ux(settings): toast-undo for Reset on override rows (closes #113)

frontend/src/__tests__/settings-accounts.test.ts

@@ -1356,6 +1356,96 @@ describe('Account overrides modal', () => {
     expect(opts.body).not.toContain('Reset');
   });
 
+  describe('toast-undo for Delete override (issue #113)', () => {
+    const overrideFixture = {
+      account_id: 'acc-1',
+      provider: 'aws',
+      service: 'rds',
+      term: 1,
+      payment: 'all-upfront',
+      coverage: 75,
+      enabled: true,
+    };
+
+    test('Delete shows info toast with Undo action and clears row (click-Undo path)', async () => {
+      (api.listAccountServiceOverrides as jest.Mock)
+        .mockResolvedValueOnce([overrideFixture])  // initial render
+        .mockResolvedValue([]);                     // reload after delete + reload after undo
+      (api.deleteAccountServiceOverride as jest.Mock).mockResolvedValue(undefined);
+      (api.saveAccountServiceOverride as jest.Mock).mockResolvedValue(overrideFixture);
+      mockConfirmDialog.mockResolvedValue(true);
+
+      const panel = document.createElement('div');
+      document.body.appendChild(panel);
+      await loadOverridesPanel('acc-1', panel, 'aws');
+
+      const deleteBtn = Array.from(panel.querySelectorAll('button'))
+        .find(b => b.textContent === 'Delete') as HTMLButtonElement;
+      expect(deleteBtn).toBeDefined();
+
+      deleteBtn.click();
+      // Flush the confirm + delete + reload chain.
+      for (let i = 0; i < 5; i++) { await new Promise(r => setTimeout(r, 0)); }
+
+      expect(api.deleteAccountServiceOverride).toHaveBeenCalledWith('acc-1', 'aws', 'rds');
+
+      // An info toast with an Undo action must have been shown.
+      const toastCalls = mockShowToast.mock.calls.map(c => c[0]) as Array<{
+        kind?: string;
+        message?: string;
+        actions?: Array<{ label: string; onClick: () => void }>;
+        timeout?: number | null;
+      }>;
+      const undoToast = toastCalls.find(t => t.kind === 'info' && t.message?.includes('aws/rds'));
+      expect(undoToast).toBeDefined();
+      expect(undoToast!.actions).toBeDefined();
+      expect(undoToast!.actions!.length).toBe(1);
+      expect(undoToast!.actions![0]!.label).toBe('Undo');
+      // 5-second TTL per issue spec.
+      expect(undoToast!.timeout).toBe(5_000);
+
+      // Simulate clicking Undo.
+      undoToast!.actions![0]!.onClick();
+      for (let i = 0; i < 5; i++) { await new Promise(r => setTimeout(r, 0)); }
+
+      // saveAccountServiceOverride must have been called with the original snapshot.
+      expect(api.saveAccountServiceOverride).toHaveBeenCalledWith(
+        'acc-1', 'aws', 'rds',
+        expect.objectContaining({
+          term: 1,
+          payment: 'all-upfront',
+          coverage: 75,
+          enabled: true,
+        }),
+      );
+    });
+
+    test('let-it-expire path: override is permanently gone after toast timeout', async () => {
+      (api.listAccountServiceOverrides as jest.Mock)
+        .mockResolvedValueOnce([overrideFixture])
+        .mockResolvedValue([]);
+      (api.deleteAccountServiceOverride as jest.Mock).mockResolvedValue(undefined);
+      mockConfirmDialog.mockResolvedValue(true);
+
+      const panel = document.createElement('div');
+      document.body.appendChild(panel);
+      await loadOverridesPanel('acc-1', panel, 'aws');
+
+      const deleteBtn = Array.from(panel.querySelectorAll('button'))
+        .find(b => b.textContent === 'Delete') as HTMLButtonElement;
+      deleteBtn.click();
+      for (let i = 0; i < 5; i++) { await new Promise(r => setTimeout(r, 0)); }
+
+      // Undo was NOT clicked; saveAccountServiceOverride must not have been called.
+      expect(api.saveAccountServiceOverride).not.toHaveBeenCalled();
+      // The delete did fire.
+      expect(api.deleteAccountServiceOverride).toHaveBeenCalledTimes(1);
+      // The panel reloaded to show the empty state (no more override rows).
+      const table = panel.querySelector('table.overrides-table');
+      expect(table).toBeNull();
+    });
+  });
+
   describe('override commitmentOptions parity (issue #107)', () => {
     test('inline payment selector hides invalid options for RDS term=3 row', async () => {
       // RDS rejects 3yr no-upfront per commitmentOptions invalidCombinations.

frontend/src/settings.ts

@@ -1195,10 +1195,48 @@ export async function loadOverridesPanel(accountId: string, panel: HTMLElement,
           destructive: true,
         });
         if (!ok) return;
+        // Snapshot all fields before deleting so the Undo action can re-PUT
+        // them if the user clicks the toast button within the 5-second window.
+        const snapshot: api.AccountServiceOverrideRequest = {
+          enabled: o.enabled,
+          term: o.term,
+          payment: o.payment,
+          coverage: o.coverage,
+          ramp_schedule: o.ramp_schedule,
+          include_engines: o.include_engines,
+          exclude_engines: o.exclude_engines,
+          include_regions: o.include_regions,
+          exclude_regions: o.exclude_regions,
+          include_types: o.include_types,
+          exclude_types: o.exclude_types,
+        };
         try {
           await api.deleteAccountServiceOverride(accountId, o.provider, o.service);
           await loadOverridesPanel(accountId, panel, provider);
           await refreshRecommendationsAfterOverrideChange();
+          // Show a 5-second undo toast. The action closure captures `snapshot`
+          // and re-PUT it if the user clicks Undo before the toast expires.
+          // Each Reset click replaces any prior toast handle so a rapid
+          // double-click cannot stack multiple Undo buttons.
+          showToast({
+            message: `Override for ${o.provider}/${o.service} deleted.`,
+            kind: 'info',
+            timeout: 5_000,
+            actions: [{
+              label: 'Undo',
+              onClick: () => {
+                void (async () => {
+                  try {
+                    await api.saveAccountServiceOverride(accountId, o.provider, o.service, snapshot);
+                    await loadOverridesPanel(accountId, panel, provider);
+                    await refreshRecommendationsAfterOverrideChange();
+                  } catch (undoErr) {
+                    showToast({ message: `Failed to restore override: ${(undoErr as Error).message}`, kind: 'error' });
+                  }
+                })();
+              },
+            }],
+          });
         } catch (err) {
           showToast({ message: `Failed to delete override: ${(err as Error).message}`, kind: 'error' });
         }