EDD Create Coupon from Slack - Allow creating a coupon `/coupon $20` or `/coupon 20%` in Slack

edd-create-coupon-slack.php

<?php
/*
Plugin Name: EDD Create Coupon from Slack
Plugin URL: http://gravityview.co
Description: Allow creating a coupon `/coupon [%]` in Slack
Version: 1.0
Author: Katz Web Services, Inc.
Author URI: http://katz.co
Contributors: katzwebservices
*/

/**
 * @return void|bool
 */
function kws_edd_slack_coupon_command() {

	// UPDATE WITH YOUR OWN TOKEN HERE
	$token = 'your-slack-command-token-here';

	# Check to see if a token has been passed as well
	if ( ! isset( $_REQUEST['token'] ) || ( $_REQUEST['token'] !== $token ) ) {
		return false;
	}

	// If just `/coupon` is sent, the default is 20%
	$coupon_amount = isset( $_REQUEST['text'] ) ? esc_attr( $_REQUEST['text'] ) : '20%';

	// Percent by default. Pass $123 for flat amount off
	if( preg_match('/\$/', $coupon_amount ) ) {
		$coupon_amount = str_replace( '$', '', $coupon_amount );
		$coupon_amount = floatval( $coupon_amount );
		$coupon_type = 'flat';
		$coupon_name = '$'.$coupon_amount .' Off';
	} else {
		$coupon_amount = str_replace( '%', '', $coupon_amount );
		$coupon_type = 'percent';
		$coupon_name = $coupon_amount .'% Off';
	}

	# Check that the token is the one that was set in Slack
	if ( $token === $_REQUEST['token'] && !empty( $coupon_amount ) ) {

		$coupon_code = strtoupper( wp_generate_password( 10, false ) );

		$discount_id = kws_edd_slack_create_coupon( $coupon_name, $coupon_code, $coupon_amount, $coupon_type );

		echo 'Discount #'. $discount_id.' created for '.$coupon_name.': '.$coupon_code;

		# We need to exit or you will send a bunch of html that Slack won't be able to handle
		exit();
	}
}

add_action( 'init', 'kws_edd_slack_coupon_command' );

/**
 * @param string $coupon_name
 * @param $coupon_code
 * @param int $amount
 * @param string $type
 * @param string $expiration
 * @return string
 */
function kws_edd_slack_create_coupon( $coupon_name = '', $coupon_code, $amount = 20, $type = 'percent', $expiration = '' ) {

	if( ! is_callable( 'edd_store_discount' ) ) {
		return;
	}

	$meta = array(
		'name'              => $coupon_name,
		'code'              => $coupon_code,
		'type'              => $type, // 'flat' or anything else is 'percent'
		'amount'            => $amount,
		'start'             => '',
		'expiration'        => ( empty( $expiration ) ? date( 'm/d/Y', strtotime("+1 week") ) : '' ),
	);

	$discount_number = edd_store_discount( $meta );

	return $discount_number;
}