content: /*
   * Copyright (C) 2015-2023 Emanuel Moecklin
   *
   * 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 com.onegravity.rteditor.converter;
  
  import android.text.TextUtils;
  import android.util.Patterns;
  
  import com.onegravity.rteditor.api.format.RTFormat;
  import com.onegravity.rteditor.api.format.RTHtml;
  import com.onegravity.rteditor.api.format.RTPlainText;
  import com.onegravity.rteditor.api.media.RTAudio;
  import com.onegravity.rteditor.api.media.RTImage;
  import com.onegravity.rteditor.api.media.RTVideo;
  
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  /**
   * Converts plain text to html
   */
  public class ConverterTextToHtml {
  
      // Number of extra bytes to allocate in a string buffer for htmlification.
      private static final int TEXT_TO_HTML_EXTRA_BUFFER_LENGTH = 512;
  
      private static final String BITCOIN_URI_PATTERN = "bitcoin:[1-9a-km-zA-HJ-NP-Z]{27,34}(\\?[a-zA-Z0-9$\\-_.+!*'(),%:@&=]*)?";
  
      private static final boolean USE_REPLACE_ALL = false;
  
      public static RTHtml<RTImage, RTAudio, RTVideo> convert(RTPlainText input) {
          String text = input.getText();
          String result = convert(text);
          return new RTHtml<>(RTFormat.HTML, result);
      }
  
      public static String convert(String text) {
          // Escape the entities and add newlines.
          String htmlified = text == null ? "" : TextUtils.htmlEncode(text);
  
          // Linkify the message.
          StringBuffer linkified = new StringBuffer(htmlified.length() + TEXT_TO_HTML_EXTRA_BUFFER_LENGTH);
          linkifyText(htmlified, linkified);
  
          // For some reason, TextUtils.htmlEncode escapes ' into &apos;, which is technically part of the XHTML 1.0
          // standard, but Gmail doesn't recognize it as an HTML entity. We unescape that here.
          String result = linkified.toString().replace("\n", "<br>\n").replace("&apos;", "&#39;");
          return result;
      }
  
      private static void linkifyText(final String text, final StringBuffer outputBuffer) {
          String prepared = replaceAll(text, BITCOIN_URI_PATTERN, "<a href=\"$0\">$0</a>");
          Matcher m = Patterns.WEB_URL.matcher(prepared);
          while (m.find()) {
              int start = m.start();
              if (start == 0 || (start != 0 && text.charAt(start - 1) != '@')) {
                  if (m.group().indexOf(':') > 0) { // With no URI-schema we may get "http:/" links with the second / missing
                      m.appendReplacement(outputBuffer, "<a href=\"$0\">$0</a>");
                  } else {
                      m.appendReplacement(outputBuffer, "<a href=\"http://$0\">$0</a>");
                  }
              } else {
                  m.appendReplacement(outputBuffer, "$0");
              }
          }
          m.appendTail(outputBuffer);
      }
  
      /**
       * A memory optimized algorithm for String.replaceAll
       */
      private static String replaceAll(String source, String search, String replace) {
          if (USE_REPLACE_ALL) {
              return source.replaceAll(search, replace);
          } else {
              Pattern p = Pattern.compile(search);
              Matcher m = p.matcher(source);
              StringBuffer sb = new StringBuffer();
              boolean atLeastOneFound = false;
              while (m.find()) {
                  m.appendReplacement(sb, replace);
                  atLeastOneFound = true;
              }
              if (atLeastOneFound) {
                  m.appendTail(sb);
                  return sb.toString();
              } else {
                  return source;
              }
          }
      }
  
  }