docs(comments): add some comments

* ci(checks): add pull request workflow and golangci-lint config

* refactor(lint): resolve golangci-lint findings

* style(tui): drop traling blank line for gofmt

* fix(cards): handle crypto/rand.Read error in storeRedirect

.github/workflows/ci.yml

@@ -0,0 +1,38 @@
+name: CI
+
+on:
+  pull_request:
+    branches: [master]
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+
+      - name: Build
+        run: go build ./...
+
+      - name: Vet
+        run: go vet ./...
+
+      - name: Format check
+        run: |
+          unformatted=$(gofmt -l $(go list -f '{{.Dir}}' ./...))
+          if [ -n "$unformatted" ]; then
+            echo "These files need gofmt:"
+            echo "$unformatted"
+            exit 1
+          fi
+
+      - name: Lint
+        uses: golangci/golangci-lint-action@v7
+        with:
+          version: v2.4.0
+
+      - name: Test (race detector)
+        run: go test -race ./...

.golangci.yml

@@ -0,0 +1,16 @@
+version: "2"
+
+run:
+  timeout: 5m
+
+linters:
+  default: none
+  enable:
+    - errcheck
+    - govet
+    - ineffassign
+    - staticcheck
+    - unused
+  exclusions:
+    paths:
+      - terminal-shop-source

api/handlers/addresses_test.go

@@ -13,7 +13,7 @@ import (
 func setupAddressTestDB(t *testing.T) (string, models.User) {
 	t.Helper()
 	testDB := "test_addresses.db"
-	os.Remove(testDB)
+	_ = os.Remove(testDB)
 	database.ResetForTesting()
 
 	db, err := database.Connect(testDB)
@@ -42,7 +42,7 @@ func setupAddressTestDB(t *testing.T) (string, models.User) {
 
 func TestGetAddressesEmpty(t *testing.T) {
 	testDB, user := setupAddressTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	handler := NewAddressHandler("", "", "")
@@ -74,7 +74,7 @@ func TestGetAddressesEmpty(t *testing.T) {
 
 func TestGetAddressesIsolation(t *testing.T) {
 	testDB, user1 := setupAddressTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	db := database.GetDB()
@@ -105,7 +105,7 @@ func TestGetAddressesIsolation(t *testing.T) {
 			Addresses []models.Address `json:"addresses"`
 		} `json:"data"`
 	}
-	json.NewDecoder(w.Body).Decode(&resp)
+	_ = json.NewDecoder(w.Body).Decode(&resp)
 
 	if len(resp.Data.Addresses) != 1 {
 		t.Fatalf("expexted 1 address for user1, got %d", len(resp.Data.Addresses))
@@ -117,7 +117,7 @@ func TestGetAddressesIsolation(t *testing.T) {
 
 func TestGetAddressesWithData(t *testing.T) {
 	testDB, user := setupAddressTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	db := database.GetDB()

api/handlers/auth_test.go

@@ -22,7 +22,7 @@ const testClientSecret = "test-client-secret"
 func setupAuthHandlerTestDB(t *testing.T) (string, *auth.JWTManager, *AuthHandler) {
 	t.Helper()
 	testDB := "test_auth.db"
-	os.Remove(testDB)
+	_ = os.Remove(testDB)
 	database.ResetForTesting()
 
 	db, err := database.Connect(testDB)
@@ -62,7 +62,7 @@ func createAuthTestUser(t *testing.T, fingerprint string) models.User {
 
 func TestGetTokenSuccess(t *testing.T) {
 	testDB, _, handler := setupAuthHandlerTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	user := createAuthTestUser(t, "SHA256:testfingerprint123")
@@ -108,7 +108,7 @@ func TestGetTokenSuccess(t *testing.T) {
 
 func TestGetTokenBadSecret(t *testing.T) {
 	testDB, _, handler := setupAuthHandlerTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	body, _ := json.Marshal(map[string]string{
@@ -128,7 +128,7 @@ func TestGetTokenBadSecret(t *testing.T) {
 
 func TestGetTokenMissingFingerprint(t *testing.T) {
 	testDB, _, handler := setupAuthHandlerTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	body, _ := json.Marshal(map[string]string{
@@ -147,7 +147,7 @@ func TestGetTokenMissingFingerprint(t *testing.T) {
 
 func TestGetTokenUnknownFingerprint(t *testing.T) {
 	testDB, _, handler := setupAuthHandlerTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	body, _ := json.Marshal(map[string]string{
@@ -167,7 +167,7 @@ func TestGetTokenUnknownFingerprint(t *testing.T) {
 
 func TestGetTokenInvalidJSON(t *testing.T) {
 	testDB, _, handler := setupAuthHandlerTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	req := httptest.NewRequest("POST", "/api/v1/auth/token", bytes.NewBufferString("{bad json"))
@@ -185,7 +185,7 @@ func TestGetTokenInvalidJSON(t *testing.T) {
 
 func TestRegisterWithSSHKeySuccess(t *testing.T) {
 	testDB, _, handler := setupAuthHandlerTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	body, _ := json.Marshal(map[string]string{
@@ -207,7 +207,7 @@ func TestRegisterWithSSHKeySuccess(t *testing.T) {
 
 func TestRegisterWithSSHKeyDuplicate(t *testing.T) {
 	testDB, _, handler := setupAuthHandlerTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	createAuthTestUser(t, "SHA256:existingfp")
@@ -229,7 +229,7 @@ func TestRegisterWithSSHKeyDuplicate(t *testing.T) {
 
 func TestRegisterWithSSHKeyMissingFields(t *testing.T) {
 	testDB, _, handler := setupAuthHandlerTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	body, _ := json.Marshal(map[string]string{
@@ -250,7 +250,7 @@ func TestRegisterWithSSHKeyMissingFields(t *testing.T) {
 
 func TestGetUserBySSHKeySuccess(t *testing.T) {
 	testDB, _, handler := setupAuthHandlerTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	createAuthTestUser(t, "SHA256:lookupfp")
@@ -267,7 +267,7 @@ func TestGetUserBySSHKeySuccess(t *testing.T) {
 
 func TestGetUserBySSHKeyNotFound(t *testing.T) {
 	testDB, _, handler := setupAuthHandlerTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	req := httptest.NewRequest("GET", "/api/v1/auth/ssh?fingerprint=SHA256:nope", nil)
@@ -282,7 +282,7 @@ func TestGetUserBySSHKeyNotFound(t *testing.T) {
 
 func TestGetUserBySSHKeyMissingParam(t *testing.T) {
 	testDB, _, handler := setupAuthHandlerTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	req := httptest.NewRequest("GET", "/api/v1/auth/ssh", nil)

api/handlers/cards.go

@@ -30,14 +30,16 @@ var (
 	payRedirectsMu sync.Mutex
 )
 
-func storeRedirect(stripeURL string) string {
+func storeRedirect(stripeURL string) (string, error) {
 	b := make([]byte, 16)
-	rand.Read(b)
+	if _, err := rand.Read(b); err != nil {
+		return "", err
+	}
 	token := hex.EncodeToString(b)
 	payRedirectsMu.Lock()
 	payRedirects[token] = stripeURL
 	payRedirectsMu.Unlock()
-	return token
+	return token, nil
 }
 
 // PayRedirect resolves a short token and redirects to the Stripe checkout URL.
@@ -166,7 +168,11 @@ func (h *CardHandler) CollectCard(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	token := storeRedirect(sess.URL)
+	token, err := storeRedirect(sess.URL)
+	if err != nil {
+		utils.RespondError(w, http.StatusInternalServerError, "INTERNAL_ERROR", "failed to generate redirect token", nil)
+		return
+	}
 	utils.RespondSuccess(w, http.StatusOK, map[string]interface{}{
 		"url": fmt.Sprintf("%s/pay/%s", h.appURL, token),
 	})

api/handlers/cart_test.go

@@ -20,7 +20,7 @@ import (
 func setupCartTestDB(t *testing.T) (string, models.User) {
 	t.Helper()
 	testDB := "test_cart.db"
-	os.Remove(testDB)
+	_ = os.Remove(testDB)
 	database.ResetForTesting()
 
 	db, err := database.Connect(testDB)
@@ -62,7 +62,7 @@ func authRequest(method, url string, body []byte, userID uint) *http.Request {
 
 func TestGetCartEmpty(t *testing.T) {
 	testDB, user := setupCartTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	handler := NewCartHandler("")
@@ -101,7 +101,7 @@ func TestGetCartEmpty(t *testing.T) {
 
 func TestSetItemAndGetCart(t *testing.T) {
 	testDB, user := setupCartTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	handler := NewCartHandler("")
@@ -157,7 +157,7 @@ func TestSetItemAndGetCart(t *testing.T) {
 
 func TestSetItemUpdateQuantity(t *testing.T) {
 	testDB, user := setupCartTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	handler := NewCartHandler("")
@@ -190,7 +190,7 @@ func TestSetItemUpdateQuantity(t *testing.T) {
 			} `json:"cart"`
 		} `json:"data"`
 	}
-	json.NewDecoder(w.Body).Decode(&resp)
+	_ = json.NewDecoder(w.Body).Decode(&resp)
 
 	if len(resp.Data.Cart.Items) != 1 {
 		t.Fatalf("Expected 1 item after update, got %d", len(resp.Data.Cart.Items))
@@ -202,7 +202,7 @@ func TestSetItemUpdateQuantity(t *testing.T) {
 
 func TestSetItemRemove(t *testing.T) {
 	testDB, user := setupCartTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	handler := NewCartHandler("")
@@ -232,7 +232,7 @@ func TestSetItemRemove(t *testing.T) {
 			} `json:"cart"`
 		} `json:"data"`
 	}
-	json.NewDecoder(w.Body).Decode(&resp)
+	_ = json.NewDecoder(w.Body).Decode(&resp)
 
 	if len(resp.Data.Cart.Items) != 0 {
 		t.Errorf("Expected 0 items after removal, got %d", len(resp.Data.Cart.Items))
@@ -241,7 +241,7 @@ func TestSetItemRemove(t *testing.T) {
 
 func TestSetItemInvalidProduct(t *testing.T) {
 	testDB, user := setupCartTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	handler := NewCartHandler("")
@@ -258,7 +258,7 @@ func TestSetItemInvalidProduct(t *testing.T) {
 
 func TestSetItemMissingCoffeeID(t *testing.T) {
 	testDB, user := setupCartTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	handler := NewCartHandler("")
@@ -275,7 +275,7 @@ func TestSetItemMissingCoffeeID(t *testing.T) {
 
 func TestClearCart(t *testing.T) {
 	testDB, user := setupCartTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	handler := NewCartHandler("")
@@ -310,7 +310,7 @@ func TestClearCart(t *testing.T) {
 			} `json:"cart"`
 		} `json:"data"`
 	}
-	json.NewDecoder(w.Body).Decode(&resp)
+	_ = json.NewDecoder(w.Body).Decode(&resp)
 
 	if len(resp.Data.Cart.Items) != 0 {
 		t.Errorf("Expected 0 items after clear, got %d", len(resp.Data.Cart.Items))
@@ -319,7 +319,7 @@ func TestClearCart(t *testing.T) {
 
 func TestSetAddress(t *testing.T) {
 	testDB, user := setupCartTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	db := database.GetDB()
@@ -358,7 +358,7 @@ func TestSetAddress(t *testing.T) {
 			} `json:"cart"`
 		} `json:"data"`
 	}
-	json.NewDecoder(w.Body).Decode(&resp)
+	_ = json.NewDecoder(w.Body).Decode(&resp)
 
 	if resp.Data.Cart.AddressID == nil || *resp.Data.Cart.AddressID != addr.ID {
 		t.Errorf("Expected address_id %d, got %v", addr.ID, resp.Data.Cart.AddressID)
@@ -367,7 +367,7 @@ func TestSetAddress(t *testing.T) {
 
 func TestSetAddressWrongUser(t *testing.T) {
 	testDB, user := setupCartTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	db := database.GetDB()
@@ -402,7 +402,7 @@ func TestSetAddressWrongUser(t *testing.T) {
 
 func TestSetCard(t *testing.T) {
 	testDB, user := setupCartTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	db := database.GetDB()
@@ -440,7 +440,7 @@ func TestSetCard(t *testing.T) {
 			} `json:"cart"`
 		} `json:"data"`
 	}
-	json.NewDecoder(w.Body).Decode(&resp)
+	_ = json.NewDecoder(w.Body).Decode(&resp)
 
 	if resp.Data.Cart.CardID == nil || *resp.Data.Cart.CardID != card.ID {
 		t.Errorf("Expected card_id %d, got %v", card.ID, resp.Data.Cart.CardID)
@@ -449,7 +449,7 @@ func TestSetCard(t *testing.T) {
 
 func TestSetCardWrongUser(t *testing.T) {
 	testDB, user := setupCartTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	db := database.GetDB()
@@ -482,7 +482,7 @@ func TestSetCardWrongUser(t *testing.T) {
 
 func TestConvertCartMissingAddress(t *testing.T) {
 	testDB, user := setupCartTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	handler := NewCartHandler("")
@@ -505,7 +505,7 @@ func TestConvertCartMissingAddress(t *testing.T) {
 
 func TestConvertCartMissingCard(t *testing.T) {
 	testDB, user := setupCartTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	handler := NewCartHandler("")
@@ -536,7 +536,7 @@ func TestConvertCartMissingCard(t *testing.T) {
 
 func TestConvertCartEmpty(t *testing.T) {
 	testDB, user := setupCartTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	handler := NewCartHandler("")
@@ -553,7 +553,7 @@ func TestConvertCartEmpty(t *testing.T) {
 
 func TestMultipleItems(t *testing.T) {
 	testDB, user := setupCartTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	handler := NewCartHandler("")
@@ -583,7 +583,7 @@ func TestMultipleItems(t *testing.T) {
 			} `json:"cart"`
 		} `json:"data"`
 	}
-	json.NewDecoder(w.Body).Decode(&resp)
+	_ = json.NewDecoder(w.Body).Decode(&resp)
 
 	if len(resp.Data.Cart.Items) != 3 {
 		t.Errorf("Expected 3 items, got %d", len(resp.Data.Cart.Items))
@@ -595,7 +595,7 @@ func TestMultipleItems(t *testing.T) {
 
 func TestCartIsolation(t *testing.T) {
 	testDB, user1 := setupCartTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	db := database.GetDB()
@@ -638,7 +638,7 @@ func TestCartIsolation(t *testing.T) {
 			} `json:"cart"`
 		} `json:"data"`
 	}
-	json.NewDecoder(w.Body).Decode(&resp)
+	_ = json.NewDecoder(w.Body).Decode(&resp)
 
 	if len(resp.Data.Cart.Items) != 1 {
 		t.Fatalf("User 1 expected 1 item, got %d", len(resp.Data.Cart.Items))
@@ -655,7 +655,7 @@ func TestCartIsolation(t *testing.T) {
 	w = httptest.NewRecorder()
 	r.ServeHTTP(w, req)
 
-	json.NewDecoder(w.Body).Decode(&resp)
+	_ = json.NewDecoder(w.Body).Decode(&resp)
 
 	if len(resp.Data.Cart.Items) != 1 {
 		t.Fatalf("User 2 expected 1 item, got %d", len(resp.Data.Cart.Items))

api/handlers/products_test.go

@@ -16,7 +16,7 @@ func setupTestDB(t *testing.T) string {
 	testDB := "test_products.db"
 
 	// Remove if exists
-	os.Remove(testDB)
+	_ = os.Remove(testDB)
 
 	// Reset singleton
 	database.ResetForTesting()
@@ -39,7 +39,7 @@ func setupTestDB(t *testing.T) string {
 
 func TestGetProduct(t *testing.T) {
 	testDB := setupTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	handler := NewProductHandler()
@@ -78,7 +78,7 @@ func TestGetProduct(t *testing.T) {
 
 func TestGetProductNotFound(t *testing.T) {
 	testDB := setupTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	handler := NewProductHandler()
@@ -98,7 +98,7 @@ func TestGetProductNotFound(t *testing.T) {
 
 func TestGetProductsEmptyDatabase(t *testing.T) {
 	testDB := "test_empty.db"
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	// Create database but don't seed

api/handlers/slack.go

@@ -133,7 +133,7 @@ func (h *SlackHandler) handleBuyLabel(orderIDStr string, p slackInteractivePaylo
 		notify.SlackPostToOrderThread(orderID, fmt.Sprintf(":x: Label purchase failed: %v", err))
 		return
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	var result struct {
 		Data struct {
@@ -201,7 +201,7 @@ func (h *SlackHandler) handleMarkStatus(orderIDStr string, p slackInteractivePay
 		notify.SlackPostToOrderThread(orderID, fmt.Sprintf(":x: Mark %s failed: %v", status, err))
 		return
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 	if resp.StatusCode >= 300 {
 		notify.SlackPostToOrderThread(orderID, fmt.Sprintf(":x: Mark %s failed (HTTP %d)", status, resp.StatusCode))
 		return
@@ -245,7 +245,7 @@ func (h *SlackHandler) editClearActions(responseURL, status, actor string) {
 		slog.Warn("slack mark_status: response_url edit failed", "error", err)
 		return
 	}
-	resp.Body.Close()
+	_ = resp.Body.Close()
 }
 
 func (h *SlackHandler) verifySignature(r *http.Request, body []byte) bool {
@@ -264,7 +264,7 @@ func (h *SlackHandler) verifySignature(r *http.Request, body []byte) bool {
 	}
 
 	mac := hmac.New(sha256.New, []byte(h.signingSecret))
-	fmt.Fprintf(mac, "v0:%d:%s", ts, body)
+	_, _ = fmt.Fprintf(mac, "v0:%d:%s", ts, body)
 	expected := "v0=" + hex.EncodeToString(mac.Sum(nil))
 
 	return hmac.Equal([]byte(expected), []byte(sigHeader))

api/main.go

@@ -40,7 +40,8 @@ func main() {
 	if err != nil {
 		log.Fatalf("Failed to connect to database: %v", err)
 	}
-	defer database.Close()
+
+	defer func() { _ = database.Close() }()
 
 	// Run migrations
 	if err := database.Migrate(db); err != nil {
@@ -61,7 +62,7 @@ func main() {
 	if err != nil {
 		log.Printf("tracing init failed (non-fatal): %v", err)
 	} else {
-		defer shutdown(context.Background())
+		defer func() { _ = shutdown(context.Background()) }()
 	}
 
 	stripeclient.InitOTel()

api/routes/routes.go

@@ -59,7 +59,7 @@ func SetupRoutes(
 	r.Get("/t/{id}", handlers.TrackingRedirect)
 	r.Get("/card-added", func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "text/html")
-		w.Write([]byte(`<!DOCTYPE html><html><body style="font-family:monospace;text-align:center;padding:4rem"><h2>Card added.</h2><p>You can close this tab.</p></body></html>`))
+		_, _ = w.Write([]byte(`<!DOCTYPE html><html><body style="font-family:monospace;text-align:center;padding:4rem"><h2>Card added.</h2><p>You can close this tab.</p></body></html>`))
 	})
 	r.Handle("/metrics", middleware.MetricsHandler())
 

pkg/api/client.go

@@ -80,7 +80,7 @@ func (c *Client) GetOrCreateToken(fingerprint, pubKeyStr, clientSecret string) (
 	if err != nil {
 		return "", models.PublicUser{}, fmt.Errorf("token refresh request failed: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	if resp.StatusCode != http.StatusOK {
 		return "", models.PublicUser{}, fmt.Errorf("token refresh returned status %d", resp.StatusCode)
@@ -137,7 +137,7 @@ func (c *Client) GetProducts() ([]models.Coffee, error) {
 	if err != nil {
 		return nil, fmt.Errorf("failed to fetch products: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	if resp.StatusCode != http.StatusOK {
 		return nil, fmt.Errorf("API returned status %d", resp.StatusCode)
@@ -167,7 +167,7 @@ func (c *Client) Health() error {
 	if err != nil {
 		return fmt.Errorf("health check failed: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	if resp.StatusCode != http.StatusOK {
 		return fmt.Errorf("API returned status %d", resp.StatusCode)
@@ -217,7 +217,7 @@ func (c *Client) RegisterUser(username, sshPublicKey, sshKeyFingerprint string)
 	if err != nil {
 		return nil, fmt.Errorf("failed to register user: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	var registerResp RegisterResponse
 	if err := json.NewDecoder(resp.Body).Decode(&registerResp); err != nil {
@@ -302,7 +302,7 @@ func (c *Client) GetCart() (*CartData, error) {
 	if err != nil {
 		return nil, fmt.Errorf("failed to fetch cart: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	var cartResp CartResponse
 	if err := json.NewDecoder(resp.Body).Decode(&cartResp); err != nil {
@@ -342,7 +342,7 @@ func (c *Client) SetCartItem(coffeeID uint, quantity int) (*CartData, error) {
 	if err != nil {
 		return nil, fmt.Errorf("failed to set cart item: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	var cartResp CartResponse
 	if err := json.NewDecoder(resp.Body).Decode(&cartResp); err != nil {
@@ -381,7 +381,7 @@ func (c *Client) SetCartAddress(addressID uint) error {
 	if err != nil {
 		return fmt.Errorf("failed to set cart address: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	var result APIResponse
 	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
@@ -420,7 +420,7 @@ func (c *Client) SetCartCard(cardID uint) error {
 	if err != nil {
 		return fmt.Errorf("failed to set cart card: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	var result APIResponse
 	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
@@ -450,7 +450,7 @@ func (c *Client) ClearCart() error {
 	if err != nil {
 		return fmt.Errorf("failed to clear cart: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	var result APIResponse
 	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
@@ -480,7 +480,7 @@ func (c *Client) ConvertCart() (*models.Order, error) {
 	if err != nil {
 		return nil, fmt.Errorf("failed to convert cart: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	var convertResp ConvertCartResponse
 	if err := json.NewDecoder(resp.Body).Decode(&convertResp); err != nil {
@@ -510,7 +510,7 @@ func (c *Client) GetCards() ([]models.Card, error) {
 	if err != nil {
 		return nil, fmt.Errorf("failed to fetch cards: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	var cardsResp CardsResponse
 	if err := json.NewDecoder(resp.Body).Decode(&cardsResp); err != nil {
@@ -553,7 +553,7 @@ func (c *Client) SaveCard(params SaveCardRequest) (*models.Card, error) {
 	if err != nil {
 		return nil, fmt.Errorf("failed to save card: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	var cardResp CardResponse
 	if err := json.NewDecoder(resp.Body).Decode(&cardResp); err != nil {
@@ -590,7 +590,7 @@ func (c *Client) CollectCard() (string, error) {
 	if err != nil {
 		return "", fmt.Errorf("failed to collect card: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	var collectResp CollectCardResponse
 	if err := json.NewDecoder(resp.Body).Decode(&collectResp); err != nil {
@@ -619,7 +619,7 @@ func (c *Client) DeleteCard(id uint) error {
 	if err != nil {
 		return fmt.Errorf("failed to delete card: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	if resp.StatusCode != http.StatusOK {
 		return fmt.Errorf("delete card failed with status %d", resp.StatusCode)
@@ -648,7 +648,7 @@ func (c *Client) GetOrders() ([]models.Order, error) {
 	if err != nil {
 		return nil, fmt.Errorf("failed to fetch orders: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	var ordersResp OrderResponse
 	if err := json.NewDecoder(resp.Body).Decode(&ordersResp); err != nil {
@@ -686,7 +686,7 @@ func (c *Client) GetAddresses() ([]models.Address, error) {
 		return nil, fmt.Errorf("failed to fetch addresses: %w", err)
 	}
 
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	var addrResp AddressResponse
 	if err := json.NewDecoder(resp.Body).Decode(&addrResp); err != nil {
@@ -732,7 +732,7 @@ func (c *Client) CreateAddress(addrReq CreateAddressRequest) (*models.Address, e
 	if err != nil {
 		return nil, fmt.Errorf("failed to create address: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	var result struct {
 		Success bool `json:"success"`
@@ -769,7 +769,7 @@ func (c *Client) DeleteAddress(id uint) error {
 	if err != nil {
 		return fmt.Errorf("failed to delete address: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	if resp.StatusCode != http.StatusOK {
 		return fmt.Errorf("delete address failed with status %d", resp.StatusCode)
@@ -804,7 +804,7 @@ func (c *Client) GetViewInit() (ViewInitData, error) {
 	if err != nil {
 		return ViewInitData{}, fmt.Errorf("view init request failed: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 	if resp.StatusCode != http.StatusOK {
 		return ViewInitData{}, fmt.Errorf("view init returned status: %d", resp.StatusCode)
 	}

pkg/auth/ssh_auth_test.go

@@ -17,7 +17,7 @@ import (
 func setupAuthTestDB(t *testing.T) string {
 	t.Helper()
 	testDB := "test_ssh_auth.db"
-	os.Remove(testDB)
+	_ = os.Remove(testDB)
 	database.ResetForTesting()
 
 	db, err := database.Connect(testDB)
@@ -47,7 +47,7 @@ func newTestSSHKey(t *testing.T) gossh.PublicKey {
 
 func TestAuthenticateSSHKeyNewUser(t *testing.T) {
 	testDB := setupAuthTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	db := database.GetDB()
@@ -72,7 +72,7 @@ func TestAuthenticateSSHKeyNewUser(t *testing.T) {
 
 func TestAuthenticateSSHKeyExistingUser(t *testing.T) {
 	testDB := setupAuthTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	db := database.GetDB()
@@ -96,7 +96,7 @@ func TestAuthenticateSSHKeyExistingUser(t *testing.T) {
 
 func TestRegisterWithSSHKey(t *testing.T) {
 	testDB := setupAuthTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	db := database.GetDB()
@@ -121,7 +121,7 @@ func TestRegisterWithSSHKey(t *testing.T) {
 
 func TestRegisterWithSSHKeyDuplicate(t *testing.T) {
 	testDB := setupAuthTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	db := database.GetDB()
@@ -145,7 +145,7 @@ func TestRegisterWithSSHKeyDuplicate(t *testing.T) {
 
 func TestIsSSHKeyRegistered(t *testing.T) {
 	testDB := setupAuthTestDB(t)
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer database.ResetForTesting()
 
 	db := database.GetDB()
@@ -164,7 +164,7 @@ func TestIsSSHKeyRegistered(t *testing.T) {
 	}
 
 	// After authentication (which auto-creates)
-	svc.AuthenticateSSHKey(key)
+	_, _, _ = svc.AuthenticateSSHKey(key)
 
 	registered, err = svc.IsSSHKeyRegistered(key)
 	if err != nil {

pkg/bring/booking.go

@@ -197,7 +197,7 @@ func (c *BookingClient) doJSON(ctx context.Context, url string, body any, out an
 	if err != nil {
 		return fmt.Errorf("request: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 	respBody, err := io.ReadAll(resp.Body)
 	if err != nil {
 		return fmt.Errorf("read response: %w", err)

pkg/bring/bring.go

@@ -110,7 +110,7 @@ func (c *Client) ValidateAddress(ctx context.Context, addr Address) (*Address, e
 	if err != nil {
 		return nil, fmt.Errorf("bring request failed: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	respBody, err := io.ReadAll(resp.Body)
 	if err != nil {

pkg/database/db.go

@@ -101,7 +101,7 @@ func Close() error {
 // WARNING: Only use this in tests!
 func ResetForTesting() {
 	if db != nil {
-		Close()
+		_ = Close()
 		db = nil
 		once = sync.Once{}
 	}

pkg/database/db_test.go

@@ -10,7 +10,7 @@ import (
 func TestConnect(t *testing.T) {
 	// Use a temporary test database
 	testDB := "test_terminalshop.db"
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer ResetForTesting()
 
 	db, err := Connect(testDB)
@@ -35,7 +35,7 @@ func TestConnect(t *testing.T) {
 
 func TestMigrate(t *testing.T) {
 	testDB := "test_migrate.db"
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer ResetForTesting()
 
 	db, err := Connect(testDB)
@@ -57,7 +57,7 @@ func TestMigrate(t *testing.T) {
 
 func TestSeed(t *testing.T) {
 	testDB := "test_seed.db"
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer ResetForTesting()
 
 	db, err := Connect(testDB)
@@ -115,7 +115,7 @@ func TestSeed(t *testing.T) {
 
 func TestGetDB(t *testing.T) {
 	testDB := "test_getdb.db"
-	defer os.Remove(testDB)
+	defer func() { _ = os.Remove(testDB) }()
 	defer ResetForTesting()
 
 	// Initialize connection

pkg/notify/slack.go

@@ -16,6 +16,7 @@ import (
 
 var slackClient = &http.Client{Timeout: 5 * time.Second}
 
+// dollars converts cents to dollars
 func dollars(cents int) string {
 	return fmt.Sprintf("$%.2f", float64(cents)/100)
 }
@@ -32,7 +33,7 @@ func postSlackMessage(token string, payload map[string]any) (string, bool) {
 		slog.Warn("slack post failed", "error", err)
 		return "", false
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	var parsed struct {
 		Ok    bool   `json:"ok"`
@@ -66,7 +67,7 @@ func slackPinCall(token, endpoint, channel, ts, benignErr string) bool {
 		slog.Warn("slack pin call failed", "endpoint", endpoint, "error", err)
 		return false
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	var parsed struct {
 		Ok    bool   `json:"ok"`

pkg/shippo/shippo.go

@@ -270,7 +270,7 @@ func (c *Client) doJSON(ctx context.Context, method, path string, body any, out
 	if err != nil {
 		return fmt.Errorf("request: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 	respBody, err := io.ReadAll(resp.Body)
 	if err != nil {
 		return fmt.Errorf("read response: %w", err)
@@ -432,7 +432,7 @@ func (c *Client) ValidateAddress(ctx context.Context, addr Address) (*Address, e
 	if err != nil {
 		return nil, fmt.Errorf("shippo request failed: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	respBody, err := io.ReadAll(resp.Body)
 	if err != nil {

pkg/tui/account.go

@@ -324,7 +324,8 @@ func (m Model) AccountUpdate(msg tea.Msg) (Model, tea.Cmd) {
 		switch selectedItem {
 		case "order history", "active orders":
 			if len(m.currentOrderList()) > 0 {
-				if m.account.orderViewState == 0 {
+				switch m.account.orderViewState {
+				case 0:
 					m.account.orderViewState = 1
 					m.account.orderCursor = 0
 					m.account.detailViewport.GotoTop()
@@ -334,8 +335,7 @@ func (m Model) AccountUpdate(msg tea.Msg) (Model, tea.Cmd) {
 						{key: "esc", value: "back"},
 						{key: "q", value: "quit"},
 					}
-				} else if m.account.orderViewState == 1 {
-					// Save scroll position before entering detail view
+				case 1:
 					m.account.orderYOffset = m.account.detailViewport.YOffset
 					m.account.orderViewState = 2
 					m.account.detailViewport.GotoTop()

pkg/tui/account_orders.go

@@ -248,4 +248,3 @@ func (m Model) displayStyle(k models.DisplayKind) lipgloss.Style {
 	}
 	return m.theme.TextHighlight()
 }
-

pkg/tui/confirmation.go

@@ -145,18 +145,18 @@ func (m Model) generateReviewContent() string {
 		if m.ShippingInfo.Street2 != "" {
 			view.WriteString(m.ShippingInfo.Street2 + "\n")
 		}
-		view.WriteString(fmt.Sprintf("%s,  %s %s,  %s\n", m.ShippingInfo.City, m.ShippingInfo.State, m.ShippingInfo.Zip, m.ShippingInfo.Country))
+		fmt.Fprintf(&view, "%s,  %s %s,  %s\n", m.ShippingInfo.City, m.ShippingInfo.State, m.ShippingInfo.Zip, m.ShippingInfo.Country)
 	}
 	view.WriteString("\n")
 
 	if m.SelectedCard != nil {
-		view.WriteString(fmt.Sprintf("cc: **** **** **** %s\n", m.SelectedCard.Last4))
+		fmt.Fprintf(&view, "cc: **** **** **** %s\n", m.SelectedCard.Last4)
 	}
 	view.WriteString("\n")
 
 	subtotal := m.CalculateSubtotal()
 
-	view.WriteString(fmt.Sprintf("subtotal: %s\n", formatUSD(subtotal)))
+	fmt.Fprintf(&view, "subtotal: %s\n", formatUSD(subtotal))
 	view.WriteString(m.theme.TextAccent().Render(fmt.Sprintf("total:    %s", formatUSD(subtotal))) + "\n")
 	view.WriteString("\n")
 	view.WriteString(m.theme.TextBrand().Render("press enter to confirm") + "\n")

pkg/tui/model.go

@@ -400,23 +400,6 @@ func (m Model) fetchCartCmd() tea.Msg {
 	return CartFetchedMsg{Cart: cart, Err: err}
 }
 
-// fetchProductsCmd fetches products from the API
-func (m Model) fetchProductsCmd() tea.Msg {
-	if m.APIClient == nil {
-		log.Println("[TUI] APIClient is nil, using fallback products")
-		return ProductsMsg{Err: nil} // No API client, use fallback
-	}
-
-	log.Printf("[TUI] Fetching products from API at %s", m.APIClient.BaseURL)
-	products, err := m.APIClient.GetProducts()
-	if err != nil {
-		log.Printf("[TUI] Failed to fetch products: %v", err)
-	} else {
-		log.Printf("[TUI] Loaded %d products from API", len(products))
-	}
-	return ProductsMsg{Products: products, Err: err}
-}
-
 func (m Model) Init() tea.Cmd {
 	return tea.Batch(
 		m.authCmd,
@@ -670,58 +653,6 @@ func (m Model) syncCartItemCmd(coffeeID uint, quantity int) (Model, tea.Cmd) {
 	}
 }
 
-// saveCardAndConvert tokenizes the card locally using the Stripe publishable
-// key (raw card data never reaches the backend), saves the token, then converts the cart
-func (m Model) saveCardAndConvert(form PaymentFormCompleteMsg) tea.Cmd {
-	return func() tea.Msg {
-		if m.APIClient == nil {
-			return CheckoutResultMsg{Err: fmt.Errorf("API client not available")}
-		}
-
-		stripe.Key = m.StripePublicKey
-		tok, err := stripetoken.New(&stripe.TokenParams{
-			Card: &stripe.CardParams{
-				Name:       stripe.String(form.CardName),
-				Number:     stripe.String(form.CardNumber),
-				ExpMonth:   stripe.String(form.ExpiryMonth),
-				ExpYear:    stripe.String(form.ExpiryYear),
-				CVC:        stripe.String(form.CVC),
-				AddressZip: stripe.String(form.BillingZip),
-			},
-		})
-		if err != nil {
-			if stripeErr, ok := err.(*stripe.Error); ok {
-				return CheckoutResultMsg{Err: fmt.Errorf("%s", stripeErr.Msg)}
-			}
-			return CheckoutResultMsg{Err: fmt.Errorf("failed to tokenize card: %w", err)}
-		}
-		card, err := m.APIClient.SaveCard(api.SaveCardRequest{Token: tok.ID})
-		if err != nil {
-			return CheckoutResultMsg{Err: fmt.Errorf("failed to save card: %w", err)}
-		}
-
-		if err := m.resolveCartAddress(); err != nil {
-			return CheckoutResultMsg{Err: err}
-		}
-
-		// 3. Set the card on the cart
-		if err := m.APIClient.SetCartCard(card.ID); err != nil {
-			return CheckoutResultMsg{Err: fmt.Errorf("failed to set card: %w", err)}
-		}
-
-		// 4. Convert the cart to an order
-		order, err := m.APIClient.ConvertCart()
-		if err != nil {
-			return CheckoutResultMsg{Err: err}
-		}
-
-		return CheckoutResultMsg{
-			OrderID: order.ID,
-			Total:   order.Total,
-		}
-	}
-}
-
 func (m Model) saveCardOnlyCmd(form PaymentFormCompleteMsg) tea.Cmd {
 	return func() tea.Msg {
 		if m.APIClient == nil {

pkg/utils/response.go

@@ -35,7 +35,7 @@ func RespondSuccess(w http.ResponseWriter, statusCode int, data interface{}) {
 		Data:    data,
 	}
 
-	json.NewEncoder(w).Encode(response)
+	_ = json.NewEncoder(w).Encode(response)
 }
 
 // RespondError sends an error JSON response
@@ -52,7 +52,7 @@ func RespondError(w http.ResponseWriter, statusCode int, code, message string, d
 		},
 	}
 
-	json.NewEncoder(w).Encode(response)
+	_ = json.NewEncoder(w).Encode(response)
 }
 
 // HealthData represents health check data

pkg/validate/validate.go

@@ -66,7 +66,7 @@ func CcnValidator(cardNumber string) error {
 func IsDigits(name string) ErrorHandler {
 	return func(str string) error {
 		for _, c := range str {
-			if !(c >= '0' && c <= '9') {
+			if c < '0' || c > '9' {
 				return fmt.Errorf("[%s] expected only digits but got %s", name, str)
 			}
 		}