/*
    * 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 org.htmlunit.corejs.javascript.Context;
  import org.htmlunit.corejs.javascript.Function;
  import org.htmlunit.corejs.javascript.NativeFunction;
  import org.htmlunit.corejs.javascript.Scriptable;
  import org.htmlunit.corejs.javascript.ScriptableObject;
  import org.htmlunit.corejs.javascript.VarScope;
  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.JsxConstructor;
  import org.htmlunit.javascript.configuration.JsxFunction;
  import org.htmlunit.javascript.host.NativeFunctionPrefixResolver;
  import org.htmlunit.javascript.host.Window;
  import org.htmlunit.xpath.xml.utils.PrefixResolver;
  
  /**
   * A JavaScript object for {@code XPathEvaluator}.
   *
   * @author Marc Guillemot
   * @author Chuck Dumont
   * @author Ronald Brill
   */
  @JsxClass
  public class XPathEvaluator extends HtmlUnitScriptable {
  
      /**
       * JavaScript constructor.
       */
      @JsxConstructor
      public void jsConstructor() {
          // nothing to do
      }
  
      /**
       * Adapts any DOM node to resolve namespaces so that an XPath expression can be easily
       * evaluated relative to the context of the node where it appeared within the document.
       * @param nodeResolver the node to be used as a context for namespace resolution
       * @return an XPathNSResolver which resolves namespaces with respect to the definitions
       *         in scope for a specified node
       */
      @JsxFunction
      public NativeXPathNSResolver createNSResolver(final Node nodeResolver) {
          final NativeXPathNSResolver resolver = new NativeXPathNSResolver();
          resolver.setElement(nodeResolver);
          resolver.setParentScope(getTopLevelScope(getParentScope()));
          resolver.setPrototype(getPrototype(resolver.getClass()));
          return resolver;
      }
  
      /**
       * Evaluates an XPath expression string and returns a result of the specified type if possible.
       * @param expression the XPath expression string to be parsed and evaluated
       * @param contextNodeObj the context node for the evaluation of this XPath expression
       * @param resolver the resolver permits translation of all prefixes, including the XML namespace prefix,
       *        within the XPath expression into appropriate namespace URIs.
       * @param type If a specific type is specified, then the result will be returned as the corresponding type
       * @param result the result object which may be reused and returned by this method
       * @return the result of the evaluation of the XPath expression
       */
      @JsxFunction
      public XPathResult evaluate(final String expression, final Object contextNodeObj,
              final Object resolver, final int type, final Object result) {
          try {
              // contextNodeObj can be either a node or an array with the node as the first element.
              if (!(contextNodeObj instanceof Node contextNode)) {
                  throw JavaScriptEngine.typeError("Illegal value for parameter 'context'");
              }
  
              PrefixResolver prefixResolver = null;
              if (resolver instanceof PrefixResolver prefixResolver1) {
                  prefixResolver = prefixResolver1;
              }
              else if (resolver instanceof NativeFunction function) {
                  prefixResolver = new NativeFunctionPrefixResolver(
                                          function, contextNode.getParentScope());
              }
  
              final XPathResult xPathResult;
              if (result instanceof XPathResult pathResult) {
                  xPathResult = pathResult;
              }
              else {
                 xPathResult = new XPathResult();
                 xPathResult.setParentScope(getParentScope());
                 xPathResult.setPrototype(getPrototype(xPathResult.getClass()));
             }
 
             xPathResult.init(contextNode.getDomNodeOrDie().getByXPath(expression, prefixResolver), type);
             return xPathResult;
         }
         catch (final Exception e) {
             throw JavaScriptEngine.typeError("Failed to execute 'evaluate': " + e.getMessage());
         }
     }
 
     /**
      * Compiles an XPathExpression which can then be used for (repeated) evaluations of the XPath expression.
      * @param context the context
      * @param scope the scope
      * @param thisObj this object
      * @param args the arguments
      * @param function the function
      * @return a XPathExpression representing the compiled form of the XPath expression.
      */
     @JsxFunction
     public static XPathExpression createExpression(final Context context, final VarScope scope,
             final Scriptable thisObj, final Object[] args, final Function function) {
         if (args.length < 1) {
             throw JavaScriptEngine.reportRuntimeError("Missing 'expression' parameter");
         }
 
         PrefixResolver prefixResolver = null;
         if (args.length > 1) {
             final Object resolver = args[1];
             if (resolver instanceof PrefixResolver prefixResolver1) {
                 prefixResolver = prefixResolver1;
             }
             else if (resolver instanceof NativeFunction nativeFunction) {
                 prefixResolver = new NativeFunctionPrefixResolver(
                                         nativeFunction, scope.getParentScope());
             }
         }
 
         final XPathEvaluator evaluator = (XPathEvaluator) thisObj;
 
         try {
             final String xpath = JavaScriptEngine.toString(args[0]);
             final Window window = (Window) (ScriptableObject.getTopLevelScope(scope)).getGlobalThis();
             final DomNode doc = window.getDocument().getDocumentElement().getDomNodeOrDie();
             final XPathExpression xPathExpression  = new XPathExpression(xpath, prefixResolver, doc);
             xPathExpression.setParentScope(evaluator.getParentScope());
             xPathExpression.setPrototype(evaluator.getPrototype(xPathExpression.getClass()));
 
             return xPathExpression;
         }
         catch (final Exception e) {
             throw JavaScriptEngine.syntaxError(
                     "Failed to compile xpath '" + args[0] + "' (" + e.getMessage() + ")");
         }
     }
 }