member-console/internal/integrations/stripe/workflows/webhook_subscription.go

package workflows

import (
	"context"
	"encoding/json"
	"fmt"
	"log/slog"

	"git.coopcloud.tech/wiki-cafe/member-console/internal/fulfillment"
)

// webhookCheckoutSessionPayload is the minimal scrubbed shape we read from a
// checkout.session.completed event. Only ids drive fulfillment — item, price,
// status, and period detail are fetched from the Stripe API by the reconciler,
// never trusted from the event payload.
type webhookCheckoutSessionPayload struct {
	Mode         string `json:"mode"`
	Subscription string `json:"subscription"`
}

// webhookSubscriptionIDPayload is the minimal scrubbed shape for
// customer.subscription.* events: the subscription id is all reconcile needs.
type webhookSubscriptionIDPayload struct {
	ID string `json:"id"`
}

// handleCheckoutSessionEvent treats checkout.session.completed as a thin eager
// trigger. It extracts the subscription id and delegates to the reconciler,
// which fetches authoritative state from the Stripe API. An empty payload
// line_items list (which Stripe always sends) no longer blocks fulfillment.
func (a *WebhookActivities) handleCheckoutSessionEvent(ctx context.Context, evt WebhookEvent) (string, error) {
	if evt.EventType != "checkout.session.completed" {
		a.Logger.Info("checkout sub-event skipped", slog.String("event_type", evt.EventType))
		return "skipped", nil
	}

	payload, err := a.readPayload(ctx, evt.ID)
	if err != nil {
		return "", err
	}
	var session webhookCheckoutSessionPayload
	if err := json.Unmarshal(payload, &session); err != nil {
		return "", fmt.Errorf("parse checkout session payload: %w", err)
	}

	if session.Mode != "subscription" {
		a.Logger.Info("checkout.session.completed skipped (not subscription mode)",
			slog.String("mode", session.Mode))
		return "completed", nil
	}
	if session.Subscription == "" {
		return "", fmt.Errorf("checkout.session.completed missing subscription id")
	}

	reason := fmt.Sprintf("stripe:checkout.session.completed:%s", evt.ProviderEventID)
	if err := fulfillment.ReconcileSubscription(ctx, a.DB, a.Logger, session.Subscription, reason); err != nil {
		return "", fmt.Errorf("reconcile subscription: %w", err)
	}

	a.Logger.Info("checkout.session.completed reconciled",
		slog.String("stripe_subscription_id", session.Subscription))
	return "completed", nil
}

// handleSubscriptionEvent routes customer.subscription.{created,updated,deleted}
// to the reconciler. Each event is a thin trigger; reconcile fetches the current
// subscription state and converges core records and entitlements. Convergence —
// not a skip-if-mapping-exists guard — provides idempotency.
func (a *WebhookActivities) handleSubscriptionEvent(ctx context.Context, evt WebhookEvent) (string, error) {
	switch evt.EventType {
	case "customer.subscription.created",
		"customer.subscription.updated",
		"customer.subscription.deleted":
		// handled below
	default:
		a.Logger.Info("subscription sub-event skipped", slog.String("event_type", evt.EventType))
		return "skipped", nil
	}

	payload, err := a.readPayload(ctx, evt.ID)
	if err != nil {
		return "", err
	}
	var sub webhookSubscriptionIDPayload
	if err := json.Unmarshal(payload, &sub); err != nil {
		return "", fmt.Errorf("parse subscription payload: %w", err)
	}
	if sub.ID == "" {
		return "", fmt.Errorf("subscription payload missing id")
	}

	reason := fmt.Sprintf("stripe:%s:%s", evt.EventType, evt.ProviderEventID)
	if err := fulfillment.ReconcileSubscription(ctx, a.DB, a.Logger, sub.ID, reason); err != nil {
		return "", fmt.Errorf("reconcile subscription: %w", err)
	}

	a.Logger.Info("subscription event reconciled",
		slog.String("event_type", evt.EventType),
		slog.String("stripe_subscription_id", sub.ID))
	return "completed", nil
}

// readPayload reads the scrubbed webhook payload for an event.
func (a *WebhookActivities) readPayload(ctx context.Context, eventID int64) ([]byte, error) {
	var payloadBytes []byte
	err := a.DB.QueryRowContext(ctx,
		`SELECT payload FROM core.webhook_events
		 WHERE id = $1 AND received_at = (SELECT received_at FROM core.webhook_events WHERE id = $1)`,
		eventID,
	).Scan(&payloadBytes)
	if err != nil {
		return nil, fmt.Errorf("read webhook payload: %w", err)
	}
	return payloadBytes, nil
}