<?php
/**
 * Sanitizes a title, replacing whitespace and a few other characters with dashes.
 *
 * Limits the output to alphanumeric characters, underscore (_) and dash (-).
 * Whitespace becomes a dash.
 *
 * @since 1.2.0
 *
 * @param string $title     The title to be sanitized.
 * @param string $raw_title Optional. Not used.
 * @param string $context   Optional. The operation for which the string is sanitized.
 * @return string The sanitized title.
 */
function sanitize_title_with_dashes( $title, $raw_title = '', $context = 'display' ) {
    $title = strip_tags( $title );
    // Preserve escaped octets.
    $title = preg_replace( '|%([a-fA-F0-9][a-fA-F0-9])|', '---$1---', $title );
    // Remove percent signs that are not part of an octet.
    $title = str_replace( '%', '', $title );
    // Restore octets.
    $title = preg_replace( '|---([a-fA-F0-9][a-fA-F0-9])---|', '%$1', $title );

    if ( seems_utf8( $title ) ) {
        if ( function_exists( 'mb_strtolower' ) ) {
            $title = mb_strtolower( $title, 'UTF-8' );
        }
        $title = utf8_uri_encode( $title, 200 );
    }

    $title = strtolower( $title );

    if ( 'save' == $context ) {
        // Convert nbsp, ndash and mdash to hyphens
        $title = str_replace( array( '%c2%a0', '%e2%80%93', '%e2%80%94' ), '-', $title );
        // Convert nbsp, ndash and mdash HTML entities to hyphens
        $title = str_replace( array( '&nbsp;', '&#160;', '&ndash;', '&#8211;', '&mdash;', '&#8212;' ), '-', $title );
        // Convert forward slash to hyphen
        $title = str_replace( '/', '-', $title );

        // Strip these characters entirely
        $title = str_replace(
            array(
                // soft hyphens
                '%c2%ad',
                // iexcl and iquest
                '%c2%a1',
                '%c2%bf',
                // angle quotes
                '%c2%ab',
                '%c2%bb',
                '%e2%80%b9',
                '%e2%80%ba',
                // curly quotes
                '%e2%80%98',
                '%e2%80%99',
                '%e2%80%9c',
                '%e2%80%9d',
                '%e2%80%9a',
                '%e2%80%9b',
                '%e2%80%9e',
                '%e2%80%9f',
                // copy, reg, deg, hellip and trade
                '%c2%a9',
                '%c2%ae',
                '%c2%b0',
                '%e2%80%a6',
                '%e2%84%a2',
                // acute accents
                '%c2%b4',
                '%cb%8a',
                '%cc%81',
                '%cd%81',
                // grave accent, macron, caron
                '%cc%80',
                '%cc%84',
                '%cc%8c',
            ),
            '',
            $title
        );

        // Convert times to x
        $title = str_replace( '%c3%97', 'x', $title );
    }

    $title = preg_replace( '/&.+?;/', '', $title ); // kill entities
    $title = str_replace( '.', '-', $title );

    $title = preg_replace( '/[^%a-z0-9 _-]/', '', $title );
    $title = preg_replace( '/\s+/', '-', $title );
    $title = preg_replace( '|-+|', '-', $title );
    $title = trim( $title, '-' );

    return $title;
}