feat(VaultUtils): add accruedInterest util

packages/blue-sdk/src/vault/Vault.ts

@@ -8,6 +8,7 @@ import {
   type IVaultMarketAllocation,
   VaultMarketAllocation,
 } from "./VaultMarketAllocation.js";
+import { VaultUtils } from "./VaultUtils";
 
 export interface Pending<T> {
   value: T;
@@ -293,6 +294,13 @@ export class AccrualVault extends Vault implements IAccrualVault {
     return MathLib.wMulDown(this.apy, MathLib.WAD - this.fee);
   }
 
+  /**
+   * Total interest paid by borrowers, increased with unrealized bad debt.
+   */
+  get accruedInterest() {
+    return VaultUtils.accruedInterest(this);
+  }
+
   public getAllocationProportion(marketId: MarketId) {
     if (this.totalAssets === 0n) return 0n;
 

packages/blue-sdk/src/vault/VaultUtils.ts

@@ -49,4 +49,23 @@ export namespace VaultUtils {
       rounding,
     );
   }
+
+  export function accruedInterest({
+    totalAssets,
+    totalSupply,
+    decimalsOffset,
+  }: {
+    totalAssets: BigIntish;
+    totalSupply: BigIntish;
+    decimalsOffset: BigIntish;
+  }) {
+    return (
+      BigInt(totalAssets) -
+      toAssets(
+        totalSupply,
+        { totalAssets: 0n, totalSupply: 0n, decimalsOffset },
+        "Down",
+      )
+    );
+  }
 }