feat: add initial project setup with core PDF tools and utilities

- Implement core PDF manipulation tools (split, merge, convert, etc.)
- Add state management and UI utilities
- Set up build configuration with Vite and TailwindCSS
- Include essential dependencies for PDF processing
- Add gitignore and basic project configuration files

src/js/logic/encrypt.ts

@@ -0,0 +1,73 @@
+import { showLoader, hideLoader, showAlert } from '../ui.js';
+import { downloadFile, readFileAsArrayBuffer } from '../utils/helpers.js';
+import { state } from '../state.js';
+import PDFDocument from 'pdfkit/js/pdfkit.standalone';
+import blobStream from 'blob-stream';
+import * as pdfjsLib from "pdfjs-dist";
+
+export async function encrypt() {
+    const file = state.files[0];
+    const password = (document.getElementById('password-input') as HTMLInputElement).value;
+    if (!password.trim()) {
+        showAlert('Input Required', 'Please enter a password.');
+        return;
+    }
+    
+    try {
+        showLoader('Preparing to process...');
+        const pdfData = await readFileAsArrayBuffer(file);
+        const pdf = await pdfjsLib.getDocument({ data: pdfData as ArrayBuffer }).promise;
+        const numPages = pdf.numPages;
+        const pageImages = [];
+
+        for (let i = 1; i <= numPages; i++) {
+            document.getElementById('loader-text').textContent = `Processing page ${i} of ${numPages}...`;
+            const page = await pdf.getPage(i);
+            const viewport = page.getViewport({ scale: 2.0 });
+            const canvas = document.createElement('canvas');
+            const context = canvas.getContext('2d');
+            canvas.height = viewport.height;
+            canvas.width = viewport.width;
+            await page.render({ canvasContext: context, viewport: viewport, canvas: canvas }).promise;
+            pageImages.push({
+                data: canvas.toDataURL('image/jpeg', 0.8),
+                width: viewport.width,
+                height: viewport.height
+            });
+        }
+
+        document.getElementById('loader-text').textContent = 'Encrypting and building PDF...';
+        const doc = new PDFDocument({
+            size: [pageImages[0].width, pageImages[0].height],
+            pdfVersion: '1.7ext3', // Use 256-bit AES encryption 
+            userPassword: password,
+            ownerPassword: password,
+            permissions: { 
+                printing: 'highResolution', 
+                modifying: false, 
+                copying: false,
+                annotating: false,
+                fillingForms: false,
+                contentAccessibility: true,
+                documentAssembly: false
+            }
+        });
+        const stream = doc.pipe(blobStream());
+        for (let i = 0; i < pageImages.length; i++) {
+            if (i > 0) doc.addPage({ size: [pageImages[i].width, pageImages[i].height] });
+            doc.image(pageImages[i].data, 0, 0, { width: pageImages[i].width, height: pageImages[i].height });
+        }
+        doc.end();
+
+        stream.on('finish', function () {
+            const blob = stream.toBlob('application/pdf');
+            downloadFile(blob, `encrypted-${file.name}`);
+            hideLoader();
+            showAlert('Success', 'Encryption complete! Your download has started.');
+        });
+    } catch (error) {
+        console.error("Error during PDF encryption:", error);
+        hideLoader();
+        showAlert('Error', 'An error occurred. The PDF might be corrupted.');
+    }
+}