feat: add receipt recover signer function for graph tally

Signed-off-by: Tomás Migone <tomas@edgeandnode.com>

Author: tmigone

packages/toolshed/src/core/graph-tally.ts

@@ -1,6 +1,10 @@
 import { BytesLike, ethers, id, Signature, Wallet } from 'ethers'
 
-import type { RAV } from './types'
+import type { RAV, Receipt } from './types'
+
+export const EIP712_DOMAIN_NAME = 'GraphTallyCollector'
+export const EIP712_DOMAIN_VERSION = '1'
+
 export const EIP712_RAV_PROOF_TYPEHASH = id(
   'ReceiptAggregateVoucher(bytes32 collectionId,address payer,address serviceProvider,address dataService,uint64 timestampNs,uint128 valueAggregate,bytes metadata)',
 )
@@ -16,6 +20,22 @@ export const EIP712_RAV_PROOF_TYPES = {
   ],
 }
 
+export const EIP712_RECEIPT_PROOF_TYPEHASH = id(
+  'Receipt(bytes32 collection_id,address payer,address data_service,address service_provider,uint64 timestamp_ns,uint64 nonce,uint128 value)',
+)
+
+export const EIP712_RECEIPT_PROOF_TYPES = {
+  Receipt: [
+    { name: 'collection_id', type: 'bytes32' },
+    { name: 'payer', type: 'address' },
+    { name: 'data_service', type: 'address' },
+    { name: 'service_provider', type: 'address' },
+    { name: 'timestamp_ns', type: 'uint64' },
+    { name: 'nonce', type: 'uint64' },
+    { name: 'value', type: 'uint128' },
+  ],
+}
+
 /**
  * Generates a signed RAV
  * @param allocationId The allocation ID
@@ -44,8 +64,8 @@ export async function generateSignedRAV(
 ): Promise<{ rav: RAV; signature: string }> {
   // Create the domain for the EIP712 signature
   const domain = {
-    name: 'GraphTallyCollector',
-    version: '1',
+    name: EIP712_DOMAIN_NAME,
+    version: EIP712_DOMAIN_VERSION,
     chainId,
     verifyingContract: graphTallyCollectorAddress,
   }
@@ -100,3 +120,26 @@ export function generateSignerProof(
   const signer = new Wallet(signerPrivateKey)
   return Signature.from(signer.signingKey.sign(proofToDigest)).serialized
 }
+
+export function recoverReceiptSigner(
+  receipt: Receipt,
+  signature: Uint8Array | string,
+  graphTallyCollectorAddress: string,
+  chainId: number,
+): string {
+  // Create the domain for the EIP712 signature
+  const domain = {
+    name: EIP712_DOMAIN_NAME,
+    version: EIP712_DOMAIN_VERSION,
+    chainId,
+    verifyingContract: graphTallyCollectorAddress,
+  }
+
+  // Normalize signature to 0x-hex string
+  const sigHex = typeof signature === 'string' ? signature : ethers.hexlify(signature)
+
+  // Recover the signer address from the signature
+  const signerAddress = ethers.verifyTypedData(domain, EIP712_RECEIPT_PROOF_TYPES, receipt, sigHex)
+
+  return signerAddress
+}

packages/toolshed/src/core/types.ts

@@ -20,3 +20,13 @@ export type RAV = {
   valueAggregate: bigint
   metadata: BytesLike
 }
+
+export type Receipt = {
+  collection_id: string
+  payer: string
+  data_service: string
+  service_provider: string
+  timestamp_ns: bigint
+  nonce: bigint
+  value: bigint
+}