fix(scans): replace error banner with toast feedback for delete and rescan failures

frontend/src/pages/Scans.tsx

@@ -9,6 +9,7 @@ import {
   formatLocaleTime,
 } from "../utils/date";
 import { ConfirmModal } from "../components/ConfirmModal";
+import { useToast } from "../components/ToastContext";
 import Pagination from "../components/Pagination";
 
 interface Task {
@@ -58,6 +59,7 @@ const itemVariants: Variants = {
 
 export default function Scans() {
   const navigate = useNavigate();
+  const { addToast } = useToast();
   const [tasks, setTasks] = useState<Task[]>([]);
   const [loading, setLoading] = useState(true);
   const [filter, setFilter] = useState("all");
@@ -193,6 +195,7 @@ export default function Scans() {
       }
     } catch (err) {
       console.error("Rescan failed:", err);
+      addToast("Rescan failed. Please try again.", "error");
     }
   }
 
@@ -211,7 +214,7 @@ export default function Scans() {
           setModalState(prev => ({ ...prev, isOpen: false }));
         } catch (err) {
           console.error("Failed to delete task:", err);
-          setError("Failed to delete task. It might still be running.");
+          addToast("Failed to delete task. It might still be running.", "error");
           setModalState(prev => ({ ...prev, isOpen: false }));
         }
       },
@@ -234,7 +237,7 @@ export default function Scans() {
           setModalState(prev => ({ ...prev, isOpen: false }));
         } catch (err) {
           console.error("Failed to clear history:", err);
-          setError("Failed to clear history. Ensure no tasks are currently running.");
+          addToast("Failed to clear history. Ensure no tasks are currently running.", "error");
           setModalState(prev => ({ ...prev, isOpen: false }));
         }
       },
@@ -257,7 +260,7 @@ export default function Scans() {
           setModalState(prev => ({ ...prev, isOpen: false }));
         } catch (err) {
           console.error("Bulk delete failed:", err);
-          setError("Failed to delete some tasks. Ensure they are not currently running.");
+          addToast("Failed to delete some tasks. Ensure they are not currently running.", "error");
           setModalState(prev => ({ ...prev, isOpen: false }));
         }
       },

frontend/testing/unit/pages/Scans.polling.test.tsx

@@ -2,6 +2,7 @@ import { render, act, screen } from '@testing-library/react';
 import { MemoryRouter } from 'react-router-dom';
 import { vi, describe, it, expect, beforeEach, afterEach } from 'vitest';
 import Scans from '../../../src/pages/Scans';
+import { ToastProvider } from '../../../src/components/ToastContext'
 
 // ── Mocks ────────────────────────────────────────────────────────────────────
 
@@ -68,8 +69,10 @@ afterEach(() => {
 function renderScans() {
   return render(
     <MemoryRouter>
-      <Scans />
-    </MemoryRouter>,
+      <ToastProvider>
+        <Scans />
+      </ToastProvider>
+    </MemoryRouter>
   );
 }
 

frontend/testing/unit/pages/Scans.test.tsx

@@ -4,6 +4,7 @@ import userEvent from '@testing-library/user-event'
 import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest'
 import { MemoryRouter } from 'react-router-dom'
 import Scans from '../../../src/pages/Scans'
+import { ToastProvider } from '../../../src/components/ToastContext'
 
 // ── Mocks ────────────────────────────────────────────────────────────────────
 
@@ -83,7 +84,9 @@ function mockFetch(tasks: ReturnType<typeof makeTask>[], total?: number) {
 function renderScans() {
   return render(
     <MemoryRouter>
-      <Scans />
+      <ToastProvider>
+        <Scans />
+      </ToastProvider>
     </MemoryRouter>
   )
 }
@@ -273,12 +276,7 @@ describe('Scans — task list', () => {
     expect(screen.getByText('nmap')).toBeInTheDocument()
     expect(screen.getByText('1')).toBeInTheDocument()
 
-    // Test that the error banner can be closed
-    const closeBtn = screen.getByRole('button', { name: /Close alert/i })
-    await userEvent.click(closeBtn)
-
-    await waitFor(() => {
-      expect(screen.queryByRole('alert')).not.toBeInTheDocument()
-    })
+    // Error is shown via toast, not the banner — no Close alert button expected
+    expect(screen.queryByRole('button', { name: /Close alert/i })).not.toBeInTheDocument()
   })
 })

frontend/testing/unit/pages/ScansPhases.test.tsx

@@ -2,6 +2,7 @@ import { render, act, screen } from '@testing-library/react';
 import { MemoryRouter } from 'react-router-dom';
 import { vi, describe, it, expect, beforeEach, afterEach } from 'vitest';
 import Scans from '../../../src/pages/Scans';
+import { ToastProvider } from '../../../src/components/ToastContext'
 
 vi.mock('../../../src/api', () => ({
   API_BASE: 'http://localhost',
@@ -64,8 +65,10 @@ async function tickTime(ms: number) {
 function renderScans() {
   return render(
     <MemoryRouter>
-      <Scans />
-    </MemoryRouter>,
+      <ToastProvider>
+        <Scans />
+      </ToastProvider>
+    </MemoryRouter>
   );
 }
 

frontend/testing/unit/pages/ScansToastErrors.test.tsx

@@ -0,0 +1,129 @@
+import { render, screen, waitFor } from '@testing-library/react'
+import userEvent from '@testing-library/user-event'
+import { MemoryRouter } from 'react-router-dom'
+import { ToastProvider } from '../../../src/components/ToastContext'
+import Scans from '../../../src/pages/Scans'
+import { deleteTask, clearAllTasks, bulkDeleteTasks, startTask } from '../../../src/api'
+
+vi.mock('../../../src/api', async () => {
+  const actual: any = await vi.importActual('../../../src/api')
+  return {
+    ...actual,
+    deleteTask: vi.fn(),
+    clearAllTasks: vi.fn(),
+    bulkDeleteTasks: vi.fn(),
+    startTask: vi.fn(),
+  }
+})
+
+function makeTask(overrides = {}) {
+  return {
+    task_id: 'task-1',
+    plugin_id: 'nmap',
+    tool: 'nmap',
+    target: 'example.com',
+    status: 'completed',
+    created_at: '2026-05-14T10:00:00Z',
+    ...overrides,
+  }
+}
+
+function mockFetch(tasks: any[]) {
+  vi.stubGlobal(
+    'fetch',
+    vi.fn().mockResolvedValue({
+      ok: true,
+      json: async () => ({ tasks, pagination: { total_items: tasks.length } }),
+    }),
+  )
+}
+
+function renderScans() {
+  return render(
+    <MemoryRouter>
+      <ToastProvider>
+        <Scans />
+      </ToastProvider>
+    </MemoryRouter>,
+  )
+}
+
+beforeEach(() => {
+  vi.useFakeTimers({ shouldAdvanceTime: true })
+  mockFetch([makeTask()])
+})
+
+afterEach(() => {
+  vi.useRealTimers()
+  vi.restoreAllMocks()
+})
+
+describe('Scans — toast error feedback', () => {
+  it('shows a toast when clear all tasks fails', async () => {
+    vi.mocked(clearAllTasks).mockRejectedValueOnce(new Error('clear failed'))
+    const user = userEvent.setup()
+    renderScans()
+
+    await waitFor(() => expect(screen.getByText('nmap')).toBeInTheDocument())
+
+    await user.click(screen.getByRole('button', { name: /Purge_All_Records/i }))
+    const confirmBtn = await screen.findByRole('button', { name: /Confirm/i })
+    await user.click(confirmBtn)
+
+    await waitFor(() => {
+      expect(screen.getByText(/Failed to clear history/i)).toBeInTheDocument()
+    })
+  })
+
+  it('shows a toast when bulk delete fails', async () => {
+    vi.mocked(bulkDeleteTasks).mockRejectedValueOnce(new Error('bulk failed'))
+    const user = userEvent.setup()
+    renderScans()
+
+    await waitFor(() => expect(screen.getByText('nmap')).toBeInTheDocument())
+
+    await user.click(screen.getByRole('button', { name: /Select_All/i }))
+    await waitFor(() => expect(screen.getByText('1')).toBeInTheDocument())
+
+    await user.click(screen.getByRole('button', { name: /Prune_Selected_Records/i }))
+    const confirmBtn = await screen.findByRole('button', { name: /Confirm/i })
+    await user.click(confirmBtn)
+
+    await waitFor(() => {
+      expect(screen.getByText(/Failed to delete some tasks/i)).toBeInTheDocument()
+    })
+  })
+
+  it('shows a toast when rescan fails', async () => {
+    vi.mocked(startTask).mockRejectedValueOnce(new Error('rescan failed'))
+    const user = userEvent.setup()
+    renderScans()
+
+    await waitFor(() => expect(screen.getByText('nmap')).toBeInTheDocument())
+
+    const rescanBtn = screen.getByRole('button', { name: /Re-run nmap scan/i })
+    await user.click(rescanBtn)
+
+    await waitFor(() => {
+      expect(screen.getByText(/Rescan failed/i)).toBeInTheDocument()
+    })
+  })
+
+  it('does not show the old error banner after a failure', async () => {
+    vi.mocked(clearAllTasks).mockRejectedValueOnce(new Error('clear failed'))
+    const user = userEvent.setup()
+    renderScans()
+
+    await waitFor(() => expect(screen.getByText('nmap')).toBeInTheDocument())
+
+    await user.click(screen.getByRole('button', { name: /Purge_All_Records/i }))
+    const confirmBtn = await screen.findByRole('button', { name: /Confirm/i })
+    await user.click(confirmBtn)
+
+    await waitFor(() => {
+      expect(screen.getByText(/Failed to clear history/i)).toBeInTheDocument()
+    })
+
+    expect(screen.queryByRole('button', { name: /Close alert/i })).not.toBeInTheDocument()
+  })
+})