Add 'get_supported_currencies' function for klarna (#3378)

* add 'get_supported_currencies' function for klarna

* add comment

* add safety check

Author: Mayisha

changelog.txt

@@ -24,6 +24,7 @@
 * Fix - Address QIT PHPStan test errors.
 * Update - Specify the JS Stripe API version as 2024-06-20.
 * Fix - Ensure payment tokens are detached from Stripe when a user is deleted, regardless of if the admin user has a Stripe account.
+* Fix - Address Klarna availability based on correct presentment currency rules.
 
 = 8.6.1 - 2024-08-09 =
 * Tweak - Improves the wording of the invalid Stripe keys errors, instructing merchants to click the "Configure connection" button instead of manually setting the keys.

includes/payment-methods/class-wc-stripe-upe-payment-method-klarna.php

@@ -82,6 +82,39 @@ public function get_available_billing_countries() {
 		return parent::get_available_billing_countries();
 	}
 
+	/**
+	 * Returns the currencies this UPE method supports for the Stripe account.
+	 *
+	 * Klarna has unique requirements for domestic transactions. The customer must be located in the same country as the merchant's Stripe account and the currency must match.
+	 * - Stores connected to US account and presenting USD can only transact with customers located in the US.
+	 * - Stores connected to US account and presenting non-USD currency can not transact with customers irrespective of their location.
+	 *
+	 * Additionally, if the merchant is in the EEA, the country they can transact with depends on the presentment currency.
+	 * EUR stores can transact with other EUR countries. Stores with currencies like GBP, CHF, etc. can only transact with customers located in those countries.
+	 * This creates the following unique situations:
+	 *  - Stores presenting EUR, with a Stripe account in any EEA country including Switzerland or the UK can transact with countries where Euros are the standard currency: AT, BE, FI, FR, GR, DE, IE, IT, NL, PT, ES.
+	 *  - Stores presenting GBP with a Stripe account in any EEA country including Switzerland or the UK can transact with: GB.
+	 *  - Stores presenting NOK with a Stripe account in France, for example, cannot sell into France. They can only sell into Norway.
+	 *
+	 * @return array Supported currencies.
+	 */
+	public function get_supported_currencies() {
+		$account         = WC_Stripe::get_instance()->account->get_cached_account_data();
+		$account_country = strtoupper( $account['country'] ?? '' );
+
+		// Countries in the EEA + UK and Switzerland can transact across all other EEA countries as long as the currency matches.
+		$eea_countries = array_merge( WC_Stripe_Helper::get_european_economic_area_countries(), [ 'CH', 'GB' ] );
+
+		// Countries outside the EEA can only transact with customers in their own currency.
+		if ( ! in_array( $account_country, $eea_countries, true ) ) {
+			return [ strtoupper( $account['default_currency'] ?? '' ) ];
+		}
+
+		// Stripe account in EEA + UK and Switzerland can present the following as store currencies.
+		// EEA currencies can only transact with countries where that currency is the standard currency.
+		return [ 'CHF', 'CZK', 'DKK', 'EUR', 'GBP', 'NOK', 'PLN', 'SEK' ];
+	}
+
 	/**
 	 * Returns whether the payment method is available for the Stripe account's country.
 	 *

readme.txt

@@ -152,5 +152,6 @@ If you get stuck, you can ask for help in the Plugin Forum.
 * Fix - Address QIT PHPStan test errors.
 * Update - Specify the JS Stripe API version as 2024-06-20.
 * Fix - Ensure payment tokens are detached from Stripe when a user is deleted, regardless of if the admin user has a Stripe account.
+* Fix - Address Klarna availability based on correct presentment currency rules.
 
 [See changelog for all versions](https://raw.githubusercontent.com/woocommerce/woocommerce-gateway-stripe/trunk/changelog.txt).

tests/phpunit/test-class-wc-stripe-upe-payment-method.php

@@ -525,6 +525,20 @@ public function test_payment_methods_with_domestic_restrictions_are_disabled_on_
 	 */
 	public function test_payment_methods_with_domestic_restrictions_are_enabled_on_currency_match() {
 		WC_Stripe_Helper::update_main_stripe_settings( [ 'testmode' => 'yes' ] );
+		WC_Stripe::get_instance()->account = $this->getMockBuilder( 'WC_Stripe_Account' )
+				->disableOriginalConstructor()
+				->setMethods(
+					[
+						'get_cached_account_data',
+					]
+				)
+				->getMock();
+		WC_Stripe::get_instance()->account->method( 'get_cached_account_data' )->willReturn(
+			[
+				'country' => 'US',
+				'default_currency' => 'USD',
+			]
+		);
 
 		$this->set_mock_payment_method_return_value( 'get_woocommerce_currency', 'USD', true );