package cgeo.geocaching.utils;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.tuple.Pair;
import android.support.annotation.NonNull;
import android.text.Html;
import android.text.Spanned;
import android.text.style.ImageSpan;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
public final class HtmlUtils {
private HtmlUtils() {
// utility class
}
/**
* Extract the text from a HTML based string. This is similar to what HTML.fromHtml(...) does, but this method also
* removes the embedded images instead of replacing them by a small rectangular representation character.
*
*/
@NonNull
public static String extractText(final CharSequence html) {
if (StringUtils.isBlank(html)) {
return StringUtils.EMPTY;
}
String result = html.toString();
// recognize images in textview HTML contents
if (html instanceof Spanned) {
final Spanned text = (Spanned) html;
final Object[] styles = text.getSpans(0, text.length(), Object.class);
final List<Pair<Integer, Integer>> removals = new ArrayList<>();
for (final Object style : styles) {
if (style instanceof ImageSpan) {
final int start = text.getSpanStart(style);
final int end = text.getSpanEnd(style);
removals.add(Pair.of(start, end));
}
}
// sort reversed and delete image spans
Collections.sort(removals, new Comparator<Pair<Integer, Integer>>() {
@Override
public int compare(final Pair<Integer, Integer> lhs, final Pair<Integer, Integer> rhs) {
return rhs.getRight().compareTo(lhs.getRight());
}
});
result = text.toString();
for (final Pair<Integer, Integer> removal : removals) {
result = result.substring(0, removal.getLeft()) + result.substring(removal.getRight());
}
}
// now that images are gone, do a normal html to text conversion
return Html.fromHtml(result).toString().trim();
}
/**
* remove all tags that completely encapsulate the given HTML, e.g. all p and span tags around the content
*/
@NonNull
public static String removeExtraTags(final String htmlIn) {
String html = StringUtils.trim(htmlIn);
while (StringUtils.startsWith(html, "<") && StringUtils.endsWith(html, ">")) {
final String tag = "<" + StringUtils.substringBetween(html, "<", ">") + ">";
final int tagLength = tag.length();
if (tagLength >= 10) {
break;
}
final String endTag = "</" + StringUtils.substring(tag, 1);
final int endTagIndex = html.length() - endTag.length();
if (!StringUtils.startsWith(html, tag) || !StringUtils.endsWith(html, endTag) || StringUtils.indexOf(html, endTag) != endTagIndex) {
break;
}
html = StringUtils.substring(html, tagLength, endTagIndex).trim();
}
return html;
}
}