<?php
/**
 * Class UPE_Payment_Gateway
 *
 * @package WCPay\Payment_Methods
 */

namespace WCPay\Payment_Methods;

use Exception;
use WCPay\Constants\Order_Status;
use WCPay\Constants\Payment_Intent_Status;
use WCPay\Constants\Payment_Method;
use WCPay\Constants\Payment_Type;
use WCPay\Exceptions\Amount_Too_Small_Exception;
use WCPay\Exceptions\Add_Payment_Method_Exception;
use WCPay\Exceptions\Process_Payment_Exception;
use WCPay\Fraud_Prevention\Fraud_Prevention_Service;
use WCPay\Logger;
use WCPay\Payment_Information;
use WCPay\Session_Rate_Limiter;
use WC_Order;
use WC_Payments;
use WC_Payments_Account;
use WC_Payments_Action_Scheduler_Service;
use WC_Payments_API_Client;
use WC_Payments_Customer_Service;
use WC_Payments_Explicit_Price_Formatter;
use WC_Payment_Gateway_WCPay;
use WC_Payments_Order_Service;
use WC_Payment_Token_CC;
use WC_Payments_Token_Service;
use WC_Payment_Token_WCPay_SEPA;
use WC_Payments_Utils;
use WP_User;



/**
 * UPE Payment method extended from WCPay generic Gateway.
 */
class UPE_Payment_Gateway extends WC_Payment_Gateway_WCPay {
	/**
	 * Internal ID of the payment gateway.
	 *
	 * @type string
	 */
	const GATEWAY_ID = 'woocommerce_payments';

	const METHOD_ENABLED_KEY = 'enabled';

	const UPE_APPEARANCE_TRANSIENT = 'wcpay_upe_appearance';

	const WC_BLOCKS_UPE_APPEARANCE_TRANSIENT = 'wcpay_wc_blocks_upe_appearance';

	const KEY_UPE_PAYMENT_INTENT = 'wcpay_upe_payment_intent';

	const KEY_UPE_SETUP_INTENT = 'wcpay_upe_setup_intent';

	/**
	 * Array mapping payment method string IDs to classes
	 *
	 * @var UPE_Payment_Method[]
	 */
	protected $payment_methods = [];

	/**
	 * Generic gateway title to be displayed at checkout, if more than one payment method is enabled.
	 *
	 * @var string
	 */
	protected $checkout_title;

	/**
	 * UPE Constructor same parameters as WC_Payment_Gateway_WCPay constructor.
	 *
	 * @param WC_Payments_API_Client               $payments_api_client             - WooCommerce Payments API client.
	 * @param WC_Payments_Account                  $account                         - Account class instance.
	 * @param WC_Payments_Customer_Service         $customer_service                - Customer class instance.
	 * @param WC_Payments_Token_Service            $token_service                   - Token class instance.
	 * @param WC_Payments_Action_Scheduler_Service $action_scheduler_service        - Action Scheduler service instance.
	 * @param array                                $payment_methods                 - Array of UPE payment methods.
	 * @param Session_Rate_Limiter                 $failed_transaction_rate_limiter - Session Rate Limiter instance.
	 * @param WC_Payments_Order_Service            $order_service                   - Order class instance.
	 */
	public function __construct(
		WC_Payments_API_Client $payments_api_client,
		WC_Payments_Account $account,
		WC_Payments_Customer_Service $customer_service,
		WC_Payments_Token_Service $token_service,
		WC_Payments_Action_Scheduler_Service $action_scheduler_service,
		array $payment_methods,
		Session_Rate_Limiter $failed_transaction_rate_limiter,
		WC_Payments_Order_Service $order_service
	) {
		parent::__construct( $payments_api_client, $account, $customer_service, $token_service, $action_scheduler_service, $failed_transaction_rate_limiter, $order_service );
		$this->title           = __( 'WooCommerce Payments', 'woocommerce-payments' );
		$this->description     = '';
		$this->checkout_title  = __( 'Popular payment methods', 'woocommerce-payments' );
		$this->payment_methods = $payment_methods;

		add_action( 'wc_ajax_wcpay_create_payment_intent', [ $this, 'create_payment_intent_ajax' ] );
		add_action( 'wc_ajax_wcpay_update_payment_intent', [ $this, 'update_payment_intent_ajax' ] );
		add_action( 'wc_ajax_wcpay_init_setup_intent', [ $this, 'init_setup_intent_ajax' ] );
		add_action( 'wc_ajax_wcpay_log_payment_error', [ $this, 'log_payment_error_ajax' ] );

		add_action( 'wp_ajax_save_upe_appearance', [ $this, 'save_upe_appearance_ajax' ] );
		add_action( 'wp_ajax_nopriv_save_upe_appearance', [ $this, 'save_upe_appearance_ajax' ] );
		add_action( 'switch_theme', [ $this, 'clear_upe_appearance_transient' ] );
		add_action( 'woocommerce_woocommerce_payments_updated', [ $this, 'clear_upe_appearance_transient' ] );

		add_action( 'wp', [ $this, 'maybe_process_upe_redirect' ] );

		if ( ! is_admin() ) {
			add_filter( 'woocommerce_gateway_title', [ $this, 'maybe_filter_gateway_title' ], 10, 2 );
		}

		add_action( 'woocommerce_order_payment_status_changed', [ __CLASS__, 'remove_upe_payment_intent_from_session' ], 10, 0 );
		add_action( 'woocommerce_after_account_payment_methods', [ $this, 'remove_upe_setup_intent_from_session' ], 10, 0 );
		add_action( 'woocommerce_subscription_payment_method_updated', [ $this, 'remove_upe_setup_intent_from_session' ], 10, 0 );
	}

	/**
	 * Registers all scripts, necessary for the gateway.
	 */
	public function register_scripts() {
		// Register Stripe's JavaScript using the same ID as the Stripe Gateway plugin. This prevents this JS being
		// loaded twice in the event a site has both plugins enabled. We still run the risk of different plugins
		// loading different versions however. If Stripe release a v4 of their JavaScript, we could consider
		// changing the ID to stripe_v4. This would allow older plugins to keep using v3 while we used any new
		// feature in v4. Stripe have allowed loading of 2 different versions of stripe.js in the past (
		// https://stripe.com/docs/stripe-js/elements/migrating).
		wp_register_script(
			'stripe',
			'https://js.stripe.com/v3/',
			[],
			'3.0',
			true
		);

		$script_dependencies = [ 'stripe', 'wc-checkout', 'wp-i18n' ];

		if ( $this->supports( 'tokenization' ) ) {
			$script_dependencies[] = 'woocommerce-tokenization-form';
		}

		wp_register_script(
			'wcpay-upe-checkout',
			plugins_url( 'dist/upe_checkout.js', WCPAY_PLUGIN_FILE ),
			$script_dependencies,
			WC_Payments::get_file_version( 'dist/upe_checkout.js' ),
			true
		);
	}

	/**
	 * Handle AJAX request for updating a payment intent for Stripe UPE.
	 *
	 * @throws Process_Payment_Exception - If nonce or setup intent is invalid.
	 */
	public function update_payment_intent_ajax() {
		try {
			$is_nonce_valid = check_ajax_referer( 'wcpay_update_payment_intent_nonce', false, false );
			if ( ! $is_nonce_valid ) {
				throw new Process_Payment_Exception(
					__( "We're not able to process this payment. Please refresh the page and try again.", 'woocommerce-payments' ),
					'wcpay_upe_intent_error'
				);
			}

			$order_id                  = isset( $_POST['wcpay_order_id'] ) ? absint( $_POST['wcpay_order_id'] ) : null;
			$payment_intent_id         = isset( $_POST['wc_payment_intent_id'] ) ? wc_clean( wp_unslash( $_POST['wc_payment_intent_id'] ) ) : '';
			$fingerprint               = isset( $_POST['wcpay-fingerprint'] ) ? wc_clean( wp_unslash( $_POST['wcpay-fingerprint'] ) ) : '';
			$save_payment_method       = isset( $_POST['save_payment_method'] ) ? 'yes' === wc_clean( wp_unslash( $_POST['save_payment_method'] ) ) : false;
			$selected_upe_payment_type = ! empty( $_POST['wcpay_selected_upe_payment_type'] ) ? wc_clean( wp_unslash( $_POST['wcpay_selected_upe_payment_type'] ) ) : '';
			$payment_country           = ! empty( $_POST['wcpay_payment_country'] ) ? wc_clean( wp_unslash( $_POST['wcpay_payment_country'] ) ) : null;

			wp_send_json_success( $this->update_payment_intent( $payment_intent_id, $order_id, $save_payment_method, $selected_upe_payment_type, $payment_country, $fingerprint ), 200 );
		} catch ( Exception $e ) {
			// Send back error so it can be displayed to the customer.
			wp_send_json_error(
				[
					'error' => [
						'message' => WC_Payments_Utils::get_filtered_error_message( $e ),
					],
				]
			);
		}
	}

	/**
	 * Updates payment intent to be able to save payment method.
	 *
	 * @param string  $payment_intent_id         The id of the payment intent to update.
	 * @param int     $order_id                  The id of the order if intent created from Order.
	 * @param boolean $save_payment_method       True if saving the payment method.
	 * @param string  $selected_upe_payment_type The name of the selected UPE payment type or empty string.
	 * @param ?string $payment_country           The payment two-letter iso country code or null.
	 *
	 * @return array|null An array with result of the update, or nothing
	 */
	public function update_payment_intent( $payment_intent_id = '', $order_id = null, $save_payment_method = false, $selected_upe_payment_type = '', $payment_country = null ) {
		$order = wc_get_order( $order_id );
		if ( ! is_a( $order, 'WC_Order' ) ) {
			return;
		}

		$check_session_order = $this->check_against_session_processing_order( $order );
		if ( is_array( $check_session_order ) ) {
			return $check_session_order;
		}
		$this->maybe_update_session_processing_order( $order_id );

		$check_existing_intention = $this->check_payment_intent_attached_to_order_succeeded( $order );
		if ( is_array( $check_existing_intention ) ) {
			return $check_existing_intention;
		}

		$amount   = $order->get_total();
		$currency = $order->get_currency();

		if ( $payment_intent_id ) {
			list( $user, $customer_id ) = $this->manage_customer_details_for_order( $order );
			$payment_type               = $this->is_payment_recurring( $order_id ) ? Payment_Type::RECURRING() : Payment_Type::SINGLE();

			$this->payments_api_client->update_intention(
				$payment_intent_id,
				WC_Payments_Utils::prepare_amount( $amount, $currency ),
				strtolower( $currency ),
				$save_payment_method,
				$customer_id,
				$this->get_metadata_from_order( $order, $payment_type ),
				$this->get_level3_data_from_order( $order ),
				$selected_upe_payment_type,
				$payment_country
			);
		}

		return [
			'success' => true,
		];
	}

	/**
	 * Handle AJAX request for creating a payment intent for Stripe UPE.
	 *
	 * @throws Process_Payment_Exception - If nonce or setup intent is invalid.
	 */
	public function create_payment_intent_ajax() {
		try {
			$is_nonce_valid = check_ajax_referer( 'wcpay_create_payment_intent_nonce', false, false );
			if ( ! $is_nonce_valid ) {
				throw new Process_Payment_Exception(
					__( "We're not able to process this payment. Please refresh the page and try again.", 'woocommerce-payments' ),
					'wcpay_upe_intent_error'
				);
			}

			// If paying from order, we need to get the total from the order instead of the cart.
			$order_id    = isset( $_POST['wcpay_order_id'] ) ? absint( $_POST['wcpay_order_id'] ) : null;
			$fingerprint = isset( $_POST['wcpay-fingerprint'] ) ? wc_clean( wp_unslash( $_POST['wcpay-fingerprint'] ) ) : '';

			$response = $this->create_payment_intent( $order_id, $fingerprint );

			// Encrypt client secret before exposing it to the browser.
			if ( $response['client_secret'] ) {
				$response['client_secret'] = WC_Payments_Utils::encrypt_client_secret( $this->account->get_stripe_account_id(), $response['client_secret'] );
			}

			if ( strpos( $response['id'], 'pi_' ) === 0 ) { // response is a payment intent (could possibly be a setup intent).
				$this->add_upe_payment_intent_to_session( $response['id'], $response['client_secret'] );
			}

			wp_send_json_success( $response, 200 );
		} catch ( Exception $e ) {
			// Send back error so it can be displayed to the customer.
			wp_send_json_error(
				[
					'error' => [
						'message' => WC_Payments_Utils::get_filtered_error_message( $e ),
					],
				]
			);
		}
	}

	/**
	 * Creates payment intent using current cart or order and store details.
	 *
	 * @param int|null $order_id The id of the order if intent created from Order.
	 * @param string   $fingerprint User fingerprint.
	 *
	 * @return array
	 */
	public function create_payment_intent( $order_id = null, $fingerprint = '' ) {
		$amount   = WC()->cart->get_total( '' );
		$currency = get_woocommerce_currency();
		$number   = 0;
		$order    = wc_get_order( $order_id );
		if ( is_a( $order, 'WC_Order' ) ) {
			$amount   = $order->get_total();
			$currency = $order->get_currency();
			$number   = $order->get_order_number();
		}

		$converted_amount = WC_Payments_Utils::prepare_amount( $amount, $currency );
		if ( 1 > $converted_amount ) {
			return $this->create_setup_intent();
		}

		$minimum_amount = WC_Payments_Utils::get_cached_minimum_amount( $currency );
		if ( ! is_null( $minimum_amount ) && $converted_amount < $minimum_amount ) {
			// Use the minimum amount in order to create an intent and display fields.
			$converted_amount = $minimum_amount;
		}

		$capture_method          = empty( $this->settings['manual_capture'] ) || 'no' === $this->settings['manual_capture'] ? 'automatic' : 'manual';
		$enabled_payment_methods = $this->get_payment_method_ids_enabled_at_checkout( $order_id, true );

		try {
			$payment_intent = $this->payments_api_client->create_intention(
				$converted_amount,
				strtolower( $currency ),
				array_values( $enabled_payment_methods ),
				$number,
				$capture_method,
				[ 'fingerprint' => $fingerprint ]
			);
		} catch ( Amount_Too_Small_Exception $e ) {
			$minimum_amount = $e->get_minimum_amount();

			WC_Payments_Utils::cache_minimum_amount( $e->get_currency(), $minimum_amount );

			/**
			 * Try to create a new payment intent with the minimum amount
			 * in order to display fields om the checkout page and allow
			 * customers to select a shipping method, which might make
			 * the total amount of the order higher than the minimum
			 * amount for the API.
			 */
			$payment_intent = $this->payments_api_client->create_intention(
				$minimum_amount,
				strtolower( $currency ),
				array_values( $enabled_payment_methods ),
				$number,
				$capture_method,
				[ 'fingerprint' => $fingerprint ]
			);
		}

		return [
			'id'            => $payment_intent->get_id(),
			'client_secret' => $payment_intent->get_client_secret(),
		];
	}

	/**
	 * Handle AJAX request for creating a setup intent without confirmation for Stripe UPE.
	 *
	 * @throws Add_Payment_Method_Exception - If nonce or setup intent is invalid.
	 */
	public function init_setup_intent_ajax() {
		try {
			$is_nonce_valid = check_ajax_referer( 'wcpay_create_setup_intent_nonce', false, false );
			if ( ! $is_nonce_valid ) {
				throw new Add_Payment_Method_Exception(
					__( "We're not able to add this payment method. Please refresh the page and try again.", 'woocommerce-payments' ),
					'invalid_referrer'
				);
			}

			$response = $this->create_setup_intent();

			// Encrypt client secret before exposing it to the browser.
			if ( $response['client_secret'] ) {
				$response['client_secret'] = WC_Payments_Utils::encrypt_client_secret( $this->account->get_stripe_account_id(), $response['client_secret'] );
			}

			$this->add_upe_setup_intent_to_session( $response['id'], $response['client_secret'] );

			wp_send_json_success( $response, 200 );
		} catch ( Exception $e ) {
			// Send back error so it can be displayed to the customer.
			wp_send_json_error(
				[
					'error' => [
						'message' => WC_Payments_Utils::get_filtered_error_message( $e ),
					],
				]
			);
		}
	}

	/**
	 * Creates setup intent without confirmation.
	 *
	 * @return array
	 */
	public function create_setup_intent() {
		// Determine the customer managing the payment methods, create one if we don't have one already.
		$user        = wp_get_current_user();
		$customer_id = $this->customer_service->get_customer_id_by_user_id( $user->ID );
		if ( null === $customer_id ) {
			$customer_data = WC_Payments_Customer_Service::map_customer_data( null, new \WC_Customer( $user->ID ) );
			$customer_id   = $this->customer_service->create_customer_for_user( $user, $customer_data );
		}

		$enabled_payment_methods = array_filter( $this->get_upe_enabled_payment_method_ids(), [ $this, 'is_enabled_for_saved_payments' ] );

		$setup_intent = $this->payments_api_client->create_setup_intention(
			$customer_id,
			array_values( $enabled_payment_methods )
		);
		return [
			'id'            => $setup_intent['id'],
			'client_secret' => $setup_intent['client_secret'],
		];
	}

	/**
	 * Create and confirm payment intent. Function used to route any payments that do not use the UPE flow through the parent process payment.
	 *
	 * @param int $order_id Order ID to process the payment for.
	 *
	 * @return array|null An array with result of payment and redirect URL, or nothing.
	 */
	public function parent_process_payment( $order_id ) {
		return parent::process_payment( $order_id );
	}

	/**
	 * Renders the credit card input fields needed to get the user's payment information on the checkout page.
	 *
	 * We also add the JavaScript which drives the UI.
	 */
	public function payment_fields() {
		do_action( 'wc_payments_add_upe_payment_fields' );
	}

	/**
	 * Update payment intent for completed checkout and return redirect URL for Stripe to confirm payment.
	 *
	 * @param int $order_id Order ID to process the payment for.
	 *
	 * @return array|null An array with result of payment and redirect URL, or nothing.
	 * @throws Exception Error processing the payment.
	 */
	public function process_payment( $order_id ) {
		$payment_intent_id         = isset( $_POST['wc_payment_intent_id'] ) ? wc_clean( wp_unslash( $_POST['wc_payment_intent_id'] ) ) : ''; // phpcs:ignore WordPress.Security.NonceVerification.Missing
		$order                     = wc_get_order( $order_id );
		$amount                    = $order->get_total();
		$currency                  = $order->get_currency();
		$converted_amount          = WC_Payments_Utils::prepare_amount( $amount, $currency );
		$payment_needed            = 0 < $converted_amount;
		$selected_upe_payment_type = ! empty( $_POST['wcpay_selected_upe_payment_type'] ) ? wc_clean( wp_unslash( $_POST['wcpay_selected_upe_payment_type'] ) ) : ''; // phpcs:ignore WordPress.Security.NonceVerification.Missing
		$payment_type              = $this->is_payment_recurring( $order_id ) ? Payment_Type::RECURRING() : Payment_Type::SINGLE();
		$save_payment_method       = $payment_type->equals( Payment_Type::RECURRING() ) || ! empty( $_POST[ 'wc-' . static::GATEWAY_ID . '-new-payment-method' ] ); // phpcs:ignore WordPress.Security.NonceVerification.Missing
		$payment_country           = ! empty( $_POST['wcpay_payment_country'] ) ? wc_clean( wp_unslash( $_POST['wcpay_payment_country'] ) ) : null; // phpcs:ignore WordPress.Security.NonceVerification.Missing

		if ( $payment_intent_id ) {
			list( $user, $customer_id ) = $this->manage_customer_details_for_order( $order );

			if ( $payment_needed ) {
				// Check if session exists before instantiating Fraud_Prevention_Service.
				if ( WC()->session ) {
					$fraud_prevention_service = Fraud_Prevention_Service::get_instance();
					// phpcs:ignore WordPress.Security.NonceVerification.Missing,WordPress.Security.ValidatedSanitizedInput.MissingUnslash,WordPress.Security.ValidatedSanitizedInput.InputNotSanitized
					if ( $fraud_prevention_service->is_enabled() && ! $fraud_prevention_service->verify_token( $_POST['wcpay-fraud-prevention-token'] ?? null ) ) {
						throw new Process_Payment_Exception(
							__( "We're not able to process this payment. Please refresh the page and try again.", 'woocommerce-payments' ),
							'fraud_prevention_enabled'
						);
					}
				}

				if ( $this->failed_transaction_rate_limiter->is_limited() ) {
					// Throwing an exception instead of adding an error notice
					// makes the error notice show up both in the regular and block checkout.
					throw new Exception( __( 'Your payment was not processed.', 'woocommerce-payments' ) );
				}

				// Try catching the error without reaching the API.
				$minimum_amount = WC_Payments_Utils::get_cached_minimum_amount( $currency );
				if ( $minimum_amount > $converted_amount ) {
					$exception = new Amount_Too_Small_Exception( 'Amount too small', $minimum_amount, $currency, 400 );
					throw new Exception( WC_Payments_Utils::get_filtered_error_message( $exception ) );
				}

				$check_session_order = $this->check_against_session_processing_order( $order );
				if ( is_array( $check_session_order ) ) {
					return $check_session_order;
				}
				$this->maybe_update_session_processing_order( $order_id );

				$check_existing_intention = $this->check_payment_intent_attached_to_order_succeeded( $order );
				if ( is_array( $check_existing_intention ) ) {
					return $check_existing_intention;
				}

				$additional_api_parameters = $this->get_mandate_params_for_order( $order );

				try {
					$updated_payment_intent = $this->payments_api_client->update_intention(
						$payment_intent_id,
						$converted_amount,
						strtolower( $currency ),
						$save_payment_method,
						$customer_id,
						$this->get_metadata_from_order( $order, $payment_type ),
						$this->get_level3_data_from_order( $order ),
						$selected_upe_payment_type,
						$payment_country,
						$additional_api_parameters
					);
				} catch ( Amount_Too_Small_Exception $e ) {
					// This code would only be reached if the cache has already expired.
					throw new Exception( WC_Payments_Utils::get_filtered_error_message( $e ) );
				}

				$intent_id              = $updated_payment_intent->get_id();
				$intent_status          = $updated_payment_intent->get_status();
				$payment_method         = $updated_payment_intent->get_payment_method_id();
				$charge                 = $updated_payment_intent->get_charge();
				$payment_method_details = $charge ? $charge->get_payment_method_details() : [];
				$payment_method_type    = $payment_method_details ? $payment_method_details['type'] : null;
				$charge_id              = $charge ? $charge->get_id() : null;

				/**
				 * Attach the intent and exchange info to the order before doing the redirect, just in case the redirect
				 * either does not complete properly, or the Stripe webhook which processes a successful order hits before
				 * the redirect completes.
				 */
				$this->attach_intent_info_to_order( $order, $intent_id, $intent_status, $payment_method, $customer_id, $charge_id, $currency );
				$this->attach_exchange_info_to_order( $order, $charge_id );
				$this->set_payment_method_title_for_order( $order, $payment_method_type, $payment_method_details );
				$this->update_order_status_from_intent( $order, $intent_id, $intent_status, $charge_id );

				$last_payment_error_code = $updated_payment_intent->get_last_payment_error()['code'] ?? '';
				if ( $this->should_bump_rate_limiter( $last_payment_error_code ) ) {
					// UPE method gives us the error of the previous payment attempt, so we use that for the Rate Limiter.
					$this->failed_transaction_rate_limiter->bump();
				}
			}
		} else {
			return $this->parent_process_payment( $order_id );
		}

		return [
			'result'         => 'success',
			'payment_needed' => $payment_needed,
			'redirect_url'   => wp_sanitize_redirect(
				esc_url_raw(
					add_query_arg(
						[
							'order_id'            => $order_id,
							'wc_payment_method'   => self::GATEWAY_ID,
							'_wpnonce'            => wp_create_nonce( 'wcpay_process_redirect_order_nonce' ),
							'save_payment_method' => $save_payment_method ? 'yes' : 'no',
						],
						$this->get_return_url( $order )
					)
				)
			),
		];
	}

	/**
	 * Returns true when viewing payment methods page.
	 *
	 * @return bool
	 */
	private function is_payment_methods_page() {
		global $wp;

		$page_id = wc_get_page_id( 'myaccount' );

		return ( $page_id && is_page( $page_id ) && ( isset( $wp->query_vars['payment-methods'] ) ) );
	}

	/**
	 * Check for a redirect payment method on order received page or setup intent on payment methods page.
	 */
	public function maybe_process_upe_redirect() {
		if ( $this->is_payment_methods_page() ) {
			// If a payment method was added using UPE, we need to clear the cache and notify the user.
			if ( $this->is_setup_intent_success_creation_redirection() ) {
					wc_add_notice( __( 'Payment method successfully added.', 'woocommerce-payments' ) );
					$user = wp_get_current_user();
					$this->customer_service->clear_cached_payment_methods_for_user( $user->ID );
			}
			return;
		}

		if ( ! is_order_received_page() ) {
			return;
		}

		$payment_method = isset( $_GET['wc_payment_method'] ) ? wc_clean( wp_unslash( $_GET['wc_payment_method'] ) ) : '';
		if ( self::GATEWAY_ID !== $payment_method ) {
			return;
		}

		$is_nonce_valid = check_admin_referer( 'wcpay_process_redirect_order_nonce' );
		if ( ! $is_nonce_valid || empty( $_GET['wc_payment_method'] ) ) {
			return;
		}

		if ( ! empty( $_GET['payment_intent_client_secret'] ) ) {
			$intent_id = isset( $_GET['payment_intent'] ) ? wc_clean( wp_unslash( $_GET['payment_intent'] ) ) : '';
		} elseif ( ! empty( $_GET['setup_intent_client_secret'] ) ) {
			$intent_id = isset( $_GET['setup_intent'] ) ? wc_clean( wp_unslash( $_GET['setup_intent'] ) ) : '';
		} else {
			return;
		}

		$order_id            = isset( $_GET['order_id'] ) ? wc_clean( wp_unslash( $_GET['order_id'] ) ) : '';
		$save_payment_method = isset( $_GET['save_payment_method'] ) ? 'yes' === wc_clean( wp_unslash( $_GET['save_payment_method'] ) ) : false;

		if ( empty( $intent_id ) || empty( $order_id ) ) {
			return;
		}

		$this->process_redirect_payment( $order_id, $intent_id, $save_payment_method );
	}

	/**
	 * Processes redirect payments.
	 *
	 * @param int|string $order_id The order ID being processed.
	 * @param string     $intent_id The Stripe setup/payment intent ID for the order payment.
	 * @param bool       $save_payment_method Boolean representing whether payment method for order should be saved.
	 *
	 * @throws Process_Payment_Exception When the payment intent has an error.
	 */
	public function process_redirect_payment( $order_id, $intent_id, $save_payment_method ) {
		try {
			$order = wc_get_order( $order_id );

			if ( ! is_object( $order ) ) {
				return;
			}

			if ( $order->has_status(
				[
					Order_Status::PROCESSING,
					Order_Status::COMPLETED,
					Order_Status::ON_HOLD,
				]
			) ) {
				return;
			}

			Logger::log( "Begin processing UPE redirect payment for order $order_id for the amount of {$order->get_total()}" );

			// Get user/customer for order.
			list( $user, $customer_id ) = $this->manage_customer_details_for_order( $order );

			$payment_needed = 0 < $order->get_total();

			// Get payment intent to confirm status.
			if ( $payment_needed ) {
				$intent                 = $this->payments_api_client->get_intent( $intent_id );
				$client_secret          = $intent->get_client_secret();
				$status                 = $intent->get_status();
				$charge                 = $intent->get_charge();
				$charge_id              = $charge ? $charge->get_id() : null;
				$currency               = $intent->get_currency();
				$payment_method_id      = $intent->get_payment_method_id();
				$payment_method_details = $charge ? $charge->get_payment_method_details() : [];
				$payment_method_type    = $payment_method_details ? $payment_method_details['type'] : null;
				$error                  = $intent->get_last_payment_error();
			} else {
				$intent                 = $this->payments_api_client->get_setup_intent( $intent_id );
				$client_secret          = $intent['client_secret'];
				$status                 = $intent['status'];
				$charge_id              = '';
				$currency               = $order->get_currency();
				$payment_method_id      = $intent['payment_method'];
				$payment_method_details = false;
				$payment_method_options = array_keys( $intent['payment_method_options'] );
				$payment_method_type    = $payment_method_options ? $payment_method_options[0] : null;
				$error                  = $intent['last_setup_error'];
			}

			if ( ! empty( $error ) ) {
				Logger::log( 'Error when processing payment: ' . $error['message'] );
				throw new Process_Payment_Exception(
					__( "We're not able to process this payment. Please try again later.", 'woocommerce-payments' ),
					'upe_payment_intent_error'
				);
			} else {
				if ( ! isset( $this->payment_methods[ $payment_method_type ] ) ) {
					return;
				}
				$payment_method = $this->payment_methods[ $payment_method_type ];

				if ( $save_payment_method && $payment_method->is_reusable() ) {
					try {
						$token = $payment_method->get_payment_token_for_user( $user, $payment_method_id );
						$this->add_token_to_order( $order, $token );
					} catch ( Exception $e ) {
						// If saving the token fails, log the error message but catch the error to avoid crashing the checkout flow.
						Logger::log( 'Error when saving payment method: ' . $e->getMessage() );
					}
				}

				$this->attach_intent_info_to_order( $order, $intent_id, $status, $payment_method_id, $customer_id, $charge_id, $currency );
				$this->attach_exchange_info_to_order( $order, $charge_id );
				$this->update_order_status_from_intent( $order, $intent_id, $status, $charge_id );
				$this->set_payment_method_title_for_order( $order, $payment_method_type, $payment_method_details );

				self::remove_upe_payment_intent_from_session();

				if ( Payment_Intent_Status::REQUIRES_ACTION === $status ) {
					// I don't think this case should be possible, but just in case...
					$next_action = $intent->get_next_action();
					if ( isset( $next_action['type'] ) && 'redirect_to_url' === $next_action['type'] && ! empty( $next_action['redirect_to_url']['url'] ) ) {
						wp_safe_redirect( $next_action['redirect_to_url']['url'] );
						exit;
					} else {
						$redirect_url = sprintf(
							'#wcpay-confirm-%s:%s:%s:%s',
							$payment_needed ? 'pi' : 'si',
							$order_id,
							WC_Payments_Utils::encrypt_client_secret( $this->account->get_stripe_account_id(), $client_secret ),
							wp_create_nonce( 'wcpay_update_order_status_nonce' )
						);
						wp_safe_redirect( $redirect_url );
						exit;
					}
				}
			}
		} catch ( Exception $e ) {
			Logger::log( 'Error: ' . $e->getMessage() );

			// Confirm our needed variables are set before using them due to there could be a server issue during the get_intent process.
			$status    = $status ?? null;
			$charge_id = $charge_id ?? null;

			/* translators: localized exception message */
			$message = sprintf( __( 'UPE payment failed: %s', 'woocommerce-payments' ), $e->getMessage() );
			$this->order_service->mark_payment_failed( $order, $intent_id, $status, $charge_id, $message );

			self::remove_upe_payment_intent_from_session();

			wc_add_notice( WC_Payments_Utils::get_filtered_error_message( $e ), 'error' );
			wp_safe_redirect( wc_get_checkout_url() );
			exit;
		}
	}

	/**
	 * Generates the configuration values, needed for UPE payment fields.
	 *
	 * @deprecated 5.0.0
	 *
	 * @return array
	 */
	public function get_payment_fields_js_config() {
		wc_deprecated_function( __FUNCTION__, '5.0.0', 'WC_Payments_UPE_Checkout::get_payment_fields_js_config' );
		return WC_Payments::get_wc_payments_checkout()->get_payment_fields_js_config();
	}

	/**
	 * True if the request contains the values that indicates a redirection after a successful setup intent creation.
	 *
	 * @return bool
	 */
	public function is_setup_intent_success_creation_redirection() {
		return ! empty( $_GET['setup_intent_client_secret'] ) && // phpcs:ignore WordPress.Security.NonceVerification.Recommended
			! empty( $_GET['setup_intent'] ) && // phpcs:ignore WordPress.Security.NonceVerification.Recommended
			! empty( $_GET['redirect_status'] ) && // phpcs:ignore WordPress.Security.NonceVerification.Recommended
			'succeeded' === $_GET['redirect_status']; // phpcs:ignore WordPress.Security.NonceVerification.Recommended
	}

	/**
	 * Adds a token to current user from a setup intent id.
	 *
	 * @param string  $setup_intent_id ID of the setup intent.
	 * @param WP_User $user            User to add token to.
	 *
	 * @return WC_Payment_Token_CC|WC_Payment_Token_WCPay_SEPA|null The added token.
	 */
	public function create_token_from_setup_intent( $setup_intent_id, $user ) {
		try {
			$setup_intent      = $this->payments_api_client->get_setup_intent( $setup_intent_id );
			$payment_method_id = $setup_intent['payment_method'];
			// TODO: When adding SEPA and Sofort, we will need a new API call to get the payment method and from there get the type.
			// Leaving 'card' as a hardcoded value for now to avoid the extra API call.
			$payment_method = $this->payment_methods['card'];

			return $payment_method->get_payment_token_for_user( $user, $payment_method_id );
		} catch ( Exception $e ) {
			wc_add_notice( WC_Payments_Utils::get_filtered_error_message( $e ), 'error', [ 'icon' => 'error' ] );
			Logger::log( 'Error when adding payment method: ' . $e->getMessage() );
		}
	}

	/**
	 * Set formatted readable payment method title for order,
	 * using payment method details from accompanying charge.
	 *
	 * @param WC_Order   $order WC Order being processed.
	 * @param string     $payment_method_type Stripe payment method key.
	 * @param array|bool $payment_method_details Array of payment method details from charge or false.
	 */
	public function set_payment_method_title_for_order( $order, $payment_method_type, $payment_method_details ) {
		if ( ! isset( $this->payment_methods[ $payment_method_type ] ) ) {
			return;
		}

		$payment_method_title = $this->payment_methods[ $payment_method_type ]->get_title( $payment_method_details );

		$order->set_payment_method( self::GATEWAY_ID );
		$order->set_payment_method_title( $payment_method_title );
		$order->save();
	}

	/**
	 * Returns the list of enabled payment method types that will function with the current checkout.
	 *
	 * @param string $order_id optional Order ID.
	 * @param bool   $force_currency_check optional Whether the currency check is required even if is_admin().
	 *
	 * @return string[]
	 */
	public function get_payment_method_ids_enabled_at_checkout( $order_id = null, $force_currency_check = false ) {
		$automatic_capture = empty( $this->get_option( 'manual_capture' ) ) || $this->get_option( 'manual_capture' ) === 'no';
		if ( $automatic_capture ) {
			$upe_enabled_payment_methods = $this->get_upe_enabled_payment_method_ids();
		} else {
			$upe_enabled_payment_methods = array_intersect( $this->get_upe_enabled_payment_method_ids(), [ Payment_Method::CARD, Payment_Method::LINK ] );
		}

		$enabled_payment_methods = [];
		$active_payment_methods  = $this->get_upe_enabled_payment_method_statuses();
		foreach ( $upe_enabled_payment_methods as $payment_method_id ) {
			$payment_method_capability_key = $this->payment_method_capability_key_map[ $payment_method_id ] ?? 'undefined_capability_key';
			if ( isset( $this->payment_methods[ $payment_method_id ] ) ) {
				// When creating a payment intent, we need to ensure the currency is matching
				// with the payment methods which are sent with the payment intent request, otherwise
				// Stripe returns an error.

				// force_currency_check = 0 is_admin = 0 currency_is_checked = 1.
				// force_currency_check = 0 is_admin = 1 currency_is_checked = 0.
				// force_currency_check = 1 is_admin = 0 currency_is_checked = 1.
				// force_currency_check = 1 is_admin = 1 currency_is_checked = 1.

				$skip_currency_check       = ! $force_currency_check && is_admin();
				$processing_payment_method = $this->payment_methods[ $payment_method_id ];
				if ( $processing_payment_method->is_enabled_at_checkout() && ( $skip_currency_check || $processing_payment_method->is_currency_valid() ) ) {
					$status = $active_payment_methods[ $payment_method_capability_key ]['status'] ?? null;
					if ( 'active' === $status ) {
						$enabled_payment_methods[] = $payment_method_id;
					}
				}
			}
		}

		// if credit card payment method is not enabled, we don't use stripe link.
		if (
			! in_array( CC_Payment_Method::PAYMENT_METHOD_STRIPE_ID, $enabled_payment_methods, true ) &&
			in_array( Link_Payment_Method::PAYMENT_METHOD_STRIPE_ID, $enabled_payment_methods, true ) ) {
			$enabled_payment_methods = array_filter(
				$enabled_payment_methods,
				static function( $method ) {
					return Link_Payment_Method::PAYMENT_METHOD_STRIPE_ID !== $method;
				}
			);
		}

		return $enabled_payment_methods;
	}

	/**
	 * Returns the list of enabled payment method types that will function with the current checkout filtered by fees.
	 *
	 * @param string $order_id optional Order ID.
	 * @param bool   $force_currency_check optional Whether the currency check is required even if is_admin().
	 *
	 * @return string[]
	 */
	public function get_payment_method_ids_enabled_at_checkout_filtered_by_fees( $order_id = null, $force_currency_check = false ) {
		$enabled_payment_methods = $this->get_payment_method_ids_enabled_at_checkout( $order_id, $force_currency_check );
		$methods_with_fees       = array_keys( $this->account->get_fees() );

		return array_values( array_intersect( $enabled_payment_methods, $methods_with_fees ) );
	}

	/**
	 * Returns the list of available payment method types for UPE.
	 * Filtering out those without configured fees, this will prevent a payment method not supported by the Stripe account's country from being returned.
	 * Note that we are not taking into account capabilities, which are taken into account when managing payment methods in settings.
	 * See https://stripe.com/docs/stripe-js/payment-element#web-create-payment-intent for a complete list.
	 *
	 * @return string[]
	 */
	public function get_upe_available_payment_methods() {
		$available_methods = parent::get_upe_available_payment_methods();

		$available_methods[] = Becs_Payment_Method::PAYMENT_METHOD_STRIPE_ID;
		$available_methods[] = Bancontact_Payment_Method::PAYMENT_METHOD_STRIPE_ID;
		$available_methods[] = Eps_Payment_Method::PAYMENT_METHOD_STRIPE_ID;
		$available_methods[] = Giropay_Payment_Method::PAYMENT_METHOD_STRIPE_ID;
		$available_methods[] = Ideal_Payment_Method::PAYMENT_METHOD_STRIPE_ID;
		$available_methods[] = Sofort_Payment_Method::PAYMENT_METHOD_STRIPE_ID;
		$available_methods[] = Sepa_Payment_Method::PAYMENT_METHOD_STRIPE_ID;
		$available_methods[] = P24_Payment_Method::PAYMENT_METHOD_STRIPE_ID;
		$available_methods[] = Link_Payment_Method::PAYMENT_METHOD_STRIPE_ID;

		$available_methods = array_values(
			apply_filters(
				'wcpay_upe_available_payment_methods',
				$available_methods
			)
		);
		$methods_with_fees = array_keys( $this->account->get_fees() );

		return array_values( array_intersect( $available_methods, $methods_with_fees ) );
	}

	/**
	 * Handle AJAX request for saving UPE appearance value to transient.
	 *
	 * @throws Exception - If nonce or setup intent is invalid.
	 */
	public function save_upe_appearance_ajax() {
		try {
			$is_nonce_valid = check_ajax_referer( 'wcpay_save_upe_appearance_nonce', false, false );
			if ( ! $is_nonce_valid ) {
				throw new Exception(
					__( 'Unable to update UPE appearance values at this time.', 'woocommerce-payments' )
				);
			}

			$is_blocks_checkout = isset( $_POST['is_blocks_checkout'] ) ? rest_sanitize_boolean( wc_clean( wp_unslash( $_POST['is_blocks_checkout'] ) ) ) : false;
			$appearance         = isset( $_POST['appearance'] ) ? json_decode( wc_clean( wp_unslash( $_POST['appearance'] ) ) ) : null;

			$appearance_transient = $is_blocks_checkout ? self::WC_BLOCKS_UPE_APPEARANCE_TRANSIENT : self::UPE_APPEARANCE_TRANSIENT;

			if ( null !== $appearance ) {
				set_transient( $appearance_transient, $appearance, DAY_IN_SECONDS );
			}

			wp_send_json_success( $appearance, 200 );
		} catch ( Exception $e ) {
			// Send back error so it can be displayed to the customer.
			wp_send_json_error(
				[
					'error' => [
						'message' => WC_Payments_Utils::get_filtered_error_message( $e ),
					],
				]
			);
		}
	}

	/**
	 * Clear the saved UPE appearance transient value.
	 */
	public function clear_upe_appearance_transient() {
		delete_transient( self::UPE_APPEARANCE_TRANSIENT );
		delete_transient( self::WC_BLOCKS_UPE_APPEARANCE_TRANSIENT );
	}

	/**
	 * Sets the title on checkout correctly before the title is displayed.
	 *
	 * @param string $title The title of the gateway being filtered.
	 * @param string $id    The id of the gateway being filtered.
	 *
	 * @return string Filtered gateway title.
	 */
	public function maybe_filter_gateway_title( $title, $id ) {
		if ( self::GATEWAY_ID === $id && $this->title === $title ) {
			$title                   = $this->checkout_title;
			$enabled_payment_methods = $this->get_payment_method_ids_enabled_at_checkout();

			if ( 1 === count( $enabled_payment_methods ) ) {
				$title = $this->payment_methods[ $enabled_payment_methods[0] ]->get_title();
			}

			if ( 0 === count( $enabled_payment_methods ) ) {
				$title = $this->payment_methods['card']->get_title();
			}
		}
		return $title;
	}

	/**
	 * Gets payment method settings to pass to client scripts
	 *
	 * @deprecated 5.0.0
	 *
	 * @return array
	 */
	private function get_enabled_payment_method_config() {
		wc_deprecated_function( __FUNCTION__, '5.0.0', 'WC_Payments_UPE_Checkout::get_enabled_payment_method_config' );
		return WC_Payments::get_wc_payments_checkout()->get_enabled_payment_method_config();
	}

	/**
	 * Function to be used with array_filter
	 * to filter UPE payment methods that support saved payments
	 *
	 * @param string $payment_method_id Stripe payment method.
	 *
	 * @return bool
	 */
	public function is_enabled_for_saved_payments( $payment_method_id ) {
		if ( ! isset( $this->payment_methods[ $payment_method_id ] ) ) {
			return false;
		}
		return $this->payment_methods[ $payment_method_id ]->is_reusable()
			&& ( is_admin() || $this->payment_methods[ $payment_method_id ]->is_currency_valid() );
	}

	/**
	 * Log UPE Payment Errors on Checkout.
	 *
	 * @throws Exception If nonce is not present or invalid or charge ID is empty or order not found.
	 */
	public function log_payment_error_ajax() {
		try {
			$is_nonce_valid = check_ajax_referer( 'wcpay_log_payment_error_nonce', false, false );
			if ( ! $is_nonce_valid ) {
				throw new Exception( 'Invalid request.' );
			}

			$charge_id = isset( $_POST['charge_id'] ) ? wc_clean( wp_unslash( $_POST['charge_id'] ) ) : '';
			if ( empty( $charge_id ) ) {
				throw new Exception( 'Charge ID cannot be empty.' );
			}

			// Get charge data from WCPay Server.
			$charge_data = $this->payments_api_client->get_charge( $charge_id );
			$order_id    = $charge_data['metadata']['order_id'];

			// Validate Order ID and proceed with logging errors and updating order status.
			$order = wc_get_order( $order_id );
			if ( ! $order ) {
				throw new Exception( 'Order not found. Unable to log error.' );
			}

			$intent_id     = $charge_data['payment_intent'] ?? $order->get_meta( '_intent_id' );
			$intent        = $this->payments_api_client->get_intent( $intent_id );
			$intent_status = $intent->get_status();
			$error_message = esc_html( rtrim( $charge_data['failure_message'], '.' ) );

			$this->order_service->mark_payment_failed( $order, $intent_id, $intent_status, $charge_id, $error_message );

			self::remove_upe_payment_intent_from_session();

			wp_send_json_success();
		} catch ( Exception $e ) {
			self::remove_upe_payment_intent_from_session();

			wp_send_json_error(
				[
					'error' => [
						'message' => $e->getMessage(),
					],
				]
			);
		}
	}

	/**
	 * Adds the id and client secret of payment intent needed to mount the UPE element in frontend to WC session.
	 *
	 * @param string $intent_id     The payment intent id.
	 * @param string $client_secret The payment intent client secret.
	 */
	private function add_upe_payment_intent_to_session( string $intent_id = '', string $client_secret = '' ) {
		$cart_hash = 'undefined';

		if ( isset( $_COOKIE['woocommerce_cart_hash'] ) ) {
			$cart_hash = sanitize_text_field( wp_unslash( $_COOKIE['woocommerce_cart_hash'] ) );
		}

		$value = $cart_hash . '-' . $intent_id . '-' . $client_secret;

		WC()->session->set( self::KEY_UPE_PAYMENT_INTENT, $value );
	}

	/**
	 * Removes the payment intent created for UPE from WC session.
	 */
	public static function remove_upe_payment_intent_from_session() {
		if ( isset( WC()->session ) ) {
			WC()->session->__unset( self::KEY_UPE_PAYMENT_INTENT );
		}
	}

	/**
	 * Adds the id and client secret of setup intent needed to mount the UPE element in frontend to WC session.
	 *
	 * @param string $intent_id     The setup intent id.
	 * @param string $client_secret The setup intent client secret.
	 */
	private function add_upe_setup_intent_to_session( string $intent_id = '', string $client_secret = '' ) {
		$value = $intent_id . '-' . $client_secret;

		WC()->session->set( self::KEY_UPE_SETUP_INTENT, $value );
	}

	/**
	 * Removes the setup intent created for UPE from WC session.
	 */
	public function remove_upe_setup_intent_from_session() {
		WC()->session->__unset( self::KEY_UPE_SETUP_INTENT );
	}

	/**
	 * Returns the checkout tile.
	 *
	 * @return string Checkout title.
	 */
	public function get_checkout_title() {
		return $this->checkout_title;
	}

	/**
	 * Returns the payment methods for this gateway.
	 *
	 * @return array|UPE_Payment_Method[]
	 */
	public function get_payment_methods() {
		return $this->payment_methods;
	}
}