fix: improve export filename and import confirmation UX (#232)

Export filename:
- Include username for multi-user/instance distinction
- Include timestamp with time (YYYYMMDD-HHMM) instead of date only
- Example: medassist-export-daniel-20260216-2108.json

Import confirmation:
- Show friendly 'Import Data?' dialog on empty instances instead of
  scary 'Replace All Data?' warning with danger button
- Only show destructive warning when there is existing data to replace
- Use primary button style for empty-state import

Closes #231

backend/src/routes/export.ts

@@ -475,7 +475,11 @@ export async function exportRoutes(app: FastifyInstance) {
 		};
 
 		// Set download headers
-		const filename = `medassist-export-${new Date().toISOString().split("T")[0]}.json`;
+		const now = new Date();
+		const dateStr = now.toISOString().replace(/[-:]/g, "").replace(/T/, "-").slice(0, 13);
+		const authUser = env.AUTH_ENABLED ? (request.user as unknown as AuthUser | null) : null;
+		const userPart = authUser?.username ? `-${authUser.username}` : "";
+		const filename = `medassist-export${userPart}-${dateStr}.json`;
 		reply.header("Content-Type", "application/json");
 		reply.header("Content-Disposition", `attachment; filename="${filename}"`);
 

frontend/src/context/AppContext.tsx

@@ -522,9 +522,11 @@ export function AppProvider({ children }: { children: React.ReactNode }) {
 				const blob = new Blob([JSON.stringify(data, null, 2)], { type: "application/json" });
 				const url = URL.createObjectURL(blob);
 				const a = document.createElement("a");
-				const dateStr = new Date().toISOString().split("T")[0];
+				const now = new Date();
+				const dateStr = now.toISOString().replace(/[-:]/g, "").replace(/T/, "-").slice(0, 13);
+				const userPart = user?.username ? `-${user.username}` : "";
 				a.href = url;
-				a.download = `${t("exportImport.downloadFilename")}-${dateStr}.json`;
+				a.download = `${t("exportImport.downloadFilename")}${userPart}-${dateStr}.json`;
 				document.body.appendChild(a);
 				a.click();
 				document.body.removeChild(a);

frontend/src/i18n/de.json

@@ -500,6 +500,9 @@
     "confirmImportMessage": "Dies löscht dauerhaft alle deine aktuellen Medikamente, Einnahmehistorie, Einstellungen und Teilen-Links und ersetzt sie durch die importierten Daten.",
     "confirmImportWarning": "Diese Aktion kann nicht rückgängig gemacht werden!",
     "confirmButton": "Ja, alles ersetzen",
+    "confirmImportEmpty": "Daten importieren?",
+    "confirmImportEmptyMessage": "Alle Medikamente, Einnahmehistorie, Einstellungen und Teilen-Links aus der ausgewählten Datei werden importiert.",
+    "confirmButtonEmpty": "Importieren",
     "cancelButton": "Abbrechen",
     "exportSuccess": "Daten erfolgreich exportiert",
     "importSuccess": "Daten erfolgreich importiert",

frontend/src/i18n/en.json

@@ -500,6 +500,9 @@
     "confirmImportMessage": "This will permanently delete all your current medications, dose history, settings, and share links, then replace them with the imported data.",
     "confirmImportWarning": "This action cannot be undone!",
     "confirmButton": "Yes, Replace All",
+    "confirmImportEmpty": "Import Data?",
+    "confirmImportEmptyMessage": "This will import all medications, dose history, settings, and share links from the selected file.",
+    "confirmButtonEmpty": "Import",
     "cancelButton": "Cancel",
     "exportSuccess": "Data exported successfully",
     "importSuccess": "Data imported successfully",

frontend/src/pages/SettingsPage.tsx

@@ -30,8 +30,11 @@ export function SettingsPage() {
 		handleImportConfirm,
 		importResult,
 		setImportResult,
+		meds,
 	} = useAppContext();
 
+	const hasExistingData = meds.length > 0;
+
 	return (
 		<section className="grid">
 			{settingsLoading ? (
@@ -799,21 +802,25 @@ export function SettingsPage() {
 			{/* Import Confirmation Modal */}
 			{showImportConfirm && (
 				<ConfirmModal
-					title={t("exportImport.confirmImport")}
+					title={t(hasExistingData ? "exportImport.confirmImport" : "exportImport.confirmImportEmpty")}
 					message={
+						hasExistingData ? (
 							<>
 								<p style={{ marginBottom: "12px" }}>{t("exportImport.confirmImportMessage")}</p>
 								<p className="warning-text">⚠️ {t("exportImport.confirmImportWarning")}</p>
 							</>
+						) : (
+							<p>{t("exportImport.confirmImportEmptyMessage")}</p>
+						)
 					}
-					confirmLabel={t("exportImport.confirmButton")}
+					confirmLabel={t(hasExistingData ? "exportImport.confirmButton" : "exportImport.confirmButtonEmpty")}
 					cancelLabel={t("exportImport.cancelButton")}
 					onConfirm={handleImportConfirm}
 					onCancel={() => {
 						setShowImportConfirm(false);
 						setPendingImportData(null);
 					}}
-					confirmVariant="danger"
+					confirmVariant={hasExistingData ? "danger" : "primary"}
 				/>
 			)}
 

frontend/src/test/pages/SettingsPage.test.tsx

@@ -86,6 +86,7 @@ const createMockContext = (overrides = {}) => ({
 	handleImportConfirm: vi.fn(),
 	importResult: null,
 	setImportResult: vi.fn(),
+	meds: [],
 	...overrides,
 });