feat: Replaced document preview with a new fullscreen viewer

frontend/src/viewer/FullscreenPreviewContext.tsx

@@ -0,0 +1,63 @@
+import React, { useState, useCallback, useMemo, useRef } from 'react';
+import FullscreenPreviewOverlay from './components/FullscreenPreviewOverlay';
+import type { Document } from '../types/documents';
+import type { Identifier } from '../types/identifiers';
+import { createSafeContext } from '../utils/createSafeContext';
+
+interface FullscreenPreviewContextType {
+    openFullscreenPreview: (doc: Document) => void;
+    closeFullscreenPreview: () => void;
+}
+
+const [FullscreenPreviewContext, useFullscreenPreviewContext] = createSafeContext<FullscreenPreviewContextType>('FullscreenPreview');
+
+interface FullscreenPreviewProviderProps {
+    children: React.ReactNode;
+    onNavigate?: (documentId: Identifier) => void;
+}
+
+export const FullscreenPreviewProvider: React.FC<FullscreenPreviewProviderProps> = ({ children, onNavigate }) => {
+    const [previewDoc, setPreviewDoc] = useState<Document | null>(null);
+    const lastFocusedElement = useRef<HTMLElement | null>(null);
+
+    const openFullscreenPreview = useCallback((doc: Document) => {
+        if (!lastFocusedElement.current) {
+            lastFocusedElement.current = document.activeElement as HTMLElement;
+        }
+        setPreviewDoc(doc);
+    }, []);
+
+    const closeFullscreenPreview = useCallback(() => {
+        setPreviewDoc(null);
+        if (lastFocusedElement.current) {
+            lastFocusedElement.current.focus();
+            lastFocusedElement.current = null;
+        }
+    }, []);
+
+    const handleMaximize = useCallback(() => {
+        if (previewDoc && onNavigate) {
+            onNavigate(previewDoc.id);
+            closeFullscreenPreview();
+        }
+    }, [previewDoc, onNavigate, closeFullscreenPreview]);
+
+    const value = useMemo(() => ({
+        openFullscreenPreview,
+        closeFullscreenPreview,
+    }), [openFullscreenPreview, closeFullscreenPreview]);
+
+    return (
+        <FullscreenPreviewContext.Provider value={value}>
+            {children}
+            <FullscreenPreviewOverlay
+                open={Boolean(previewDoc)}
+                onClose={closeFullscreenPreview}
+                onMaximize={onNavigate ? handleMaximize : undefined}
+                document={previewDoc}
+            />
+        </FullscreenPreviewContext.Provider>
+    );
+};
+
+export { useFullscreenPreviewContext };