Initial commit
diff --git a/includes/class-wc-stripe-blocks-support.php b/includes/class-wc-stripe-blocks-support.php
new file mode 100644
index 0000000..0aa6fbb
--- /dev/null
+++ b/includes/class-wc-stripe-blocks-support.php
@@ -0,0 +1,417 @@
+<?php
+use Automattic\WooCommerce\Blocks\Payments\Integrations\AbstractPaymentMethodType;
+use Automattic\WooCommerce\Blocks\Payments\PaymentResult;
+use Automattic\WooCommerce\Blocks\Payments\PaymentContext;
+
+defined( 'ABSPATH' ) || exit;
+
+/**
+ * WC_Stripe_Blocks_Support class.
+ *
+ * @extends AbstractPaymentMethodType
+ */
+final class WC_Stripe_Blocks_Support extends AbstractPaymentMethodType {
+	/**
+	 * Payment method name defined by payment methods extending this class.
+	 *
+	 * @var string
+	 */
+	protected $name = 'stripe';
+
+	/**
+	 * The Payment Request configuration class used for Shortcode PRBs. We use it here to retrieve
+	 * the same configurations.
+	 *
+	 * @var WC_Stripe_Payment_Request
+	 */
+	private $payment_request_configuration;
+
+	/**
+	 * Constructor
+	 *
+	 * @param WC_Stripe_Payment_Request  The Stripe Payment Request configuration used for Payment
+	 *                                   Request buttons.
+	 */
+	public function __construct( $payment_request_configuration = null ) {
+		add_action( 'woocommerce_rest_checkout_process_payment_with_context', [ $this, 'add_payment_request_order_meta' ], 8, 2 );
+		add_action( 'woocommerce_rest_checkout_process_payment_with_context', [ $this, 'add_stripe_intents' ], 9999, 2 );
+		$this->payment_request_configuration = null !== $payment_request_configuration ? $payment_request_configuration : new WC_Stripe_Payment_Request();
+	}
+
+	/**
+	 * Initializes the payment method type.
+	 */
+	public function initialize() {
+		$this->settings = get_option( 'woocommerce_stripe_settings', [] );
+	}
+
+	/**
+	 * Returns if this payment method should be active. If false, the scripts will not be enqueued.
+	 *
+	 * @return boolean
+	 */
+	public function is_active() {
+		return ! empty( $this->settings['enabled'] ) && 'yes' === $this->settings['enabled'];
+	}
+
+	/**
+	 * Returns an array of scripts/handles to be registered for this payment method.
+	 *
+	 * @return array
+	 */
+	public function get_payment_method_script_handles() {
+		// Ensure Stripe JS is enqueued
+		wp_register_script(
+			'stripe',
+			'https://js.stripe.com/v3/',
+			[],
+			'3.0',
+			true
+		);
+
+		if ( WC_Stripe_Feature_Flags::is_upe_checkout_enabled() ) {
+			$this->register_upe_payment_method_script_handles();
+		} else {
+			$this->register_legacy_payment_method_script_handles();
+		}
+
+		return [ 'wc-stripe-blocks-integration' ];
+	}
+
+	/**
+	 * Registers the UPE JS scripts.
+	 */
+	private function register_upe_payment_method_script_handles() {
+		$asset_path   = WC_STRIPE_PLUGIN_PATH . '/build/upe_blocks.asset.php';
+		$version      = WC_STRIPE_VERSION;
+		$dependencies = [];
+		if ( file_exists( $asset_path ) ) {
+			$asset        = require $asset_path;
+			$version      = is_array( $asset ) && isset( $asset['version'] )
+				? $asset['version']
+				: $version;
+			$dependencies = is_array( $asset ) && isset( $asset['dependencies'] )
+				? $asset['dependencies']
+				: $dependencies;
+		}
+
+		wp_enqueue_style(
+			'wc-stripe-blocks-checkout-style',
+			WC_STRIPE_PLUGIN_URL . '/build/upe_blocks.css',
+			[],
+			$version
+		);
+
+		wp_register_script(
+			'wc-stripe-blocks-integration',
+			WC_STRIPE_PLUGIN_URL . '/build/upe_blocks.js',
+			array_merge( [ 'stripe' ], $dependencies ),
+			$version,
+			true
+		);
+		wp_set_script_translations(
+			'wc-stripe-blocks-integration',
+			'woocommerce-gateway-stripe'
+		);
+	}
+
+	/**
+	 * Registers the classic JS scripts.
+	 */
+	private function register_legacy_payment_method_script_handles() {
+		$asset_path   = WC_STRIPE_PLUGIN_PATH . '/build/index.asset.php';
+		$version      = WC_STRIPE_VERSION;
+		$dependencies = [];
+		if ( file_exists( $asset_path ) ) {
+			$asset        = require $asset_path;
+			$version      = is_array( $asset ) && isset( $asset['version'] )
+				? $asset['version']
+				: $version;
+			$dependencies = is_array( $asset ) && isset( $asset['dependencies'] )
+				? $asset['dependencies']
+				: $dependencies;
+		}
+		wp_register_script(
+			'wc-stripe-blocks-integration',
+			WC_STRIPE_PLUGIN_URL . '/build/index.js',
+			array_merge( [ 'stripe' ], $dependencies ),
+			$version,
+			true
+		);
+		wp_set_script_translations(
+			'wc-stripe-blocks-integration',
+			'woocommerce-gateway-stripe'
+		);
+	}
+
+	/**
+	 * Returns an array of key=>value pairs of data made available to the payment methods script.
+	 *
+	 * @return array
+	 */
+	public function get_payment_method_data() {
+		// We need to call array_merge_recursive so the blocks 'button' setting doesn't overwrite
+		// what's provided from the gateway or payment request configuration.
+		return array_replace_recursive(
+			$this->get_gateway_javascript_params(),
+			$this->get_payment_request_javascript_params(),
+			// Blocks-specific options
+			[
+				'icons'                          => $this->get_icons(),
+				'supports'                       => $this->get_supported_features(),
+				'showSavedCards'                 => $this->get_show_saved_cards(),
+				'showSaveOption'                 => $this->get_show_save_option(),
+				'isAdmin'                        => is_admin(),
+				'shouldShowPaymentRequestButton' => $this->should_show_payment_request_button(),
+				'button'                         => [
+					'customLabel' => $this->payment_request_configuration->get_button_label(),
+				],
+			]
+		);
+	}
+
+	/**
+	 * Returns true if the PRB should be shown on the current page, false otherwise.
+	 *
+	 * Note: We use `has_block()` in this function, which isn't supported until WP 5.0. However,
+	 * WooCommerce Blocks hasn't supported a WP version lower than 5.0 since 2019. Since this
+	 * function is only called when the WooCommerce Blocks extension is available, it should be
+	 * safe to call `has_block()` here.
+	 * That said, we only run those checks if the `has_block()` function exists, just in case.
+	 *
+	 * @return boolean  True if PRBs should be displayed, false otherwise
+	 */
+	private function should_show_payment_request_button() {
+		// TODO: Remove the `function_exists()` check once the minimum WP version has been bumped
+		//       to version 5.0.
+		if ( function_exists( 'has_block' ) ) {
+			// Don't show if PRBs are supposed to be hidden on the cart page.
+			if (
+				has_block( 'woocommerce/cart' )
+				&& ! $this->payment_request_configuration->should_show_prb_on_cart_page()
+			) {
+				return false;
+			}
+
+			// Don't show if PRBs are supposed to be hidden on the checkout page.
+			if (
+				has_block( 'woocommerce/checkout' )
+				&& ! $this->payment_request_configuration->should_show_prb_on_checkout_page()
+			) {
+				return false;
+			}
+
+			// Don't show PRB if there are unsupported products in the cart.
+			if (
+				( has_block( 'woocommerce/checkout' ) || has_block( 'woocommerce/cart' ) )
+				&& ! $this->payment_request_configuration->allowed_items_in_cart()
+			) {
+				return false;
+			}
+		}
+
+		return $this->payment_request_configuration->should_show_payment_request_button();
+	}
+
+	/**
+	 * Returns the Stripe Payment Gateway JavaScript configuration object.
+	 *
+	 * @return array  the JS configuration from the Stripe Payment Gateway.
+	 */
+	private function get_gateway_javascript_params() {
+		$js_configuration = [];
+
+		$gateways = WC()->payment_gateways->get_available_payment_gateways();
+		if ( isset( $gateways['stripe'] ) ) {
+			$js_configuration = $gateways['stripe']->javascript_params();
+		}
+
+		return apply_filters(
+			'wc_stripe_params',
+			$js_configuration
+		);
+	}
+
+	/**
+	 * Returns the Stripe Payment Request JavaScript configuration object.
+	 *
+	 * @return array  the JS configuration for Stripe Payment Requests.
+	 */
+	private function get_payment_request_javascript_params() {
+		return apply_filters(
+			'wc_stripe_payment_request_params',
+			$this->payment_request_configuration->javascript_params()
+		);
+	}
+
+	/**
+	 * Determine if store allows cards to be saved during checkout.
+	 *
+	 * @return bool True if merchant allows shopper to save card (payment method) during checkout.
+	 */
+	private function get_show_saved_cards() {
+		return isset( $this->settings['saved_cards'] ) ? 'yes' === $this->settings['saved_cards'] : false;
+	}
+
+	/**
+	 * Determine if the checkbox to enable the user to save their payment method should be shown.
+	 *
+	 * @return bool True if the save payment checkbox should be displayed to the user.
+	 */
+	private function get_show_save_option() {
+		$saved_cards = $this->get_show_saved_cards();
+		// This assumes that Stripe supports `tokenization` - currently this is true, based on
+		// https://github.com/woocommerce/woocommerce-gateway-stripe/blob/master/includes/class-wc-gateway-stripe.php#L95 .
+		// See https://github.com/woocommerce/woocommerce-gateway-stripe/blob/ad19168b63df86176cbe35c3e95203a245687640/includes/class-wc-gateway-stripe.php#L271 and
+		// https://github.com/woocommerce/woocommerce/wiki/Payment-Token-API .
+		return apply_filters( 'wc_stripe_display_save_payment_method_checkbox', filter_var( $saved_cards, FILTER_VALIDATE_BOOLEAN ) );
+	}
+
+	/**
+	 * Returns the title string to use in the UI (customisable via admin settings screen).
+	 *
+	 * @return string Title / label string
+	 */
+	private function get_title() {
+		return isset( $this->settings['title'] ) ? $this->settings['title'] : __( 'Credit / Debit Card', 'woocommerce-gateway-stripe' );
+	}
+
+	/**
+	 * Return the icons urls.
+	 *
+	 * @return array Arrays of icons metadata.
+	 */
+	private function get_icons() {
+		$icons_src = [
+			'visa'       => [
+				'src' => WC_STRIPE_PLUGIN_URL . '/assets/images/visa.svg',
+				'alt' => __( 'Visa', 'woocommerce-gateway-stripe' ),
+			],
+			'amex'       => [
+				'src' => WC_STRIPE_PLUGIN_URL . '/assets/images/amex.svg',
+				'alt' => __( 'American Express', 'woocommerce-gateway-stripe' ),
+			],
+			'mastercard' => [
+				'src' => WC_STRIPE_PLUGIN_URL . '/assets/images/mastercard.svg',
+				'alt' => __( 'Mastercard', 'woocommerce-gateway-stripe' ),
+			],
+		];
+
+		if ( 'USD' === get_woocommerce_currency() ) {
+			$icons_src['discover'] = [
+				'src' => WC_STRIPE_PLUGIN_URL . '/assets/images/discover.svg',
+				'alt' => __( 'Discover', 'woocommerce-gateway-stripe' ),
+			];
+			$icons_src['jcb']      = [
+				'src' => WC_STRIPE_PLUGIN_URL . '/assets/images/jcb.svg',
+				'alt' => __( 'JCB', 'woocommerce-gateway-stripe' ),
+			];
+			$icons_src['diners']   = [
+				'src' => WC_STRIPE_PLUGIN_URL . '/assets/images/diners.svg',
+				'alt' => __( 'Diners', 'woocommerce-gateway-stripe' ),
+			];
+		}
+		return $icons_src;
+	}
+
+	/**
+	 * Add payment request data to the order meta as hooked on the
+	 * woocommerce_rest_checkout_process_payment_with_context action.
+	 *
+	 * @param PaymentContext $context Holds context for the payment.
+	 * @param PaymentResult  $result  Result object for the payment.
+	 */
+	public function add_payment_request_order_meta( PaymentContext $context, PaymentResult &$result ) {
+		$data = $context->payment_data;
+		if ( ! empty( $data['payment_request_type'] ) && 'stripe' === $context->payment_method ) {
+			$this->add_order_meta( $context->order, $data['payment_request_type'] );
+		}
+
+		// hook into stripe error processing so that we can capture the error to
+		// payment details (which is added to notices and thus not helpful for
+		// this context).
+		if ( 'stripe' === $context->payment_method ) {
+			add_action(
+				'wc_gateway_stripe_process_payment_error',
+				function( $error ) use ( &$result ) {
+					$payment_details                 = $result->payment_details;
+					$payment_details['errorMessage'] = wp_strip_all_tags( $error->getLocalizedMessage() );
+					$result->set_payment_details( $payment_details );
+				}
+			);
+		}
+	}
+
+	/**
+	 * Handles any potential stripe intents on the order that need handled.
+	 *
+	 * This is configured to execute after legacy payment processing has
+	 * happened on the woocommerce_rest_checkout_process_payment_with_context
+	 * action hook.
+	 *
+	 * @param PaymentContext $context Holds context for the payment.
+	 * @param PaymentResult  $result  Result object for the payment.
+	 */
+	public function add_stripe_intents( PaymentContext $context, PaymentResult &$result ) {
+		if ( 'stripe' === $context->payment_method
+			&& (
+				! empty( $result->payment_details['payment_intent_secret'] )
+				|| ! empty( $result->payment_details['setup_intent_secret'] )
+			)
+		) {
+			$payment_details       = $result->payment_details;
+			$verification_endpoint = add_query_arg(
+				[
+					'order'       => $context->order->get_id(),
+					'nonce'       => wp_create_nonce( 'wc_stripe_confirm_pi' ),
+					'redirect_to' => rawurlencode( $result->redirect_url ),
+				],
+				home_url() . \WC_Ajax::get_endpoint( 'wc_stripe_verify_intent' )
+			);
+
+			if ( ! empty( $payment_details['save_payment_method'] ) ) {
+				$verification_endpoint = add_query_arg(
+					[ 'save_payment_method' => true ],
+					$verification_endpoint
+				);
+			}
+
+			$payment_details['verification_endpoint'] = $verification_endpoint;
+			$result->set_payment_details( $payment_details );
+			$result->set_status( 'success' );
+		}
+	}
+
+	/**
+	 * Handles adding information about the payment request type used to the order meta.
+	 *
+	 * @param \WC_Order $order The order being processed.
+	 * @param string    $payment_request_type The payment request type used for payment.
+	 */
+	private function add_order_meta( \WC_Order $order, $payment_request_type ) {
+		if ( 'apple_pay' === $payment_request_type ) {
+			$order->set_payment_method_title( 'Apple Pay (Stripe)' );
+			$order->save();
+		} elseif ( 'google_pay' === $payment_request_type ) {
+			$order->set_payment_method_title( 'Google Pay (Stripe)' );
+			$order->save();
+		} elseif ( 'payment_request_api' === $payment_request_type ) {
+			$order->set_payment_method_title( 'Payment Request (Stripe)' );
+			$order->save();
+		}
+	}
+
+	/**
+	 * Returns an array of supported features.
+	 *
+	 * @return string[]
+	 */
+	public function get_supported_features() {
+		$gateways = WC()->payment_gateways->get_available_payment_gateways();
+		if ( isset( $gateways['stripe'] ) ) {
+			$gateway = $gateways['stripe'];
+			return array_filter( $gateway->supports, [ $gateway, 'supports' ] );
+		}
+		return [];
+	}
+}