From 7caedad3a310ba27a39d010aa61beb6cb4078d69 Mon Sep 17 00:00:00 2001
From: Chris Duncan <chris@zoso.dev>
Date: Tue, 15 Jul 2025 21:06:22 -0700
Subject: [PATCH] Add signing method to Account class and simplify Block sign
 method accordingly.

---
 src/lib/account.ts | 24 ++++++++++++++++++++++++
 src/lib/block.ts   | 19 +++++--------------
 2 files changed, 29 insertions(+), 14 deletions(-)

diff --git a/src/lib/account.ts b/src/lib/account.ts
index 23cf0b7..f85699d 100644
--- a/src/lib/account.ts
+++ b/src/lib/account.ts
@@ -6,6 +6,7 @@ import { ACCOUNT_KEY_BYTE_LENGTH, ACCOUNT_KEY_HEX_LENGTH, ALPHABET, PREFIX, PREF
 import { base32, bytes, hex, utf8 } from './convert'
 import { Rpc } from './rpc'
 import { NanoNaClWorker, SafeWorker } from '#workers'
+import { ChangeBlock, ReceiveBlock, SendBlock } from './block'
 
 /**
 * Represents a single Nano address and the associated public key. To include the
@@ -216,6 +217,29 @@ export class Account {
 		this.#weight = BigInt(weight)
 	}
 
+	/**
+	* Signs a block using the private key of the account.
+	*
+	* @param {(ChangeBlock|ReceiveBlock|SendBlock)} block -
+	*/
+	async sign (block: ChangeBlock | ReceiveBlock | SendBlock): Promise<string> {
+		if (this.isLocked || this.#prv.buffer.detached) {
+			throw new Error('Failed to sign block with locked Account')
+		}
+		try {
+			const headers = {
+				method: 'detached'
+			}
+			const data = {
+				privateKey: new Uint8Array(this.#prv).buffer,
+				msg: hex.toBytes(block.hash).buffer
+			}
+			return await NanoNaClWorker.add(headers, data)
+		} catch (err) {
+			throw new Error(`Failed to sign block`, { cause: err })
+		}
+	}
+
 	/**
 	* Unlocks the account using the same password as used prior to lock it.
 	*
diff --git a/src/lib/block.ts b/src/lib/block.ts
index 12bc6c8..025eb80 100644
--- a/src/lib/block.ts
+++ b/src/lib/block.ts
@@ -16,7 +16,7 @@ import { NanoNaClWorker } from '#workers'
 */
 abstract class Block {
 	account: Account
-	type: string = 'state'
+	type: 'state' = 'state'
 	abstract subtype: 'send' | 'receive' | 'change'
 	abstract previous: string
 	abstract representative: Account
@@ -139,20 +139,11 @@ abstract class Block {
 			}
 			this.signature = result.signature
 		} else {
-			const key = input ?? this.account.privateKey
-			if (key == null) {
-				throw new Error('No valid key found to sign block')
-			}
-			const account = await Account.fromPrivateKey(key)
 			try {
-				const headers = {
-					method: 'detached'
-				}
-				const data = {
-					privateKey: hex.toBytes(account.privateKey).buffer,
-					msg: hex.toBytes(this.hash).buffer
-				}
-				this.signature = await NanoNaClWorker.add(headers, data)
+				const account = (typeof input === 'string')
+					? await Account.fromPrivateKey(input)
+					: this.account
+				this.signature = await account.sign(this)
 			} catch (err) {
 				throw new Error(`Failed to sign block`, { cause: err })
 			}
-- 
2.47.3