feat: get-xcm-delivery-fee

src/adapters/polkadot.ts

@@ -1,6 +1,6 @@
 import { Storage } from "@acala-network/sdk/utils/storage";
 import { AnyApi, FixedPointNumber as FN } from "@acala-network/sdk-core";
-import { combineLatest, map, Observable } from "rxjs";
+import { combineLatest, map, Observable, from } from "rxjs";
 
 import { SubmittableExtrinsic } from "@polkadot/api/types";
 import { DeriveBalancesAll } from "@polkadot/api-derive/balances/types";
@@ -14,6 +14,7 @@ import { BalanceData, BasicToken, TransferParams } from "../types";
 import {
   createRouteConfigs,
   getDestAccountInfo,
+  getPolkadotXcmDeleveryFee,
   validateAddress,
 } from "../utils";
 
@@ -172,8 +173,9 @@ class BasePolkadotAdapter extends BaseCrossChainAdapter {
       balance: this.balanceAdapter
         .subscribeBalance(token, address)
         .pipe(map((i) => i.available)),
+      deliveryFee: from(getPolkadotXcmDeleveryFee(this.chain.id, to, this.api)),
     }).pipe(
-      map(({ balance, txFee }) => {
+      map(({ balance, txFee, deliveryFee }) => {
         const tokenMeta = this.balanceAdapter?.getToken(token);
         const feeFactor = 1.2;
         const fee = FN.fromInner(txFee, tokenMeta?.decimals).mul(
@@ -183,6 +185,7 @@ class BasePolkadotAdapter extends BaseCrossChainAdapter {
         // always minus ed
         return balance
           .minus(fee)
+          .minus(deliveryFee)
           .minus(FN.fromInner(tokenMeta?.ed || "0", tokenMeta?.decimals));
       })
     );

src/utils/get-xcm-delivery-fee.ts

@@ -0,0 +1,119 @@
+import { AnyApi, FixedPointNumber } from "@acala-network/sdk-core";
+import { XcmVersionedXcm } from "@polkadot/types/lookup";
+import { Codec, Observable } from "@polkadot/types/types";
+import { firstValueFrom } from "rxjs";
+
+import { ChainId, chains } from "../configs";
+
+// refer to https://github.com/albertov19/xcmTools/blob/main/calculateKusamaDeliveryFees.ts
+// delivery_fee_factor * (base_fee + encoded_msg_len * per_byte_fee)
+// TODO: when most chains added xcm delivery fee, may move these to bridge package
+
+/**
+ * Only for polkadot and kusama dmp
+ */
+export async function getPolkadotXcmDeleveryFee(
+  from: ChainId,
+  to: ChainId,
+  fromApi?: AnyApi
+) {
+  if (from !== "polkadot" && from !== "kusama") {
+    throw new Error("from chain must be polkadot or kusama");
+  }
+  if (!fromApi) return FixedPointNumber.ZERO;
+  const decimal = fromApi?.registry.chainDecimals[0];
+  const paraID = chains[to].paraChainId;
+
+  // https://github.com/polkadot-fellows/runtimes/blob/16635f6abda9c5fe4b62231d632ab6f6695b48f7/system-parachains/constants/src/polkadot.rs#L60C29-L60C43
+  // https://github.com/polkadot-fellows/runtimes/blob/16635f6abda9c5fe4b62231d632ab6f6695b48f7/system-parachains/constants/src/kusama.rs#L38
+  const UNITS =
+    from === "polkadot" ? BigInt(10000000000) : BigInt(1000000000000);
+  const QUID = UNITS / BigInt(30);
+  const CENTS = QUID / BigInt(100);
+  // const GRAND = QUID / BigInt(1000);
+  const MILLICENTS = CENTS / BigInt(1000);
+
+  const byteFee = BigInt(10) * MILLICENTS;
+  const baseDeliveryFee = BigInt(3) * CENTS;
+
+  const exampleXcm: XcmVersionedXcm = fromApi?.createType(
+    "XcmVersionedXcm",
+    exampleXcmMessage
+  ) as any;
+  const xcmBytes = exampleXcm.toU8a();
+
+  const deliveryFeeFactor: Codec = await firstValueFrom(
+    fromApi?.query.dmp.deliveryFeeFactor(BigInt(paraID)) as Observable<Codec>
+  );
+
+  const convDeliveryFeeFactor =
+    BigInt(deliveryFeeFactor.toString()) / BigInt(10 ** 18);
+
+  const fee =
+    convDeliveryFeeFactor *
+    (baseDeliveryFee + BigInt(xcmBytes.length) * byteFee);
+
+  console.log(
+    fee,
+    FixedPointNumber.fromInner(fee.toString(), decimal)
+      .mul(new FixedPointNumber(1.2))
+      .toString()
+  );
+
+  return FixedPointNumber.fromInner(fee.toString(), decimal).mul(
+    new FixedPointNumber(1.2) // add some buffer
+  );
+}
+
+const exampleXcmMessage = {
+  V3: [
+    {
+      WithdrawAsset: [
+        {
+          assets: [
+            {
+              ConcreteFungible: {
+                id: "Here",
+                amount: "20000000000000",
+              },
+            },
+          ],
+          effects: [
+            {
+              BuyExecution: {
+                fees: "0",
+                weight_limit: {
+                  Unlimited: null,
+                },
+              },
+            },
+            {
+              DepositAsset: {
+                assets: "All",
+                dest: {
+                  X1: {
+                    Parachain: "2000",
+                  },
+                },
+              },
+            },
+            {
+              DepositReserveAsset: {
+                assets: "All",
+                dest: {
+                  X1: {
+                    AccountId32: {
+                      network: "Any",
+                      id: "0x76c7e05b8ee00557f8f7e11f283aacd3bbee59c1d9fd588ebbe1b6c435fe504c",
+                    },
+                  },
+                },
+                effects: [],
+              },
+            },
+          ],
+        },
+      ],
+    },
+  ],
+};

src/utils/index.ts

@@ -5,3 +5,4 @@ export * from "./xtokens-params";
 export * from "./polkadot-xcm-params";
 export * from "./create-route-configs";
 export * from "./destination-utils";
+export * from "./get-xcm-delivery-fee";