feat: auto-generate manifest

bin/manifest.js

@@ -0,0 +1,43 @@
+// utils to generate a manifest.json file for a frames v2 app
+const { mnemonicToAccount } = require('viem/accounts');
+
+async function generateManifest(fid, seedPhrase) {
+  if (!Number.isInteger(fid) || fid <= 0) {
+    throw new Error('FID must be a positive integer');
+  }
+
+  let account;
+  try {
+    account = mnemonicToAccount(seedPhrase);
+  } catch (error) {
+    throw new Error('Invalid seed phrase');
+  }
+  const custodyAddress = account.address;
+
+  const header = {
+    fid,
+    type: 'custody', // question: do we want to support type of 'app_key', which indicates the signature is from a registered App Key for the FID
+    key: custodyAddress,
+  };
+  const encodedHeader = Buffer.from(JSON.stringify(header), 'utf-8').toString('base64');
+
+  const payload = {
+    domain: 'warpcast.com'
+  };
+  const encodedPayload = Buffer.from(JSON.stringify(payload), 'utf-8').toString('base64url');
+
+  const signature = await account.signMessage({ 
+    message: `${encodedHeader}.${encodedPayload}`
+  });
+  const encodedSignature = Buffer.from(signature, 'utf-8').toString('base64url');
+
+  const jsonJfs = {
+    header: encodedHeader,
+    payload: encodedPayload,
+    signature: encodedSignature
+  };
+
+  return jsonJfs;
+}
+
+module.exports = { generateManifest };