Optimistic Discover decisions and deck refill (#108)

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

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>
   )
 }