openreader/src/contexts/PDFContext.tsx

345 lines
No EOL
11 KiB
TypeScript

'use client';
import {
createContext,
useContext,
useState,
ReactNode,
useEffect,
useCallback,
useMemo,
} from 'react';
import { indexedDBService, type PDFDocument } from '@/services/indexedDB';
import { v4 as uuidv4 } from 'uuid';
import { pdfjs } from 'react-pdf';
import stringSimilarity from 'string-similarity';
import nlp from 'compromise';
// Set worker from public directory
pdfjs.GlobalWorkerOptions.workerSrc = '/pdf.worker.mjs';
interface PDFContextType {
documents: PDFDocument[];
addDocument: (file: File) => Promise<string>;
getDocument: (id: string) => Promise<PDFDocument | undefined>;
removeDocument: (id: string) => Promise<void>;
isLoading: boolean;
error: string | null;
extractTextFromPDF: (pdfData: Blob) => Promise<string>;
highlightPattern: (text: string, pattern: string, containerRef: React.RefObject<HTMLDivElement>) => void;
clearHighlights: () => void;
handleTextClick: (
event: MouseEvent,
pdfText: string,
containerRef: React.RefObject<HTMLDivElement>,
stopAndPlayFromIndex: (index: number) => void,
isProcessing: boolean
) => void;
}
const PDFContext = createContext<PDFContextType | undefined>(undefined);
export function PDFProvider({ children }: { children: ReactNode }) {
const [documents, setDocuments] = useState<PDFDocument[]>([]);
const [isLoading, setIsLoading] = useState(true);
const [error, setError] = useState<string | null>(null);
// Load documents from IndexedDB on mount
useEffect(() => {
const loadDocuments = async () => {
try {
setError(null);
await indexedDBService.init();
const docs = await indexedDBService.getAllDocuments();
setDocuments(docs);
} catch (error) {
console.error('Failed to load documents:', error);
setError('Failed to initialize document storage. Please check if your browser supports IndexedDB.');
} finally {
setIsLoading(false);
}
};
loadDocuments();
}, []);
// Add a new document to IndexedDB
const addDocument = useCallback(async (file: File): Promise<string> => {
setError(null);
const id = uuidv4();
const newDoc: PDFDocument = {
id,
name: file.name,
size: file.size,
lastModified: file.lastModified,
data: new Blob([file], { type: file.type }),
};
try {
await indexedDBService.addDocument(newDoc);
setDocuments((prev) => [...prev, newDoc]);
return id;
} catch (error) {
console.error('Failed to add document:', error);
setError('Failed to save the document. Please try again.');
throw error;
}
}, []);
// Get a document by ID from IndexedDB
const getDocument = useCallback(async (id: string): Promise<PDFDocument | undefined> => {
setError(null);
try {
return await indexedDBService.getDocument(id);
} catch (error) {
console.error('Failed to get document:', error);
setError('Failed to retrieve the document. Please try again.');
return undefined;
}
}, []);
// Remove a document by ID from IndexedDB
const removeDocument = useCallback(async (id: string): Promise<void> => {
setError(null);
try {
await indexedDBService.removeDocument(id);
setDocuments((prev) => prev.filter((doc) => doc.id !== id));
} catch (error) {
console.error('Failed to remove document:', error);
setError('Failed to remove the document. Please try again.');
throw error;
}
}, []);
// Extract text from a PDF file
const extractTextFromPDF = useCallback(async (pdfData: Blob): Promise<string> => {
try {
const reader = new FileReader();
const dataUrl = await new Promise<string>((resolve, reject) => {
reader.onload = () => resolve(reader.result as string);
reader.onerror = () => reject(reader.error);
reader.readAsDataURL(pdfData);
});
const base64Data = dataUrl.split(',')[1];
const binaryData = atob(base64Data);
const bytes = new Uint8Array(binaryData.length);
for (let i = 0; i < binaryData.length; i++) {
bytes[i] = binaryData.charCodeAt(i);
}
const loadingTask = pdfjs.getDocument({ data: bytes });
const pdf = await loadingTask.promise;
let fullText = '';
for (let i = 1; i <= pdf.numPages; i++) {
const page = await pdf.getPage(i);
const textContent = await page.getTextContent();
const pageText = textContent.items.map((item: any) => item.str).join(' ');
fullText += pageText + ' ';
}
return fullText;
} catch (error) {
console.error('Error extracting text from PDF:', error);
throw new Error('Failed to extract text from PDF');
}
}, []);
// Clear all highlights in the PDF viewer
const clearHighlights = useCallback(() => {
const textNodes = document.querySelectorAll('.react-pdf__Page__textContent span');
textNodes.forEach((node) => {
const element = node as HTMLElement;
element.style.backgroundColor = '';
element.style.opacity = '1';
});
}, []);
// Find the best text match using string similarity
const findBestTextMatch = useCallback((
elements: Array<{ element: HTMLElement; text: string }>,
targetText: string,
maxCombinedLength: number
) => {
let bestMatch = {
elements: [] as HTMLElement[],
rating: 0,
text: '',
lengthDiff: Infinity,
};
for (let i = 0; i < elements.length; i++) {
let combinedText = '';
let currentElements = [];
for (let j = i; j < Math.min(i + 10, elements.length); j++) {
const node = elements[j];
const newText = combinedText ? `${combinedText} ${node.text}` : node.text;
if (newText.length > maxCombinedLength) break;
combinedText = newText;
currentElements.push(node.element);
const similarity = stringSimilarity.compareTwoStrings(targetText, combinedText);
const lengthDiff = Math.abs(combinedText.length - targetText.length);
const lengthPenalty = lengthDiff / targetText.length;
const adjustedRating = similarity * (1 - lengthPenalty * 0.5);
if (adjustedRating > bestMatch.rating) {
bestMatch = {
elements: [...currentElements],
rating: adjustedRating,
text: combinedText,
lengthDiff,
};
}
}
}
return bestMatch;
}, []);
// Highlight matching text in the PDF viewer
const highlightPattern = useCallback((text: string, pattern: string, containerRef: React.RefObject<HTMLDivElement>) => {
clearHighlights();
if (!pattern?.trim()) return;
const cleanPattern = pattern.trim().replace(/\s+/g, ' ');
const container = containerRef.current;
if (!container) return;
const textNodes = container.querySelectorAll('.react-pdf__Page__textContent span');
const allText = Array.from(textNodes).map((node) => ({
element: node as HTMLElement,
text: (node.textContent || '').trim(),
})).filter((node) => node.text.length > 0);
const bestMatch = findBestTextMatch(allText, cleanPattern, cleanPattern.length * 2);
const similarityThreshold = bestMatch.lengthDiff < cleanPattern.length * 0.3 ? 0.3 : 0.5;
if (bestMatch.rating >= similarityThreshold) {
bestMatch.elements.forEach((element) => {
element.style.backgroundColor = 'grey';
element.style.opacity = '0.4';
});
if (bestMatch.elements.length > 0) {
setTimeout(() => {
const element = bestMatch.elements[0];
const container = containerRef.current;
if (!container || !element) return;
const containerRect = container.getBoundingClientRect();
const elementRect = element.getBoundingClientRect();
container.scrollTo({
top: container.scrollTop + (elementRect.top - containerRect.top) - containerRect.height / 2,
behavior: 'smooth',
});
}, 100);
}
}
}, [clearHighlights, findBestTextMatch]);
// Handle text click events in the PDF viewer
const handleTextClick = useCallback((
event: MouseEvent,
pdfText: string,
containerRef: React.RefObject<HTMLDivElement>,
stopAndPlayFromIndex: (index: number) => void,
isProcessing: boolean
) => {
if (isProcessing) return; // Don't process clicks while TTS is processing
const target = event.target as HTMLElement;
if (!target.matches('.react-pdf__Page__textContent span')) return;
const parentElement = target.closest('.react-pdf__Page__textContent');
if (!parentElement) return;
const spans = Array.from(parentElement.querySelectorAll('span'));
const clickedIndex = spans.indexOf(target);
const contextWindow = 3;
const startIndex = Math.max(0, clickedIndex - contextWindow);
const endIndex = Math.min(spans.length - 1, clickedIndex + contextWindow);
const contextText = spans
.slice(startIndex, endIndex + 1)
.map((span) => span.textContent)
.join(' ')
.trim();
if (!contextText?.trim()) return;
const cleanContext = contextText.trim().replace(/\s+/g, ' ');
const allText = Array.from(parentElement.querySelectorAll('span')).map((node) => ({
element: node as HTMLElement,
text: (node.textContent || '').trim(),
})).filter((node) => node.text.length > 0);
const bestMatch = findBestTextMatch(allText, cleanContext, cleanContext.length * 2);
const similarityThreshold = bestMatch.lengthDiff < cleanContext.length * 0.3 ? 0.3 : 0.5;
if (bestMatch.rating >= similarityThreshold) {
const matchText = bestMatch.text;
const sentences = nlp(pdfText).sentences().out('array') as string[];
let bestSentenceMatch = { sentence: '', rating: 0 };
for (const sentence of sentences) {
const rating = stringSimilarity.compareTwoStrings(matchText, sentence);
if (rating > bestSentenceMatch.rating) {
bestSentenceMatch = { sentence, rating };
}
}
if (bestSentenceMatch.rating >= 0.5) {
const sentenceIndex = sentences.findIndex((sentence) => sentence === bestSentenceMatch.sentence);
if (sentenceIndex !== -1) {
stopAndPlayFromIndex(sentenceIndex);
highlightPattern(pdfText, bestSentenceMatch.sentence, containerRef);
}
}
}
}, [highlightPattern, findBestTextMatch]);
// Memoize the context value to prevent unnecessary re-renders
const contextValue = useMemo(
() => ({
documents,
addDocument,
getDocument,
removeDocument,
isLoading,
error,
extractTextFromPDF,
highlightPattern,
clearHighlights,
handleTextClick,
}),
[
documents,
addDocument,
getDocument,
removeDocument,
isLoading,
error,
extractTextFromPDF,
highlightPattern,
clearHighlights,
handleTextClick,
]
);
return (
<PDFContext.Provider value={contextValue}>
{children}
</PDFContext.Provider>
);
}
export function usePDF() {
const context = useContext(PDFContext);
if (context === undefined) {
throw new Error('usePDF must be used within a PDFProvider');
}
return context;
}