WP / Comment form custom fields

<?php
add_filter('comment_form_default_fields', 'custom_fields');
function custom_fields($fields) {

        $commenter = wp_get_current_commenter();
        $req = get_option( 'require_name_email' );
        $aria_req = ( $req ? " aria-required='true'" : '' );

        $fields[ 'author' ] = '<p class="comment-form-author">'.
            '<label for="author">' . __( 'Name' ) . '</label>'.
            ( $req ? '<span class="required">*</span>' : '' ).
            '<input id="author" name="author" type="text" value="'. esc_attr( $commenter['comment_author'] ) .
            '" size="30" tabindex="1"' . $aria_req . ' /></p>';

        $fields[ 'email' ] = '<p class="comment-form-email">'.
            '<label for="email">' . __( 'Email' ) . '</label>'.
            ( $req ? '<span class="required">*</span>' : '' ).
            '<input id="email" name="email" type="text" value="'. esc_attr( $commenter['comment_author_email'] ) .
            '" size="30"  tabindex="2"' . $aria_req . ' /></p>';

        $fields[ 'url' ] = '<p class="comment-form-url">'.
            '<label for="url">' . __( 'Website' ) . '</label>'.
            '<input id="url" name="url" type="text" value="'. esc_attr( $commenter['comment_author_url'] ) .
            '" size="30"  tabindex="3" /></p>';

        $fields[ 'phone' ] = '<p class="comment-form-phone">'.
            '<label for="phone">' . __( 'Phone' ) . '</label>'.
            '<input id="phone" name="phone" type="text" size="30"  tabindex="4" /></p>';

    return $fields;
}

add_action( 'comment_form_logged_in_after', 'additional_fields' );
add_action( 'comment_form_after_fields', 'additional_fields' );

function additional_fields () {
    echo '<p class="comment-form-title">'.
    '<label for="title">' . __( 'Comment Title' ) . '</label>'.
    '<input id="title" name="title" type="text" size="30"  tabindex="5" /></p>';

    echo '<p class="comment-form-rating">'.
    '<label for="rating">'. __('Rating') . '<span class="required">*</span></label>
    <span class="commentratingbox">';

        //Current rating scale is 1 to 5. If you want the scale to be 1 to 10, then set the value of $i to 10.
        for( $i=1; $i <= 5; $i++ )
        echo '<span class="commentrating"><input type="radio" name="rating" id="rating" value="'. $i .'"/>'. $i .'</span>';

    echo'</span></p>';

}

add_action( 'comment_post', 'save_comment_meta_data' );
function save_comment_meta_data( $comment_id ) {
    if ( ( isset( $_POST['phone'] ) ) && ( $_POST['phone'] != '') )
    $phone = wp_filter_nohtml_kses($_POST['phone']);
    add_comment_meta( $comment_id, 'phone', $phone );

    if ( ( isset( $_POST['title'] ) ) && ( $_POST['title'] != '') )
    $title = wp_filter_nohtml_kses($_POST['title']);
    add_comment_meta( $comment_id, 'title', $title );

    if ( ( isset( $_POST['rating'] ) ) && ( $_POST['rating'] != '') )
    $rating = wp_filter_nohtml_kses($_POST['rating']);
    add_comment_meta( $comment_id, 'rating', $rating );
}

add_filter( 'preprocess_comment', 'verify_comment_meta_data' );
function verify_comment_meta_data( $commentdata ) {
    if ( ! isset( $_POST['rating'] ) )
    wp_die( __( 'Error: You did not add a rating. Hit the Back button on your Web browser and resubmit your comment with a rating.' ) );
    return $commentdata;
}

add_filter( 'comment_text', 'modify_comment');
function modify_comment( $text ){

    $plugin_url_path = WP_PLUGIN_URL;

    if( $commenttitle = get_comment_meta( get_comment_ID(), 'title', true ) ) {
        $commenttitle = '<strong>' . esc_attr( $commenttitle ) . '</strong><br/>';
        $text = $commenttitle . $text;
    }

    if( $commentrating = get_comment_meta( get_comment_ID(), 'rating', true ) ) {
        $commentrating = '<p class="comment-rating">    <img src="'. $plugin_url_path .
        '/ExtendComment/images/'. $commentrating . 'star.gif"/><br/>Rating: <strong>'. $commentrating .' / 5</strong></p>';
        $text = $text . $commentrating;
        return $text;
    } else {
        return $text;
    }
}

// Add an edit option to comment editing screen

add_action( 'add_meta_boxes_comment', 'extend_comment_add_meta_box' );
function extend_comment_add_meta_box() {
    add_meta_box( 'title', __( 'Comment Metadata - Extend Comment' ), 'extend_comment_meta_box', 'comment', 'normal', 'high' );
}

function extend_comment_meta_box ( $comment ) {
    $phone = get_comment_meta( $comment->comment_ID, 'phone', true );
    $title = get_comment_meta( $comment->comment_ID, 'title', true );
    $rating = get_comment_meta( $comment->comment_ID, 'rating', true );
    wp_nonce_field( 'extend_comment_update', 'extend_comment_update', false );
    ?>
    <p>
        <label for="phone"><?php _e( 'Phone' ); ?></label>
        <input type="text" name="phone" value="<?php echo esc_attr( $phone ); ?>" class="widefat" />
    </p>
    <p>
        <label for="title"><?php _e( 'Comment Title' ); ?></label>
        <input type="text" name="title" value="<?php echo esc_attr( $title ); ?>" class="widefat" />
    </p>
    <p>
        <label for="rating"><?php _e( 'Rating: ' ); ?></label>
            <span class="commentratingbox">
            <?php for( $i=1; $i <= 5; $i++ ) {
                echo '<span class="commentrating"><input type="radio" name="rating" id="rating" value="'. $i .'"';
                if ( $rating == $i ) echo ' checked="checked"';
                echo ' />'. $i .' </span>';
                }
            ?>
            </span>
    </p>
    <?php
}

// Update comment meta data from comment editing screen

add_action( 'edit_comment', 'extend_comment_edit_metafields' );

function extend_comment_edit_metafields( $comment_id ) {
    if( ! isset( $_POST['extend_comment_update'] ) || ! wp_verify_nonce( $_POST['extend_comment_update'], 'extend_comment_update' ) ) return;

    if ( ( isset( $_POST['phone'] ) ) && ( $_POST['phone'] != '') ) :
    $phone = wp_filter_nohtml_kses($_POST['phone']);
    update_comment_meta( $comment_id, 'phone', $phone );
    else :
    delete_comment_meta( $comment_id, 'phone');
    endif;

    if ( ( isset( $_POST['title'] ) ) && ( $_POST['title'] != '') ):
    $title = wp_filter_nohtml_kses($_POST['title']);
    update_comment_meta( $comment_id, 'title', $title );
    else :
    delete_comment_meta( $comment_id, 'title');
    endif;

    if ( ( isset( $_POST['rating'] ) ) && ( $_POST['rating'] != '') ):
    $rating = wp_filter_nohtml_kses($_POST['rating']);
    update_comment_meta( $comment_id, 'rating', $rating );
    else :
    delete_comment_meta( $comment_id, 'rating');
    endif;

}