feat: Implement digital signatures for participant consent and introduce study forms management.

src/lib/pdf-generator.ts

@@ -0,0 +1,61 @@
+export interface PdfOptions {
+    filename?: string;
+}
+
+const getHtml2PdfOptions = (filename?: string) => ({
+    margin: 0.5,
+    filename: filename ?? 'document.pdf',
+    image: { type: 'jpeg' as const, quality: 0.98 },
+    html2canvas: { scale: 2, useCORS: true, backgroundColor: "#ffffff", windowWidth: 800 },
+    jsPDF: { unit: 'in', format: 'letter' as const, orientation: 'portrait' as const }
+});
+
+const createPrintWrapper = (htmlContent: string) => {
+    const printWrapper = document.createElement("div");
+    printWrapper.style.position = "absolute";
+    printWrapper.style.left = "-9999px";
+    printWrapper.style.top = "0px";
+    printWrapper.className = "light"; // Prevent dark mode variables from bleeding into the physical PDF
+
+    const element = document.createElement("div");
+    element.innerHTML = htmlContent;
+    // Assign standard prose layout and explicitly white/black print colors
+    element.className = "prose prose-sm max-w-none p-12 bg-white text-black";
+    element.style.width = "800px";
+    element.style.backgroundColor = "white";
+    element.style.color = "black";
+
+    printWrapper.appendChild(element);
+    document.body.appendChild(printWrapper);
+
+    return { printWrapper, element };
+};
+
+export async function downloadPdfFromHtml(htmlContent: string, options: PdfOptions = {}): Promise<void> {
+    // @ts-ignore - Dynamic import to prevent SSR issues with window/document
+    const html2pdf = (await import('html2pdf.js')).default;
+
+    const { printWrapper, element } = createPrintWrapper(htmlContent);
+
+    try {
+        const opt = getHtml2PdfOptions(options.filename);
+        await html2pdf().set(opt).from(element).save();
+    } finally {
+        document.body.removeChild(printWrapper);
+    }
+}
+
+export async function generatePdfBlobFromHtml(htmlContent: string, options: PdfOptions = {}): Promise<Blob> {
+    // @ts-ignore - Dynamic import to prevent SSR issues with window/document
+    const html2pdf = (await import('html2pdf.js')).default;
+
+    const { printWrapper, element } = createPrintWrapper(htmlContent);
+
+    try {
+        const opt = getHtml2PdfOptions(options.filename);
+        const pdfBlob = await html2pdf().set(opt).from(element).output('blob');
+        return pdfBlob;
+    } finally {
+        document.body.removeChild(printWrapper);
+    }
+}