/*
    * 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.html.serializer;
  
  import static org.htmlunit.BrowserVersionFeatures.JS_INNER_TEXT_SVG_NL;
  
  import org.htmlunit.BrowserVersion;
  import org.htmlunit.SgmlPage;
  import org.htmlunit.WebWindow;
  import org.htmlunit.css.ComputedCssStyleDeclaration;
  import org.htmlunit.css.StyleAttributes.Definition;
  import org.htmlunit.html.DomElement;
  import org.htmlunit.html.DomNode;
  import org.htmlunit.html.DomText;
  import org.htmlunit.html.HtmlBreak;
  import org.htmlunit.html.HtmlDefinitionTerm;
  import org.htmlunit.html.HtmlDetails;
  import org.htmlunit.html.HtmlHead;
  import org.htmlunit.html.HtmlListItem;
  import org.htmlunit.html.HtmlNoFrames;
  import org.htmlunit.html.HtmlParagraph;
  import org.htmlunit.html.HtmlScript;
  import org.htmlunit.html.HtmlStyle;
  import org.htmlunit.html.HtmlSummary;
  import org.htmlunit.html.HtmlSvg;
  import org.htmlunit.html.HtmlTextArea;
  import org.htmlunit.html.HtmlTitle;
  import org.htmlunit.html.ScriptElement;
  import org.htmlunit.html.serializer.HtmlSerializerInnerOuterText.HtmlSerializerTextBuilder.Mode;
  import org.htmlunit.svg.SvgTitle;
  import org.htmlunit.util.StringUtils;
  
  /**
   * Special serializer to generate the output we need
   * for innerText and outerText.
   *
   * @author Ronald Brill
   */
  public class HtmlSerializerInnerOuterText {
  
      private final BrowserVersion browserVersion_;
  
      /**
       * Ctor.
       *
       * @param browserVersion the {@link BrowserVersion}
       */
      public HtmlSerializerInnerOuterText(final BrowserVersion browserVersion) {
          super();
          browserVersion_ = browserVersion;
      }
  
      /**
       * Converts an HTML node to text.
       * @param node a node
       * @return the text representation according to the setting of this serializer
       */
      public String asText(final DomNode node) {
          if (node instanceof HtmlBreak) {
              return "";
          }
  
          // included scripts are ignored, but if we ask for the script itself....
          if (node instanceof ScriptElement) {
              final HtmlSerializerTextBuilder builder = new HtmlSerializerTextBuilder();
              appendChildren(builder, node, Mode.WHITE_SPACE_NORMAL, false);
              return builder.getText();
          }
  
          // when calling on the title itself we have to output
          final boolean insideHead = node instanceof HtmlTitle;
  
          final HtmlSerializerTextBuilder builder = new HtmlSerializerTextBuilder();
          appendNode(builder, node, whiteSpaceStyle(node, Mode.WHITE_SPACE_NORMAL), insideHead);
          return builder.getText();
      }
  
      /**
       * Iterate over all Children and call appendNode() for every.
       *
       * @param builder the StringBuilder to add to
       * @param node the node to process
       * @param mode the {@link Mode} to use for processing
       * @param insideHead true if inside head section
       */
      protected void appendChildren(final HtmlSerializerTextBuilder builder, final DomNode node,
              final Mode mode, final boolean insideHead) {
         for (final DomNode child : node.getChildren()) {
             appendNode(builder, child, mode, insideHead);
         }
     }
 
     /**
      * The core distribution method call the different appendXXX
      * methods depending on the type of the given node.
      *
      * @param builder the StringBuilder to add to
      * @param node the node to process
      * @param mode the {@link Mode} to use for processing
      * @param insideHead true if inside head section
      */
     protected void appendNode(final HtmlSerializerTextBuilder builder, final DomNode node,
             final Mode mode, final boolean insideHead) {
         if (node instanceof DomText text) {
             appendText(builder, text, mode);
         }
         else if (node instanceof HtmlBreak break1) {
             appendBreak(builder, break1);
         }
         else if (node instanceof HtmlParagraph paragraph) {
             appendParagraph(builder, paragraph, mode, insideHead);
         }
         else if (node instanceof HtmlListItem item) {
             appendListItem(builder, item, mode, insideHead);
         }
         else if (node instanceof HtmlDetails details) {
             appendDetails(builder, details, mode, insideHead);
         }
         else if (node instanceof HtmlHead) {
             appendChildren(builder, node, mode, true);
         }
         else if (node instanceof HtmlNoFrames) {
             appendChildren(builder, node, Mode.PLAIN, insideHead);
         }
         else if (node instanceof HtmlTitle && !insideHead) {
             // nothing to do
         }
         else if (node instanceof HtmlTextArea) {
             // nothing to do
         }
         else if (node instanceof ScriptElement) {
             if (insideHead) {
                 appendChildren(builder, node, mode, insideHead);
             }
         }
         else if (node instanceof HtmlDefinitionTerm item) {
             appendDefinitionTerm(builder, item, mode, insideHead);
         }
         else if (node instanceof HtmlSvg) {
             if (browserVersion_.hasFeature(JS_INNER_TEXT_SVG_NL)) {
                 builder.appendRequiredLineBreak();
                 appendChildren(builder, node, mode, insideHead);
                 builder.appendRequiredLineBreak();
             }
             else {
                 appendChildren(builder, node, mode, insideHead);
             }
         }
         else if (node instanceof SvgTitle) {
             // nothing to do
         }
         else {
             appendChildren(builder, node, mode, insideHead);
         }
     }
 
     /**
      * Process {@link DomText}.
      *
      * @param builder the StringBuilder to add to
      * @param domText the target to process
      * @param mode the {@link Mode} to use for processing
      */
     protected void appendText(final HtmlSerializerTextBuilder builder, final DomText domText, final Mode mode) {
         final DomNode parent = domText.getParentNode();
         if (parent instanceof HtmlTitle
                 || parent instanceof HtmlStyle
                 || parent instanceof HtmlScript) {
             builder.append(domText.getData(), Mode.PLAIN);
             return;
         }
 
         if (parent == null
                 || parent instanceof HtmlNoFrames
                 || parent.isDisplayed()) {
             builder.append(domText.getData(), mode);
         }
     }
 
     /**
      * Process {@link HtmlBreak}.
      *
      * @param builder the StringBuilder to add to
      * @param htmlBreak the target to process
      */
     protected void appendBreak(final HtmlSerializerTextBuilder builder,
             final HtmlBreak htmlBreak) {
         builder.appendRequiredLineBreak();
     }
 
     /**
      * Process {@link HtmlListItem}.
      *
      * @param builder the StringBuilder to add to
      * @param htmlParagraph the target to process
      * @param mode the {@link Mode} to use for processing
      * @param insideHead true if inside head section
      */
     protected void appendParagraph(final HtmlSerializerTextBuilder builder,
             final HtmlParagraph htmlParagraph, final Mode mode, final boolean insideHead) {
         builder.appendRequiredLineBreak();
         appendChildren(builder, htmlParagraph, mode, insideHead);
         builder.appendRequiredLineBreak();
     }
 
     /**
      * Process {@link HtmlListItem}.
      *
      * @param builder the StringBuilder to add to
      * @param htmlListItem the target to process
      * @param mode the {@link Mode} to use for processing
      * @param insideHead true if inside head section
      */
     protected void appendListItem(final HtmlSerializerTextBuilder builder,
             final HtmlListItem htmlListItem, final Mode mode, final boolean insideHead) {
         builder.appendRequiredLineBreak();
         appendChildren(builder, htmlListItem, mode, insideHead);
         builder.appendRequiredLineBreak();
     }
 
     /**
      * Process {@link HtmlDetails}.
      * @param builder the StringBuilder to add to
      * @param htmlDetails the target to process
      * @param mode the {@link Mode} to use for processing
      * @param insideHead true if inside head section
      */
     protected void appendDetails(final HtmlSerializerTextBuilder builder,
                     final HtmlDetails htmlDetails, final Mode mode, final boolean insideHead) {
         if (htmlDetails.isOpen()) {
             appendChildren(builder, htmlDetails, mode, insideHead);
             return;
         }
 
         for (final DomNode child : htmlDetails.getChildren()) {
             if (child instanceof HtmlSummary) {
                 appendNode(builder, child, mode, insideHead);
             }
         }
     }
 
     /**
      * Process {@link HtmlDefinitionTerm}.
      *
      * @param builder the StringBuilder to add to
      * @param htmlDefinitionTerm the target to process
      * @param mode the {@link Mode} to use for processing
      * @param insideHead true if inside head section
      */
     protected void appendDefinitionTerm(final HtmlSerializerTextBuilder builder,
             final HtmlDefinitionTerm htmlDefinitionTerm, final Mode mode, final boolean insideHead) {
         builder.appendRequiredLineBreak();
         appendChildren(builder, htmlDefinitionTerm, mode, insideHead);
         builder.appendRequiredLineBreak();
     }
 
     private static Mode whiteSpaceStyle(final DomNode domNode, final Mode defaultMode) {
         if (domNode instanceof DomElement) {
             final SgmlPage page = domNode.getPage();
             if (page != null) {
                 if (page.getWebClient().getOptions().isCssEnabled()) {
                     DomNode node = domNode;
                     while (node != null) {
                         if (node instanceof DomElement) {
                             final WebWindow window = page.getEnclosingWindow();
                             if (window != null) {
                                 final ComputedCssStyleDeclaration style =
                                         window.getComputedStyle((DomElement) domNode, null);
                                 final String value = style.getStyleAttribute(Definition.WHITE_SPACE, false);
 
                                 if (!StringUtils.isEmptyOrNull(value)) {
                                     if ("normal".equalsIgnoreCase(value)) {
                                         return Mode.WHITE_SPACE_NORMAL;
                                     }
                                     if ("nowrap".equalsIgnoreCase(value)) {
                                         return Mode.WHITE_SPACE_NORMAL;
                                     }
                                     if ("pre".equalsIgnoreCase(value)) {
                                         return Mode.WHITE_SPACE_PRE;
                                     }
                                     if ("pre-wrap".equalsIgnoreCase(value)) {
                                         return Mode.WHITE_SPACE_PRE;
                                     }
                                     if ("pre-line".equalsIgnoreCase(value)) {
                                         return Mode.WHITE_SPACE_PRE_LINE;
                                     }
                                 }
                             }
                         }
                         node = node.getParentNode();
                     }
                 }
             }
         }
         return defaultMode;
     }
 
     /**
      * Helper to compose the text for the serializer based on several modes.
      */
     protected static class HtmlSerializerTextBuilder {
 
         /** Mode. */
         protected enum Mode {
             /**
              * The mode for plain.
              */
             PLAIN,
 
             /**
              * Sequences of white space are collapsed. Newline characters
              * in the source are handled the same as other white space.
              * Lines are broken as necessary to fill line boxes.
              */
             WHITE_SPACE_NORMAL,
 
             /**
              * Sequences of white space are preserved. Lines are only broken
              * at newline characters in the source and at <br> elements.
              */
             WHITE_SPACE_PRE,
 
             /**
              * Sequences of white space are collapsed. Lines are broken
              * at newline characters, at <br> and as necessary
              * to fill line boxes.
              */
             WHITE_SPACE_PRE_LINE
         }
 
         private enum State {
             DEFAULT,
             EMPTY,
             BLANK_AT_END,
             BLANK_AT_END_AFTER_NEWLINE,
             NEWLINE_AT_END,
             BREAK_AT_END,
             BLOCK_SEPARATOR_AT_END,
             REQUIRED_LINE_BREAK_AT_END
         }
 
         private State state_;
         private final StringBuilder builder_;
         private int trimRightPos_;
 
         /**
          * Ctor.
          */
         public HtmlSerializerTextBuilder() {
             builder_ = new StringBuilder();
             state_ = State.EMPTY;
             trimRightPos_ = 0;
         }
 
         /**
          * Append a line separator.
          */
         public void appendRequiredLineBreak() {
             if (state_ == State.EMPTY) {
                 return;
             }
 
             // trimRight
             builder_.setLength(trimRightPos_);
             if (trimRightPos_ == 0) {
                 state_ = State.EMPTY;
             }
 
             builder_.append('\n');
             state_ = State.REQUIRED_LINE_BREAK_AT_END;
         }
 
         /**
          * Append the provided content.
          * see https://drafts.csswg.org/css-text-3/#white-space
          *
          * @param content the content to add
          * @param mode the {@link Mode}
          */
         public void append(final String content, final Mode mode) {
             if (content == null) {
                 return;
             }
             int length = content.length();
             if (length == 0) {
                 return;
             }
 
             if (mode == Mode.PLAIN) {
                 builder_.append(content);
                 state_ = State.DEFAULT;
                 trimRightPos_ = builder_.length();
                 return;
             }
 
             length--;
             final int contentLength = content.length();
             for (int i = 0; i < contentLength; i++) {
                 char c = content.charAt(i);
 
                 // handle \r
                 if (c == '\r') {
                     if (length != i) {
                         continue;
                     }
                     c = '\n';
                 }
 
                 if (c == '\n') {
                     if (mode == Mode.WHITE_SPACE_PRE) {
                         switch (state_) {
                             case EMPTY:
                             case BLOCK_SEPARATOR_AT_END:
                                 break;
                             default:
                                 builder_.append('\n');
                                 state_ = State.NEWLINE_AT_END;
                                 trimRightPos_ = builder_.length();
                                 break;
                         }
                         continue;
                     }
 
                     if (mode == Mode.WHITE_SPACE_PRE_LINE) {
                         switch (state_) {
                             case EMPTY:
                             case BLOCK_SEPARATOR_AT_END:
                                 break;
                             case BLANK_AT_END:
                                 builder_.setLength(trimRightPos_);
                                 builder_.append('\n');
                                 state_ = State.NEWLINE_AT_END;
                                 trimRightPos_ = builder_.length();
                                 break;
                             default:
                                 builder_.append('\n');
                                 state_ = State.NEWLINE_AT_END;
                                 trimRightPos_ = builder_.length();
                                 break;
                         }
                         continue;
                     }
 
                     switch (state_) {
                         case EMPTY:
                         case BLANK_AT_END:
                         case BLANK_AT_END_AFTER_NEWLINE:
                         case BLOCK_SEPARATOR_AT_END:
                         case NEWLINE_AT_END:
                         case BREAK_AT_END:
                         case REQUIRED_LINE_BREAK_AT_END:
                             break;
                         default:
                             builder_.append(' ');
                             state_ = State.BLANK_AT_END;
                             break;
                     }
                     continue;
                 }
 
                 if (c == ' ' || c == '\t' || c == '\f') {
                     if (mode == Mode.WHITE_SPACE_PRE) {
                         if (c == '\t') {
                             builder_.append('\t');
                         }
                         else {
                             builder_.append(' ');
                         }
                         state_ = State.BLANK_AT_END;
                         trimRightPos_ = builder_.length();
 
                         continue;
                     }
 
                     if (mode == Mode.WHITE_SPACE_PRE_LINE) {
                         switch (state_) {
                             case EMPTY:
                             case BLANK_AT_END:
                             case BLANK_AT_END_AFTER_NEWLINE:
                             case BREAK_AT_END:
                             case NEWLINE_AT_END:
                                 break;
                             default:
                                 builder_.append(' ');
                                 state_ = State.BLANK_AT_END;
                                 break;
                         }
                         continue;
                     }
 
                     switch (state_) {
                         case EMPTY:
                         case BLANK_AT_END:
                         case BLANK_AT_END_AFTER_NEWLINE:
                         case BLOCK_SEPARATOR_AT_END:
                         case NEWLINE_AT_END:
                         case BREAK_AT_END:
                         case REQUIRED_LINE_BREAK_AT_END:
                             break;
                         default:
                             builder_.append(' ');
                             state_ = State.BLANK_AT_END;
                             break;
                     }
                     continue;
                 }
 
                 builder_.append(c);
                 state_ = State.DEFAULT;
                 trimRightPos_ = builder_.length();
             }
         }
 
         /**
          * @return the constructed text.
          */
         public String getText() {
             return builder_.substring(0, trimRightPos_);
         }
     }
 }