unsupervised-scheduler/src/Payment/PaymentService.php

<?php
declare(strict_types=1);

namespace Unsupervised\Schedular\Payment;

use Unsupervised\Schedular\Booking\BookingRepository;
use Unsupervised\Schedular\Booking\Lesson;
use Unsupervised\Schedular\GroupClass\EnrollmentRepository;

/**
 * Orchestrates payment creation and confirmation across the payment ledger and
 * the registrations (lessons / enrolments) they pay for.
 */
class PaymentService {

	public function __construct(
		private PaymentRepository $payments,
		private BillingMethodResolver $resolver,
		private ReceiptMailer $mailer,
		private BookingRepository $bookings,
		private EnrollmentRepository $enrollments,
		private StudioSettings $settings,
		private StripeGateway $stripe,
		private CreditRepository $credits,
	) {}

	/**
	 * Create the payment for a new registration and link it. Comped students are
	 * marked paid and confirmed immediately; everyone else gets a pending payment
	 * (card via Stripe — coming soon; e-transfer confirmed manually). The
	 * e-transfer destination is frozen now from the offering override or the studio
	 * default. Returns null when the registration has no price to charge.
	 *
	 * A `$dueDate`/`$periodKey` mark a payment generated later by the daily billing
	 * scan (weekly / monthly) rather than taken at registration; both stay null for
	 * the pay-now flow.
	 */
	public function createForRegistration( string $type, int $registrationId, int $studentId, int $instructorId, float $amount, string $currency, ?string $offeringEtransferEmail = null, ?string $dueDate = null, ?string $periodKey = null ): ?Payment {
		if ( $amount <= 0.0 ) {
			return null;
		}

		$method = $this->resolver->resolve( $studentId );
		$status = Payment::METHOD_COMP === $method ? Payment::STATUS_PAID : Payment::STATUS_PENDING;

		$etransferEmail = null !== $offeringEtransferEmail && '' !== $offeringEtransferEmail
			? $offeringEtransferEmail
			: ( '' !== $this->settings->etransferEmail() ? $this->settings->etransferEmail() : null );

		// HST is frozen from the studio default at booking; comped students are not taxed.
		$taxRate   = Payment::METHOD_COMP === $method ? 0.0 : $this->settings->hstRate();
		$taxAmount = round( $amount * $taxRate / 100, 2 );

		$id = $this->payments->insert(
			new Payment(
				studentId:        $studentId,
				instructorId:     $instructorId,
				registrationType: $type,
				registrationId:   $registrationId,
				amount:           $amount,
				currency:         $currency,
				method:           $method,
				status:           $status,
				taxRate:          $taxRate,
				taxAmount:        $taxAmount,
				dueDate:          $dueDate,
				periodKey:        $periodKey,
				etransferEmail:   $etransferEmail,
			)
		);

		$this->linkPayment( $type, $registrationId, $id );

		if ( Payment::STATUS_PAID === $status ) {
			$this->finalizePaid( $id, $type, $registrationId, $studentId );
		}

		return $this->payments->findById( $id );
	}

	/**
	 * Whether a scheduled payment already exists for a registration and billing
	 * period — the daily billing scan's dedup check for group enrolments (whose one
	 * row maps to many periodic charges). Delegates to the ledger.
	 */
	public function scheduledPaymentExists( string $type, int $registrationId, string $periodKey ): bool {
		return $this->payments->existsForPeriod( $type, $registrationId, $periodKey );
	}

	/**
	 * Tag the payments the daily scan emailed a student together with a shared
	 * notice-batch reference, so a lump-sum e-transfer can be reconciled to the
	 * pending payments it covers. Delegates to the ledger.
	 *
	 * @param list<int> $ids
	 */
	public function assignNoticeBatch( array $ids, string $batch ): void {
		$this->payments->assignNoticeBatch( $ids, $batch );
	}

	/**
	 * Studio-admin confirmation that a pending payment (e-transfer) was received.
	 * Marks it paid, confirms the registration, and emails the receipt.
	 */
	public function markPaid( int $paymentId ): bool {
		$payment = $this->payments->findById( $paymentId );
		if ( null === $payment ) {
			return false;
		}
		if ( $payment->isPaid() ) {
			return true;
		}

		$this->finalizePaid( $paymentId, $payment->registrationType, $payment->registrationId, $payment->studentId );

		return true;
	}

	/**
	 * Void the still-pending payment of a cancelled registration so it drops
	 * out of the confirmation queue. Paid payments are left alone — refunds
	 * are a manual, admin-side decision. Scheduled payments (weekly / monthly)
	 * are also left alone: a monthly charge can cover several lessons and may
	 * already be collected, so cancelling one lesson must never void it or
	 * trigger a rebill.
	 */
	public function voidPending( ?int $paymentId ): void {
		if ( null === $paymentId ) {
			return;
		}

		$payment = $this->payments->findById( $paymentId );
		if ( null !== $payment && ! $payment->isScheduled() && Payment::STATUS_PENDING === $payment->status ) {
			$this->payments->updateStatus( $paymentId, Payment::STATUS_FAILED );
		}
	}

	/**
	 * Credit a student for a cancelled lesson they had already paid for. The credit
	 * is one lesson's share of the covering payment's total (including tax) — the
	 * whole total for a single-lesson payment, or `total ÷ lessons covered` for a
	 * payment that spans several (a monthly scheduled charge, or a weekly series paid
	 * upfront). The original payment is left untouched; the credit is applied to the
	 * student's future scheduled-billing charges. Returns null when the lesson was
	 * never paid, has no covering payment, or was already credited.
	 */
	public function creditForCancelledLesson( Lesson $lesson ): ?Credit {
		if ( null === $lesson->id ) {
			return null;
		}

		$paymentId = $lesson->paymentId;
		if ( null === $paymentId && null !== $lesson->seriesId ) {
			// Series lessons other than the anchor carry no payment_id of their own;
			// the whole reservation is paid through the anchor's payment.
			$anchor    = $this->payments->findByRegistration( Payment::REG_LESSON, $lesson->seriesId );
			$paymentId = $anchor?->id;
		}
		if ( null === $paymentId ) {
			return null;
		}

		$payment = $this->payments->findById( $paymentId );
		if ( null === $payment || ! $payment->isPaid() ) {
			return null;
		}

		if ( $this->credits->existsForLesson( $lesson->id ) ) {
			return null;
		}

		$share = round( $payment->total() / $this->coveredLessonCount( $lesson, $payment ), 2 );
		if ( $share <= 0.0 ) {
			return null;
		}

		$id = $this->credits->insert(
			new Credit(
				studentId:       $payment->studentId,
				amount:          $share,
				remaining:       $share,
				currency:        $payment->currency,
				sourcePaymentId: $payment->id,
				sourceLessonId:  $lesson->id,
				reason:          sprintf(
					/* translators: %d: cancelled lesson id */
					__( 'Credit for cancelled lesson #%d', 'unsupervised-schedular' ),
					$lesson->id
				),
			)
		);

		return $this->credits->findById( $id );
	}

	/**
	 * How many lessons the covering payment was billed for, so its total can be split
	 * into a per-lesson credit. A weekly series paid upfront (unscheduled) covers the
	 * whole series; every other case — a single booking, a weekly scheduled lesson
	 * (one payment each), or a monthly scheduled charge (payment linked to each
	 * lesson) — is answered by how many lessons point at the payment. Never below one.
	 */
	private function coveredLessonCount( Lesson $lesson, Payment $payment ): int {
		if ( ! $payment->isScheduled() && null !== $lesson->seriesId ) {
			return max( 1, $this->bookings->countBySeries( $lesson->seriesId ) );
		}

		return max( 1, $this->bookings->countByPaymentId( (int) $payment->id ) );
	}

	/**
	 * Apply a student's available credit balance against a set of freshly-created
	 * pending payments (the ones a billing scan just generated for them), oldest
	 * charge first. Each payment's `credit_applied` is raised by the amount covered;
	 * a payment fully covered is marked paid-by-credit and its registration confirmed
	 * so it leaves the confirmation queue. The credit ledger is drawn down by the
	 * total applied. Returns a map of payment id to the credit applied to it, so the
	 * caller can reflect the reduction on the student's notice.
	 *
	 * @param list<Payment> $payments
	 * @return array<int, float>
	 */
	public function applyCredits( int $studentId, array $payments ): array {
		$balance = $this->credits->availableBalance( $studentId );
		if ( $balance <= 0.0 ) {
			return [];
		}

		$applied  = [];
		$consumed = 0.0;

		foreach ( $payments as $payment ) {
			if ( null === $payment->id || $balance <= 0.0 ) {
				continue;
			}

			$owing = $payment->netDue();
			if ( $owing <= 0.0 ) {
				continue;
			}

			$amount = round( min( $balance, $owing ), 2 );
			if ( $amount <= 0.0 ) {
				continue;
			}

			$this->payments->addCreditApplied( $payment->id, $amount );

			// Fully covered by credit: settle it so it drops out of the pending queue.
			if ( $amount >= $owing ) {
				$this->payments->markPaid( $payment->id, 'USC-' . $payment->id );
				$this->confirmRegistration( $payment->registrationType, $payment->registrationId );
			}

			$applied[ $payment->id ] = $amount;
			$balance                 = round( $balance - $amount, 2 );
			$consumed                = round( $consumed + $amount, 2 );
		}

		if ( $consumed > 0.0 ) {
			$this->credits->consume( $studentId, $consumed );
		}

		return $applied;
	}

	/**
	 * Resolve the client-side payment step for a freshly created registration.
	 * For a card payment a Stripe PaymentIntent is created (or replayed
	 * idempotently) and its client secret returned so the browser can confirm the
	 * card; e-transfer returns the destination and amount to display; comp/paid
	 * needs no further action. Returns null when the registration has no payment,
	 * the caller does not own it, or Stripe could not create the intent.
	 *
	 * @return array<string, mixed>|null
	 */
	public function createIntent( string $type, int $registrationId, int $studentId ): ?array {
		$payment = $this->payments->findByRegistration( $type, $registrationId );
		if ( null === $payment || null === $payment->id || $payment->studentId !== $studentId ) {
			return null;
		}

		$base = [
			'payment_id' => $payment->id,
			'method'     => $payment->method,
			'status'     => $payment->status,
			'amount'     => $payment->total(),
			'currency'   => $payment->currency,
		];

		// Comp (already paid) or anything else settled needs no client action.
		if ( $payment->isPaid() || Payment::METHOD_CARD !== $payment->method ) {
			if ( Payment::METHOD_ETRANSFER === $payment->method ) {
				$base['etransfer_email'] = $payment->etransferEmail;
			}

			return $base;
		}

		$intent = $this->stripe->createIntent( $payment );
		if ( null === $intent ) {
			return null;
		}

		$this->payments->setStripeIntentId( $payment->id, (string) $intent->id );

		$base['client_secret']   = (string) $intent->client_secret;
		$base['publishable_key'] = $this->settings->publishableKey();

		return $base;
	}

	/**
	 * Process a verified Stripe webhook. Returns false only when the signature
	 * fails verification (so the endpoint can reply 400); a true result means the
	 * event was authentic and has been acknowledged, whether or not it matched a
	 * ledger row. A succeeded intent finalises the matching payment exactly once;
	 * a failed intent marks an unpaid payment `failed`.
	 */
	public function handleWebhook( string $payload, string $signatureHeader ): bool {
		$event = $this->stripe->verifyWebhook( $payload, $signatureHeader );
		if ( null === $event ) {
			return false;
		}

		$intent = $event->data->object ?? null;
		if ( ! $intent instanceof \Stripe\PaymentIntent ) {
			return true;
		}

		$payment = $this->payments->findByStripeIntentId( (string) $intent->id );
		if ( null === $payment || null === $payment->id ) {
			return true;
		}

		if ( 'payment_intent.succeeded' === $event->type && ! $payment->isPaid() ) {
			$this->finalizePaid( $payment->id, $payment->registrationType, $payment->registrationId, $payment->studentId );
		} elseif ( 'payment_intent.payment_failed' === $event->type && ! $payment->isPaid() ) {
			$this->payments->updateStatus( $payment->id, Payment::STATUS_FAILED );
		}

		return true;
	}

	private function finalizePaid( int $paymentId, string $type, int $registrationId, int $studentId ): void {
		$this->payments->markPaid( $paymentId, 'USC-' . $paymentId );
		$this->confirmRegistration( $type, $registrationId );

		$paid = $this->payments->findById( $paymentId );
		$user = get_userdata( $studentId );
		if ( null !== $paid && $this->mailer->send( $paid, $user instanceof \WP_User ? $user : null ) ) {
			$this->payments->markReceiptSent( $paymentId );
		}
	}

	private function confirmRegistration( string $type, int $registrationId ): void {
		if ( Payment::REG_LESSON !== $type ) {
			// Group enrolments are already `active`; no status change on payment.
			return;
		}

		// A weekly reservation's payment is linked to its anchor lesson but pays
		// for the whole series, so settling it confirms every lesson in the series.
		$lesson = $this->bookings->findById( $registrationId );
		if ( null !== $lesson && null !== $lesson->seriesId ) {
			$this->bookings->updateStatusForSeries( $lesson->seriesId, Lesson::STATUS_CONFIRMED );
			return;
		}

		$this->bookings->updateStatus( $registrationId, Lesson::STATUS_CONFIRMED );
	}

	private function linkPayment( string $type, int $registrationId, int $paymentId ): void {
		if ( Payment::REG_LESSON === $type ) {
			$this->bookings->setPaymentId( $registrationId, $paymentId );
		} elseif ( Payment::REG_ENROLLMENT === $type ) {
			$this->enrollments->setPaymentId( $registrationId, $paymentId );
		}
	}
}