From bf0e917e64372b7a9bb7782ff8bc8ea69149bd36 Mon Sep 17 00:00:00 2001
From: mmaurello <93129175+mmaurello@users.noreply.github.com>
Date: Wed, 20 Mar 2024 02:03:48 +1300
Subject: [PATCH] fix Hydra decimals as Options (#220)

* fix Hydra decimals as Options

* add changeset
---
 .changeset/rare-bikes-return.md                 |  5 +++++
 .../src/polkadot/PolkadotService.interfaces.ts  |  4 ++--
 packages/sdk/src/polkadot/PolkadotService.ts    | 17 +++++++++++++----
 3 files changed, 20 insertions(+), 6 deletions(-)
 create mode 100644 .changeset/rare-bikes-return.md

diff --git a/.changeset/rare-bikes-return.md b/.changeset/rare-bikes-return.md
new file mode 100644
index 00000000..e5288dd2
--- /dev/null
+++ b/.changeset/rare-bikes-return.md
@@ -0,0 +1,5 @@
+---
+'@moonbeam-network/xcm-sdk': patch
+---
+
+Fix decimal fetching for HydraDX
diff --git a/packages/sdk/src/polkadot/PolkadotService.interfaces.ts b/packages/sdk/src/polkadot/PolkadotService.interfaces.ts
index f8d5044f..d0e24a1a 100644
--- a/packages/sdk/src/polkadot/PolkadotService.interfaces.ts
+++ b/packages/sdk/src/polkadot/PolkadotService.interfaces.ts
@@ -1,7 +1,7 @@
-import { Bytes, Struct, u8 } from '@polkadot/types';
+import { Bytes, Option, Struct, u8 } from '@polkadot/types';
 
 export interface AssetMetadata extends Struct {
   readonly name: Bytes;
   readonly symbol: Bytes;
-  readonly decimals: u8;
+  readonly decimals: u8 | Option<u8>;
 }
diff --git a/packages/sdk/src/polkadot/PolkadotService.ts b/packages/sdk/src/polkadot/PolkadotService.ts
index 837f5846..7a1ba476 100644
--- a/packages/sdk/src/polkadot/PolkadotService.ts
+++ b/packages/sdk/src/polkadot/PolkadotService.ts
@@ -125,9 +125,13 @@ export class PolkadotService {
 
     const data = (await fn(asset)) as AssetMetadata | Option<AssetMetadata>;
     const unwrapped = 'unwrapOrDefault' in data ? data.unwrapOrDefault() : data;
+    const decimals =
+      'unwrapOrDefault' in unwrapped.decimals
+        ? unwrapped.decimals.unwrapOrDefault()
+        : unwrapped.decimals;
 
     return {
-      decimals: unwrapped.decimals.toNumber(),
+      decimals: decimals.toNumber(),
       symbol: unwrapped.symbol.toString(),
     };
   }
@@ -149,12 +153,17 @@ export class PolkadotService {
   async getAssetDecimals(asset: Asset): Promise<number> {
     const metaId = this.chain.getMetadataAssetId(asset);
 
-    return (
+    const decimals =
       this.chain.getAssetDecimals(asset) ||
       (await this.getAssetDecimalsFromQuery(metaId)) ||
       (await this.getAssetMeta(metaId))?.decimals ||
-      this.decimals
-    );
+      this.decimals; // TODO remove this and handle it separately only for native assets
+
+    if (!decimals) {
+      throw new Error(`No decimals found for asset ${asset.originSymbol}`);
+    }
+
+    return decimals;
   }
 
   async query(config: SubstrateQueryConfig): Promise<bigint> {