Improve web signing flow and locale handling

backend/src/modules/signing/signing.service.js

@@ -39,6 +39,34 @@ function getSignatureWidth(style, signerName = '') {
   return Math.max(170, Math.min(270, Math.round(calculatedWidth)));
 }
 
+function buildLocalizedSignatureTimestamp({ locale, timeZone } = {}) {
+  const now = new Date();
+  const normalizedLocale = locale || 'es-EC';
+  const options = timeZone ? { timeZone } : {};
+
+  try {
+    return {
+      dateStr: now.toLocaleDateString(normalizedLocale, {
+        day: '2-digit',
+        month: '2-digit',
+        year: 'numeric',
+        ...options,
+      }),
+      timeStr: now.toLocaleTimeString(normalizedLocale, {
+        hour: '2-digit',
+        minute: '2-digit',
+        hour12: true,
+        ...options,
+      }),
+    };
+  } catch {
+    return {
+      dateStr: now.toLocaleDateString('es-EC', { day: '2-digit', month: '2-digit', year: 'numeric' }),
+      timeStr: now.toLocaleTimeString('es-EC', { hour: '2-digit', minute: '2-digit', hour12: true }),
+    };
+  }
+}
+
 // ── Style: CLASSIC (blue bar + DS badge) ──────────────────────────────────────
 async function drawStyleClassic(pdfDoc, page, sx, sy, sw, sh, { signerName, reason, dateStr, timeStr, location }) {
   const f1 = await pdfDoc.embedFont(StandardFonts.HelveticaBold);
@@ -222,6 +250,8 @@ const signPdf = async ({
   qrBackground = 'transparent',
   qrBorder = 'none',
   verificationUrl = null,
+  clientLocale = null,
+  clientTimeZone = null,
   outputDir = null,
   outputBaseName = null,
 }) => {
@@ -258,9 +288,10 @@ const signPdf = async ({
   };
   const { x: sx, y: sy, width: sw, height: sh } = sigRect;
 
-  const now     = new Date();
-  const dateStr = now.toLocaleDateString('es-EC', { day: '2-digit', month: '2-digit', year: 'numeric' });
-  const timeStr = now.toLocaleTimeString('es-EC', { hour: '2-digit', minute: '2-digit', hour12: true });
+  const { dateStr, timeStr } = buildLocalizedSignatureTimestamp({
+    locale: clientLocale,
+    timeZone: clientTimeZone,
+  });
 
   const info = { signerName, reason, dateStr, timeStr, location, signatureImageBase64, verificationUrl, qrPosition, qrBackground, qrBorder };