Add pseudo code with instructions for nfc render method

lib/nfcRenderer.js

@@ -0,0 +1,198 @@
+/*!
+ * VC NFC Renderer Library
+ * Handles NFC rendering for Verifiable Credentials
+ * Supports both static and dynamic rendering modes
+ * TODO: Eventually, create a reusable and
+ * indpendent library with NFC functionality.
+ */
+
+// ==================================================
+// PUBLIC API
+// ==================================================
+
+/**
+ * Check if a credential supports NFC rendering.
+ *
+ * @param {object} credential - The verifiable credential.
+ * @returns {boolean} True if NFC is supported.
+ */
+export function supportsNFC(credential) {
+  return true | false;
+}
+
+/**
+ * Get NFC rendering information from a credential.
+ *
+ * @param {object} credential - The verifiable credential.
+ * @returns {object} {suite, hasPayload, isDynamic, renderMethod}.
+ */
+export function getNFCInfo(credential) {
+  return {};
+}
+
+/**
+ * Render a credential to NFC payload bytes.
+ *
+ * @param {object} credential - The verifiable credential.
+ * @param {object} options - Rendering options.
+ * @returns {Promise<Uint8Array>} - NFC payload as bytes.
+ */
+export async function renderToNFC(credential, options = {}) {
+  // step 1: Find the NFC render method
+  _findNFCRenderMethod(credential);
+  // step 2: Determine rendering mode based on suite
+  const suite = _getRenderSuite(renderMethod);
+
+  // step 3: Route to appropriate renderer
+  switch(suite) {
+    case 'nfc-static':
+      return _renderStatic(renderMethod, credential, options);
+    case 'nfc-dynamic':
+      return _renderDynamic(renderMethod, credential, options);
+    case 'nfc':
+      // TODO: Try static first, fall back to dynamic if renderProperty exists.
+    default:
+      throw new Error(`Unsupported renderSuite: ${suite}`);
+  }
+}
+
+// ==================================================
+// Render Method Detection
+// ==================================================
+
+/**
+ * Find the NFC-compatible render method in a credential.
+ *
+ * @private
+ */
+
+function _findNFCRenderMethod(credential) {
+  // Look for method.type = 'TemplateRenderMethod' or for legacy support
+  // 'NfcRenderingTemplate2024'
+}
+
+/**
+ * Get the render suite, with fallback for legacy formats.
+ *
+ * @private
+ */
+
+function _getRenderSuite(renderMethod) {
+  // legacy format - default to static
+  if(renderMethod.type === 'NfcRenderingTemplate2024') {
+    return 'nfc-static';
+  }
+
+  // generic fallback -- Question - do we need generic fallback??
+  return 'nfc';
+}
+
+/**
+ * Check if render method has a static payload.
+ *
+ * @private
+ */
+
+function _hasStaticPayload(renderMethod) {
+
+  // An example with pre-encoded NFC payload stored directly in the credential.
+
+  // {
+  //   "renderMethod": {
+  //     "type": "TemplateRenderMethod",
+  //     "renderSuite": "nfc-static",
+  //     "template": "data:application/octet-stream;base64,SGVsbG8="
+  //   }
+  // }
+
+}
+
+// ==================================================
+// Static Rendering
+// ==================================================
+
+/**
+ * Render static NFC payload.
+ * The payload is already encoded in the render method.
+ *
+ * @private
+ */
+
+async function _renderStatic(renderMethod, credential, options) {
+  // Extract the payload/template field.
+  // Detect the encoding format.
+  // Decode to bytes.
+  // Return bytes.
+  return;
+}
+
+// ==================================================
+// Dynamic Rendering
+// ==================================================
+
+/**
+ * Render dynamic NFC payload by extracting data from credential.
+ *
+ * @private
+ */
+
+async function _renderDynamic(renderMethod, credential, options) {
+  // An example - extract values from credential at runtime using JSON
+  // Pointers based on renderProperty mappings.
+
+  //{
+  //  "credentialSubject": {
+  //    "studentId": "STU123456",
+  //    "barcode": "987654321"
+  //    },
+  //  "renderMethod": {
+  //    "type": "TemplateRenderMethod",
+  //    "renderSuite": "nfc-dynamic",
+  //    "renderProperty": [
+  //      "/credentialSubject/studentId",
+  //      "/credentialSubject/barcode"
+  //    ]
+  //  }
+  //}
+
+  // Questions: Does order matter in renderProperty array?
+  // Should we support named properties instead?
+
+  // "renderProperty": {
+  //   "fn": "/credentialSubject/firstName",
+  //   "ln": "/credentialSubject/lastName"
+  // }
+
+  // Should we enforce NFC size limits? If yes, where??
+
+  // Validate configuration - renderProperty exists.
+  // Normalize renderProperty to array.
+  // Extract values from credential using JSON pointers.
+  // Encode values to bytes or other formats if needed.
+  // Decode values to bytes if needed.
+  // Build the NFC payload from the extracted values.
+  return _buildDynamicPayload(extractedValues, renderMethod, options);
+}
+
+/**
+ * Build NFC payload from extracted credential values.
+ *
+ * @private
+ */
+
+function _buildDynamicPayload(extractedValues, renderMethod, options) {
+  // TODO: Support different payload formats (CBOR-LD, JSON-LD, custom)
+  // Custom - simple concatenation of UTF-8 encoded strings.
+
+  // Question: What should be the payload formats supports available by default?
+  // CBOR/JSON Encoding
+  return;
+}
+
+// ==================================================
+// Encoding/Decoding utility functions goes here
+// ==================================================
+
+// ==================================================
+// JSON Pointer utility functions goes here
+// ==================================================