/**
* Extract a summary of a text, optionaly with a keyword highlighted
*
* @param string $txt Text
* @param int $l Max length of the summary
* @param string|array $limiter Prefix and Suffix. e.g: "..." or ["", "..."]
* @param string $keyword Highlighted keyword
* @return string Summary
*/
public static function summary($txt, $l, $limiter = '', $keyword = null)
{
$start = 0;
$txt = trim(preg_replace('#\\s+#', ' ', $txt));
$keyword = trim(preg_replace('#\\s+#', ' ', $keyword));
if (is_array($limiter)) {
$limiterLeft = $limiter[0];
$limiterRight = $limiter[1];
} else {
$limiterLeft = $limiter;
$limiterRight = $limiter;
}
if (strlen($txt) <= $l) {
return $txt;
}
if (isset($keyword)) {
$txt_ = strtolower(text::removeAccents($txt));
$keyword = strtolower(text::removeAccents($keyword));
$p = strpos($txt_, $keyword);
if ($p === false && strpos($keyword, ' ') !== false) {
$keyword = preg_split('# +#', $keyword);
foreach ($keyword as $keyword_) {
$p = strpos($txt_, $keyword_);
if ($p !== false) {
$keyword = $keyword_;
break;
}
}
}
if ($p !== false) {
$start = round($p + strlen($keyword) / 2 - $l / 3);
if ($start < 0) {
$start = 0;
}
if ($start > strlen($txt) - $l) {
$start = strlen($txt) - $l;
}
if ($start != 0) {
if (($pos = strpos($txt, ' ', $start)) !== false) {
$start = strpos($txt, ' ', $start) + 1;
}
}
}
}
if ($start + $l >= strlen($txt)) {
$txt = substr($txt, $start);
$limiterRight = '';
} else {
$txt = substr($txt, $start, $l);
if (($pos = strrpos($txt, ' ')) !== false) {
$txt = substr($txt, 0, $pos);
}
}
if ($start == 0) {
$limiterLeft = '';
}
return $limiterLeft . trim($txt) . $limiterRight;
}
