import { Texts } from "./texts.js";
import { cacheConfiguration, sameCacheConfiguration } from "./cache.js";
import { configDefinition, configValues } from "./annotator-config.js";
import { presentAnnotations } from "./annotation-display.js";
import { Options } from "./controls.js";
import { Choice, SegmentedControl, useCommandControl } from "@quixos/camino-react/ui";
import { renderAnnotations, type AnnotationRender } from "./render-hooks.js";
import { useCallback, useEffect, useLayoutEffect, useMemo, useRef, useState } from "react";
import {
  referenceOf,
  useCaminoQuery,
  useInterface,
  useLiveControl,
  useMutationFeedback,
  type ExactReference,
} from "@quixos/camino-react";
import { interfaces, queries, type Modules } from "./gen/client.js";
import { useVocabulary, VocabularyLabel } from "./vocabulary.js";
import { useCachedAnnotations } from "./cached-results.js";
import { extensionActions, WordMenu, type ReaderContext } from "./extensions.js";
import { createReaderExtensions } from "./reader-extensions.js";
import type { CanvasContextTarget } from "./canvas/Surface.js";
import { Surface } from "./canvas/Surface.js";
import { copyText, selectionRange, type Selection } from "./canvas/selection.js";
import { intersects, type Annotation, type Range } from "./canvas/types.js";
import type { ReadingWindow } from "./canvas/pages.js";
import type { ProcessingRegion } from "./canvas/processing.js";
import { useProcessing } from "./processing.js";
import { HoverIntent, processorMatches, selectSuccessfulAnnotationJobs } from "./work.js";
import { ReaderSettings } from "./editor.js";
import { Importer, SpeechSettings, Playback, Rewrite } from "./sources.js";
import {
  accepted,
  asInterface,
  errorMessage,
  type Catalog,
  type DocNode,
  type FeatureNode,
  type Root,
  type ReaderNode,
} from "./model.js";
import { readingStyle } from "./style.js";
import { usePageViews } from "./page-views.js";
import type { NavigationValues } from "./model.js";

export const Reader: Modules["Reader"] = ({ subject, navigation, input }) => {
  const app = useRef<HTMLElement>(null);
  useLayoutEffect(() => {
    const resize = () => {
      if (app.current)
        app.current.style.setProperty("--reader-top", Math.max(0, app.current.getBoundingClientRect().top) + "px");
    };
    resize();
    const observer = new ResizeObserver(resize);
    observer.observe(document.documentElement);
    window.addEventListener("resize", resize);
    return () => {
      observer.disconnect();
      window.removeEventListener("resize", resize);
    };
  }, []);
  const root = input.body.root,
    library = subject;
  const nav = useInterface(interfaces.ReadingNavigation, navigation.reference),
    ops = useInterface(
      {
        catalog: interfaces.LanguageReader.catalog,
        ensureReaders: interfaces.LanguageReader.ensureReaders,
        ensureVocabulary: interfaces.LanguageReader.ensureVocabulary,
      },
      library,
    );
  const feedback = useMutationFeedback();
  const ui = input.nav.root.ui;
  const panel = ui.panel,
    page = ui.page;
  const setUI = (changes: Partial<typeof ui>) => {
    if (nav.status === "ready") feedback.track(nav.value.ui.set({ ...ui, ...changes }));
  };
  const setPanel = (panel: string) => setUI({ panel });
  const setPage = (page: string) => setUI({ page });
  const [catalog, setCatalog] = useState<Catalog>([]),
    [error, setError] = useState(""),
    [pendingDocument, setPendingDocument] = useState<ExactReference | null>(null);
  const chosen = input.nav.root.document ?? root.documents.entries.find((e) => !e.node.archived)?.node;
  const renders = useMemo(
    () => Object.fromEntries(catalog.map((item) => [item.key, configDefinition(item.config).renders])),
    [catalog],
  );
  const revisions = useMemo(
    () => Object.fromEntries(catalog.map((item) => [item.key, item.processorRevision])),
    [catalog, root.inferenceProfile],
  );
  const revisionAliases = useMemo(
    () =>
      Object.fromEntries(
        catalog.map((item) => [item.key, configDefinition(item.config).cache?.previousRevisions ?? []]),
      ),
    [catalog],
  );
  const computations = useMemo(
    () =>
      Object.fromEntries(
        root.features.entries.map(({ node: feature }) => {
          const entry = catalog.find((item) => item.key === feature.data.processor);
          const definition = configDefinition(entry?.config ?? "{}");
          const options = {
            ...Object.fromEntries(definition.fields.map((field) => [field.key, field.default])),
            ...configValues(feature.options),
          };
          return [
            referenceOf(feature).object,
            cacheConfiguration(
              definition.cache?.identity ?? feature.data.processor,
              feature.data.scope,
              feature.data.generation,
              options,
              definition.cache?.inputs ?? [],
            ),
          ];
        }),
      ),
    [catalog, root.features.entries],
  );
  const pendingAuthors = root.tasks.entries
    .map((e) => e.node)
    .filter(
      (t) =>
        t.data.kind === "customize" &&
        ["queued", "running", "waiting_input"].includes(
          t.thread?.active?.progress.status ?? t.request?.progress.status ?? t.data.status,
        ),
    );
  const selected = pendingDocument
    ? asInterface(pendingDocument, "document")
    : chosen
      ? asInterface(referenceOf(chosen), "document")
      : undefined;
  useEffect(() => {
    if (pendingDocument?.object === input.nav.root.document?._camino.ref.object) setPendingDocument(null);
  }, [pendingDocument?.object, input.nav.root.document?._camino.ref.object]);
  const contentQuery = useCaminoQuery(queries.DocumentContentView, {
    enabled: !!selected,
    root: selected,
    input: {},
    admission: { query: queries.DocumentContentInputs, input: {} },
  });
  const contentReady =
    contentQuery.status === "ready" &&
    referenceOf(contentQuery.data.root).object === selected?.object &&
    (!pendingDocument || input.nav.root.document?._camino.ref.object === pendingDocument.object);
  useEffect(() => {
    let closed = false;
    if (ops.status === "ready")
      void ops.value.catalog
        .call(null)
        .then((value) => {
          if (!closed) setCatalog(value);
        })
        .catch((error) => {
          if (!closed) setError(errorMessage(error));
        });
    return () => {
      closed = true;
    };
  }, [ops.status, ops.status === "ready" ? ops.value : null]);
  const open = (ref: ExactReference) => {
    if (nav.status !== "ready") return;
    setPendingDocument(ref);
    const ticket = nav.value.open.call(asInterface(ref, "document"));
    feedback.track(ticket);
    void ticket.settled.then(
      (outcome) => {
        if (outcome.status !== "accepted")
          setPendingDocument((current) => (current?.object === ref.object ? null : current));
      },
      () => setPendingDocument((current) => (current?.object === ref.object ? null : current)),
    );
    setUI({ panel: "", page: "reading" });
  };
  useEffect(() => {
    if (ops.status === "ready" && !root.defaultReader)
      void accepted(ops.value.ensureReaders.call(null)).catch((e) => setError(errorMessage(e)));
  }, [ops.status, root.defaultReader]);
  useEffect(() => {
    if (ops.status === "ready" && !root.defaultVocabulary)
      void accepted(ops.value.ensureVocabulary.call(null)).catch((e) => setError(errorMessage(e)));
  }, [ops.status, root.defaultVocabulary]);
  const selectedDoc = contentQuery.status === "ready" && contentReady ? contentQuery.data.root : null;
  const activeReader = root.readers.entries
    .map((e) => e.node)
    .find(
      (r) =>
        referenceOf(r).object === (selectedDoc?.reader?._camino.ref.object ?? root.defaultReader?._camino.ref.object),
    );
  const openReaderSettings = () => {
    if (nav.status !== "ready") return;
    feedback.track(
      nav.value.selectSettings.call({
        reader: selectedDoc?.reader
          ? asInterface(referenceOf(selectedDoc.reader), "reader")
          : root.defaultReader
            ? asInterface(referenceOf(root.defaultReader), "reader")
            : null,
        feature: null,
        section: "general",
        open: true,
        document: null,
      }),
    );
  };
  return (
    <section
      ref={app}
      className="lr-app"
      aria-label="Text reader"
      style={
        {
          background: activeReader?.data.background,
          "--ink": activeReader?.palette.text,
          "--green": activeReader?.palette.accent,
        } as React.CSSProperties
      }
    >
      <style>{readingStyle}</style>
      <main className="lr-main">
        {pendingAuthors.length > 0 && (
          <button className="lr-building-status" onClick={openReaderSettings}>
            <span className="lr-spinner" />
            {pendingAuthors.length === 1 ? "Building annotator…" : `Building ${pendingAuthors.length} annotators…`}
          </button>
        )}
        {page === "library" ? (
          <Texts
            root={root}
            selected={selected?.object}
            open={open}
            add={() => setPanel("import")}
            speech={() => setPanel("speech")}
          />
        ) : contentQuery.status === "ready" && contentReady ? (
          <ReadingDocument
            key={selected!.object}
            document={{ ...contentQuery.data.root, jobs: { entries: [] } }}
            library={library}
            root={root}
            revisions={revisions}
            revisionAliases={revisionAliases}
            computations={computations}
            renders={renders}
            reader={activeReader}
            onOpen={open}
            navigation={navigation.reference}
            cursor={input.nav.root.cursor}
            readingView={input.nav.root.reading}
            annotationTarget={input.nav.root.annotationTarget}
            viewports={input.nav.root.viewports}
            panel={panel}
            setPanel={setPanel}
            onAnnotations={openReaderSettings}
            onLibrary={() => setPage("library")}
          />
        ) : (
          <div className="lr-empty">
            <h2>{selected ? "Opening text…" : "No text selected"}</h2>
            {!selected && <button onClick={() => setPanel("import")}>Add a text</button>}
          </div>
        )}
        {(error || feedback.message || contentQuery.status === "error") && (
          <p role="alert" className="lr-error">
            {error || feedback.message || "Unable to open this document."}
          </p>
        )}
      </main>
      {panel === "import" && (
        <Importer
          library={library}
          root={root}
          initialReader={activeReader ? referenceOf(activeReader).object : undefined}
          navigation={navigation.reference}
          navigationValues={input.nav.root}
          close={() => setPanel("")}
          added={(ref) => {
            setPendingDocument(ref);
            setUI({ page: "reading", panel: "" });
          }}
        />
      )}
      {panel === "speech" && <SpeechSettings library={library} close={() => setPanel("")} />}
      {panel === "features" && (
        <ReaderSettings
          library={library}
          root={root}
          catalog={catalog}
          navigationValues={input.nav.root}
          document={selected}
          previewDocument={selectedDoc ? { ...selectedDoc, jobs: { entries: [] } } : null}
          previewCursor={input.nav.root.reading.position}
          initialReader={activeReader ? referenceOf(activeReader).object : undefined}
          navigation={navigation.reference}
          close={() => setPanel("")}
        />
      )}
    </section>
  );
};
function ReadingDocument({
  document: contentDoc,
  library,
  root,
  revisions,
  revisionAliases,
  computations,
  renders,
  reader,
  onOpen,
  navigation,
  cursor,
  readingView,
  annotationTarget,
  viewports,
  onAnnotations,
  onLibrary,
  panel,
  setPanel,
}: {
  document: DocNode;
  library: ExactReference;
  root: Root;
  revisions: Record<string, string>;
  revisionAliases: Record<string, readonly string[]>;
  computations: Record<string, string>;
  renders: Record<string, AnnotationRender[] | undefined>;
  reader?: ReaderNode;
  onOpen: (ref: ExactReference) => void;
  navigation: ExactReference;
  cursor: { anchor: number; focus: number; size: number };
  readingView: { displayMode: string; position: number };
  annotationTarget: NavigationValues["annotationTarget"];
  viewports: NavigationValues["viewports"];
  panel: string;
  setPanel: (panel: string) => void;
  onAnnotations: () => void;
  onLibrary: () => void;
}) {
  const cachedAnnotations = useCachedAnnotations(referenceOf(contentDoc));
  const annotationsReady = cachedAnnotations.ready;
  const doc = useMemo(
    () => ({
      ...contentDoc,
      jobs: cachedAnnotations.ready ? { entries: cachedAnnotations.entries } : contentDoc.jobs,
    }),
    [contentDoc, cachedAnnotations.ready, cachedAnnotations.entries],
  );
  const ops = useInterface({ prepareVariant: interfaces.ReadingDocument.prepareVariant }, referenceOf(doc)),
    nav = useInterface(interfaces.ReadingNavigation, navigation),
    feedback = useMutationFeedback();
  const [selection, setSelection] = useState<Selection>({ anchor: cursor.anchor, focus: cursor.focus }),
    [hover, setHover] = useState<Range | null>(null),
    [window, setWindow] = useState<ReadingWindow>({ visible: { start: 0, end: 0 }, nearby: { start: 0, end: 0 } }),
    [message, setMessage] = useState(""),
    [noteHover, setNoteHover] = useState<{ owner: string | null; range: Range } | null>(null),
    [menu, setMenu] = useState<CanvasContextTarget | null>(null);
  const focusControl = useLiveControl({
    key: navigation.object + "/annotation-target",
    operation: interfaces.ReadingNavigation.annotationTarget.set,
    reference: navigation,
  });
  const [earlyFocus, setEarlyFocus] = useState<{ target: Range | null } | null>(null);
  const focus = earlyFocus
    ? earlyFocus.target
    : focusControl.value === undefined
      ? annotationTarget
      : focusControl.value;
  const setFocus = (target: Range | null) => {
    if (focusControl.ready) focusControl.request(target);
    else setEarlyFocus({ target });
  };
  useEffect(() => {
    if (focusControl.ready && earlyFocus) {
      focusControl.request(earlyFocus.target);
      setEarlyFocus(null);
    }
  }, [focusControl.ready, earlyFocus]);
  const pageViews = usePageViews(navigation, viewports, readingView.displayMode === "pages");
  const rewrite = panel === "rewrite",
    setRewrite = (open: boolean) => setPanel(open ? "rewrite" : "");
  const cursorTimer = useRef<ReturnType<typeof setTimeout> | null>(null),
    hoverIntent = useRef(new HoverIntent()),
    viewTimer = useRef<ReturnType<typeof setTimeout> | null>(null);
  const viewRef = useRef(readingView);
  viewRef.current = readingView;
  const [surfacePosition, setSurfacePosition] = useState(readingView.position);
  const viewEchoes = useRef(new Set<number>()),
    previousMode = useRef(readingView.displayMode);
  useLayoutEffect(() => {
    // Delayed publication of our own save must not undo newer local movement.
    // Positions written by another shared view still move this viewport.
    const modeChanged = previousMode.current !== readingView.displayMode;
    previousMode.current = readingView.displayMode;
    if (!viewEchoes.current.delete(readingView.position) || modeChanged) setSurfacePosition(readingView.position);
  }, [readingView.position, readingView.displayMode]);
  const viewWrite = useRef<string | null>(null),
    modeWrite = useRef<string | null>(null);
  function saveReading(value: typeof readingView) {
    if (nav.status !== "ready") throw Error("Reading navigation is not ready");
    const ticket = nav.value.reading.set(value, { requires: viewWrite.current ? [viewWrite.current] : [] });
    if (value.position !== viewRef.current.position) viewEchoes.current.add(value.position);
    viewWrite.current = ticket.operationId;
    void ticket.settled.then(
      (result) => {
        if (result.status !== "accepted") viewEchoes.current.delete(value.position);
        if (result.status !== "accepted" && viewWrite.current === ticket.operationId) viewWrite.current = null;
        if (modeWrite.current === ticket.operationId) modeWrite.current = null;
      },
      () => {
        viewEchoes.current.delete(value.position);
        if (viewWrite.current === ticket.operationId) viewWrite.current = null;
        if (modeWrite.current === ticket.operationId) modeWrite.current = null;
      },
    );
    return ticket;
  }
  const features = useMemo(() => {
      const members = new Set(reader?.features.entries.map((e) => referenceOf(e.node).object) ?? []);
      return root.features.entries.map((e) => e.node).filter((f) => members.has(referenceOf(f).object));
    }, [root.features.entries, reader]),
    jobs = useMemo(() => doc.jobs.entries.map(({ node }) => node), [doc.jobs.entries]);
  const enabled = features.filter((feature) => feature.data.enabled);
  const displays = enabled.flatMap((feature) =>
    (renders[feature.data.processor] ?? [{ style: feature.data.style, reveal: feature.data.reveal }]).map((render) => ({
      ...feature,
      data: { ...feature.data, style: render.style, reveal: render.reveal },
    })),
  );
  const model = useProcessing({
    document: doc,
    annotationsReady,
    features,
    revisions,
    revisionAliases,
    computations,
    renders,
    window,
    error: setMessage,
  });
  const currentSection = window.visible;
  useEffect(() => {
    if (focus) void model.focus(focus, "click");
  }, [focus?.start, focus?.end, model.ready]);
  const viewControl = useCommandControl({
    key: navigation.object + "/mode",
    value: readingView.displayMode,
    submit:
      nav.status === "ready"
        ? (mode: string) => {
            if (viewTimer.current) clearTimeout(viewTimer.current);
            setSurfacePosition(window.visible.start);
            const ticket = saveReading({ displayMode: mode, position: window.visible.start });
            modeWrite.current = ticket.operationId;
            return ticket;
          }
        : null,
  });
  const onWindow = useCallback(
    (next: ReadingWindow) => {
      setWindow((previous) => (JSON.stringify(previous) === JSON.stringify(next) ? previous : next));
      if (viewTimer.current) clearTimeout(viewTimer.current);
      if (nav.status === "ready" && next.visible.start !== viewRef.current.position)
        viewTimer.current = setTimeout(() => {
          if (nav.status === "ready" && !modeWrite.current)
            feedback.track(saveReading({ displayMode: viewRef.current.displayMode, position: next.visible.start }));
        }, 250);
    },
    [nav.status, nav.status === "ready" ? nav.value : null],
  );
  const selectedRange = selectionRange(selection),
    selectedText = doc.data.text.slice(selectedRange.start, selectedRange.end),
    activeRange = displays.some((f) => f.data.style === "sidebar" && f.data.reveal === "hover")
      ? (hover ?? focus)
      : focus;
  useEffect(() => {
    if (!cursorTimer.current) {
      setSelection({ anchor: cursor.anchor, focus: cursor.focus });
    }
  }, [cursor.anchor, cursor.focus]);
  useEffect(
    () => () => {
      if (cursorTimer.current) clearTimeout(cursorTimer.current);
      hoverIntent.current.cancel();
      if (viewTimer.current) clearTimeout(viewTimer.current);
    },
    [],
  );
  function updateSelection(value: Selection) {
    setSelection(value);
    if (cursorTimer.current) clearTimeout(cursorTimer.current);
    cursorTimer.current = setTimeout(() => {
      cursorTimer.current = null;
      if (nav.status === "ready") feedback.track(nav.value.cursor.set({ ...value, size: cursor.size }));
    }, 180);
  }
  const request = model.request;
  const vocabularyRef = reader?.vocabulary
    ? referenceOf(reader.vocabulary)
    : root.defaultVocabulary
      ? referenceOf(root.defaultVocabulary)
      : null;
  const vocabulary = useVocabulary(vocabularyRef);
  const vocabularyAPI = useInterface(
    { remember: interfaces.ReadingVocabulary.remember },
    vocabularyRef ? asInterface(vocabularyRef, "vocabulary") : undefined,
    !!vocabularyRef,
  );
  const [savingWord, setSavingWord] = useState<string | null>(null);
  const extensions = useMemo(
    () =>
      createReaderExtensions({
        vocabulary: vocabularyRef,
        name: vocabulary.node?.name ?? "Vocabulary",
        known: vocabulary.known,
        busy: savingWord,
        ready: vocabularyAPI.status === "ready",
        report: (error) => setMessage(errorMessage(error)),
        async remember(word) {
          if (vocabularyAPI.status !== "ready" || savingWord) return;
          setSavingWord(word);
          try {
            await accepted(vocabularyAPI.value.remember.call(word));
          } finally {
            setSavingWord(null);
          }
        },
      }),
    [vocabularyRef?.object, vocabulary.node?.name, vocabulary.known, vocabularyAPI, savingWord],
  );
  const annotationMap = useMemo(() => {
    const result: Annotation[] = [],
      seen = new Set<string>();
    for (const feature of enabled)
      for (const job of selectSuccessfulAnnotationJobs(
        jobs,
        (job) =>
          processorMatches(job.data, revisions[feature.data.processor], revisionAliases[feature.data.processor]) &&
          job.data.sourceRevision === doc.data.sourceRevision &&
          sameCacheConfiguration(computations[referenceOf(feature).object], job.configuration),
      )) {
        let items: {
          start: number;
          end: number;
          text: string;
          tag: string;
          color?: string;
          fontFamily?: string;
          fontSize?: number;
        }[];
        try {
          items = JSON.parse(job.data.output).items;
        } catch {
          continue;
        }
        if (!Array.isArray(items)) continue;
        for (const [index, item] of presentAnnotations(feature.data.processor, items, configValues(feature.options), {
          source: doc.data.text,
          vocabulary: vocabulary.known,
        }).entries()) {
          const featureId = referenceOf(feature).object,
            key = `${featureId}:${item.start}:${item.end}`;
          if (seen.has(key)) continue;
          seen.add(key);
          result.push(
            ...renderAnnotations(
              {
                ...item,
                activation: { start: job.data.start, end: job.data.end },
                id: `${featureId}:${job.data.key}:${index}`,
                feature: featureId,
                // Broader context sits above word labels. Graph relation order
                // does not express lane order and can differ between workspaces.
                priority:
                  (feature.data.scope === "word" ? 0 : feature.data.scope === "sentence" ? 1 : 2) * features.length +
                  features.indexOf(feature),
                style: item.style ?? (feature.data.style as Annotation["style"]),
                reveal: item.reveal ?? (feature.data.reveal as Annotation["reveal"]),
                color: item.color ?? feature.data.color,
              },
              doc.data.text,
              item.style ? undefined : renders[feature.data.processor],
            ),
          );
        }
      }
    return result;
  }, [jobs, features, revisions, revisionAliases, doc.data.sourceRevision, computations, renders, vocabulary.known]);
  const visible = useCallback(
    (id: string) => {
      const annotation = annotationMap.find((item) => item.id === id),
        feature = features.find((feature) => referenceOf(feature).object === annotation?.feature);
      if (!annotation || !feature) return false;
      const reveal = annotation.reveal ?? feature.data.reveal;
      if (reveal === "click" && feature.data.generation === "focus" && feature.data.scope !== "word")
        return (
          !!focus &&
          (model.clickScopes[referenceOf(feature).object] ?? []).some(
            (scope) => annotation.activation?.start === scope.start && annotation.activation?.end === scope.end,
          )
        );
      const range = reveal === "hover" ? hover : reveal === "click" ? focus : null;
      return reveal === "always" || (!!range && intersects(annotation, range));
    },
    [annotationMap, features, focus, hover, model.clickScopes],
  );
  function choose(range: Range) {
    setFocus(range);
    setHover(null);
    hoverIntent.current.cancel();
    model.cancelHover();
  }
  function hoverWord(range: Range | null) {
    if (hover?.start === range?.start && hover?.end === range?.end) return;
    setHover(range);
    hoverIntent.current.cancel();
    model.cancelHover();
    if (range)
      hoverIntent.current.schedule(() => {
        void model.focus(range, "hover");
      });
  }

  const context: ReaderContext = {
    library,
    document: referenceOf(doc),
    sourceRevision: doc.data.sourceRevision,
    text: doc.data.text,
    reader,
    target: selectedRange.end > selectedRange.start ? selectedRange : focus,
    targetKind: selectedRange.end > selectedRange.start ? "selection" : "word",
    annotations: annotationMap,
    highlight: useCallback((range: Range | null) => setNoteHover(range ? { owner: null, range } : null), []),
  };
  const wordActions = extensionActions(extensions, context);
  const sidebarExtensions = extensions.filter(
    (extension) => extension.Sidebar && (extension.sidebarVisible?.(context) ?? true),
  );
  const sidebar = annotationMap
    .filter((item) => visible(item.id) && item.style === "sidebar" && intersects(item, activeRange ?? currentSection))
    .slice(0, 12);
  const sidebarJobs = displays
    .filter((feature) => feature.data.style === "sidebar")
    .flatMap((feature) =>
      jobs
        .filter(
          (job) =>
            job.data.kind === "annotation" &&
            processorMatches(job.data, revisions[feature.data.processor], revisionAliases[feature.data.processor]) &&
            sameCacheConfiguration(job.configuration, computations[referenceOf(feature).object]) &&
            job.data.sourceRevision === doc.data.sourceRevision &&
            intersects(
              job.data,
              (feature.data.reveal === "hover" ? hover : feature.data.reveal === "click" ? focus : currentSection) ?? {
                start: 0,
                end: 0,
              },
            ),
        )
        .map((job) => ({ feature, job })),
    );
  const pendingSidebars = displays
    .filter((feature) => feature.data.style === "sidebar")
    .flatMap((feature) =>
      model.pending
        .filter(
          (item) =>
            computations[referenceOf(item.feature).object] === computations[referenceOf(feature).object] &&
            intersects(
              item.range,
              (feature.data.reveal === "hover" ? hover : feature.data.reveal === "click" ? focus : currentSection) ?? {
                start: 0,
                end: 0,
              },
            ),
        )
        .map((item) => ({ feature, range: item.range })),
    );
  const hoveredPanelPresent =
    !noteHover?.owner ||
    sidebar.some((item) => noteHover?.owner === "annotation:" + item.id) ||
    pendingSidebars.some(
      ({ feature, range }) => noteHover?.owner === "pending:" + referenceOf(feature).object + ":" + range.start,
    ) ||
    sidebarJobs.some(
      ({ feature, job }) =>
        job.data.status !== "ready" &&
        noteHover?.owner === "job:" + referenceOf(feature).object + ":" + referenceOf(job).object,
    );
  useLayoutEffect(() => {
    if (!hoveredPanelPresent) setNoteHover(null);
  }, [hoveredPanelPresent]);
  const processing = useMemo(() => {
    const scopes: ProcessingRegion[] = [];
    for (const job of jobs) {
      const feature = enabled.find(
        (f) =>
          sameCacheConfiguration(computations[referenceOf(f).object], job.configuration) &&
          processorMatches(job.data, revisions[f.data.processor], revisionAliases[f.data.processor]),
      );
      if (
        !feature ||
        job.data.kind !== "annotation" ||
        job.data.status !== "queued" ||
        job.data.sourceRevision !== doc.data.sourceRevision ||
        !processorMatches(job.data, revisions[feature.data.processor], revisionAliases[feature.data.processor])
      )
        continue;
      scopes.push({
        feature: referenceOf(feature).object,
        range: { start: job.data.start, end: job.data.end },
        label: `Preparing ${feature.data.name}`,
        color: feature.data.color,
      });
    }
    return scopes;
  }, [jobs, features, revisions, root.inferenceProfile, doc.data.sourceRevision, computations]);
  const previousLayoutAnnotations = useRef<Annotation[]>([]);
  const layoutAnnotations = useMemo(() => {
    const next = annotationMap.filter(
      (a) => !["overhead", "replace", "bold", "italic"].includes(a.style) || visible(a.id),
    );
    const previous = previousLayoutAnnotations.current;
    if (next.length === previous.length && next.every((annotation, index) => annotation === previous[index]))
      return previous;
    previousLayoutAnnotations.current = next;
    return next;
  }, [annotationMap, visible]);
  const pendingTooltips = displays
    .filter((feature) => feature.data.style === "tooltip")
    .flatMap((feature) => {
      const range = feature.data.reveal === "hover" ? hover : focus;
      if (
        !range ||
        annotationMap.some((item) => item.feature === referenceOf(feature).object && intersects(item, range))
      )
        return [];
      const waiting =
        model.pending.some(
          (item) => item.feature.data.processor === feature.data.processor && intersects(item.range, range),
        ) ||
        jobs.some(
          (job) =>
            job.data.status === "queued" &&
            job.data.sourceRevision === doc.data.sourceRevision &&
            job.configuration === computations[referenceOf(feature).object] &&
            processorMatches(job.data, revisions[feature.data.processor], revisionAliases[feature.data.processor]) &&
            intersects(job.data, range),
        );
      return waiting
        ? [
            {
              ...range,
              id: "pending:" + referenceOf(feature).object,
              feature: referenceOf(feature).object,
              style: "tooltip" as const,
              text: "Preparing…",
              color: feature.data.color,
              label: feature.data.name,
              trigger: feature.data.reveal as "hover" | "click",
            },
          ]
        : [];
    });
  const variant = useMemo(() => {
    try {
      const value = JSON.parse(doc.adaptation);
      return Array.isArray(value.sections)
        ? (value as { source: string; sections: { start: number; end: number; text?: string }[] })
        : null;
    } catch {
      return null;
    }
  }, [doc.adaptation]);
  const next = variant?.sections.find((s) => s.text === undefined),
    variantJob = next
      ? [...jobs]
          .sort((a, b) => b.data.createdAt.localeCompare(a.data.createdAt))
          .find((j) => j.data.kind === "variant" && j.data.start === next.start && j.data.end === next.end)
      : undefined;
  const preparingVariant = useRef(false);
  const prepareVariant = useCallback(
    (retry = false) => {
      if (ops.status !== "ready" || preparingVariant.current) return;
      preparingVariant.current = true;
      void accepted(ops.value.prepareVariant.call({ createdAt: new Date().toISOString(), retry }))
        .catch((e) => setMessage(errorMessage(e)))
        .finally(() => {
          preparingVariant.current = false;
        });
    },
    [ops.status, ops.status === "ready" ? ops.value : null],
  );
  useEffect(() => {
    if (next && !variantJob && (!doc.data.text || window.nearby.end >= doc.data.text.length - 1200)) prepareVariant();
  }, [next?.start, variantJob, doc.data.text.length, window.nearby.end, prepareVariant]);
  return (
    <>
      <header className="lr-document-head">
        <div>
          <button className="lr-library-link" onClick={onLibrary}>
            ‹ Texts
          </button>

          <h2>{doc.data.title}</h2>
          {doc.data.url && (
            <a
              className="lr-source-link"
              href={doc.data.url}
              title={doc.data.attribution}
              target="_blank"
              rel="noreferrer"
            >
              Original source ↗
            </a>
          )}
        </div>
        <div className="lr-toolbar">
          <button onClick={onAnnotations}>Reader settings</button>
          <button onClick={() => setRewrite(true)}>Adapt text</button>
          <Playback
            library={library}
            text={selectedText || doc.data.text.slice(currentSection.start, currentSection.end)}
          />
          <div className="lr-view-mode">
            <SegmentedControl
              label="Reading layout"
              value={readingView.displayMode}
              disabled={!viewControl.ready || viewControl.pending}
              options={[
                { value: "pages", label: "Pages", icon: "pages" },
                { value: "scroll", label: "Scroll", icon: "scroll" },
              ]}
              onChange={(value) => {
                void viewControl.request(value);
              }}
            />
          </div>
        </div>
      </header>
      {vocabulary.continuation}
      {cachedAnnotations.continuation}
      <div className="lr-reading-layout">
        <div className="lr-text-region">
          <div
            className="lr-page"
            style={{ maxWidth: reader?.data.width || "none", background: reader?.data.background }}
          >
            <Surface
              text={doc.data.text}
              annotations={layoutAnnotations}
              fontSize={reader?.data.size ?? 23}
              fontFamily={reader?.data.font}
              textColor={reader?.palette.text}
              accentColor={reader?.palette.accent}
              visible={visible}
              selection={selection}
              onSelection={updateSelection}
              onFocus={choose}
              onContextMenu={setMenu}
              onHover={hoverWord}
              onWindow={onWindow}
              mode={readingView.displayMode}
              position={surfacePosition}
              pageSize={pageViews.pageSize}
              onSize={pageViews.reportSize}
              hover={hover}
              emphasis={noteHover?.range ?? null}
              focus={focus}
              tooltips={[
                ...annotationMap
                  .filter((item) => item.style === "tooltip")
                  .map((item) => {
                    const feature = features.find((f) => referenceOf(f).object === item.feature)!;
                    return {
                      ...item,
                      label: feature.data.name,
                      trigger: (item.reveal ?? feature.data.reveal) as "hover" | "click",
                    };
                  }),
                ...pendingTooltips,
              ]}
              onDismissTooltip={() => {
                setFocus(null);
                hoverWord(null);
              }}
              processing={[
                ...processing,
                ...model.pending.map(({ feature, range }) => ({
                  feature: referenceOf(feature).object,
                  range,
                  label: `Preparing ${feature.data.name}`,
                  color: feature.data.color,
                })),
              ]}
            />
            {!annotationsReady && enabled.length > 0 && (
              <div className="lr-variant-status" role="status">
                Loading annotations…
              </div>
            )}
            {variant && next && (
              <div className="lr-variant-status" role="status">
                <span>
                  {variantJob && ["failed", "skipped", "uncertain"].includes(variantJob.data.status)
                    ? variantJob.data.error || "Adaptation paused"
                    : "Preparing more text…"}{" "}
                  · {variant.sections.filter((s) => s.text !== undefined).length} of {variant.sections.length} sections
                </span>
                {variantJob && ["failed", "skipped", "uncertain"].includes(variantJob.data.status) && (
                  <button onClick={() => prepareVariant(true)}>Try again</button>
                )}
              </div>
            )}
            {doc.canonical && (
              <div className="lr-variant-status">
                Adapted from {doc.canonical.data.title}. Sections are prepared as you read.
              </div>
            )}
          </div>
        </div>
        {(displays.some((feature) => feature.data.style === "sidebar") || sidebarExtensions.length > 0) && (
          <aside className="lr-margin" aria-label="Reading helpers">
            <div className="lr-context">
              <span className="lr-context-title">Notes</span>
              {activeRange ? (
                <h3 lang="zh">{doc.data.text.slice(activeRange.start, activeRange.end)}</h3>
              ) : (
                <p className="lr-muted">Choose a word for its meaning, or a sentence for its translation.</p>
              )}
              {sidebar.map((item) => (
                <article
                  className="lr-note"
                  key={item.id}
                  style={{ borderColor: item.color }}
                  onPointerEnter={() =>
                    setNoteHover({ owner: "annotation:" + item.id, range: { start: item.start, end: item.end } })
                  }
                  onPointerLeave={() => setNoteHover(null)}
                >
                  <small>{features.find((f) => referenceOf(f).object === item.feature)?.data.name}</small>
                  <p>{item.text}</p>
                </article>
              ))}
              {pendingSidebars.map(({ feature, range }) => (
                <div
                  className="lr-job"
                  key={referenceOf(feature).object + ":" + range.start}
                  onPointerEnter={() =>
                    setNoteHover({ owner: "pending:" + referenceOf(feature).object + ":" + range.start, range })
                  }
                  onPointerLeave={() => setNoteHover(null)}
                >
                  <small>{feature.data.name}</small>
                  <p role="status">Preparing…</p>
                </div>
              ))}
              {sidebarJobs
                .filter(({ job }) => job.data.status !== "ready")
                .map(({ job, feature }) => (
                  <div
                    className="lr-job"
                    key={referenceOf(feature).object + ":" + referenceOf(job).object}
                    onPointerEnter={() =>
                      setNoteHover({
                        owner: "job:" + referenceOf(feature).object + ":" + referenceOf(job).object,
                        range: job.data,
                      })
                    }
                    onPointerLeave={() => setNoteHover(null)}
                  >
                    <small>{feature.data.name}</small>
                    <p role="status">
                      {job.data.status === "queued"
                        ? job.request?.progress.status === "waiting_input"
                          ? "Waiting for your answer"
                          : "Preparing…"
                        : job.data.error || `Request ${job.data.status}`}
                    </p>
                    {["failed", "skipped", "uncertain"].includes(job.data.status) && (
                      <button onClick={() => request(feature, job.data, true)}>Try again</button>
                    )}
                  </div>
                ))}
              {sidebarExtensions.map(({ id, Sidebar }) =>
                Sidebar ? <Sidebar key={id} context={context} actions={wordActions} /> : null,
              )}
            </div>
          </aside>
        )}
      </div>
      {processing.length > 0 && (
        <p className="reading-sr" role="status">
          {processing.map((item) => item.label).join(". ")}
        </p>
      )}
      {(message || feedback.message) && (
        <p className="lr-feedback" role="status">
          {message || feedback.message}
        </p>
      )}
      {menu && (
        <WordMenu
          target={menu}
          actions={extensionActions(extensions, { ...context, target: menu.range, targetKind: menu.kind })}
          close={() => setMenu(null)}
          report={(error) => setMessage(errorMessage(error))}
        />
      )}
      {rewrite && (
        <Rewrite document={referenceOf(doc)} library={library} created={onOpen} close={() => setRewrite(false)} />
      )}
    </>
  );
}