desktop redo

frontend/src/DesktopWorkspace.jsx

@@ -39,52 +39,139 @@ const CARD_MAX = 340;
 const TAG_REMOVE_DISTANCE = 160;
 const STACK_HIT_EPSILON = 4;
 const POINTER_DRAG_THRESHOLD_SQUARED = 16;
+const LONG_PRESS_DURATION_MS = 450;
 
 const DEBUG_DRAG = false;
 const DEBUG_FOCUS = true;
 const DEBUG_DROP = true;
 
-const resolveDeskPointerIntent = ({
-  alreadySelected = false,
-  selectedCount = 0,
-  stackDocIds = null,
-  metaOrCtrl = false,
-  pointerButton = 0,
+const CLICK_ACTIONS = {
+  selectSingle: 'selectSingle',
+  openDetail: 'openDetail',
+  addCard: 'addCard',
+  addStack: 'addStack',
+  none: 'none',
+};
+
+const DRAG_ACTIONS = {
+  dragSelectSingle: 'dragSelectSingle',
+  dragSelection: 'dragSelection',
+  dragSelectStack: 'dragSelectStack',
+  none: 'none',
+};
+
+const createPointerIntent = ({
+  doc,
+  entryDescriptor,
+  selectedDocumentIds,
+  metaKey,
+  pointerButton,
+  pointerType,
+  stackHits,
 }) => {
-  const stackList = Array.isArray(stackDocIds) && stackDocIds.length > 0 ? [...stackDocIds] : null;
+  const alreadySelected = selectedDocumentIds.includes(doc.id);
+  const selectionCount = Array.isArray(selectedDocumentIds) ? selectedDocumentIds.length : 0;
 
-  if (!metaOrCtrl) {
-    return {
-      callEntryPointer: true,
-      skipSelection: false,
-      stackDragDocIds: null,
-      stackClickDocIds: null,
-      stackReplace: false,
-      openDetailOnRelease: alreadySelected && pointerButton === 0 && selectedCount > 0,
-    };
+  let clickAction = CLICK_ACTIONS.none;
+  let dragAction = DRAG_ACTIONS.none;
+
+  if (metaKey) {
+    clickAction = CLICK_ACTIONS.addStack;
+    dragAction = DRAG_ACTIONS.dragSelectStack;
+  } else if (alreadySelected) {
+    clickAction = CLICK_ACTIONS.openDetail;
+    dragAction = selectionCount > 1 ? DRAG_ACTIONS.dragSelection : DRAG_ACTIONS.dragSelectSingle;
+  } else {
+    clickAction = CLICK_ACTIONS.selectSingle;
+    dragAction = DRAG_ACTIONS.dragSelectSingle;
   }
 
-  if (alreadySelected) {
-    return {
-      callEntryPointer: false,
-      skipSelection: true,
-      stackDragDocIds: stackList,
-      stackClickDocIds: stackList,
-      stackReplace: Boolean(stackList),
-      openDetailOnRelease: false,
-    };
-  }
+  const stackList = Array.isArray(stackHits) && stackHits.length > 0
+    ? stackHits.slice()
+    : [String(doc.id)];
+
+  const stackDocIdsForDrag = dragAction === DRAG_ACTIONS.dragSelectStack ? stackList : null;
+  const stackDocIdsForClick = clickAction === CLICK_ACTIONS.addStack ? stackList : null;
 
   return {
-    callEntryPointer: true,
-    skipSelection: false,
-    stackDragDocIds: stackList,
-    stackClickDocIds: null,
-    stackReplace: Boolean(stackList),
-    openDetailOnRelease: false,
+    docId: doc.id,
+    entryDescriptor,
+    pointerType,
+    pointerButton,
+    selectedAtDown: alreadySelected,
+    selectionCountAtDown: selectionCount,
+    metaKey,
+    clickAction,
+    dragAction,
+    stackDocIdsForDrag,
+    stackDocIdsForClick,
+    stackReplaceOnClick: clickAction === CLICK_ACTIONS.addStack,
+    stackReplaceOnDrag: dragAction === DRAG_ACTIONS.dragSelectStack,
+    clickSelectionApplied: false,
+    stackSelectionApplied: false,
+    longPressTriggered: false,
   };
 };
 
+const applyClickPlanImmediately = ({ intent, event, onEntryPointer, onDocumentStackSelect }) => {
+  switch (intent.clickAction) {
+    case CLICK_ACTIONS.selectSingle:
+    case CLICK_ACTIONS.addCard:
+      if (typeof onEntryPointer === 'function') {
+        onEntryPointer(intent.entryDescriptor, event);
+      }
+      intent.clickSelectionApplied = true;
+      break;
+    case CLICK_ACTIONS.addStack:
+      if (
+        Array.isArray(intent.stackDocIdsForClick)
+        && intent.stackDocIdsForClick.length > 0
+        && typeof onDocumentStackSelect === 'function'
+      ) {
+        onDocumentStackSelect(intent.stackDocIdsForClick, event, { replace: intent.stackReplaceOnClick });
+        intent.clickSelectionApplied = true;
+        intent.stackSelectionApplied = true;
+      }
+      break;
+    case CLICK_ACTIONS.openDetail:
+    default:
+      intent.clickSelectionApplied = true;
+      break;
+  }
+};
+
+const finalizeClickSelection = ({ intent, event, onEntryPointer, onDocumentStackSelect }) => {
+  if (!intent || intent.clickSelectionApplied) {
+    return;
+  }
+
+  applyClickPlanImmediately({ intent, event, onEntryPointer, onDocumentStackSelect });
+};
+
+const applyLongPressSelection = ({ intent, stackDocIds, syntheticEvent, onDocumentStackSelect }) => {
+  if (!intent) {
+    return;
+  }
+
+  const stackCopy = Array.isArray(stackDocIds) && stackDocIds.length > 0
+    ? stackDocIds.slice()
+    : [intent.docId];
+
+  if (typeof onDocumentStackSelect === 'function') {
+    onDocumentStackSelect(stackCopy, syntheticEvent, { replace: true });
+  }
+
+  intent.clickAction = CLICK_ACTIONS.addStack;
+  intent.dragAction = DRAG_ACTIONS.dragSelectStack;
+  intent.stackDocIdsForClick = stackCopy;
+  intent.stackDocIdsForDrag = stackCopy;
+  intent.stackReplaceOnClick = true;
+  intent.stackReplaceOnDrag = true;
+  intent.clickSelectionApplied = true;
+  intent.stackSelectionApplied = true;
+  intent.longPressTriggered = true;
+};
+
 const signedDistance = (ax, ay, bx, by, px, py) => (bx - ax) * (py - ay) - (by - ay) * (px - ax);
 
 const clipPolygonWithEdge = (subject, edgeStart, edgeEnd) => {
@@ -2006,10 +2093,11 @@ const DesktopWorkspaceView = () => {
   const { handlePointerDown, handlePointerMove, handlePointerUp, handlePointerCancel } =
     useDocumentDrag();
 
-  const deferredSelectionRef = useRef(null);
   const pointerIntentRef = useRef(null);
   const pointerStartRef = useRef({ x: 0, y: 0 });
   const pointerMovedRef = useRef(false);
+  const longPressTimerRef = useRef(null);
+  const longPressActiveRef = useRef(false);
 
   const resolveStackDocIds = useCallback(
     (event, targetDocId = null) => {
@@ -2145,6 +2233,58 @@ const DesktopWorkspaceView = () => {
 
   const allSizesReady = items.every((doc) => ensureDocumentSize(doc));
 
+  const resetLongPressState = useCallback(() => {
+    if (longPressTimerRef.current) {
+      clearTimeout(longPressTimerRef.current);
+      longPressTimerRef.current = null;
+    }
+    longPressActiveRef.current = false;
+  }, []);
+
+  const scheduleLongPress = useCallback(
+    ({ doc, modifierActive, pointerType }) => {
+      if (modifierActive || pointerType !== 'touch') {
+        longPressActiveRef.current = false;
+        return;
+      }
+
+      longPressActiveRef.current = true;
+      if (typeof window === 'undefined') {
+        return;
+      }
+
+      longPressTimerRef.current = window.setTimeout(() => {
+        if (!longPressActiveRef.current || pointerMovedRef.current) {
+          resetLongPressState();
+          return;
+        }
+
+        const intent = pointerIntentRef.current;
+        if (!intent || intent.docId !== doc.id) {
+          resetLongPressState();
+          return;
+        }
+
+        const syntheticEvent = {
+          clientX: pointerStartRef.current.x,
+          clientY: pointerStartRef.current.y,
+        };
+        const stackHits = resolveStackDocIds(syntheticEvent, doc.id);
+        applyLongPressSelection({
+          intent,
+          stackDocIds: stackHits,
+          syntheticEvent,
+          onDocumentStackSelect,
+        });
+        pointerIntentRef.current = intent;
+        resetLongPressState();
+      }, LONG_PRESS_DURATION_MS);
+    },
+    [onDocumentStackSelect, resetLongPressState, resolveStackDocIds],
+  );
+
+  useEffect(() => () => resetLongPressState(), [resetLongPressState]);
+
   const handleShellKeyDown = useCallback(
     (event) => {
       if (!event || event.defaultPrevented) {
@@ -2293,75 +2433,56 @@ const DesktopWorkspaceView = () => {
                       y: Number.isFinite(event.clientY) ? event.clientY : 0,
                     };
                     pointerMovedRef.current = false;
-                    const selectionCountAtDown = Array.isArray(selectedDocumentIds)
-                      ? selectedDocumentIds.length
-                      : 0;
-                    const alreadySelected = selectedDocumentIds.includes(doc.id);
-                    const metaOrCtrlOnly =
-                      (event.metaKey || event.ctrlKey) && !event.shiftKey && !event.altKey;
+                    resetLongPressState();
 
-                    const modifierActive =
-                      Boolean(event.metaKey || event.ctrlKey || event.shiftKey || event.altKey);
                     const pointerButton = typeof event.button === 'number' ? event.button : 0;
-                    const stackHits = metaOrCtrlOnly ? resolveStackDocIds(event, doc.id) : null;
-                    const pointerIntent = resolveDeskPointerIntent({
-                      alreadySelected,
-                      selectedCount: selectionCountAtDown,
-                      stackDocIds: stackHits,
-                      metaOrCtrl: metaOrCtrlOnly,
-                      pointerButton,
-                    });
+                    const pointerType = typeof event.pointerType === 'string' ? event.pointerType : '';
+                    const metaKey = (event.metaKey || event.ctrlKey) && !event.shiftKey && !event.altKey;
+                    const modifierActive = Boolean(event.metaKey || event.ctrlKey || event.shiftKey || event.altKey);
 
-                    const stackDragDocIds = pointerIntent.stackDragDocIds;
-                    const stackClickDocIds = pointerIntent.stackClickDocIds;
-
-                    if (alreadySelected && typeof onPromoteSelection === 'function') {
-                      onPromoteSelection(doc.id, event);
-                    }
-                    pointerIntentRef.current = {
-                      docId: doc.id,
-                      selectedAtDown: alreadySelected,
-                      selectionCountAtDown,
-                      modifierActive,
-                      pointerButton,
-                      openDetailOnRelease:
-                        pointerIntent.openDetailOnRelease && typeof onDocumentOpen === 'function',
-                      stackDragDocIds,
-                      stackClickDocIds,
-                      stackClickApplied: false,
+                    const entryDescriptor = {
+                      type: 'document',
+                      id: doc.id,
+                      key: `document:${doc.id}`,
                     };
 
-                    const deferSelection =
-                      !modifierActive
-                      && alreadySelected
-                      && Array.isArray(selectedDocumentIds)
-                      && selectedDocumentIds.length > 1;
+                    const stackHits = metaKey ? resolveStackDocIds(event, doc.id) : null;
 
-                    const skipPointerSelection = pointerIntent.skipSelection;
+                    const intent = createPointerIntent({
+                      doc,
+                      entryDescriptor,
+                      selectedDocumentIds,
+                      metaKey,
+                      pointerButton,
+                      pointerType,
+                      stackHits,
+                    });
 
-                    if (skipPointerSelection) {
-                      deferredSelectionRef.current = null;
-                    } else if (deferSelection) {
-                      deferredSelectionRef.current = {
-                        entry: { type: 'document', id: doc.id, key: `document:${doc.id}` },
-                        applySelection: false,
-                      };
-                    } else {
-                      deferredSelectionRef.current = null;
-                      if (pointerIntent.callEntryPointer && typeof onEntryPointer === 'function') {
-                        onEntryPointer(
-                          { type: 'document', id: doc.id, key: `document:${doc.id}` },
-                          event,
-                        );
-                      }
+                    if (intent.selectedAtDown && typeof onPromoteSelection === 'function') {
+                      onPromoteSelection(doc.id, event);
                     }
 
+                    applyClickPlanImmediately({
+                      intent,
+                      event,
+                      onEntryPointer,
+                      onDocumentStackSelect,
+                    });
+
+                    pointerIntentRef.current = intent;
+
                     handlePointerDown(event, doc.id, {
-                      stackDocIds: stackDragDocIds,
-                      stackSelectionApplied: false,
-                      wasSelected: alreadySelected,
+                      stackDocIds: intent.stackDocIdsForDrag,
+                      stackSelectionApplied: intent.stackSelectionApplied,
+                      wasSelected: intent.selectedAtDown,
                       modifierActive,
-                      stackReplace: pointerIntent.stackReplace,
+                      stackReplace: intent.stackReplaceOnDrag,
+                    });
+
+                    scheduleLongPress({
+                      doc,
+                      modifierActive,
+                      pointerType,
                     });
                   }}
                   onPointerMove={(event) => {
@@ -2370,66 +2491,55 @@ const DesktopWorkspaceView = () => {
                     const dy = Number.isFinite(event.clientY) ? event.clientY - start.y : 0;
                     if (dx * dx + dy * dy > POINTER_DRAG_THRESHOLD_SQUARED) {
                       pointerMovedRef.current = true;
+                      resetLongPressState();
                     }
                     handlePointerMove(event);
                   }}
                   onPointerUp={(event) => {
-                    const deferredInfo = deferredSelectionRef.current;
                     const pointerState = pointerIntentRef.current;
                     const pointerMoved = pointerMovedRef.current;
 
+                    resetLongPressState();
                     handlePointerUp(event);
 
-                    if (!pointerMoved && deferredInfo && typeof onEntryPointer === 'function') {
-                      const entry = deferredInfo.entry || deferredInfo;
-                      const applySelection = deferredInfo.applySelection !== false;
-                      if (applySelection && entry) {
-                        onEntryPointer(entry, event);
+                    if (!pointerMoved && pointerState) {
+                      finalizeClickSelection({
+                        intent: pointerState,
+                        event,
+                        onEntryPointer,
+                        onDocumentStackSelect,
+                      });
+
+                      if (
+                        pointerState.clickAction === CLICK_ACTIONS.openDetail
+                        && !pointerState.longPressTriggered
+                        && typeof onDocumentOpen === 'function'
+                        && pointerState.docId === doc.id
+                      ) {
+                        const expectedButton =
+                          typeof pointerState.pointerButton === 'number'
+                            ? pointerState.pointerButton
+                            : 0;
+                        const releasedButton = typeof event.button === 'number'
+                          ? event.button
+                          : expectedButton;
+                        const isPrimaryRelease = expectedButton === 0 && releasedButton === 0;
+                        const stillSelected = Array.isArray(selectedDocumentIds)
+                          && selectedDocumentIds.includes(doc.id);
+                        if (isPrimaryRelease && stillSelected) {
+                          const useSelection = pointerState.selectedAtDown
+                            && pointerState.selectionCountAtDown > 0;
+                          onDocumentOpen(doc.id, { useSelection });
+                        }
                       }
                     }
 
-                    if (
-                      !pointerMoved
-                      && pointerState
-                      && pointerState.selectedAtDown
-                      && Array.isArray(pointerState.stackClickDocIds)
-                      && pointerState.stackClickDocIds.length > 0
-                      && !pointerState.stackClickApplied
-                      && typeof onDocumentStackSelect === 'function'
-                    ) {
-                      onDocumentStackSelect(pointerState.stackClickDocIds, event, { replace: false });
-                      pointerState.stackClickApplied = true;
-                    }
-
-                    if (
-                      !pointerMoved
-                      && pointerState
-                      && pointerState.docId === doc.id
-                      && pointerState.openDetailOnRelease
-                      && typeof onDocumentOpen === 'function'
-                    ) {
-                      const expectedButton =
-                        typeof pointerState.pointerButton === 'number'
-                          ? pointerState.pointerButton
-                          : 0;
-                      const releasedButton = typeof event.button === 'number' ? event.button : expectedButton;
-                      const isPrimaryRelease = expectedButton === 0 && releasedButton === 0;
-                      const stillSelected = Array.isArray(selectedDocumentIds)
-                        && selectedDocumentIds.includes(doc.id);
-                      if (isPrimaryRelease && stillSelected) {
-                        const useSelection =
-                          pointerState.selectedAtDown && pointerState.selectionCountAtDown > 0;
-                        onDocumentOpen(doc.id, { useSelection });
-                      }
-                    }
-
-                    deferredSelectionRef.current = null;
                     pointerIntentRef.current = null;
                     pointerMovedRef.current = false;
                   }}
                   onPointerCancel={(event) => {
-                    deferredSelectionRef.current = null;
                     pointerMovedRef.current = false;
+                    resetLongPressState();
                     pointerIntentRef.current = null;
                     handlePointerCancel(event);
                   }}

frontend/src/detail/DetailPanel.jsx

@@ -13,7 +13,8 @@ import { useAssetNavigator } from '../hooks/useAssetNavigator';
 import { describeDocumentSummary } from '../documents/documentSummary';
 import { createDocumentActionState } from '../documents/documentActions';
 import PreviewZoomOverlay from './PreviewZoomOverlay';
-import DocumentSummarySection, {
+import DocumentInfoPanel from '../documents/DocumentInfoPanel';
+import {
   TagSection,
   CorrespondentSection,
   sortCorrespondents,
@@ -407,6 +408,94 @@ const DetailPanel = ({
     return sortCorrespondents(singleDoc.correspondents || []);
   }, [singleDoc]);
 
+  const singleSummaryProps = useMemo(
+    () => ({
+      tagLookupById,
+      tagOptions: tags,
+      onTagAdd: (doc, value, extras) => onTagAdd(doc, value, extras),
+      onTagRemove: (docId, tagId) => onTagRemove(docId, tagId),
+      correspondents: singleCorrespondents,
+      correspondentOptions,
+      onCorrespondentAdd,
+      onCorrespondentRemove,
+      onUpdateTitle,
+      onUpdateIssued,
+    }),
+    [
+      tagLookupById,
+      tags,
+      onTagAdd,
+      onTagRemove,
+      singleCorrespondents,
+      correspondentOptions,
+      onCorrespondentAdd,
+      onCorrespondentRemove,
+      onUpdateTitle,
+      onUpdateIssued,
+    ],
+  );
+
+  const singleHasOcr = useMemo(() => {
+    if (!singleDoc || typeof getDocumentAsset !== 'function') {
+      return false;
+    }
+    return Boolean(getDocumentAsset(singleDoc, 'ocr-text'));
+  }, [singleDoc, getDocumentAsset]);
+
+  const loadSingleOcrContent = useCallback(async ({ signal } = {}) => {
+    if (!singleDoc || !singleHasOcr || typeof getDocumentAsset !== 'function') {
+      return '';
+    }
+
+    const updateUrl = () =>
+      resolveDocumentAssetUrl(singleDoc, 'ocr-text', {
+        ensureAssetUrl,
+        getAsset: getDocumentAsset,
+      });
+
+    const asset = getDocumentAsset(singleDoc, 'ocr-text');
+    let url = updateUrl();
+
+    if (!url && singleDoc.id && asset?.id && typeof ensureAssetUrl === 'function') {
+      await ensureAssetUrl(singleDoc.id, asset, { start: 1, limit: 1 });
+      if (signal?.aborted) {
+        throw new DOMException('Aborted', 'AbortError');
+      }
+      url = updateUrl();
+    }
+
+    if (!url) {
+      return '';
+    }
+
+    const response = await fetch(url, {
+      method: 'GET',
+      mode: 'cors',
+      credentials: 'omit',
+      signal,
+    });
+
+    if (!response.ok) {
+      throw new Error(`Unexpected status: ${response.status}`);
+    }
+
+    return response.text();
+  }, [singleDoc, singleHasOcr, getDocumentAsset, ensureAssetUrl]);
+
+  const singleContentConfig = useMemo(
+    () => ({
+      enabled: singleHasOcr,
+      id: 'content',
+      label: 'Content',
+      loadContent: loadSingleOcrContent,
+      loadingMessage: 'Loading OCR content…',
+      emptyMessage: 'No OCR content available.',
+      unavailableMessage: 'No OCR content available.',
+      errorMessage: 'Failed to load OCR content.',
+    }),
+    [singleHasOcr, loadSingleOcrContent],
+  );
+
   const bulkCorrespondents = useMemo(() => {
     if (selectedDocuments.length <= 1) {
       const doc = selectedDocuments[0];
@@ -766,19 +855,17 @@ const DetailPanel = ({
             </div>
           ) : null}
         </div>
-        <DocumentSummarySection
-          document={singleDoc}
-          tagLookupById={tagLookupById}
-          tagOptions={tags}
-          onTagAdd={(doc, value, extras) => onTagAdd(doc, value, extras)}
-          onTagRemove={(docId, tagId) => onTagRemove(docId, tagId)}
-          correspondents={singleCorrespondents}
-          correspondentOptions={correspondentOptions}
-          onCorrespondentAdd={onCorrespondentAdd}
-          onCorrespondentRemove={onCorrespondentRemove}
-          onUpdateTitle={onUpdateTitle}
-          onUpdateIssued={onUpdateIssued}
-        />
+        <div className="document-viewer__details">
+          <DocumentInfoPanel
+            document={singleDoc}
+            summaryProps={singleSummaryProps}
+            contentConfig={singleContentConfig}
+            classNamePrefix="document-viewer"
+            defaultTabId="details"
+            resetKey={singleDocId}
+            hideTabNavWhenSingle={false}
+          />
+        </div>
       </>
     );
   };

frontend/src/documents/DocumentInfoPanel.jsx

@@ -0,0 +1,302 @@
+import React, { useEffect, useMemo, useState } from 'react';
+import DocumentSummarySection from './DocumentSummarySection';
+import { buildDocumentMetadataItems, extractDocumentMetadataPayload } from './documentMetadata';
+
+const DocumentInfoPanel = ({
+  document,
+  summaryProps = {},
+  metadataItems: metadataItemsProp,
+  metadataPayload: metadataPayloadProp,
+  metadataTabLabel = 'Metadata',
+  detailsTabLabel = 'Details',
+  contentConfig: contentConfigProp = null,
+  activeTab: controlledActiveTab,
+  onTabChange,
+  defaultTabId = 'details',
+  resetKey = null,
+  classNamePrefix = 'document-info',
+  hideTabNavWhenSingle = true,
+}) => {
+  const base = classNamePrefix;
+
+  const metadataItems = useMemo(() => {
+    if (Array.isArray(metadataItemsProp) && metadataItemsProp.length) {
+      return metadataItemsProp;
+    }
+    return buildDocumentMetadataItems(document);
+  }, [metadataItemsProp, document]);
+
+  const metadataPayload = useMemo(() => {
+    if (metadataPayloadProp !== undefined) {
+      return metadataPayloadProp;
+    }
+    return extractDocumentMetadataPayload(document);
+  }, [metadataPayloadProp, document]);
+
+  const contentConfig = contentConfigProp || null;
+  const contentEnabled = Boolean(contentConfig && (contentConfig.enabled ?? true));
+  const showContentTab = Boolean(contentConfig && ((contentConfig.forceDisplay ?? contentEnabled)));
+
+  const [contentState, setContentState] = useState(() => {
+    if (!contentConfig) {
+      return null;
+    }
+    if (!contentEnabled || typeof contentConfig.loadContent !== 'function') {
+      return { status: contentEnabled ? 'idle' : 'unavailable', data: null, error: null };
+    }
+    return { status: 'idle', data: null, error: null };
+  });
+
+  useEffect(() => {
+    if (!contentConfig || !showContentTab) {
+      setContentState(null);
+      return undefined;
+    }
+
+    if (!contentEnabled || typeof contentConfig.loadContent !== 'function') {
+      setContentState({ status: contentEnabled ? 'idle' : 'unavailable', data: null, error: null });
+      return undefined;
+    }
+
+    let cancelled = false;
+    const controller = new AbortController();
+
+    setContentState({ status: 'loading', data: null, error: null });
+
+    Promise.resolve(contentConfig.loadContent({ signal: controller.signal }))
+      .then((result) => {
+        if (cancelled) {
+          return;
+        }
+        if (result && result.length) {
+          setContentState({ status: 'loaded', data: result, error: null });
+        } else {
+          setContentState({ status: 'empty', data: '', error: null });
+        }
+      })
+      .catch((error) => {
+        if (cancelled || error?.name === 'AbortError') {
+          return;
+        }
+        setContentState({
+          status: 'error',
+          data: null,
+          error,
+        });
+      });
+
+    return () => {
+      cancelled = true;
+      controller.abort();
+      contentConfig.onCancel?.();
+    };
+  }, [contentConfig, contentEnabled, showContentTab, document?.id, resetKey]);
+
+  const visibleTabs = useMemo(() => {
+    const tabsList = [];
+
+    tabsList.push({
+      id: 'details',
+      label: detailsTabLabel,
+      render: () => (
+        <section className={`${base}__section`}>
+          {metadataItems.length ? (
+            <dl className={`${base}__section-list`}>
+              {metadataItems.map(({ label, value }) => (
+                <div className={`${base}__section-item`} key={label}>
+                  <dt>{label}</dt>
+                  <dd>{value || '—'}</dd>
+                </div>
+              ))}
+            </dl>
+          ) : (
+            <p className={`${base}__section-placeholder`}>No details available.</p>
+          )}
+        </section>
+      ),
+    });
+
+    if (showContentTab && contentConfig) {
+      tabsList.push({
+        id: contentConfig.id || 'content',
+        label: contentConfig.label || 'Content',
+        render: () => {
+          const messageClass = `${base}__message`;
+          const errorClass = `${base}__message ${base}__message--error`;
+          const objectClass = `${base}__object ${base}__object--ocr-text`;
+
+          if (!contentEnabled || !contentConfig.loadContent) {
+            return (
+              <div className={messageClass}>
+                {contentConfig.unavailableMessage || 'Content not available.'}
+              </div>
+            );
+          }
+
+          if (!contentState) {
+            return (
+              <div className={messageClass}>
+                {contentConfig.emptyMessage || 'No content available.'}
+              </div>
+            );
+          }
+
+          switch (contentState.status) {
+            case 'loading':
+              return (
+                <div className={messageClass}>
+                  {contentConfig.loadingMessage || 'Loading content…'}
+                </div>
+              );
+            case 'error': {
+              const errorMessage =
+                contentConfig.errorMessage
+                || (contentState.error instanceof Error ? contentState.error.message : null)
+                || 'Failed to load content.';
+              return <div className={errorClass}>{errorMessage}</div>;
+            }
+            case 'empty':
+              return (
+                <div className={messageClass}>
+                  {contentConfig.emptyMessage || 'No content available.'}
+                </div>
+              );
+            case 'loaded':
+              return (
+                <pre className={objectClass}>{contentState.data}</pre>
+              );
+            case 'unavailable':
+              return (
+                <div className={messageClass}>
+                  {contentConfig.unavailableMessage || 'Content not available.'}
+                </div>
+              );
+            default:
+              return (
+                <div className={messageClass}>
+                  {contentConfig.emptyMessage || 'No content available.'}
+                </div>
+              );
+          }
+        },
+      });
+    }
+
+    if (metadataPayload) {
+      tabsList.push({
+        id: 'metadata',
+        label: metadataTabLabel,
+        render: () => (
+          <section className={`${base}__section ${base}__section--metadata-json`}>
+            <pre className={`${base}__metadata-json`}>
+              {JSON.stringify(metadataPayload, null, 2)}
+            </pre>
+          </section>
+        ),
+      });
+    }
+
+    return tabsList;
+  }, [
+    base,
+    detailsTabLabel,
+    metadataItems,
+    contentConfig,
+    contentEnabled,
+    contentState,
+    metadataPayload,
+    metadataTabLabel,
+    showContentTab,
+  ]);
+
+  const fallbackTabId = useMemo(() => {
+    if (!visibleTabs.length) {
+      return null;
+    }
+    if (defaultTabId && visibleTabs.some((tab) => tab.id === defaultTabId)) {
+      return defaultTabId;
+    }
+    return visibleTabs[0].id;
+  }, [visibleTabs, defaultTabId]);
+
+  const isControlled = controlledActiveTab !== undefined && controlledActiveTab !== null;
+  const [uncontrolledTab, setUncontrolledTab] = useState(
+    isControlled ? controlledActiveTab : fallbackTabId,
+  );
+
+  useEffect(() => {
+    if (!isControlled) {
+      setUncontrolledTab(fallbackTabId);
+    }
+  }, [fallbackTabId, resetKey, isControlled]);
+
+  useEffect(() => {
+    if (isControlled && controlledActiveTab && !visibleTabs.some((tab) => tab.id === controlledActiveTab)) {
+      const nextTab = fallbackTabId;
+      if (nextTab && nextTab !== controlledActiveTab) {
+        onTabChange?.(nextTab);
+      }
+    }
+  }, [isControlled, controlledActiveTab, visibleTabs, fallbackTabId, onTabChange]);
+
+  const activeTabId = isControlled ? controlledActiveTab : uncontrolledTab;
+
+  const handleTabSelect = (tabId) => {
+    if (!visibleTabs.some((tab) => tab.id === tabId)) {
+      return;
+    }
+    if (!isControlled) {
+      setUncontrolledTab(tabId);
+    }
+    if (tabId !== activeTabId) {
+      onTabChange?.(tabId);
+    }
+  };
+
+  const singleTab = visibleTabs.length === 1 ? visibleTabs[0] : null;
+  const shouldHideNav = hideTabNavWhenSingle && singleTab;
+
+  return (
+    <>
+      <DocumentSummarySection
+        document={document}
+        {...summaryProps}
+      />
+      {shouldHideNav ? (
+        <div className={`${base}__tabpanes ${base}__tabpanes--single`}>
+          <div className={`${base}__tabpanel`}>
+            {renderTabContent(singleTab, { document })}
+          </div>
+        </div>
+      ) : (
+        <div className={`${base}__tabs-wrapper`}>
+          <div className={`${base}__tabs`} role="tablist" aria-label="Document details">
+            {visibleTabs.map((tab) => (
+              <button
+                key={tab.id}
+                type="button"
+                role="tab"
+                aria-selected={tab.id === activeTabId}
+                className={`${base}__tab${tab.id === activeTabId ? ' is-active' : ''}`}
+                onClick={() => handleTabSelect(tab.id)}
+              >
+                {tab.label}
+              </button>
+            ))}
+          </div>
+          <div className={`${base}__tabpanes`}>
+            {visibleTabs.map((tab) => (
+              tab.id === activeTabId ? (
+                <div key={tab.id} role="tabpanel" className={`${base}__tabpanel`}>
+                  {renderTabContent(tab, { document })}
+                </div>
+              ) : null
+            ))}
+          </div>
+        </div>
+      )}
+    </>
+  );
+};
+
+export default DocumentInfoPanel;

frontend/src/documents/DocumentsPanel.jsx

@@ -755,6 +755,22 @@ export const createDocumentsTableHeaderActions = ({
 
   return (
     <>
+      {isDeskView && typeof onShowDeskHelp === 'function' ? (
+        <>
+          <button
+            type="button"
+            className="icon-button"
+            onClick={onShowDeskHelp}
+            aria-label="Show desk view tips"
+            title="Show desk view tips"
+          >
+            <InfoIcon />
+          </button>
+          <span className="main-content__actions-divider" aria-hidden="true">
+            <MinusVerticalIcon />
+          </span>
+        </>
+      ) : null}
       <div className="view-toggle" role="group" aria-label="Change view">
         <button
           type="button"
@@ -796,17 +812,6 @@ export const createDocumentsTableHeaderActions = ({
       >
         <RefreshIcon />
       </button>
-      {isDeskView && typeof onShowDeskHelp === 'function' ? (
-        <button
-          type="button"
-          className="icon-button"
-          onClick={onShowDeskHelp}
-          aria-label="Show desk view tips"
-          title="Show desk view tips"
-        >
-          <InfoIcon />
-        </button>
-      ) : null}
     </>
   );
 };

frontend/src/documents/documentMetadata.js

@@ -0,0 +1,49 @@
+const formatDateTime = (value) => {
+  if (!value) {
+    return '—';
+  }
+  const date = new Date(value);
+  return Number.isNaN(date.getTime()) ? '—' : date.toLocaleString();
+};
+
+export const buildDocumentMetadataItems = (document) => {
+  if (!document) {
+    return [];
+  }
+
+  const metadata = document.current_version || {};
+
+  return [
+    { label: 'Created at', value: formatDateTime(document.created_at) },
+    { label: 'Updated at', value: formatDateTime(document.updated_at) },
+    {
+      label: 'Filename',
+      value: document.filename,
+    },
+    {
+      label: 'Original filename',
+      value: document.original_name || '—',
+    },
+    {
+      label: 'SHA-256 checksum',
+      value: metadata.checksum || '—',
+    },
+    {
+      label: 'Content type',
+      value: document.content_type || '—',
+    },
+  ];
+};
+
+export const extractDocumentMetadataPayload = (document) => {
+  if (!document || !document.metadata) {
+    return null;
+  }
+  const keys = Object.keys(document.metadata);
+  if (!keys.length) {
+    return null;
+  }
+  return document.metadata;
+};
+
+export default buildDocumentMetadataItems;

frontend/src/preview/DocumentViewerPanel.jsx

@@ -1,20 +1,14 @@
-import React, { useEffect, useMemo, useState } from 'react';
+import React, { useCallback, useMemo } from 'react';
 import { DownloadIcon, CloseIcon } from '../ui/icons';
-import DocumentSummarySection, {
+import {
   buildCorrespondentOptions,
   sortCorrespondents,
 } from '../documents/DocumentSummarySection';
+import DocumentInfoPanel from '../documents/DocumentInfoPanel';
+import { extractDocumentMetadataPayload } from '../documents/documentMetadata';
 import { createDocumentActionState } from '../documents/documentActions';
 import { resolveDocumentAssetUrl } from '../asset_manager';
 
-const formatDateTime = (value) => {
-  if (!value) {
-    return '—';
-  }
-  const date = new Date(value);
-  return Number.isNaN(date.getTime()) ? '—' : date.toLocaleString();
-};
-
 const DocumentViewerPanel = ({
   document,
   documentId,
@@ -42,32 +36,6 @@ const DocumentViewerPanel = ({
     [correspondents],
   );
 
-  const metadataItems = useMemo(() => {
-    if (!document) {
-      return [];
-    }
-    return [
-      { label: 'Created at', value: formatDateTime(document.created_at) },
-      { label: 'Updated at', value: formatDateTime(document.updated_at) },
-      {
-        label: 'Filename',
-        value: document.filename,
-      },
-      {
-        label: 'Original filename',
-        value: document.original_name || '—',
-      },
-      {
-        label: 'SHA-256 checksum',
-        value: document.current_version?.checksum || '—',
-      },
-      {
-        label: 'Content type',
-        value: document.content_type || '—',
-      },
-    ];
-  }, [document]);
-
   const previewContent = useMemo(() => {
     if (!document || !previewEntry?.url) {
       return null;
@@ -128,31 +96,41 @@ const DocumentViewerPanel = ({
     );
   }, [previewEntry, document]);
 
-  const metadataPayload = useMemo(() => {
-    if (!document || !document.metadata || Object.keys(document.metadata).length === 0) {
-      return null;
-    }
-    return document.metadata;
-  }, [document]);
+  const metadataPayload = useMemo(
+    () => extractDocumentMetadataPayload(document),
+    [document],
+  );
 
-  const [activeTab, setActiveTab] = useState('details');
-  useEffect(() => {
-    setActiveTab('details');
-  }, [document?.id, hasOcr, metadataPayload]);
+  const summaryProps = useMemo(
+    () => ({
+      tagLookupById,
+      tagOptions,
+      onTagAdd,
+      onTagRemove,
+      correspondents: sortedCorrespondents,
+      correspondentOptions,
+      onCorrespondentAdd,
+      onCorrespondentRemove,
+      onUpdateTitle,
+      onUpdateIssued,
+    }),
+    [
+      tagLookupById,
+      tagOptions,
+      onTagAdd,
+      onTagRemove,
+      sortedCorrespondents,
+      correspondentOptions,
+      onCorrespondentAdd,
+      onCorrespondentRemove,
+      onUpdateTitle,
+      onUpdateIssued,
+    ],
+  );
 
-  const [ocrContent, setOcrContent] = useState(null);
-  const [ocrLoading, setOcrLoading] = useState(false);
-  const [ocrError, setOcrError] = useState(null);
-
-  useEffect(() => {
-    let cancelled = false;
+  const loadOcrContent = useCallback(async ({ signal } = {}) => {
     if (!document || !hasOcr || typeof getDocumentAsset !== 'function') {
-      setOcrContent(null);
-      setOcrLoading(false);
-      setOcrError(null);
-      return () => {
-        cancelled = true;
-      };
+      return '';
     }
 
     const updateUrl = () =>
@@ -162,68 +140,47 @@ const DocumentViewerPanel = ({
       });
 
     const asset = getDocumentAsset(document, 'ocr-text');
+    let url = updateUrl();
 
-    const ensureAndUpdate = async () => {
-      setOcrLoading(true);
-      setOcrError(null);
-
-      let url = updateUrl();
-      if (!url && document.id && asset?.id && typeof ensureAssetUrl === 'function') {
-        try {
-          await ensureAssetUrl(document.id, asset, { start: 1, limit: 1 });
-          url = updateUrl();
-        } catch (error) {
-          if (!cancelled) {
-            setOcrError('Unable to load OCR content.');
-          }
-        }
+    if (!url && document.id && asset?.id && typeof ensureAssetUrl === 'function') {
+      await ensureAssetUrl(document.id, asset, { start: 1, limit: 1 });
+      if (signal?.aborted) {
+        throw new DOMException('Aborted', 'AbortError');
       }
+      url = updateUrl();
+    }
 
-      let textContent = null;
-      if (!cancelled && url) {
-        const controller = new AbortController();
+    if (!url) {
+      return '';
+    }
 
-        try {
-          const response = await fetch(url, {
-            method: 'GET',
-            mode: 'cors',
-            credentials: 'omit',
-            signal: controller.signal,
-          });
+    const response = await fetch(url, {
+      method: 'GET',
+      mode: 'cors',
+      credentials: 'omit',
+      signal,
+    });
 
-          if (!response.ok) {
-            throw new Error(`Unexpected status: ${response.status}`);
-          }
+    if (!response.ok) {
+      throw new Error(`Unexpected status: ${response.status}`);
+    }
 
-          textContent = await response.text();
-        } catch (error) {
-          if (!cancelled) {
-            console.error('[OCR] Failed to fetch text', error);
-            setOcrError('Unable to load OCR content.');
-          }
-        }
+    return response.text();
+  }, [document, hasOcr, getDocumentAsset, ensureAssetUrl]);
 
-        if (!cancelled) {
-          setOcrContent(textContent);
-        }
-
-        controller.abort();
-      }
-
-      if (!cancelled) {
-        if (!textContent) {
-          setOcrContent(null);
-        }
-        setOcrLoading(false);
-      }
-    };
-
-    ensureAndUpdate();
-
-    return () => {
-      cancelled = true;
-    };
-  }, [document, hasOcr, ensureAssetUrl, getDocumentAsset]);
+  const contentTabConfig = useMemo(
+    () => ({
+      enabled: hasOcr,
+      id: 'content',
+      label: 'Content',
+      loadContent: loadOcrContent,
+      loadingMessage: 'Loading OCR content…',
+      emptyMessage: 'No OCR content available.',
+      unavailableMessage: 'No OCR content available.',
+      errorMessage: 'Failed to load OCR content.',
+    }),
+    [hasOcr, loadOcrContent],
+  );
 
   if (!document) {
     return (
@@ -243,96 +200,16 @@ const DocumentViewerPanel = ({
   return (
     <section className="document-viewer">
       <div className="document-viewer__details">
-        <DocumentSummarySection
+        <DocumentInfoPanel
           document={document}
-          tagLookupById={tagLookupById}
-          tagOptions={tagOptions}
-          onTagAdd={onTagAdd}
-          onTagRemove={onTagRemove}
-          correspondents={sortedCorrespondents}
-          correspondentOptions={correspondentOptions}
-          onCorrespondentAdd={onCorrespondentAdd}
-          onCorrespondentRemove={onCorrespondentRemove}
-          onUpdateTitle={onUpdateTitle}
-          onUpdateIssued={onUpdateIssued}
+          summaryProps={summaryProps}
+          metadataPayload={metadataPayload}
+          contentConfig={contentTabConfig}
+          defaultTabId="details"
+          classNamePrefix="document-viewer"
+          hideTabNavWhenSingle={false}
+          resetKey={document?.id}
         />
-        <div className="document-viewer__tabs-wrapper">
-          <div className="document-viewer__tabs" role="tablist" aria-label="Document details">
-            <button
-              type="button"
-              role="tab"
-              aria-selected={activeTab === 'details'}
-              className={`document-viewer__tab${activeTab === 'details' ? ' is-active' : ''}`}
-              onClick={() => setActiveTab('details')}
-            >
-              Details
-            </button>
-            {hasOcr ? (
-              <button
-                type="button"
-                role="tab"
-                aria-selected={activeTab === 'content'}
-                className={`document-viewer__tab${activeTab === 'content' ? ' is-active' : ''}`}
-                onClick={() => setActiveTab('content')}
-              >
-                Content
-              </button>
-            ) : null}
-            {metadataPayload ? (
-              <button
-                type="button"
-                role="tab"
-                aria-selected={activeTab === 'metadata'}
-                className={`document-viewer__tab${activeTab === 'metadata' ? ' is-active' : ''}`}
-                onClick={() => setActiveTab('metadata')}
-              >
-                Metadata
-              </button>
-            ) : null}
-          </div>
-          <div className="document-viewer__tabpanes">
-            {activeTab === 'details' ? (
-              <div role="tabpanel" className="document-viewer__tabpanel">
-                <section className="document-viewer__section">
-                  <dl className="document-viewer__section-list">
-                    {metadataItems.map(({ label, value }) => (
-                      <div className="document-viewer__section-item" key={label}>
-                        <dt>{label}</dt>
-                        <dd>{value || '—'}</dd>
-                      </div>
-                    ))}
-                  </dl>
-                </section>
-              </div>
-            ) : null}
-            {activeTab === 'content' && hasOcr ? (
-              <div role="tabpanel" className="document-viewer__tabpanel">
-                {ocrLoading ? (
-                  <div className="document-viewer__message">Loading OCR content…</div>
-                ) : ocrError ? (
-                  <div className="document-viewer__message document-viewer__message--error">
-                    {ocrError}
-                  </div>
-                ) : ocrContent ? (
-                  <pre className="document-viewer__object document-viewer__object--ocr-text">
-                    {ocrContent}
-                  </pre>
-                ) : (
-                  <div className="document-viewer__message">No OCR content available.</div>
-                )}
-              </div>
-            ) : null}
-            {activeTab === 'metadata' && metadataPayload ? (
-              <div role="tabpanel" className="document-viewer__tabpanel">
-                <section className="document-viewer__section document-viewer__section--metadata-json">
-                  <pre className="document-viewer__metadata-json">
-                    {JSON.stringify(metadataPayload, null, 2)}
-                  </pre>
-                </section>
-              </div>
-            ) : null}
-          </div>
-        </div>
       </div>
       <div className="document-viewer__viewport">
         {!previewEntry?.url ? (

frontend/src/styles.css

@@ -1011,6 +1011,11 @@ button.danger:hover:not([disabled]) {
   display: flex;
 }
 
+.document-viewer__tabpanes--single {
+  flex: 1;
+  min-height: 0;
+}
+
 .document-viewer__tabpanel {
   flex: 1;
   min-height: 0;