/**
 * 文本中Url检测处理
 *
 * @author: NPF
 * @date: 2018/1/15.
 */
public class UrlFilter {
  /**
   * URL匹配正则
   */
  private static final String REGEX_URL = "((http(s)?|(ftp))://)?([a-z]+\\.)?[a-z\\d]+\\.[a-z\\d]+([/^a-z\\d\\.\\?]+)?([a-z\\d=&]+)?";
  private static UrlFilter mInstance = null;

  private UrlFilter() {
  }

  public UrlFilter getInstance() {
      if (null == mInstance) {
          synchronized (UrlFilter.class) {
              if (null == mInstance) {
                  mInstance = new UrlFilter();
              }
          }
      }
      return mInstance;
  }

  /**
   * URL过滤
   *
   * @param str   需要处理的字符串
   * @param inter 匹配到的url点击事件回调
   * @return
   */
  public SpannableString urlFilter(String str, UrlClickInter inter) {
      SpannableString spannableString = new SpannableString(str);
      Pattern sinaPattenUrl = Pattern.compile(REGEX_URL, Pattern.CASE_INSENSITIVE);
      try {
          urlFilter(spannableString, sinaPattenUrl, 0, inter);
      } catch (Exception e) {
          e.printStackTrace();
          return new SpannableString("");
      }
      return spannableString;
  }

  /**
   * URL过滤
   *
   * @param spannableString
   * @param patten
   * @param start
   * @param inter
   */
  private void urlFilter(final SpannableString spannableString, Pattern patten, int start, final UrlClickInter inter) {
      try {
          final Matcher matcher = patten.matcher(spannableString);
          int end = -1;
          while (matcher.find()) {
              String key = matcher.group();
              if (matcher.start() < start) {
                  continue;
              }
              end = matcher.start() + key.length();
              initUrlClick(spannableString, matcher.start(), end, inter);
              break;
          }
          if (end != -1 && end < spannableString.length()) {
              urlFilter(spannableString, patten, end, inter);
          }
      } catch (Exception e) {
          e.printStackTrace();
      }
  }

  /**
   * 处理Url点击事件
   *
   * @param spannableString
   * @param start
   * @param end
   * @param inter
   */
  private void initUrlClick(final SpannableString spannableString, final int start, final int end, final UrlClickInter inter) {
      spannableString.setSpan(new ClickableSpan() {
          @Override
          public void onClick(View widget) {
              inter.onClick(spannableString.subSequence(start, end).toString());
          }

          @Override
          public void updateDrawState(TextPaint ds) {
              ds.setColor(ds.linkColor);
              ds.setUnderlineText(false);
          }
      }, start, end, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
  }

  /**
   * 事件回调
   */
  public interface UrlClickInter {
      void onClick(String url);
  }

}