
 
     /**
      * Returns the type of this result.
      *
      * @return the code representing the type of this result
      */
     @JsxGetter
     public int getResultType() {
         return resultType_;
     }
 
     /**
      * Returns the number of nodes in this snapshot.
      *
      * @return the number of nodes in the result snapshot
      */
     @JsxGetter
     public int getSnapshotLength() {
         if (resultType_ != UNORDERED_NODE_SNAPSHOT_TYPE && resultType_ != ORDERED_NODE_SNAPSHOT_TYPE) {
             throw JavaScriptEngine.reportRuntimeError("Cannot get snapshotLength for type: " + resultType_);
         }
         return result_.size();
     }
 
     /**
      * Returns the value of this single-node result.
      *
      * @return the value of this single-node result, which may be {@code null}
      */
     @JsxGetter
     public Node getSingleNodeValue() {
         if (resultType_ != ANY_UNORDERED_NODE_TYPE && resultType_ != FIRST_ORDERED_NODE_TYPE) {
             throw JavaScriptEngine.reportRuntimeError("Cannot get singleNodeValue for type: " + resultType_);
         }
         if (!result_.isEmpty()) {
             return ((DomNode) result_.get(0)).getScriptableObject();
         }
         return null;
     }
 
     /**
      * Returns whether this iterator has become invalid.
      *
      * @return {@code true} if {@code resultType} is
      *         {@link #UNORDERED_NODE_ITERATOR_TYPE} or
      *         {@link #ORDERED_NODE_ITERATOR_TYPE} and the document has been
      *         modified since this result was returned
      */
     @JsxGetter
     public boolean isInvalidIteratorState() {
         return false;
     }
 
     /**
      * Returns the next node in the result.
      *
      * @return the next node, or {@code null} if there are no more nodes
      */
     @JsxFunction
     public Node iterateNext() {
         if (resultType_ != UNORDERED_NODE_ITERATOR_TYPE && resultType_ != ORDERED_NODE_ITERATOR_TYPE) {
             throw JavaScriptEngine.reportRuntimeError("Cannot get iterateNext for type: " + resultType_);
         }
         if (iteratorIndex_ < result_.size()) {
             return ((DomNode) result_.get(iteratorIndex_++)).getScriptableObject();
         }
         return null;
     }
 
     /**
      * Returns the node at the specified index in the snapshot.
      *
      * @param index the index into the snapshot collection
      * @return the node at the specified index, or {@code null} if the index
      *         is out of range
      */
     @JsxFunction
     public Node snapshotItem(final int index) {
         if (resultType_ != UNORDERED_NODE_SNAPSHOT_TYPE && resultType_ != ORDERED_NODE_SNAPSHOT_TYPE) {
             throw JavaScriptEngine.reportRuntimeError("Cannot get snapshotLength for type: " + resultType_);
         }
         if (index >= 0 && index < result_.size()) {
             return ((DomNode) result_.get(index)).getScriptableObject();
         }
         return null;
     }
 
     /**
      * Returns the value of this numeric result.
      *
      * @return the value of this numeric result
      */
     @JsxGetter
     public double getNumberValue() {
         if (resultType_ != NUMBER_TYPE) {
             throw JavaScriptEngine.reportRuntimeError("Cannot get numberValue for type: " + resultType_);
         }
 
         if (result_.size() == 1) {
             final Object o = result_.get(0);
             if (o instanceof Number) {
                 return ((Double) o).doubleValue();
             }
             if (o instanceof Boolean boolean1) {
                 return boolean1.booleanValue() ? 1 : 0;
             }
         }
 
         final String asString = asString();
         double answer;
         try {
             answer = Double.parseDouble(asString);
         }
         catch (final NumberFormatException e) {
             answer = Double.NaN;
         }
         return answer;
     }
 
     /**
      * Returns the value of this boolean result.
      *
      * @return the value of this boolean result
      */
     @JsxGetter
     @SuppressWarnings("PMD.BooleanGetMethodName")
     public boolean getBooleanValue() {
         if (resultType_ != BOOLEAN_TYPE) {
             throw JavaScriptEngine.reportRuntimeError("Cannot get booleanValue for type: " + resultType_);
         }
 
         if (result_.size() == 1) {
             final Object o = result_.get(0);
             if (o instanceof Number) {
                 final double d = ((Double) o).doubleValue();
                 if (Double.isNaN(d) || Double.isInfinite(d)) {
                     return true;
                 }
 
                 return 0.0 != d;
             }
             if (o instanceof String string) {
                 return !string.isEmpty();
             }
             if (o instanceof Boolean boolean1) {
                 return boolean1.booleanValue();
             }
         }
 
         return !result_.isEmpty();
     }
 
     /**
      * Returns the value of this string result.
      *
      * @return the value of this string result
      */
     @JsxGetter
     public String getStringValue() {
         if (resultType_ != STRING_TYPE) {
             throw JavaScriptEngine.reportRuntimeError("Cannot get stringValue for type: " + resultType_);
         }
         return asString();
     }
 
     private String asString() {
         if (result_.isEmpty()) {
             return "";
         }
 
         final Object resultObj = result_.get(0);
         if (resultObj instanceof DomAttr attr) {
             return attr.getValue();
         }
         if (resultObj instanceof DomNode node) {
             return node.asNormalizedText();
         }
         return resultObj.toString();
     }
 }