Optimistic Discover decisions and deck refill (#108)

Co-authored-by: orchestrator-agent <20+orchestrator-agent@code.cubecraftcreations.com>

web/src/discover/DiscoverPage.test.tsx

@@ -8,6 +8,7 @@ import { declaredStyle } from '../test/cssRules.ts'
 import { errorResponse, fakeLocation, jsonResponse, ME } from '../test/fetchStub.ts'
 import { expectMinHitArea } from '../test/hitArea.ts'
 import { mockViewport } from '../test/matchMedia.ts'
+import { DECK_KEY } from './api.ts'
 import { DiscoverPage } from './DiscoverPage.tsx'
 
 const DECK = '/api/v1/suggestions/deck'
@@ -41,16 +42,16 @@ const ORZO = suggestionBody('s3', 'Lemon garlic shrimp orzo', { difficulty: 'har
 type Responder = () => Response | Promise<Response>
 
 // stubServer stands in for the API: GET of the deck answers the current
-// server.deck and the Quest log has questLog dinners; every other request
-// is answered by responders, keyed "METHOD path". Any other request fails
-// the test.
+// server.deck and the Quest log the current server.questLog dinners; every
+// other request is answered by responders, keyed "METHOD path". Any other
+// request fails the test.
 function stubServer(deck: unknown[], responders: Record<string, Responder> = {}, questLog = 6) {
-  const server = { deck, fetchMock: undefined as unknown as Mock<typeof fetch> }
+  const server = { deck, questLog, fetchMock: undefined as unknown as Mock<typeof fetch> }
   const all: Record<string, Responder> = {
     'GET /api/v1/me': () => jsonResponse(200, ME),
     [`GET ${DECK}`]: () => jsonResponse(200, { suggestions: server.deck }),
     [`GET ${QUEST_LOG}`]: () =>
-      jsonResponse(200, { dinners: Array.from({ length: questLog }, (_, i) => ({ id: `q${i}`, name: `Quest ${i}` })) }),
+      jsonResponse(200, { dinners: Array.from({ length: server.questLog }, (_, i) => ({ id: `q${i}`, name: `Quest ${i}` })) }),
     ...responders,
   }
   server.fetchMock = vi.fn<typeof fetch>((input, init) => {
@@ -70,6 +71,11 @@ function sent(fetchMock: Mock<typeof fetch>) {
     .map(([input, init]) => `${init?.method} ${String(input)}`)
 }
 
+// deckReads counts the GET /api/v1/suggestions/deck requests.
+function deckReads(fetchMock: Mock<typeof fetch>) {
+  return fetchMock.mock.calls.filter(([input, init]) => (init?.method ?? 'GET') === 'GET' && String(input) === DECK).length
+}
+
 // jobPolls counts the GET /api/v1/jobs/j1 requests.
 function jobPolls(fetchMock: Mock<typeof fetch>) {
   return fetchMock.mock.calls.filter(([input, init]) => (init?.method ?? 'GET') === 'GET' && String(input) === '/api/v1/jobs/j1').length
@@ -97,13 +103,13 @@ async function finishRunning(animations: FakeAnimation[]) {
 }
 
 // renderPage loads /me (for the CSRF token every write needs) and renders
-// the Discover page.
-async function renderPage() {
+// the Discover page with queryClient.
+async function renderPage(queryClient = createQueryClient()) {
   const api = createApiClient(fakeLocation('/discover'), createNetworkStatus(window), createVerifiedSession(localStorage))
   await api.loadMe()
   return render(
     <ApiProvider client={api}>
-      <QueryClientProvider client={createQueryClient()}>
+      <QueryClientProvider client={queryClient}>
         <DiscoverPage />
       </QueryClientProvider>
     </ApiProvider>,
@@ -505,6 +511,663 @@ describe('DiscoverPage', () => {
     expect(screen.getByRole('heading', { name: 'All caught up' })).toBeInTheDocument()
   })
 
+  describe('optimistic decisions', () => {
+    const PAELLA = suggestionBody('s4', 'Sheet pan paella')
+    const SOUP = suggestionBody('s5', 'Tortellini soup')
+    const accepted = (quest: typeof BOWLS, replenish: string | null = null) =>
+      jsonResponse(200, { suggestion: { ...quest, status: 'accepted' }, replenish_job_id: replenish })
+    const declined = (quest: typeof BOWLS) => jsonResponse(200, { suggestion: { ...quest, status: 'declined' }, replenish_job_id: null })
+    // topCard is the deck's top card, the one read out.
+    const topCard = () => screen.getAllByRole('article')[0]
+
+    it('Try it takes the card off the deck and bumps the Quest log count once the exit finishes, before the answer', async () => {
+      const accept = deferred()
+      const server = stubServer([BOWLS, TIKKA, ORZO, PAELLA], { 'POST /api/v1/suggestions/s1/accept': () => accept.promise })
+      const animations = stubAnimate({ autoFinish: false })
+      await renderPage()
+      await screen.findByRole('article', { name: 'Korean beef bowls' })
+      await screen.findByText('Quest log · 6')
+
+      // Nothing is applied on the press: the card is still leaving.
+      fireEvent.click(screen.getByRole('button', { name: 'Try it' }))
+      expect(screen.getByRole('article', { name: 'Korean beef bowls' })).toBeInTheDocument()
+      expect(screen.getByText('Quest log · 6')).toBeInTheDocument()
+      expect(sent(server.fetchMock)).toEqual([])
+
+      // Once it is gone the decision is applied, and sent.
+      await finishRunning(animations)
+      await finishRunning(animations)
+      await screen.findByText('Quest log · 7')
+      expect(topCard()).toHaveAccessibleName('Crock pot chicken tikka masala')
+      expect(screen.queryByRole('article', { name: 'Korean beef bowls' })).not.toBeInTheDocument()
+      expect(sent(server.fetchMock)).toEqual(['POST /api/v1/suggestions/s1/accept'])
+      expect(screen.getByRole('button', { name: 'Try it' })).toBeDisabled()
+
+      server.deck = [TIKKA, ORZO, PAELLA]
+      server.questLog = 7
+      accept.resolve(accepted(BOWLS))
+      await waitFor(() => expect(screen.getByRole('button', { name: 'Try it' })).toBeEnabled())
+      expect(screen.getByText('Quest log · 7')).toBeInTheDocument()
+      expect(topCard()).toHaveAccessibleName('Crock pot chicken tikka masala')
+      // The deck is read again once the decision is saved.
+      expect(deckReads(server.fetchMock)).toBe(2)
+      expect(screen.queryByRole('alert')).not.toBeInTheDocument()
+    })
+
+    it('Pass takes the card off the deck before the answer, leaving the Quest log count', async () => {
+      const decline = deferred()
+      const server = stubServer([BOWLS, TIKKA, ORZO, PAELLA], { 'POST /api/v1/suggestions/s1/decline': () => decline.promise })
+      await renderPage()
+      await screen.findByRole('article', { name: 'Korean beef bowls' })
+      await screen.findByText('Quest log · 6')
+
+      fireEvent.click(screen.getByRole('button', { name: 'Pass' }))
+      await waitFor(() => expect(topCard()).toHaveAccessibleName('Crock pot chicken tikka masala'))
+      expect(screen.queryByRole('article', { name: 'Korean beef bowls' })).not.toBeInTheDocument()
+      expect(screen.getByText('Quest log · 6')).toBeInTheDocument()
+      expect(sent(server.fetchMock)).toEqual(['POST /api/v1/suggestions/s1/decline'])
+
+      server.deck = [TIKKA, ORZO, PAELLA]
+      decline.resolve(declined(BOWLS))
+      await waitFor(() => expect(screen.getByRole('button', { name: 'Pass' })).toBeEnabled())
+      expect(screen.getByText('Quest log · 6')).toBeInTheDocument()
+      expect(deckReads(server.fetchMock)).toBe(2)
+    })
+
+    it('puts a refused Try it back on top of the deck, reverts the Quest log count and offers Retry', async () => {
+      const accept = deferred()
+      let refuse = true
+      const server = stubServer([BOWLS, TIKKA, ORZO, PAELLA], {
+        'POST /api/v1/suggestions/s1/accept': () => (refuse ? accept.promise : accepted(BOWLS)),
+      })
+      await renderPage()
+      await screen.findByRole('article', { name: 'Korean beef bowls' })
+      await screen.findByText('Quest log · 6')
+
+      fireEvent.click(screen.getByRole('button', { name: 'Try it' }))
+      await screen.findByText('Quest log · 7')
+      expect(topCard()).toHaveAccessibleName('Crock pot chicken tikka masala')
+
+      // The server refuses the request itself: the deck read again after it
+      // still has the Side quest pending, in the server's order.
+      server.deck = [TIKKA, BOWLS, ORZO, PAELLA]
+      accept.resolve(errorResponse(400, 'invalid_request'))
+      const alert = await screen.findByRole('alert')
+      expect(alert).toHaveTextContent("Couldn't save that choice.")
+      expect(topCard()).toHaveAccessibleName('Korean beef bowls')
+      expect(deckReads(server.fetchMock)).toBe(2)
+      expect(screen.getAllByRole('article', { hidden: true }).map((card) => card.querySelector('h2')!.textContent)).toEqual([
+        'Korean beef bowls',
+        'Crock pot chicken tikka masala',
+        'Lemon garlic shrimp orzo',
+      ])
+      expect(screen.getByText('Quest log · 6')).toBeInTheDocument()
+      expect(screen.getByRole('button', { name: 'Try it' })).toBeEnabled()
+
+      // Retry sends the same decision again, applied again at once.
+      refuse = false
+      server.deck = [TIKKA, ORZO, PAELLA]
+      server.questLog = 7
+      fireEvent.click(within(alert).getByRole('button', { name: 'Retry' }))
+      await waitFor(() => expect(screen.queryByRole('alert')).not.toBeInTheDocument())
+      expect(sent(server.fetchMock)).toEqual(['POST /api/v1/suggestions/s1/accept', 'POST /api/v1/suggestions/s1/accept'])
+      expect(topCard()).toHaveAccessibleName('Crock pot chicken tikka masala')
+      expect(screen.getByText('Quest log · 7')).toBeInTheDocument()
+    })
+
+    it('keeps a saved decision off the deck when a read started during it answers late', async () => {
+      const decline = deferred()
+      let late: ReturnType<typeof deferred> | null = null
+      const server = stubServer([BOWLS, TIKKA, ORZO, PAELLA], {
+        'POST /api/v1/suggestions/s1/decline': () => decline.promise,
+        [`GET ${DECK}`]: () => late?.promise ?? jsonResponse(200, { suggestions: server.deck }),
+      })
+      const queryClient = createQueryClient()
+      await renderPage(queryClient)
+      await screen.findByRole('article', { name: 'Korean beef bowls' })
+
+      fireEvent.click(screen.getByRole('button', { name: 'Pass' }))
+      await waitFor(() => expect(sent(server.fetchMock)).toEqual(['POST /api/v1/suggestions/s1/decline']))
+      expect(topCard()).toHaveAccessibleName('Crock pot chicken tikka masala')
+
+      // A read of the deck starts before the decision is saved, and answers
+      // only after: with the Side quest still pending.
+      late = deferred()
+      const stale = late
+      await act(async () => void queryClient.invalidateQueries({ queryKey: DECK_KEY }))
+      expect(deckReads(server.fetchMock)).toBe(2)
+      late = null
+      server.deck = [TIKKA, ORZO, PAELLA]
+      decline.resolve(declined(BOWLS))
+      await waitFor(() => expect(screen.getByRole('button', { name: 'Pass' })).toBeEnabled())
+      await act(async () => stale.resolve(jsonResponse(200, { suggestions: [BOWLS, TIKKA, ORZO, PAELLA] })))
+
+      // The late answer is dropped, and the deck is read again after the save.
+      await act(async () => await new Promise((resolve) => setTimeout(resolve, 0)))
+      expect(screen.queryByRole('article', { name: 'Korean beef bowls' })).not.toBeInTheDocument()
+      await waitFor(() => expect(deckReads(server.fetchMock)).toBe(3))
+      expect(screen.getAllByRole('article', { hidden: true }).map((card) => card.querySelector('h2')!.textContent)).toEqual([
+        'Crock pot chicken tikka masala',
+        'Lemon garlic shrimp orzo',
+        'Sheet pan paella',
+      ])
+    })
+
+    it('keeps the card off the deck while its decision is unanswered when a read of the deck lands with it still pending, then reads the deck again once it is saved', async () => {
+      const decline = deferred()
+      const server = stubServer([BOWLS, TIKKA, ORZO, PAELLA], { 'POST /api/v1/suggestions/s1/decline': () => decline.promise })
+      const queryClient = createQueryClient()
+      await renderPage(queryClient)
+      await screen.findByRole('article', { name: 'Korean beef bowls' })
+
+      fireEvent.click(screen.getByRole('button', { name: 'Pass' }))
+      await waitFor(() => expect(sent(server.fetchMock)).toEqual(['POST /api/v1/suggestions/s1/decline']))
+      expect(topCard()).toHaveAccessibleName('Crock pot chicken tikka masala')
+
+      // A read of the deck lands before the decision is saved, with the Side
+      // quest still pending: the card stays off the deck.
+      await act(async () => await queryClient.refetchQueries({ queryKey: DECK_KEY }))
+      await act(async () => await new Promise((resolve) => setTimeout(resolve, 0)))
+      expect(deckReads(server.fetchMock)).toBe(2)
+      expect(queryClient.getQueryData<{ id: string }[]>(DECK_KEY)?.map((q) => q.id)).toEqual(['s1', 's2', 's3', 's4'])
+      expect(screen.getAllByRole('article', { hidden: true }).map((card) => card.querySelector('h2')!.textContent)).toEqual([
+        'Crock pot chicken tikka masala',
+        'Lemon garlic shrimp orzo',
+        'Sheet pan paella',
+      ])
+
+      // Once it is saved, the deck read after it is the deck shown.
+      server.deck = [TIKKA, ORZO, PAELLA]
+      decline.resolve(declined(BOWLS))
+      await waitFor(() => expect(screen.getByRole('button', { name: 'Pass' })).toBeEnabled())
+      expect(deckReads(server.fetchMock)).toBe(3)
+      expect(screen.queryByRole('article', { name: 'Korean beef bowls' })).not.toBeInTheDocument()
+      expect(screen.getAllByRole('article', { hidden: true }).map((card) => card.querySelector('h2')!.textContent)).toEqual([
+        'Crock pot chicken tikka masala',
+        'Lemon garlic shrimp orzo',
+        'Sheet pan paella',
+      ])
+      expect(screen.queryByRole('alert')).not.toBeInTheDocument()
+    })
+
+    it('keeps the card off the deck while its decision is unanswered when a read of the deck lands with it still pending, then puts it back on top with a Retry once it is refused', async () => {
+      const accept = deferred()
+      const server = stubServer([BOWLS, TIKKA, ORZO, PAELLA], { 'POST /api/v1/suggestions/s1/accept': () => accept.promise })
+      const queryClient = createQueryClient()
+      await renderPage(queryClient)
+      await screen.findByRole('article', { name: 'Korean beef bowls' })
+
+      fireEvent.click(screen.getByRole('button', { name: 'Try it' }))
+      await waitFor(() => expect(sent(server.fetchMock)).toEqual(['POST /api/v1/suggestions/s1/accept']))
+      expect(topCard()).toHaveAccessibleName('Crock pot chicken tikka masala')
+
+      // A read of the deck lands mid-decision, in the server's order.
+      server.deck = [TIKKA, BOWLS, ORZO, PAELLA]
+      await act(async () => await queryClient.refetchQueries({ queryKey: DECK_KEY }))
+      await act(async () => await new Promise((resolve) => setTimeout(resolve, 0)))
+      expect(deckReads(server.fetchMock)).toBe(2)
+      expect(screen.getAllByRole('article', { hidden: true }).map((card) => card.querySelector('h2')!.textContent)).toEqual([
+        'Crock pot chicken tikka masala',
+        'Lemon garlic shrimp orzo',
+        'Sheet pan paella',
+      ])
+
+      // The server refuses it; the deck read after it still has it pending.
+      accept.resolve(errorResponse(400, 'invalid_request'))
+      const alert = await screen.findByRole('alert')
+      expect(alert).toHaveTextContent("Couldn't save that choice.")
+      expect(within(alert).getByRole('button', { name: 'Retry' })).toBeInTheDocument()
+      expect(deckReads(server.fetchMock)).toBe(3)
+      expect(screen.getAllByRole('article', { hidden: true }).map((card) => card.querySelector('h2')!.textContent)).toEqual([
+        'Korean beef bowls',
+        'Crock pot chicken tikka masala',
+        'Lemon garlic shrimp orzo',
+      ])
+    })
+
+    it('leaves the Quest log count alone for a dinner already in it, on Try it and on its refusal', async () => {
+      const accept = deferred()
+      stubServer([BOWLS, TIKKA, ORZO, PAELLA], {
+        'POST /api/v1/suggestions/s1/accept': () => accept.promise,
+        // A read of the Quest log already has the dinner the stale deck offers.
+        [`GET ${QUEST_LOG}`]: () =>
+          jsonResponse(200, {
+            dinners: [
+              { id: 'q0', name: 'Quest 0' },
+              { id: 'dinner-s1', name: 'Korean beef bowls' },
+            ],
+          }),
+      })
+      await renderPage()
+      await screen.findByRole('article', { name: 'Korean beef bowls' })
+      await screen.findByText('Quest log · 2')
+
+      fireEvent.click(screen.getByRole('button', { name: 'Try it' }))
+      await waitFor(() => expect(topCard()).toHaveAccessibleName('Crock pot chicken tikka masala'))
+      expect(screen.getByText('Quest log · 2')).toBeInTheDocument()
+
+      accept.resolve(errorResponse(500, 'internal'))
+      await screen.findByRole('alert')
+      expect(topCard()).toHaveAccessibleName('Korean beef bowls')
+      expect(screen.getByText('Quest log · 2')).toBeInTheDocument()
+    })
+
+    it('takes out of the Quest log only the entry a refused Try it added, after a read of the Quest log lands during it', async () => {
+      const accept = deferred()
+      const questLog = [{ id: 'q0', name: 'Quest 0' }]
+      const server = stubServer([BOWLS, TIKKA, ORZO, PAELLA], {
+        'POST /api/v1/suggestions/s1/accept': () => accept.promise,
+        [`GET ${QUEST_LOG}`]: () => jsonResponse(200, { dinners: questLog }),
+      })
+      const queryClient = createQueryClient()
+      await renderPage(queryClient)
+      await screen.findByRole('article', { name: 'Korean beef bowls' })
+      await screen.findByText('Quest log · 1')
+
+      fireEvent.click(screen.getByRole('button', { name: 'Try it' }))
+      await waitFor(() => expect(sent(server.fetchMock)).toEqual(['POST /api/v1/suggestions/s1/accept']))
+      expect(screen.getByText('Quest log · 2')).toBeInTheDocument()
+
+      // The decision is saved, and a read of the Quest log lands with its
+      // dinner in it; then the answer to the decision is lost.
+      questLog.push({ id: 'dinner-s1', name: 'Korean beef bowls' })
+      await act(async () => await queryClient.invalidateQueries({ queryKey: ['dinners', 'quest_log'] }))
+      accept.resolve(errorResponse(500, 'internal'))
+      await screen.findByRole('alert')
+      expect(screen.getByText('Quest log · 2')).toBeInTheDocument()
+      // The answer was lost, so the Quest log is read again.
+      const questLogReads = () => server.fetchMock.mock.calls.filter(([input]) => String(input) === QUEST_LOG).length
+      await waitFor(() => expect(questLogReads()).toBe(3))
+      expect(screen.getByText('Quest log · 2')).toBeInTheDocument()
+    })
+
+    it('sends a decision for the card thrown out even when a read of the deck took it away during the exit, offering no Retry for it', async () => {
+      const server = stubServer([BOWLS], {
+        'POST /api/v1/suggestions/s1/accept': () => errorResponse(500, 'internal'),
+      })
+      const queryClient = createQueryClient()
+      const animations = stubAnimate({ autoFinish: false })
+      await renderPage(queryClient)
+      await screen.findByRole('article', { name: 'Korean beef bowls' })
+
+      // While the card leaves, a read of the deck takes the last card away.
+      fireEvent.click(screen.getByRole('button', { name: 'Try it' }))
+      server.deck = []
+      await act(async () => await queryClient.invalidateQueries({ queryKey: DECK_KEY }))
+      await screen.findByRole('heading', { name: 'All caught up' })
+
+      await finishRunning(animations)
+      await finishRunning(animations)
+      const alert = await screen.findByRole('alert')
+      expect(sent(server.fetchMock)).toEqual(['POST /api/v1/suggestions/s1/accept'])
+      // The deck read after it confirms the Side quest is decided: the card
+      // is not put back, and there is nothing to retry.
+      expect(alert).toHaveTextContent('That side quest has been decided already.')
+      expect(within(alert).queryByRole('button')).not.toBeInTheDocument()
+      expect(screen.queryByRole('article')).not.toBeInTheDocument()
+      expect(screen.getByRole('heading', { name: 'All caught up' })).toBeInTheDocument()
+    })
+
+    it('keeps a card off the deck when a read during its decision left it out and the answer is lost, and reads the deck again', async () => {
+      let lose!: (error: Error) => void
+      const accept = new Promise<Response>((_, reject) => (lose = reject))
+      let late: ReturnType<typeof deferred> | null = null
+      const server = stubServer([BOWLS, TIKKA, ORZO, PAELLA], {
+        'POST /api/v1/suggestions/s1/accept': () => accept,
+        [`GET ${DECK}`]: () => late?.promise ?? jsonResponse(200, { suggestions: server.deck }),
+      })
+      const queryClient = createQueryClient()
+      await renderPage(queryClient)
+      await screen.findByRole('article', { name: 'Korean beef bowls' })
+
+      fireEvent.click(screen.getByRole('button', { name: 'Try it' }))
+      await waitFor(() => expect(sent(server.fetchMock)).toEqual(['POST /api/v1/suggestions/s1/accept']))
+
+      // The decision is saved, and a read of the deck started during it
+      // answers without the Side quest; then the answer to the decision is
+      // lost on the way back.
+      late = deferred()
+      const delayed = late
+      await act(async () => void queryClient.invalidateQueries({ queryKey: DECK_KEY }))
+      late = null
+      server.deck = [TIKKA, ORZO, PAELLA]
+      await act(async () => delayed.resolve(jsonResponse(200, { suggestions: server.deck })))
+      const reads = deckReads(server.fetchMock)
+      await act(async () => lose(new TypeError('Failed to fetch')))
+
+      await screen.findByRole('alert')
+      expect(screen.queryByRole('article', { name: 'Korean beef bowls' })).not.toBeInTheDocument()
+      // The decision may have been saved: the deck is read again.
+      await waitFor(() => expect(deckReads(server.fetchMock)).toBe(reads + 1))
+      expect(screen.queryByRole('article', { name: 'Korean beef bowls' })).not.toBeInTheDocument()
+      expect(topCard()).toHaveAccessibleName('Crock pot chicken tikka masala')
+    })
+
+    it('keeps a card off the deck when another session already decided it (409), and reads the deck again', async () => {
+      const accept = deferred()
+      let read: ReturnType<typeof deferred> | null = null
+      const server = stubServer([BOWLS, TIKKA, ORZO, PAELLA], {
+        'POST /api/v1/suggestions/s1/accept': () => accept.promise,
+        [`GET ${DECK}`]: () => read?.promise ?? jsonResponse(200, { suggestions: server.deck }),
+      })
+      await renderPage()
+      await screen.findByRole('article', { name: 'Korean beef bowls' })
+
+      fireEvent.click(screen.getByRole('button', { name: 'Try it' }))
+      await waitFor(() => expect(sent(server.fetchMock)).toEqual(['POST /api/v1/suggestions/s1/accept']))
+
+      // Another session passed on it first; no read of the deck lands
+      // during the decision.
+      read = deferred()
+      const pending = read
+      server.deck = [TIKKA, ORZO, PAELLA]
+      await act(async () => accept.resolve(errorResponse(409, 'suggestion_decided')))
+      await waitFor(() => expect(deckReads(server.fetchMock)).toBe(2))
+      expect(screen.queryByRole('article', { name: 'Korean beef bowls' })).not.toBeInTheDocument()
+      // The decision is not over until that read lands.
+      expect(screen.queryByRole('alert')).not.toBeInTheDocument()
+      expect(screen.getByRole('button', { name: 'Try it' })).toBeDisabled()
+
+      await act(async () => pending.resolve(jsonResponse(200, { suggestions: server.deck })))
+      const alert = await screen.findByRole('alert')
+      expect(screen.queryByRole('article', { name: 'Korean beef bowls' })).not.toBeInTheDocument()
+      expect(topCard()).toHaveAccessibleName('Crock pot chicken tikka masala')
+      // It was decided: there is no decision to retry.
+      expect(alert).toHaveTextContent('That side quest has been decided already.')
+      expect(within(alert).queryByRole('button')).not.toBeInTheDocument()
+      expect(screen.getByRole('button', { name: 'Try it' })).toBeEnabled()
+    })
+
+    it('reads the Quest log again after a Pass another session beat with Try it (409), counting its dinner', async () => {
+      const server = stubServer([BOWLS, TIKKA, ORZO, PAELLA], {
+        'POST /api/v1/suggestions/s1/decline': () => {
+          // Another session tried it first: its dinner is in the Quest log.
+          server.deck = [TIKKA, ORZO, PAELLA]
+          server.questLog = 7
+          return errorResponse(409, 'suggestion_decided')
+        },
+      })
+      await renderPage()
+      await screen.findByRole('article', { name: 'Korean beef bowls' })
+      await screen.findByText('Quest log · 6')
+
+      fireEvent.click(screen.getByRole('button', { name: 'Pass' }))
+      const alert = await screen.findByRole('alert')
+      expect(alert).toHaveTextContent('That side quest has been decided already.')
+      expect(screen.getByText('Quest log · 7')).toBeInTheDocument()
+      expect(topCard()).toHaveAccessibleName('Crock pot chicken tikka masala')
+    })
+
+    it('locks the next decision until the reads after a failed one land, then puts the still-pending card back on top with a Retry', async () => {
+      let read: ReturnType<typeof deferred> | null = null
+      const server = stubServer([BOWLS, TIKKA, ORZO, PAELLA], {
+        'POST /api/v1/suggestions/s1/accept': () => {
+          read = deferred()
+          return errorResponse(500, 'internal')
+        },
+        [`GET ${DECK}`]: () => read?.promise ?? jsonResponse(200, { suggestions: server.deck }),
+      })
+      await renderPage()
+      await screen.findByRole('article', { name: 'Korean beef bowls' })
+
+      // The decision failed and was not saved; the deck read after it is slow.
+      fireEvent.click(screen.getByRole('button', { name: 'Try it' }))
+      await waitFor(() => expect(deckReads(server.fetchMock)).toBe(2))
+      const slow = read!
+      read = null
+      expect(topCard()).toHaveAccessibleName('Crock pot chicken tikka masala')
+
+      // Deciding the next card does nothing while that read is out.
+      expect(screen.getByRole('button', { name: 'Pass' })).toBeDisabled()
+      fireEvent.click(screen.getByRole('button', { name: 'Pass' }))
+      fireEvent.keyDown(window, { key: 'ArrowLeft' })
+      await act(async () => await new Promise((resolve) => setTimeout(resolve, 0)))
+      expect(sent(server.fetchMock)).toEqual(['POST /api/v1/suggestions/s1/accept'])
+      expect(screen.queryByRole('alert')).not.toBeInTheDocument()
+
+      await act(async () => slow.resolve(jsonResponse(200, { suggestions: server.deck })))
+      const alert = await screen.findByRole('alert')
+      expect(alert).toHaveTextContent("Couldn't save that choice.")
+      expect(topCard()).toHaveAccessibleName('Korean beef bowls')
+      expect(screen.getByRole('button', { name: 'Try it' })).toBeEnabled()
+
+      // Retry sends it again.
+      fireEvent.click(within(alert).getByRole('button', { name: 'Retry' }))
+      await waitFor(() => expect(sent(server.fetchMock)).toEqual(['POST /api/v1/suggestions/s1/accept', 'POST /api/v1/suggestions/s1/accept']))
+    })
+
+    it('settles a failed decision on its own read of the deck when a batch poll reads the deck again during it', async () => {
+      const job = (suggestionIds: string[]) =>
+        jsonResponse(200, {
+          id: 'j1',
+          kind: 'suggestion_batch',
+          status: 'running',
+          result: { batch_id: 'b1', stage: 'suggesting', suggestion_ids: suggestionIds, dropped: 0 },
+          error: null,
+        })
+      let poll: ReturnType<typeof deferred> | null = null
+      let read: ReturnType<typeof deferred> | null = null
+      let refuse = true
+      const server = stubServer([BOWLS, TIKKA, ORZO, PAELLA], {
+        'POST /api/v1/suggestions/s1/decline': () => {
+          server.deck = [TIKKA, ORZO, PAELLA]
+          return jsonResponse(200, { suggestion: { ...BOWLS, status: 'declined' }, replenish_job_id: 'j1' })
+        },
+        'POST /api/v1/suggestions/s2/accept': () => {
+          if (!refuse) return accepted(TIKKA)
+          read = deferred()
+          return errorResponse(500, 'internal')
+        },
+        'GET /api/v1/jobs/j1': () => poll?.promise ?? job([]),
+        [`GET ${DECK}`]: () => read?.promise ?? jsonResponse(200, { suggestions: server.deck }),
+      })
+      const queryClient = createQueryClient()
+      await renderPage(queryClient)
+      await screen.findByRole('article', { name: 'Korean beef bowls' })
+
+      // A Pass starts a replenish batch, whose job is polled.
+      fireEvent.click(screen.getByRole('button', { name: 'Pass' }))
+      await waitFor(() => expect(jobPolls(server.fetchMock)).toBe(1))
+      await waitFor(() => expect(screen.getByRole('button', { name: 'Try it' })).toBeEnabled())
+      expect(topCard()).toHaveAccessibleName('Crock pot chicken tikka masala')
+      poll = deferred()
+      const polled = poll
+      await waitFor(() => expect(jobPolls(server.fetchMock)).toBe(2), { timeout: 2000 })
+
+      // Try it fails without being saved; the deck read it makes is slow.
+      const reads = deckReads(server.fetchMock)
+      fireEvent.click(screen.getByRole('button', { name: 'Try it' }))
+      await waitFor(() => expect(deckReads(server.fetchMock)).toBe(reads + 1))
+      const reconciling = read!
+      read = deferred()
+      const after = read
+      expect(screen.getByRole('button', { name: 'Try it' })).toBeDisabled()
+
+      // The batch stores a Side quest while that read is out: its read of
+      // the deck waits for the decision's rather than replacing it.
+      const SOUP = suggestionBody('s5', 'Tortellini soup')
+      server.deck = [TIKKA, ORZO, PAELLA, SOUP]
+      await act(async () => polled.resolve(job(['s5'])))
+      await act(async () => await new Promise((resolve) => setTimeout(resolve, 0)))
+      expect(deckReads(server.fetchMock)).toBe(reads + 1)
+      expect(screen.getByRole('button', { name: 'Try it' })).toBeDisabled()
+
+      // The decision's read has the Side quest still pending: the card goes
+      // back on top with a Retry, and the decision settles on that read.
+      await act(async () => reconciling.resolve(jsonResponse(200, { suggestions: server.deck })))
+      await waitFor(() => expect(screen.getByRole('button', { name: 'Try it' })).toBeEnabled())
+      const alert = screen.getByRole('alert')
+      expect(alert).toHaveTextContent("Couldn't save that choice.")
+      expect(within(alert).getByRole('button', { name: 'Retry' })).toBeInTheDocument()
+      expect(topCard()).toHaveAccessibleName('Crock pot chicken tikka masala')
+
+      // The batch's read goes out after it, and brings its Side quest.
+      await waitFor(() => expect(deckReads(server.fetchMock)).toBe(reads + 2))
+      read = null
+      await act(async () => after.resolve(jsonResponse(200, { suggestions: server.deck })))
+      await waitFor(() => expect(queryClient.getQueryData<{ id: string }[]>(DECK_KEY)?.map((q) => q.id)).toEqual(['s2', 's3', 's4', 's5']))
+      expect(topCard()).toHaveAccessibleName('Crock pot chicken tikka masala')
+
+      // Retry sends it again.
+      refuse = false
+      fireEvent.click(within(alert).getByRole('button', { name: 'Retry' }))
+      await waitFor(() =>
+        expect(sent(server.fetchMock)).toEqual([
+          'POST /api/v1/suggestions/s1/decline',
+          'POST /api/v1/suggestions/s2/accept',
+          'POST /api/v1/suggestions/s2/accept',
+        ]),
+      )
+    })
+
+    it('does not put a failed decision back on the deck when a later read, landing before it settles, has it decided', async () => {
+      let log: ReturnType<typeof deferred> | null = null
+      const server = stubServer([BOWLS, TIKKA, ORZO, PAELLA], {
+        'POST /api/v1/suggestions/s1/accept': () => {
+          log = deferred()
+          return errorResponse(500, 'internal')
+        },
+        [`GET ${QUEST_LOG}`]: () => log?.promise ?? jsonResponse(200, { dinners: [] }),
+      })
+      const queryClient = createQueryClient()
+      await renderPage(queryClient)
+      await screen.findByRole('article', { name: 'Korean beef bowls' })
+
+      // The decision fails; the deck read after it still has the Side quest
+      // pending, and the Quest log read after it is slow.
+      fireEvent.click(screen.getByRole('button', { name: 'Try it' }))
+      await waitFor(() => expect(log).not.toBeNull())
+      const slow = log!
+      log = null
+      await waitFor(() => expect(deckReads(server.fetchMock)).toBe(2))
+
+      // Another session decides it, and a read of the deck lands meanwhile.
+      server.deck = [TIKKA, ORZO, PAELLA]
+      await act(async () => await queryClient.refetchQueries({ queryKey: DECK_KEY }))
+      await act(async () => slow.resolve(jsonResponse(200, { dinners: [] })))
+
+      const alert = await screen.findByRole('alert')
+      expect(screen.queryByRole('article', { name: 'Korean beef bowls' })).not.toBeInTheDocument()
+      expect(topCard()).toHaveAccessibleName('Crock pot chicken tikka masala')
+      expect(alert).toHaveTextContent('That side quest has been decided already.')
+      expect(within(alert).queryByRole('button', { name: 'Retry' })).not.toBeInTheDocument()
+    })
+
+    it('withdraws the Retry for a failed decision once a later read of the deck has it decided', async () => {
+      const server = stubServer([BOWLS, TIKKA, ORZO, PAELLA], {
+        'POST /api/v1/suggestions/s1/accept': () => errorResponse(500, 'internal'),
+      })
+      const queryClient = createQueryClient()
+      await renderPage(queryClient)
+      await screen.findByRole('article', { name: 'Korean beef bowls' })
+
+      fireEvent.click(screen.getByRole('button', { name: 'Try it' }))
+      const alert = await screen.findByRole('alert')
+      expect(within(alert).getByRole('button', { name: 'Retry' })).toBeInTheDocument()
+      expect(topCard()).toHaveAccessibleName('Korean beef bowls')
+
+      // Another session decides it, and the next read of the deck says so.
+      server.deck = [TIKKA, ORZO, PAELLA]
+      await act(async () => await queryClient.refetchQueries({ queryKey: DECK_KEY }))
+      await waitFor(() => expect(topCard()).toHaveAccessibleName('Crock pot chicken tikka masala'))
+      expect(screen.getByRole('alert')).toHaveTextContent('That side quest has been decided already.')
+      expect(screen.queryByRole('button', { name: 'Retry' })).not.toBeInTheDocument()
+    })
+
+    it('reads the deck again after a 500 to a decision, rather than putting the card back', async () => {
+      const decline = deferred()
+      const server = stubServer([BOWLS, TIKKA, ORZO, PAELLA], {
+        'POST /api/v1/suggestions/s1/decline': () => decline.promise,
+      })
+      await renderPage()
+      await screen.findByRole('article', { name: 'Korean beef bowls' })
+
+      fireEvent.click(screen.getByRole('button', { name: 'Pass' }))
+      await waitFor(() => expect(sent(server.fetchMock)).toEqual(['POST /api/v1/suggestions/s1/decline']))
+
+      // The decision was saved, and the answer to it is a 500 all the same.
+      server.deck = [TIKKA, ORZO, PAELLA]
+      await act(async () => decline.resolve(errorResponse(500, 'internal')))
+      await screen.findByRole('alert')
+      expect(screen.queryByRole('article', { name: 'Korean beef bowls' })).not.toBeInTheDocument()
+      await waitFor(() => expect(deckReads(server.fetchMock)).toBe(2))
+      expect(screen.queryByRole('article', { name: 'Korean beef bowls' })).not.toBeInTheDocument()
+      expect(topCard()).toHaveAccessibleName('Crock pot chicken tikka masala')
+    })
+
+    it('reads the deck again once a saved decision leaves fewer than 3 cards', async () => {
+      const server = stubServer([BOWLS, TIKKA, ORZO], {
+        'POST /api/v1/suggestions/s1/decline': () => {
+          server.deck = [TIKKA, ORZO, PAELLA, SOUP]
+          return declined(BOWLS)
+        },
+      })
+      await renderPage()
+      await screen.findByRole('article', { name: 'Korean beef bowls' })
+      expect(deckReads(server.fetchMock)).toBe(1)
+
+      fireEvent.click(screen.getByRole('button', { name: 'Pass' }))
+      await waitFor(() => expect(deckReads(server.fetchMock)).toBe(2))
+      await waitFor(() =>
+        expect(screen.getAllByRole('article', { hidden: true }).map((card) => card.querySelector('h2')!.textContent)).toEqual([
+          'Crock pot chicken tikka masala',
+          'Lemon garlic shrimp orzo',
+          'Sheet pan paella',
+        ]),
+      )
+    })
+
+    it('shows skeleton cards, not "All caught up", while the replenish job a decision started runs', async () => {
+      const polls = [
+        { id: 'j1', kind: 'suggestion_batch', status: 'running', result: { batch_id: 'b1', stage: 'suggesting', suggestion_ids: [], dropped: 0 }, error: null },
+        { id: 'j1', kind: 'suggestion_batch', status: 'succeeded', result: { batch_id: 'b1', stage: 'done', suggestion_ids: ['s2'], dropped: 0 }, error: null },
+      ]
+      const server = stubServer([BOWLS], {
+        'POST /api/v1/suggestions/s1/accept': () => {
+          server.deck = []
+          return accepted(BOWLS, 'j1')
+        },
+        'GET /api/v1/jobs/j1': () => {
+          const job = polls.shift()!
+          if (job.status === 'succeeded') server.deck = [TIKKA]
+          return jsonResponse(200, job)
+        },
+      })
+      await renderPage()
+      await screen.findByRole('article', { name: 'Korean beef bowls' })
+
+      fireEvent.click(screen.getByRole('button', { name: 'Try it' }))
+      expect(await screen.findByText('Finding new side quests…')).toBeInTheDocument()
+      expect(screen.getAllByTestId('skeleton-card')).toHaveLength(3)
+      expect(screen.getByRole('region', { name: 'Side quests loading' })).toHaveAttribute('aria-busy', 'true')
+      expect(screen.queryByRole('heading', { name: 'All caught up' })).not.toBeInTheDocument()
+
+      await screen.findByRole('article', { name: 'Crock pot chicken tikka masala' }, { timeout: 3000 })
+      expect(screen.queryByTestId('skeleton-card')).not.toBeInTheDocument()
+      expect(screen.queryByRole('heading', { name: 'All caught up' })).not.toBeInTheDocument()
+      // The decision's replenish is followed; no batch is asked for.
+      expect(sent(server.fetchMock)).toEqual(['POST /api/v1/suggestions/s1/accept'])
+    })
+
+    it('shows skeleton cards, not "All caught up", while the decision that emptied the deck is unanswered', async () => {
+      const accept = deferred()
+      const server = stubServer([BOWLS], { 'POST /api/v1/suggestions/s1/accept': () => accept.promise })
+      await renderPage()
+      await screen.findByRole('article', { name: 'Korean beef bowls' })
+
+      fireEvent.click(screen.getByRole('button', { name: 'Try it' }))
+      await waitFor(() => expect(screen.getAllByTestId('skeleton-card')).toHaveLength(3))
+      expect(screen.queryByRole('heading', { name: 'All caught up' })).not.toBeInTheDocument()
+      expect(screen.queryByText('Finding new side quests…')).not.toBeInTheDocument()
+
+      // Saved without a replenish, the deck is caught up.
+      server.deck = []
+      accept.resolve(accepted(BOWLS))
+      await screen.findByRole('heading', { name: 'All caught up' })
+      expect(screen.queryByTestId('skeleton-card')).not.toBeInTheDocument()
+    })
+  })
+
   describe('motion', () => {
     const accepted = (quest: typeof BOWLS) => jsonResponse(200, { suggestion: { ...quest, status: 'accepted' }, replenish_job_id: null })
     const declined = (quest: typeof BOWLS) => jsonResponse(200, { suggestion: { ...quest, status: 'declined' }, replenish_job_id: null })
@@ -989,15 +1652,21 @@ describe('DiscoverPage', () => {
       const server = stubServer([BOWLS, TIKKA], {
         'POST /api/v1/suggestions/s1/accept': () => (++calls === 1 ? errorResponse(500, 'internal') : retry.promise),
       })
-      await renderPage()
-      const card = await screen.findByRole('article', { name: 'Korean beef bowls' })
+      const queryClient = createQueryClient()
+      await renderPage(queryClient)
+      await screen.findByRole('article', { name: 'Korean beef bowls' })
       fireEvent.click(screen.getByRole('button', { name: 'Try it' }))
       const alert = await screen.findByRole('alert')
+      // A read of the deck puts the refused Side quest back in the server's
+      // order, still pending, behind the card dragged during its Retry.
+      server.deck = [TIKKA, BOWLS]
+      await act(async () => await queryClient.invalidateQueries({ queryKey: DECK_KEY }))
+      const card = await screen.findByRole('article', { name: 'Crock pot chicken tikka masala' })
 
       press(card)
       drag(card, 60, 0)
       fireEvent.click(within(alert).getByRole('button', { name: 'Retry' }))
-      await waitFor(() => expect(screen.getByRole('button', { name: 'Try it' })).toBeDisabled())
+      expect(screen.getByRole('button', { name: 'Try it' })).toBeDisabled()
       drag(card, -160, 0)
       expect(card.style.transform).toBe('translate(60px,0px) rotate(3.3333333333333335deg)')
       const started = vi.mocked(Element.prototype.animate).mock.calls.length
@@ -1005,7 +1674,12 @@ describe('DiscoverPage', () => {
       expect(card.style.transform).toBe('')
       expect(within(card).getByText('Try it!').style.opacity).toBe('')
       expect(vi.mocked(Element.prototype.animate).mock.calls.length).toBe(started)
-      expect(sent(server.fetchMock)).toEqual(['POST /api/v1/suggestions/s1/accept', 'POST /api/v1/suggestions/s1/accept'])
+      await waitFor(() =>
+        expect(sent(server.fetchMock)).toEqual(['POST /api/v1/suggestions/s1/accept', 'POST /api/v1/suggestions/s1/accept']),
+      )
+      // The retried Side quest leaves the deck while the Retry is out.
+      await waitFor(() => expect(screen.queryByRole('article', { name: 'Korean beef bowls' })).not.toBeInTheDocument())
+      server.deck = [TIKKA]
       retry.resolve(accepted(BOWLS))
       await waitFor(() => expect(screen.getByRole('button', { name: 'Try it' })).toBeEnabled())
     })

web/src/discover/DiscoverPage.tsx

@@ -12,11 +12,14 @@ import {
   BATCH_JOB_KIND,
   DECK_KEY,
   parseBatchResult,
+  stillPending,
+  useDeciding,
   useDeck,
   useDecide,
   useQuestLog,
   useStartBatch,
   type Choice,
+  type SideQuest,
 } from './api.ts'
 import { DeckCard, DECK_DEPTH, type SwipeHandlers } from './DeckCard.tsx'
 import {
@@ -88,32 +91,44 @@ function QuestLogPill({ dinners, ref }: { dinners: { id: string; name: string }[
 // DiscoverPage is mock 1a: the deck of Side quests to Try it or Pass, one
 // at a time from the top card. A decision from the buttons, the ← / → keys
 // or a swipe of the top card throws it out (motion.ts) and sends the
-// decision once it is gone; Retry sends a refused one again. Input is
-// locked from the press until the decision settles: the lock is a ref, set
-// before anything starts, so a second press before the next render does
-// nothing, and busy mirrors it to disable the buttons.
+// decision once it is gone, taking the card off the deck at once (see
+// useDecide); Retry sends a failed one again while the deck's newest read
+// still has its Side quest pending. Input is locked from the press
+// until the decision settles, which is once the deck and the Quest log have
+// been read again after it, so no decision starts under those reads. The lock is a
+// ref, set before anything starts, so a second press before the next render
+// does nothing, and busy mirrors it to disable the buttons.
 export function DiscoverPage() {
   const queryClient = useQueryClient()
   const deck = useDeck()
+  // The deck shown: the deck's newest read, less the Side quests being
+  // decided, which a read landing mid-decision may still have pending.
+  const inFlight = useDeciding()
+  const cards = deck.data?.filter((quest) => !inFlight.has(quest.id))
   const questLog = useQuestLog()
   const decision = useDecide()
   const startBatch = useStartBatch()
-  const job = useJob<unknown>(BATCH_JOB_KIND, startBatch.data?.job_id ?? null)
+  // The job of the batch last known to be finding Side quests: the one Get
+  // more now started or joined, or the replenish a decision started.
+  const [batchJobId, setBatchJobId] = useState<string | null>(null)
+  const job = useJob<unknown>(BATCH_JOB_KIND, batchJobId)
 
-  const top = deck.data?.[0]
+  const top = cards?.[0]
   const [busy, setBusy] = useState(false)
-  const jobRunning = startBatch.isSuccess && job.status !== 'succeeded' && job.status !== 'failed'
+  const jobRunning = batchJobId !== null && job.status !== 'succeeded' && job.status !== 'failed'
   const finding = startBatch.isPending || jobRunning
+  const { mutate: mutateStartBatch } = startBatch
+  const getMore = useCallback(() => mutateStartBatch(undefined, { onSuccess: (b) => setBatchJobId(b.job_id) }), [mutateStartBatch])
 
   // The batch's result as far as it has gone, or why it cannot be read.
   const batch = useMemo(() => {
     if (job.result === null) return { stored: 0, error: null }
     try {
-      return { stored: parseBatchResult(`GET /api/v1/jobs/${startBatch.data?.job_id}`, job.result).suggestion_ids.length, error: null }
+      return { stored: parseBatchResult(`GET /api/v1/jobs/${batchJobId}`, job.result).suggestion_ids.length, error: null }
     } catch (error) {
       return { stored: 0, error: error as Error }
     }
-  }, [job.result, startBatch.data?.job_id])
+  }, [job.result, batchJobId])
   // The job's failure, the latest poll's failure, an answer that is not the
   // batch's job, or an unreadable result.
   const batchError = job.error ?? batch.error
@@ -122,8 +137,8 @@ export function DiscoverPage() {
   const passRef = useRef<HTMLButtonElement>(null)
   const tryRef = useRef<HTMLButtonElement>(null)
   const questLogRef = useRef<HTMLSpanElement>(null)
-  // The top card's exit while it runs or its decision is unsettled, and the
-  // Side quest the last decision sent was for, until the deck moves past it.
+  // The top card's exit until its decision settles, and the Side quest the
+  // last decision sent was for, until the deck moves past it.
   const exit = useRef<Exit | null>(null)
   const leaving = useRef<string | null>(null)
   const drag = useRef<Drag | null>(null)
@@ -143,17 +158,22 @@ export function DiscoverPage() {
     setBusy(true)
     return true
   }, [])
-  // send records a decision. A refused one puts the card back.
+  // send records a decision. A failed one stops the card's exit, so a card
+  // useDecide put back on the deck is at rest; a saved one that started a
+  // replenish batch follows its job.
   const send = useCallback(
-    (variables: { id: string; choice: Choice }) => {
-      leaving.current = variables.id
+    (variables: { quest: SideQuest; choice: Choice }) => {
+      leaving.current = variables.quest.id
       mutateDecision(variables, {
+        onSuccess: (replenishJobId) => {
+          if (replenishJobId !== null) setBatchJobId(replenishJobId)
+        },
         onError: () => {
           exit.current?.cancel()
-          exit.current = null
           leaving.current = null
         },
         onSettled: () => {
+          exit.current = null
           deciding.current = false
           setBusy(false)
         },
@@ -162,7 +182,7 @@ export function DiscoverPage() {
     [mutateDecision],
   )
   const submit = useCallback(
-    (variables: { id: string; choice: Choice }) => {
+    (variables: { quest: SideQuest; choice: Choice }) => {
       if (lock()) send(variables)
     },
     [lock, send],
@@ -207,7 +227,7 @@ export function DiscoverPage() {
         () => {
           // The Quest log pill is missing while the Quest log fails to load.
           if (choice === 'try' && !reduced && questLogRef.current !== null) bump(questLogRef.current)
-          send({ id: top.id, choice })
+          send({ quest: top, choice })
         },
         (error: unknown) => {
           if (!isAbort(error)) throw error
@@ -278,7 +298,6 @@ export function DiscoverPage() {
   useLayoutEffect(() => {
     if (leaving.current === null || leaving.current === topId) return
     leaving.current = null
-    exit.current = null
     if (topId === undefined || prefersReducedMotion()) return
     promote([...deckRef.current!.querySelectorAll<HTMLElement>(':scope > article')])
   }, [topId])
@@ -297,17 +316,29 @@ export function DiscoverPage() {
   }, [decide])
 
   // The batch stores its Side quests as it goes, so the deck is read again
-  // whenever it reports more, and once it ends.
+  // whenever it reports more, and once it ends. A read already out may be a
+  // decision's, which must not be cut short: the batch's read waits for it,
+  // then goes out after it, as it may predate what the batch reported.
   const { stored } = batch
   useEffect(() => {
     if (job.status === undefined) return
-    void queryClient.invalidateQueries({ queryKey: DECK_KEY })
+    const after = queryClient.isFetching({ queryKey: DECK_KEY }) > 0
+    void queryClient
+      .invalidateQueries({ queryKey: DECK_KEY }, { cancelRefetch: false })
+      .then(() => (after ? queryClient.invalidateQueries({ queryKey: DECK_KEY }, { cancelRefetch: false }) : undefined))
   }, [queryClient, job.status, stored])
 
+  // A failed decision can be retried only while the deck's newest read
+  // still has its Side quest pending: anything else decided it already.
+  const pending = decision.isError ? stillPending(deck, decision.variables.quest.id) : undefined
+  const retryable = pending !== undefined && pending !== null
+
   let body
   if (deck.isError) {
     body = <ErrorBanner onRetry={() => void deck.refetch()}>Couldn't load your side quests. {deck.error.message}</ErrorBanner>
-  } else if (deck.isPending || (deck.data.length === 0 && finding)) {
+  } else if (deck.isPending || (cards!.length === 0 && (finding || decision.isPending))) {
+    // An empty deck is not caught up while a batch finds more Side quests,
+    // or while the last decision may yet start one or come back refused.
     body = (
       <section aria-busy="true" aria-label="Side quests loading" className={styles.loading}>
         <div className={styles.deck}>
@@ -325,12 +356,12 @@ export function DiscoverPage() {
     body = (
       <>
         {startBatch.isError && (
-          <ErrorBanner onRetry={() => startBatch.mutate()}>Couldn't ask for more side quests. {startBatch.error.message}</ErrorBanner>
+          <ErrorBanner onRetry={getMore}>Couldn't ask for more side quests. {startBatch.error.message}</ErrorBanner>
         )}
         {batchError !== null && (
-          <ErrorBanner onRetry={() => startBatch.mutate()}>Couldn't find new side quests. {batchError.message}</ErrorBanner>
+          <ErrorBanner onRetry={getMore}>Couldn't find new side quests. {batchError.message}</ErrorBanner>
         )}
-        <EmptyState title="All caught up" action={{ label: 'Get more now', onClick: () => startBatch.mutate() }}>
+        <EmptyState title="All caught up" action={{ label: 'Get more now', onClick: getMore }}>
           New side quests arrive Sunday.
         </EmptyState>
       </>
@@ -339,7 +370,7 @@ export function DiscoverPage() {
     body = (
       <>
         <div ref={deckRef} className={styles.deck}>
-          {deck.data.slice(0, DECK_DEPTH.length).map((quest, depth) => (
+          {cards!.slice(0, DECK_DEPTH.length).map((quest, depth) => (
             <DeckCard key={quest.id} quest={quest} depth={depth} swipe={depth === 0 ? swipe : undefined} />
           ))}
         </div>
@@ -351,11 +382,6 @@ export function DiscoverPage() {
             <Icon icon={Heart} size="nav" />
           </IconButton>
         </div>
-        {decision.isError && (
-          <ErrorBanner onRetry={() => submit(decision.variables!)}>
-            Couldn't save that choice. {decision.error.message}
-          </ErrorBanner>
-        )}
       </>
     )
   }
@@ -373,6 +399,15 @@ export function DiscoverPage() {
         <ErrorBanner onRetry={() => void questLog.refetch()}>Couldn't load the Quest log. {questLog.error.message}</ErrorBanner>
       )}
       {body}
+      {/* A failed decision is shown whatever the deck has come to since. */}
+      {decision.isError &&
+        (retryable ? (
+          <ErrorBanner onRetry={() => submit(decision.variables)}>Couldn't save that choice. {decision.error.message}</ErrorBanner>
+        ) : pending === undefined ? (
+          <ErrorBanner>Couldn't save that choice. {decision.error.message}</ErrorBanner>
+        ) : (
+          <ErrorBanner>That side quest has been decided already. {decision.error.message}</ErrorBanner>
+        ))}
     </div>
   )
 }

web/src/discover/api.ts

@@ -1,4 +1,4 @@
-import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query'
+import { useMutation, useMutationState, useQuery, useQueryClient } from '@tanstack/react-query'
 import { useApi } from '../api/index.ts'
 import { isRecord } from '../api/errors.ts'
 import { DIFFICULTIES, DINNERS_PATH, oneOf, photoId, type Difficulty } from '../dinners/api.ts'
@@ -8,14 +8,18 @@ export const DECK_PATH = `${SUGGESTIONS_PATH}/deck`
 export const BATCHES_PATH = `${SUGGESTIONS_PATH}/batches`
 export const QUEST_LOG_PATH = `${DINNERS_PATH}?status=quest_log`
 
-// DECK_KEY is the deck's query; QUEST_LOG_KEY the Quest log's.
+// DECK_KEY is the deck's query; QUEST_LOG_KEY the Quest log's;
+// DECIDE_KEY the decisions'.
 export const DECK_KEY = ['suggestions', 'deck'] as const
 export const QUEST_LOG_KEY = ['dinners', 'quest_log'] as const
+const DECIDE_KEY = ['suggestions', 'decide'] as const
 
-// SideQuest is a pending suggestion as the deck shows it. photo_id is the
-// stored photo's id, from photo_url; reason is the "Why this?".
+// SideQuest is a pending suggestion as the deck shows it. dinner_id is the
+// dinner Try it moves to the Quest log; photo_id is the stored photo's id,
+// from photo_url; reason is the "Why this?".
 export type SideQuest = {
   id: string
+  dinner_id: string
   name: string
   photo_id: string | undefined
   difficulty: Difficulty | null
@@ -61,6 +65,7 @@ function parseSideQuest(where: string, body: unknown): SideQuest {
   if (
     !isRecord(body) ||
     typeof body.id !== 'string' ||
+    typeof body.dinner_id !== 'string' ||
     typeof body.name !== 'string' ||
     typeof body.reason !== 'string'
   ) {
@@ -68,6 +73,7 @@ function parseSideQuest(where: string, body: unknown): SideQuest {
   }
   return {
     id: body.id,
+    dinner_id: body.dinner_id,
     name: body.name,
     photo_id: photoId(where, body.photo_url),
     difficulty: body.difficulty === null ? null : oneOf(where, 'difficulty', DIFFICULTIES, body.difficulty),
@@ -126,31 +132,102 @@ export function useStartBatch() {
   })
 }
 
+// stillPending says whether the deck's newest read has the Side quest id
+// pending, after a failed decision on it: the Side quest when it does, null
+// when it does not, and undefined when that read failed, which says neither.
+// deck is the deck query's state, from the cache or useDeck.
+export function stillPending(deck: { status: string; data: SideQuest[] | undefined } | undefined, id: string): SideQuest | null | undefined {
+  if (deck?.status !== 'success') return undefined
+  return deck.data!.find((q) => q.id === id) ?? null
+}
+
+// useDeciding is the ids of the Side quests whose decisions are pending:
+// sent and not yet settled. The deck shown leaves them out, whatever a read
+// of the deck has said meanwhile.
+export function useDeciding(): Set<string> {
+  const ids = useMutationState<string>({
+    filters: { mutationKey: DECIDE_KEY, status: 'pending' },
+    select: (mutation) => (mutation.state.variables as { quest: SideQuest }).quest.id,
+  })
+  return new Set(ids)
+}
+
 // useDecide records Try it (POST /api/v1/suggestions/{id}/accept) or Pass
-// (POST /api/v1/suggestions/{id}/decline), then reads the deck and the
-// Quest log again. The answer must be that suggestion, decided that way.
+// (POST /api/v1/suggestions/{id}/decline) on the Side quest the household
+// decided on, whether or not a read of the deck has since taken it away.
+// The answer must be that suggestion, decided that way; the mutation's data
+// is the id of the replenish job the decision started, or null.
+//
+// The decision is applied at once: the Side quest leaves the deck shown
+// while it is pending (see useDeciding) and, on Try it, its dinner joins the
+// Quest log unless it is there already. Nothing else is worked out here:
+// the server is the record of both. However the decision ends, saved or
+// failed, the deck and the Quest log are read again, and the decision is
+// pending until those reads land, so the next one (which DiscoverPage locks
+// out until then) cannot start under them. A read under way when the
+// decision ends is replaced by the read made after it, and DiscoverPage's
+// batch reads wait for that one rather than replace it.
+// A failed decision waits for the deck read it makes itself. Whether its
+// Side quest is still pending is then the deck query's to say, from its
+// newest successful read: once the reads have landed, a Side quest the deck
+// still has goes back on top of it.
 export function useDecide() {
   const { apiFetch } = useApi()
   const queryClient = useQueryClient()
-  return useMutation({
-    mutationFn: async ({ id, choice }: { id: string; choice: Choice }) => {
-      const action = choice === 'try' ? 'accept' : 'decline'
-      const path = `${SUGGESTIONS_PATH}/${encodeURIComponent(id)}/${action}`
-      const body = await apiFetch<unknown>(path, { method: 'POST' })
-      if (
-        !isRecord(body) ||
-        !isRecord(body.suggestion) ||
-        body.suggestion.id !== id ||
-        body.suggestion.status !== DECISION_STATUS[choice]
-      ) {
-        throw new Error(`POST ${path}: response is not the ${DECISION_STATUS[choice]} suggestion`)
+
+  // send POSTs the decision and checks the answer.
+  async function send(id: string, choice: Choice): Promise<string | null> {
+    const action = choice === 'try' ? 'accept' : 'decline'
+    const path = `${SUGGESTIONS_PATH}/${encodeURIComponent(id)}/${action}`
+    const body = await apiFetch<unknown>(path, { method: 'POST' })
+    if (
+      !isRecord(body) ||
+      !isRecord(body.suggestion) ||
+      body.suggestion.id !== id ||
+      body.suggestion.status !== DECISION_STATUS[choice]
+    ) {
+      throw new Error(`POST ${path}: response is not the ${DECISION_STATUS[choice]} suggestion`)
+    }
+    if (body.replenish_job_id !== null && typeof body.replenish_job_id !== 'string') {
+      throw new Error(`POST ${path}: response has no replenish_job_id`)
+    }
+    return body.replenish_job_id
+  }
+
+  return useMutation<string | null, Error, { quest: SideQuest; choice: Choice }>({
+    mutationKey: DECIDE_KEY,
+    mutationFn: async ({ quest, choice }) => {
+      try {
+        return await send(quest.id, choice)
+      } catch (error) {
+        // The deck is read again as the decision's own fetch, replacing any
+        // read already out. A failed read is the deck query's error, shown
+        // with the deck; the decision's own error is the one thrown.
+        await queryClient
+          .getQueryCache()
+          .build<SideQuest[]>(queryClient, { queryKey: DECK_KEY })
+          .fetch(undefined, { cancelRefetch: true })
+          .catch(() => undefined)
+        throw error
       }
     },
-    onSuccess: async () => {
-      await Promise.all([
-        queryClient.invalidateQueries({ queryKey: DECK_KEY }),
-        queryClient.invalidateQueries({ queryKey: QUEST_LOG_KEY }),
-      ])
+    onMutate: ({ quest, choice }) => {
+      if (choice !== 'try') return
+      // A stale deck can offer a Side quest whose dinner the Quest log has.
+      queryClient.setQueryData<QuestLogDinner[]>(QUEST_LOG_KEY, (dinners) =>
+        dinners === undefined || dinners.some((d) => d.id === quest.dinner_id) ? dinners : dinners.concat({ id: quest.dinner_id, name: quest.name }),
+      )
+    },
+    onSettled: async (_replenishJobId, error, { quest }) => {
+      if (error === null) {
+        await Promise.all([queryClient.invalidateQueries({ queryKey: DECK_KEY }), queryClient.invalidateQueries({ queryKey: QUEST_LOG_KEY })])
+        return
+      }
+      // A failed decision has read the deck already; any read since is newer.
+      await queryClient.invalidateQueries({ queryKey: QUEST_LOG_KEY })
+      const pending = stillPending(queryClient.getQueryState<SideQuest[]>(DECK_KEY), quest.id)
+      if (pending === null || pending === undefined) return
+      queryClient.setQueryData<SideQuest[]>(DECK_KEY, (deck) => [pending, ...deck!.filter((q) => q.id !== pending.id)])
     },
   })
 }

web/src/ui/ErrorBanner.test.tsx

@@ -24,6 +24,12 @@ describe('ErrorBanner', () => {
     expect(screen.getByRole('button', { name: 'Rebuild week' })).toBeInTheDocument()
   })
 
+  it('has no button without onRetry', () => {
+    render(<ErrorBanner>That was done already.</ErrorBanner>)
+    expect(screen.getByRole('alert')).toHaveTextContent('That was done already.')
+    expect(screen.queryByRole('button')).not.toBeInTheDocument()
+  })
+
   it('is a neutral-100 card with grape-700 text', () => {
     render(<ErrorBanner onRetry={() => {}}>Offline</ErrorBanner>)
     expect(declaredStyle(screen.getByRole('alert')).background).toBe('var(--color-neutral-100)')

web/src/ui/ErrorBanner.tsx

@@ -6,16 +6,18 @@ import styles from './ErrorBanner.module.css'
 export type ErrorBannerProps = {
   // What went wrong, in the caller's words.
   children: ReactNode
-  onRetry: () => void
+  // What Retry does; without it there is nothing to retry and no button.
+  onRetry?: () => void
   retryLabel?: string
 }
 
-// Muted neutral-100 card with grape-700 text and a Retry button.
+// Muted neutral-100 card with grape-700 text and, given onRetry, a Retry
+// button.
 export function ErrorBanner({ children, onRetry, retryLabel = 'Retry' }: ErrorBannerProps) {
   return (
     <Card tone="muted" role="alert" className={styles.banner}>
       <p className={styles.message}>{children}</p>
-      <Button onClick={onRetry}>{retryLabel}</Button>
+      {onRetry !== undefined && <Button onClick={onRetry}>{retryLabel}</Button>}
     </Card>
   )
 }