/*
    * Copyright (c) 2002-2025 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.html;
  
  import static org.htmlunit.html.DomElement.ATTRIBUTE_NOT_DEFINED;
  
  import java.nio.charset.Charset;
  
  import org.apache.commons.lang3.StringUtils;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.htmlunit.FailingHttpStatusCodeException;
  import org.htmlunit.SgmlPage;
  import org.htmlunit.WebClient;
  import org.htmlunit.WebWindow;
  import org.htmlunit.html.HtmlPage.JavaScriptLoadResult;
  import org.htmlunit.javascript.AbstractJavaScriptEngine;
  import org.htmlunit.javascript.PostponedAction;
  import org.htmlunit.javascript.host.Window;
  import org.htmlunit.javascript.host.dom.Document;
  import org.htmlunit.javascript.host.event.Event;
  import org.htmlunit.javascript.host.event.EventTarget;
  import org.htmlunit.javascript.host.html.HTMLDocument;
  import org.htmlunit.protocol.javascript.JavaScriptURLConnection;
  import org.htmlunit.util.EncodingSniffer;
  import org.htmlunit.util.MimeType;
  import org.htmlunit.xml.XmlPage;
  
  /**
   * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
   *
   * A helper class to be used by elements which support {@link ScriptElement}.
   *
   * @author Ahmed Ashour
   * @author Ronald Brill
   * @author Ronny Shapiro
   * @author Sven Strickroth
   */
  public final class ScriptElementSupport {
  
      private static final Log LOG = LogFactory.getLog(ScriptElementSupport.class);
  
      /** Invalid source attribute which should be ignored (used by JS libraries like jQuery). */
      private static final String SLASH_SLASH_COLON = "//:";
  
      private ScriptElementSupport() {
          // util class
      }
  
      /**
       * Support method that is called from the (html or svg) script and the link tag.
       *
       * @param script the ScriptElement to work for
       * @param postponed whether to use {@link org.htmlunit.javascript.PostponedAction} or not
       */
      public static void onAllChildrenAddedToPage(final ScriptElement script, final boolean postponed) {
          final DomElement element = (DomElement) script;
          if (element.getOwnerDocument() instanceof XmlPage) {
              return;
          }
          if (LOG.isDebugEnabled()) {
              LOG.debug("Script node added: " + element.asXml());
          }
  
          final SgmlPage page = element.getPage();
          final WebClient webClient = page.getWebClient();
          if (!webClient.isJavaScriptEngineEnabled()) {
              LOG.debug("Script found but not executed because javascript engine is disabled");
              return;
          }
  
          final String srcAttrib = script.getScriptSource();
          final boolean hasNoSrcAttrib = ATTRIBUTE_NOT_DEFINED == srcAttrib;
          if (!hasNoSrcAttrib && script.isDeferred()) {
              return;
          }
  
          final WebWindow webWindow = page.getEnclosingWindow();
          if (webWindow != null) {
              final StringBuilder description = new StringBuilder()
                      .append("Execution of ")
                      .append(hasNoSrcAttrib ? "inline " : "external ")
                      .append(element.getClass().getSimpleName());
              if (!hasNoSrcAttrib) {
                  description.append(" (").append(srcAttrib).append(')');
              }
  
             final PostponedAction action = new PostponedAction(page, description.toString()) {
                 @Override
                 public void execute() {
                     // see HTMLDocument.setExecutingDynamicExternalPosponed(boolean)
                     HTMLDocument jsDoc = null;
                     final Window window = webWindow.getScriptableObject();
                     if (window != null) {
                         jsDoc = (HTMLDocument) window.getDocument();
                         jsDoc.setExecutingDynamicExternalPosponed(element.getStartLineNumber() == -1
                                 && !hasNoSrcAttrib);
                     }
                     try {
                         executeScriptIfNeeded(script, false, false);
                     }
                     finally {
                         if (jsDoc != null) {
                             jsDoc.setExecutingDynamicExternalPosponed(false);
                         }
                     }
                 }
             };
 
             final AbstractJavaScriptEngine<?> engine = webClient.getJavaScriptEngine();
             if (element.hasAttribute("async") && !hasNoSrcAttrib) {
                 engine.addPostponedAction(action);
             }
             else if (postponed && !hasNoSrcAttrib) {
                 engine.addPostponedAction(action);
             }
             else {
                 try {
                     action.execute();
                     engine.processPostponedActions();
                 }
                 catch (final RuntimeException e) {
                     throw e;
                 }
                 catch (final Exception e) {
                     throw new RuntimeException(e);
                 }
             }
         }
     }
 
     /**
      * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
      *
      * Executes this script node if necessary and/or possible.
      *
      * @param script the ScriptElement to work for
      * @param ignoreAttachedToPage don't do the isAttachedToPage check
      * @param ignorePageIsAncestor don't do the element.getPage().isAncestorOf(element) check
      */
     public static void executeScriptIfNeeded(final ScriptElement script, final boolean ignoreAttachedToPage,
             final boolean ignorePageIsAncestor) {
         if (!isExecutionNeeded(script, ignoreAttachedToPage, ignorePageIsAncestor)) {
             return;
         }
 
         final String src = script.getScriptSource();
         final DomElement element = (DomElement) script;
         if (SLASH_SLASH_COLON.equals(src)) {
             executeEvent(element, Event.TYPE_ERROR);
             return;
         }
 
         final HtmlPage page = (HtmlPage) element.getPage();
         if (src != ATTRIBUTE_NOT_DEFINED) {
             if (!src.startsWith(JavaScriptURLConnection.JAVASCRIPT_PREFIX)) {
                 // <script src="[url]"></script>
                 if (LOG.isDebugEnabled()) {
                     LOG.debug("Loading external JavaScript: " + src);
                 }
                 try {
                     script.setExecuted(true);
                     Charset charset = EncodingSniffer.toCharset(script.getScriptCharset());
                     if (charset == null) {
                         charset = page.getCharset();
                     }
 
                     final JavaScriptLoadResult result;
                     final Window win = page.getEnclosingWindow().getScriptableObject();
                     final Document doc = win.getDocument();
                     try {
                         doc.setCurrentScript(element.getScriptableObject());
                         result = page.loadExternalJavaScriptFile(src, charset);
                     }
                     finally {
                         doc.setCurrentScript(null);
                     }
 
                     if (result == JavaScriptLoadResult.SUCCESS) {
                         executeEvent(element, Event.TYPE_LOAD);
                     }
                     else if (result == JavaScriptLoadResult.DOWNLOAD_ERROR) {
                         executeEvent(element, Event.TYPE_ERROR);
                     }
                     else if (result == JavaScriptLoadResult.NO_CONTENT) {
                         executeEvent(element, Event.TYPE_LOAD);
                     }
                 }
                 catch (final FailingHttpStatusCodeException e) {
                     executeEvent(element, Event.TYPE_ERROR);
                     throw e;
                 }
             }
         }
         else if (element.getFirstChild() != null) {
             // <script>[code]</script>
             final Window win = page.getEnclosingWindow().getScriptableObject();
             final Document doc = win.getDocument();
             try {
                 doc.setCurrentScript(element.getScriptableObject());
                 executeInlineScriptIfNeeded(script);
             }
             finally {
                 doc.setCurrentScript(null);
             }
         }
     }
 
     /**
      * Indicates if script execution is necessary and/or possible.
      *
      * @param script the ScriptElement to work for
      * @param ignoreAttachedToPage don't do the isAttachedToPage check
      * @param ignorePageIsAncestor don't do the element.getPage().isAncestorOf(element) check
      * @return {@code true} if the script should be executed
      */
     private static boolean isExecutionNeeded(final ScriptElement script, final boolean ignoreAttachedToPage,
             final boolean ignorePageIsAncestor) {
         if (script.isExecuted() || script.wasCreatedByDomParser()) {
             return false;
         }
 
         final DomElement element = (DomElement) script;
         if (!ignoreAttachedToPage && !element.isAttachedToPage()) {
             return false;
         }
 
         // If JavaScript is disabled, we don't need to execute.
         final SgmlPage page = element.getPage();
         if (!page.getWebClient().isJavaScriptEnabled()) {
             return false;
         }
 
         // If innerHTML or outerHTML is being parsed
         final HtmlPage htmlPage = element.getHtmlPageOrNull();
         if (htmlPage != null && htmlPage.isParsingHtmlSnippet()) {
             return false;
         }
 
         // If the script node is nested in an iframe, a noframes, or a noscript node, we don't need to execute.
         for (DomNode o = element; o != null; o = o.getParentNode()) {
             if (o instanceof HtmlInlineFrame || o instanceof HtmlNoFrames) {
                 return false;
             }
         }
 
         // If the underlying page no longer owns its window, the client has moved on (possibly
         // because another script set window.location.href), and we don't need to execute.
         if (page.getEnclosingWindow() != null && page.getEnclosingWindow().getEnclosedPage() != page) {
             return false;
         }
 
         // If the script language is not JavaScript, we can't execute.
         final String t = element.getAttributeDirect("type");
         final String l = element.getAttributeDirect("language");
         if (!isJavaScript(t, l)) {
             // Was at warn level before 2.46 but other types or tricky implementations with unsupported types
             // are common out there and too many peoples out there thinking the is the root of problems.
             // Browsers are also not warning about this.
             if (LOG.isDebugEnabled()) {
                 LOG.debug("Script is not JavaScript (type: '" + t + "', language: '" + l + "'). Skipping execution.");
             }
             return false;
         }
 
         // If the script's root ancestor node is not the page, then the script is not a part of the page.
         // If it isn't yet part of the page, don't execute the script; it's probably just being cloned.
         return ignorePageIsAncestor || element.getPage().isAncestorOf(element);
     }
 
     /**
      * Returns true if a script with the specified type and language attributes is actually JavaScript.
      * According to <a href="http://www.w3.org/TR/REC-html40/types.html#h-6.7">W3C recommendation</a>
      * are content types case insensitive.<br>
      *
      * @param typeAttribute the type attribute specified in the script tag
      * @param languageAttribute the language attribute specified in the script tag
      * @return true if the script is JavaScript
      */
     public static boolean isJavaScript(String typeAttribute, final String languageAttribute) {
         typeAttribute = typeAttribute.trim();
 
         if (StringUtils.isNotEmpty(typeAttribute)) {
             return MimeType.isJavascriptMimeType(typeAttribute);
         }
 
         if (StringUtils.isNotEmpty(languageAttribute)) {
             return StringUtils.startsWithIgnoreCase(languageAttribute, "javascript");
         }
         return true;
     }
 
     private static void executeEvent(final DomElement element, final String type) {
         final EventTarget eventTarget = element.getScriptableObject();
         final Event event = new Event(element, type);
 
         event.setParentScope(eventTarget);
         event.setPrototype(eventTarget.getPrototype(event.getClass()));
 
         eventTarget.executeEventLocally(event);
     }
 
     /**
      * Executes this script node as inline script if necessary and/or possible.
      */
     private static void executeInlineScriptIfNeeded(final ScriptElement script) {
         if (!isExecutionNeeded(script, false, false)) {
             return;
         }
 
         final String src = script.getScriptSource();
         if (src != ATTRIBUTE_NOT_DEFINED) {
             return;
         }
 
         final DomElement element = (DomElement) script;
         final String forr = element.getAttributeDirect("for");
         String event = element.getAttributeDirect("event");
         // The event name can be like "onload" or "onload()".
         if (event.endsWith("()")) {
             event = event.substring(0, event.length() - 2);
         }
 
         final String scriptCode = getScriptCode(element);
         if (forr == ATTRIBUTE_NOT_DEFINED || "onload".equals(event)) {
             final String url = element.getPage().getUrl().toExternalForm();
             final int line1 = element.getStartLineNumber();
             final int line2 = element.getEndLineNumber();
             final int col1 = element.getStartColumnNumber();
             final int col2 = element.getEndColumnNumber();
             final String desc = "script in " + url + " from (" + line1 + ", " + col1
                 + ") to (" + line2 + ", " + col2 + ")";
 
             script.setExecuted(true);
             ((HtmlPage) element.getPage()).executeJavaScript(scriptCode, desc, line1);
         }
     }
 
     /**
      * Gets the script held within the script tag.
      */
     private static String getScriptCode(final DomElement element) {
         final Iterable<DomNode> textNodes = element.getChildren();
         final StringBuilder scriptCode = new StringBuilder();
         for (final DomNode node : textNodes) {
             if (node instanceof DomText) {
                 final DomText domText = (DomText) node;
                 scriptCode.append(domText.getData());
             }
         }
         return scriptCode.toString();
     }
 
 }