feat: add order reconciliation job for crash recovery

Adds a background goruotine that runs every 5 minutes to find pending
orders with no Stripe ID older than 10 mins and patches them if stripe
shows a succeeded PaymentIntent. Covers the edge case where the server
crashes after charging but before the DB transaction commits. Also tags
PaymentIntents with order_id metadata at createion to make them
searchable

api/handlers/cart.go

@@ -392,6 +392,9 @@ func (h *CartHandler) ConvertCart(w http.ResponseWriter, r *http.Request) {
 		},
 	}
 	piParams.SetIdempotencyKey(fmt.Sprintf("order-%d", order.ID))
+	piParams.Metadata = map[string]string{
+		"order_id": fmt.Sprintf("%d", order.ID),
+	}
 
 	pi, err := paymentintent.New(piParams)
 	if err != nil {

api/handlers/reconcile.go

@@ -0,0 +1,74 @@
+package handlers
+
+import (
+	"fmt"
+	"log"
+	"time"
+
+	"terminalShop/pkg/database"
+	"terminalShop/pkg/models"
+
+	"github.com/stripe/stripe-go/v78"
+	"github.com/stripe/stripe-go/v78/paymentintent"
+	"gorm.io/gorm"
+)
+
+// ReconcileOrders finds pending orders with no Stripe ID older than 10 minutes
+// and checks whether Stripe has a succeeded PaymentIntent for them. This fixes
+// the case where the server crashed after charging but before the DB transaction
+// completed.
+func ReconcileOrders(stripeKey string) {
+	stripe.Key = stripeKey
+	db := database.GetDB()
+
+	var orders []models.Order
+	cutoff := time.Now().Add(-10 * time.Minute)
+	db.Where("status = ? AND stripe_payment_id = '' AND created_at < ?",
+		models.OrderStatusPending, cutoff).Find(&orders)
+
+	if len(orders) == 0 {
+		return
+	}
+
+	log.Printf("[reconcile] checking %d pending orders", len(orders))
+
+	for _, order := range orders {
+		params := &stripe.PaymentIntentSearchParams{
+			SearchParams: stripe.SearchParams{
+				Query: fmt.Sprintf("metadata['order_id']:'%d' AND status:'succeeded'", order.ID),
+			},
+		}
+
+		iter := paymentintent.Search(params)
+		for iter.Next() {
+			pi := iter.PaymentIntent()
+			log.Printf("[reconcile] found succeeded PI %s for order %d — patching", pi.ID, order.ID)
+
+			txErr := db.Transaction(func(tx *gorm.DB) error {
+				if err := tx.Model(&order).Updates(map[string]interface{}{
+					"status":            models.OrderStatusPaid,
+					"stripe_payment_id": pi.ID,
+				}).Error; err != nil {
+					return err
+				}
+				var cart models.Cart
+				if err := tx.Where("user_id = ?", order.UserID).First(&cart).Error; err != nil {
+					return nil // cart already gone, nothing to clear
+				}
+				if err := tx.Where("cart_id = ?", cart.ID).Delete(&models.CartItem{}).Error; err != nil {
+					return err
+				}
+				return tx.Model(&cart).Updates(map[string]interface{}{
+					"address_id": nil,
+					"card_id":    nil,
+				}).Error
+			})
+			if txErr != nil {
+				log.Printf("[reconcile] failed to patch order %d: %v", order.ID, txErr)
+			}
+		}
+		if err := iter.Err(); err != nil {
+			log.Printf("[reconcile] stripe search error for order %d: %v", order.ID, err)
+		}
+	}
+}

api/main.go

@@ -10,8 +10,9 @@ import (
 	"syscall"
 	"time"
 
-	"terminalShop/pkg/auth"
+	"terminalShop/api/handlers"
 	"terminalShop/api/routes"
+	"terminalShop/pkg/auth"
 	"terminalShop/pkg/config"
 	"terminalShop/pkg/database"
 )
@@ -19,6 +20,8 @@ import (
 const version = "v0.1.0"
 
 func main() {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
 	// Load configuration
 	cfg, err := config.Load()
 	if err != nil {
@@ -73,14 +76,30 @@ func main() {
 		}
 	}()
 
+	// Start reconciliation job. runs every 5 minutes to catch any orders
+	// that were charged but not recorded due to a crash.
+	go func() {
+		ticker := time.NewTicker(5 * time.Minute)
+		defer ticker.Stop()
+		for {
+			select {
+			case <-ticker.C:
+				handlers.ReconcileOrders(cfg.StripeSecretKey)
+			case <-ctx.Done():
+				return
+			}
+		}
+	}()
+
 	log.Println("API server started. Press Ctrl+C to shutdown.")
 
 	// Block until signal received
 	<-done
+	cancel()
 	log.Println("Server is shutting down...")
 
 	// Graceful shutdown with 30 second timeout
-	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	ctx, cancel = context.WithTimeout(context.Background(), 30*time.Second)
 	defer cancel()
 
 	if err := server.Shutdown(ctx); err != nil {