myCRED to myCRED Coupon

/**
 * Convert myCRED Points into myCRED Coupon
 * Requires myCRED 1.5 or higher!
 * @version 1.1
 */
add_shortcode( 'mycred_to_mycred_coupon', 'mycred_pro_render_points_to_mycred_coupon' );
function mycred_pro_render_points_to_mycred_coupon( $atts, $content = NULL ) {

    // Users must be logged in
    if ( ! is_user_logged_in() )
        return 'You must be logged in to generate store coupons.';

    // myCRED must be enabled
    if ( ! function_exists( 'mycred_get_unique_coupon_code' ) )
        return 'myCRED must be enabled to use this shortcode';

    extract( shortcode_atts( array(
        'min'          => 1,
        'type'         => 'mycred_default',
        'button_label' => 'Create Coupon'
    ), $atts ) );

    // Load myCRED
    $mycred = mycred( $type );

    // Prep
    $error   = $code = false;
    $output  = '';
    $user_id = get_current_user_id();

    // No need to show this for excluded users
    if ( $mycred->exclude_user( $user_id ) ) return;

    $balance = $mycred->get_users_balance( $user_id );

    // Minimum
    if ( $mycred->amount( $min ) > 0 && $balance < $mycred->amount( $min ) )
        return '<o>You are required to have at least 1 point.</p>';

    // Form submission
    if ( isset( $_POST['mycred_to_mycred'] ) && wp_verify_nonce( $_POST['mycred_to_mycred']['token'], 'points-to-mycred-coupon' ) ) {

        // Make sure amounts are always positive
        $amount = abs( $_POST['mycred_to_mycred']['amount'] );
        $amount = $mycred->number( $amount );

        // Make sure amount is not zero
        if ( $amount == $mycred->zero() )
            $error = 'Amount can not be zero';

        if ( $amount < $mycred->number( $min ) )
            $error = 'You must convert minimum 1 point!';

        // Make sure user has enough points
        if ( $amount > $balance )
            $error = 'Insufficient Funds. Please try a lower amount';

        // If no errors
        if ( $error === false ) {

            // Create myCRED Coupon
            $code          = mycred_get_unique_coupon_code();
            $new_coupon_id = mycred_create_new_coupon( array(
                'code'        => $code,
                'value'       => $amount,
                'global_max'  => 1,
                'user_max'    => 1,
                'min_balance' => 0,
                'max_balance' => 0,
                'expires'     => ''
            ) );

            // Deduct points from user
            $mycred->add_creds(
                'points_to_coupon',
                $user_id,
                0-$amount,
                '%plural% conversion into store coupon: %post_title%',
                $new_coupon_id,
                array( 'ref_type' => 'post', 'code' => $code ),
                $type
            );

            $balance = $balance-$amount;
            $balance = $mycred->number( $balance );

            // Send coupon as an email just in case
            $user = wp_get_current_user();
            wp_mail( $user->user_email, 'Your Coupon Code', 'This is your new store coupon code: ' . $code );

        }

    }

    // Show users current balance
    $output .= '
<p>Your current balance is: ' . $mycred->format_creds( $balance ) . '</p>';

    // Error
    if ( $error !== false )
        $output .= '<p style="color:red;">' . $error . '</p>';

    // Success
    elseif ( $code !== false )
        $output .= '<p>Your coupon code is: <strong>' . $code . '</strong></p>';

    // The form for those who have points
    if ( $balance > $mycred->zero() )
        $output .= '
<form action="" method="post">
    <input type="hidden" name="mycred_to_mycred[token]" value="' . wp_create_nonce( 'points-to-mycred-coupon' ) . '" />
    <label>Amount</label>
    <input type="text" size="5" name="mycred_to_mycred[amount]" value="" />
    <input type="submit" name="submit" value="' . $button_label . '" />
</form>';

    // Not enough points
    else
        $output .= '<p>Not enough points to create coupons.</p>';

    return $output;
}