feat: add rejectMultisigProposal method to SolanaAgentKit and implement proposal rejection functionality

src/agent/index.ts

@@ -55,6 +55,7 @@ import { transfer_from_multisig } from "../tools/squads_multisig/transfer_from_m
 import { create_proposal } from "../tools/squads_multisig/create_proposal";
 import { approve_proposal } from "../tools/squads_multisig/approve_proposal";
 import { execute_transaction } from "../tools/squads_multisig/execute_proposal";
+import { reject_proposal } from "../tools/squads_multisig/reject_proposal";
 
 /**
  * Main class for interacting with Solana blockchain
@@ -397,6 +398,12 @@ export class SolanaAgentKit {
     return approve_proposal(this, transactionIndex);
   }
 
+  async rejectMultisigProposal(
+    transactionIndex?: number | bigint,
+  ): Promise<string> {
+    return reject_proposal(this, transactionIndex);
+  }
+
   async executeMultisigTransaction(
     transactionIndex?: number | bigint,
   ): Promise<string> {

src/tools/squads_multisig/reject_proposal.ts

@@ -0,0 +1,52 @@
+import { SolanaAgentKit } from "../../index";
+import * as multisig from "@sqds/multisig";
+const { Multisig } = multisig.accounts;
+
+/**
+ * Rejects a proposal in a Solana multisig setup.
+ *
+ * @param agent - The SolanaAgentKit instance containing the wallet and connection.
+ * @param transactionIndex - Optional. The index of the transaction to reject. If not provided, the current transaction index will be used.
+ * @returns A promise that resolves to the transaction ID of the rejection transaction.
+ * @throws Will throw an error if the transaction fails.
+ */
+export async function reject_proposal(
+  agent: SolanaAgentKit,
+  transactionIndex?: number | bigint,
+): Promise<string> {
+  try {
+    const createKey = agent.wallet;
+    const [multisigPda] = multisig.getMultisigPda({
+      createKey: createKey.publicKey,
+    });
+    const multisigInfo = await Multisig.fromAccountAddress(
+      agent.connection,
+      multisigPda,
+    );
+    const currentTransactionIndex = Number(multisigInfo.transactionIndex);
+    if (!transactionIndex) {
+      transactionIndex = BigInt(currentTransactionIndex);
+    } else if (typeof transactionIndex !== "bigint") {
+      transactionIndex = BigInt(transactionIndex);
+    }
+    // const [proposalPda, proposalBump] = multisig.getProposalPda({
+    //   multisigPda,
+    //   transactionIndex,
+    // });
+    const multisigTx = multisig.transactions.proposalReject({
+      blockhash: (await agent.connection.getLatestBlockhash()).blockhash,
+      feePayer: agent.wallet.publicKey,
+      multisigPda,
+      transactionIndex: transactionIndex,
+      member: agent.wallet.publicKey,
+    });
+
+    multisigTx.sign([agent.wallet]);
+    const tx = await agent.connection.sendRawTransaction(
+      multisigTx.serialize(),
+    );
+    return tx;
+  } catch (error: any) {
+    throw new Error(`Transfer failed: ${error}`);
+  }
+}