/*
   * Copyright 2012-2025 Christophe Friederich
   *
   * 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
   *
   * http://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.devacfr.maven.skins.reflow.snippet;
  
  import com.google.common.collect.Iterables;
  import com.google.common.collect.Lists;
  import java.io.IOException;
  import java.util.List;
  import javax.annotation.Nonnull;
  import javax.annotation.Nullable;
  import org.devacfr.maven.skins.reflow.JsoupUtils;
  import org.jsoup.nodes.Comment;
  import org.jsoup.nodes.Document;
  import org.jsoup.nodes.Element;
  import org.jsoup.nodes.Node;
  import org.jsoup.nodes.TextNode;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Specific process for each type of snippet component.
   *
   * @author Christophe Friederich
   * @version 2.4
   */
  public abstract class Processor {
  
    private static final Logger LOGGER = LoggerFactory.getLogger(Processor.class);
  
    /** */
    protected final SnippetParser parser;
  
    /**
     * Default constructor
     *
     * @param parser
     *          current parser.
     */
    public Processor(final SnippetParser parser) {
      this.parser = parser;
    }
  
    /**
     * Specific parsing for each {@link ComponentToken}.
     *
     * @param token
     *          the current token.
     */
    public void parse(final ComponentToken token) {
      if (LOGGER.isDebugEnabled()) {
        LOGGER.debug("Parse Token: {}", token);
      }
      switch (token.tag()) {
        case empty:
          this.handleEmptyTag(token);
          break;
  
        case start:
          this.handleStartTag(token);
          parser.push(token);
          parser.parse();
          break;
  
        case end:
          final ComponentToken startToken = parser.pop();
          final ComponentToken endToken = token;
          this.handleCloseTag(startToken, endToken);
          break;
        case html:
          this.handleHtmlTag(token);
          break;
        default:
          throw new SnippetParseException("unknown token tag " + token.tag());
      }
    }
  
    /**
     * Append child {@link Node} in html rendering.
     *
     * @param node
     *          the node to use.
     * @param writer
     *          the html writer
     * @throws IOException
     *           If an I/O error occurs.
     */
   protected abstract void appendChildrenToHtml(Node node, Appendable writer) throws IOException;
 
   /**
    * Handle start tag mismatch.
    *
    * @param token
    *          the token
    */
   protected void handleStartTag(final ComponentToken token) {
     // do nothing
   }
 
   /**
    * Handle close tag mismatch.
    *
    * @param startToken
    *          the start token
    * @param endToken
    *          the end token.
    */
   protected void handleCloseTag(final ComponentToken startToken, final ComponentToken endToken) {
     // do nothing
   }
 
   /**
    * Handle empty tag.
    *
    * @param token
    *          the token
    */
   protected void handleEmptyTag(final ComponentToken token) {
     // do nothing
   }
 
   /**
    * Handle html tag.
    *
    * @param token
    *          the token
    */
   protected void handleHtmlTag(final ComponentToken token) {
     // do nothing
   }
 
   /**
    * Convert the snippet to html.
    *
    * @param startToken
    *          the start token
    * @param endToken
    *          the end token.
    * @return Returns a new {@link Element} representing html represention of snippet.
    */
   protected Element convertToHtml(@Nonnull final ComponentToken startToken, @Nullable final ComponentToken endToken) {
     final Element startElement = startToken.getElement();
     final Node previousElement = startElement.previousSibling();
     Element endElement = null;
     if (endToken != null) {
       endElement = endToken.getElement();
     }
     final Document doc = JsoupUtils.createHtmlDocument("");
     final Element tmp = doc.body();
     final Node parent = startElement.parentNode();
 
     final StringBuilder html = new StringBuilder(ComponentResolver.convertElementTextToHtml(startElement));
     final List<Node> nodesToRemove = Lists.newArrayList();
     nodesToRemove.add(startElement);
     if (endElement != null) {
       boolean startCopy = false;
 
       for (final Node n : parent.childNodes()) {
         if (n.equals(endElement)) {
           nodesToRemove.add(n);
           break;
         }
         if (startCopy) {
           try {
             appendChildrenToHtml(n, html);
           } catch (final IOException e) {
             throw new RuntimeException(e.getMessage(), e);
           }
           nodesToRemove.add(n);
         }
         if (n.equals(startElement)) {
           startCopy = true;
         }
       }
       html.append(ComponentResolver.convertElementTextToHtml(endElement));
     }
     tmp.html(html.toString());
     final Element component = tmp.children().first();
     final Element parentElement = startElement.parent();
 
     if (previousElement != null) {
       previousElement.after(component);
     } else {
       if (parentElement.children().first() != null) {
         parentElement.children().first().before(component);
       } else {
         parentElement.children().add(component);
       }
     }
     nodesToRemove.forEach(Node::remove);
     return component;
   }
 
   /**
    * Specific process for snippet web component.
    *
    * @author Christophe Friederich
    * @version 2.4
    */
   public static class WebComponentProcessor extends Processor {
 
     /**
      * Default constructor
      *
      * @param parser
      *          current parser.
      */
     public WebComponentProcessor(final SnippetParser parser) {
       super(parser);
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     protected void appendChildrenToHtml(final Node node, final Appendable writer) throws IOException {
       if (node instanceof Element) {
         final Element el = (Element) node;
         // when use code highlighting
         if ("div".equals(el.tagName()) && el.hasClass("source")) {
           writer.append(el.text());
         } else {
           // comment can be enclose in <p> element.
           if (Iterables.tryFind(el.childNodes(), n -> n instanceof Comment).isPresent()) {
             writer.append(el.data());
           } else {
             writer.append(el.outerHtml());
           }
         }
       } else if (node instanceof Comment) {
         writer.append(((Comment) node).getData());
       } else if (node instanceof TextNode) {
         writer.append(((TextNode) node).text());
       }
     }
 
     @Override
     protected void handleStartTag(ComponentToken token) {
 
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     protected void handleEmptyTag(final ComponentToken token) {
       SnippetContext snippetContext = parser.getSnippetContext();
       Element componentElement = convertToHtml(token, null);
       Component<?> component = snippetContext.create(componentElement, token, null);
       snippetContext.render(component);
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     protected void handleCloseTag(final ComponentToken startToken, final ComponentToken endToken) {
       SnippetContext snippetContext = parser.getSnippetContext();
       // if (snippetContext.getCurrentWebComponentToken() != null) {
       // return;
       // }
       if (!endToken.isCloseTagOf(startToken)) {
         throw new RuntimeException("start token " + startToken + " should be closed by " + startToken.getCloseTag()
             + ", but found " + endToken);
       }
 
       Element componentElement = convertToHtml(startToken, endToken);
       Component<?> component = snippetContext.create(componentElement, startToken, endToken);
       snippetContext.render(component);
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     protected void handleHtmlTag(final ComponentToken token) {
       SnippetContext snippetContext = parser.getSnippetContext();
       Element componentElement = token.getElement();
       Component<?> component = snippetContext.create(componentElement, token, null);
       snippetContext.render(component);
     }
 
   }
 
 }