recurring-edd.php

<?php
  /**
	 * Retrieve the plan ID for an item in the cart
	 *
	 * @access      public
	 * @since       2.4
	 * @return      string
	 */
	public function get_plan_id( $subscription = array() ) {

		$name = get_post_field( 'post_name', $subscription['id'] );

		if( isset( $subscription['price_id'] ) && false !== $subscription['price_id'] ) {

			$name .= ' - ' . edd_get_price_option_name( $subscription['id'], $subscription['price_id'] );

		}

		$plan_id = $name . '_' . $subscription['recurring_amount'] . '_' . $subscription['period'];
		$plan_id = sanitize_key( $plan_id );

		try {

			$plan     = \Stripe\Plan::retrieve( $plan_id );
			$currency = strtolower( edd_get_currency() );

			if( $plan->currency != $currency ) {

				$plan_id = $plan_id . '_' . $currency;
				$args    = $this->get_plan_args( $subscription, $name, $plan_id );

				try {

					$plan    = \Stripe\Plan::retrieve( $plan_id );
					$plan_id = is_array( $plan ) ? $plan['id'] : $plan->id;

				} catch ( Exception $e ) {

					$plan_id = $this->create_stripe_plan( $args );

				}

			}

		} catch ( Exception $e ) {

			$args = $this->get_plan_args( $subscription, $name, $plan_id );
			$plan_id = $this->create_stripe_plan( $args );

		}

		return $plan_id;

	}