reorder / rewrap bbcodes - php

Question

I'm trying to reorder the BBCodes but I failed
so
[̶b̶]̶[̶i̶]̶[̶u̶]̶f̶o̶o̶[̶/̶b̶]̶[̶/̶u̶]̶[̶/̶i̶]̶ ̶-̶ ̶w̶r̶o̶n̶g̶ ̶o̶r̶d̶e̶r̶ ̶ ̶
I̶ ̶w̶a̶n̶t̶ ̶i̶t̶ ̶t̶o̶ ̶b̶e̶:̶ ̶
̶[̶b̶]̶[̶i̶]̶[̶u̶]̶f̶o̶o̶[̶/̶u̶]̶[̶/̶i̶]̶[̶/̶b̶]̶ ̶-̶ ̶r̶i̶g̶h̶t̶ ̶o̶r̶d̶e̶r̶
PIC:
I tried with
<?php
$string = '[b][i][u]foo[/b][/u][/i]';
$search = array('/\[b](.+?)\[\/b]/is', '/\[i](.+?)\[\/i]/is', '/\[u](.+?)\[\/u]/is');
$replace = array('[b]$1[/b]', '[i]$1[/i]', '[u]$1[/u]');
echo preg_replace($search, $replace, $string);
?>
OUTPUT: [b][i][u]foo[/b][/u][/i]
any suggestions ? thanks!

Answer 1

phew, spent awhile thinking of the logic to do this. (feel free to put it in a function)
this only works for the scenario given. Like other users have commented it's impossible. You shouldn't be doing this. Or even on server side. I'd use a client side parser just to throw a syntax error.
supports [b]a[i]b[u]foo[/b]baa[/u]too[/i]
and bbcode with custom values [url=test][i][u]foo[/url][/u][/i]
Will break with
[b] bold [/b][u] underline[/u]
And [b] bold [u][/b] underline[/u]
//input string to be reorganized
$string = '[url=test][i][u]foo[/url][/u][/i]';
echo $string . "<br />";
//search for all opentags (including ones with values
$tagsearch = "/\[([A-Za-z]+)[A-Za-z=._%?&:\/-]*\]/";
preg_match_all($tagsearch, $string, $tags);
//search for all close tags to store them for later
$closetagsearch = "/(\[\/([A-Za-z]+)\])/is";
preg_match_all($closetagsearch, $string, $closetags);
//flip the open tags for reverse parsing (index one is just letters)
$tags[1] = array_reverse($tags[1]);
//create temp var to store new ordered string
$temp = "";
//this is the last known position in the original string after a match
$last = 0;
//iterate through each char of the input string
for ($i = 0, $len = strlen($string); $i < $len; $i++) {
//if we run out of tags to replace/find stop looping
if (empty($tags[1]) || empty($closetags[1]))
continue;
//this is the part of the string that has no matches
$good = substr($string, $last, $i - $last);
//next closing tag to search for
$next = $closetags[1][0];
//how many chars ahead to compare against
$scope = substr($string, $i, strlen($next));
//if we have a match
if ($scope === "$next") {
//add to the temp variable with a modified
//version of an open tag letter to become a close tag
$temp .= $good . substr_replace("[" . $tags[1][0] . "]", "/", 1, 0);
//remove the first key/value in both arrays
array_shift($tags[1]);
array_shift($closetags[1]);
//update the last known unmatched char
$last += strlen($good . $scope);
}
}
echo $temp;
Please also note: it might be the users intention to nest the tags out of order :X