Unify ratio calculations %19

Author: phroi

src/Form.tsx

@@ -1,11 +1,11 @@
 import {
+  calculateRatio,
   direction2Symbol,
   reservedCKB,
   symbol2Direction,
   toText,
 } from "./utils.ts";
 import { CKB, max, min, type I8Header } from "@ickb/lumos-utils";
-import { ckb2Ickb, ickb2Ckb } from "@ickb/v1-core";
 import type { JSX } from "react";
 
 export default function Form({
@@ -132,10 +132,12 @@ function approxConversion(
   amount: bigint,
   tipHeader: I8Header,
 ): string {
-  let convertedAmount = isCkb2Udt
-    ? ckb2Ickb(amount, tipHeader)
-    : ickb2Ckb(amount, tipHeader);
   //Worst case scenario is a 0.1% fee for bot
-  convertedAmount -= convertedAmount / 1000n;
+  const { ckbMultiplier, udtMultiplier } = calculateRatio(isCkb2Udt, tipHeader);
+
+  const convertedAmount = isCkb2Udt
+    ? (amount * ckbMultiplier) / udtMultiplier
+    : (amount * udtMultiplier) / ckbMultiplier;
+
   return toText(convertedAmount);
 }

src/transaction.ts

@@ -14,7 +14,6 @@ import {
   addWithdrawalRequestGroups,
   ickb2Ckb,
   ickbDeposit,
-  ickbExchangeRatio,
   ickbRequestWithdrawalFrom,
   orderMelt,
   orderMint,
@@ -23,6 +22,7 @@ import {
   type OrderRatio,
 } from "@ickb/v1-core";
 import {
+  calculateRatio,
   maxEpoch,
   orderMaturityEstimate,
   txInfoPadding,
@@ -133,14 +133,7 @@ export function convert(
   }
   Object.freeze(ickbPool);
 
-  const { ckbMultiplier, udtMultiplier } = ickbExchangeRatio(tipHeader);
-  const ratio: OrderRatio = {
-    ckbMultiplier,
-    //   Pay 0.1% fee to bot
-    udtMultiplier:
-      udtMultiplier + (isCkb2Udt ? 1n : -1n) * (udtMultiplier / 1000n),
-  };
-
+  const ratio = calculateRatio(isCkb2Udt, tipHeader);
   const depositAmount = ckbSoftCapPerDeposit(tipHeader);
   const N = isCkb2Udt ? Number(amount / depositAmount) : ickbPool.length;
   const txCache = Array<TxInfo | undefined>(N);

src/utils.ts

@@ -13,6 +13,7 @@ import {
   type I8Script,
 } from "@ickb/lumos-utils";
 import { parseEpoch, type EpochSinceValue } from "@ckb-lumos/base/lib/since";
+import { ickbExchangeRatio, type OrderRatio } from "@ickb/v1-core";
 
 export interface RootConfig extends ChainConfig {
   queryClient: QueryClient;
@@ -132,3 +133,17 @@ export const txInfoPadding: TxInfo = Object.freeze({
 
 // reservedCKB are reserved for state rent in conversions
 export const reservedCKB = 1000n * CKB;
+
+// Fix up ratio to pay 0.1% fee to bot
+export function calculateRatio(
+  isCkb2Udt: boolean,
+  tipHeader: I8Header,
+): OrderRatio {
+  const { ckbMultiplier, udtMultiplier } = ickbExchangeRatio(tipHeader);
+  return {
+    ckbMultiplier,
+    //   Pay 0.1% fee to bot
+    udtMultiplier:
+      udtMultiplier + (isCkb2Udt ? 1n : -1n) * (udtMultiplier / 1000n),
+  };
+}