From e3df20917715b8e78886d1988aeadd835b6bbf2a Mon Sep 17 00:00:00 2001
From: Kyle Fang <zhigang1992@gmail.com>
Date: Fri, 13 Dec 2024 05:17:02 +0000
Subject: [PATCH] feat: add isSponsoredTxServiceAvailable and fix PC

---
 package.json                   |  2 +-
 src/alexSDK.ts                 | 19 +++++++++++++++--
 src/config.ts                  |  1 +
 src/helpers/SponsorTxHelper.ts | 39 +++++++++++++++++++++++++++-------
 4 files changed, 50 insertions(+), 11 deletions(-)

diff --git a/package.json b/package.json
index 26c56da..fbb2eb9 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "packageManager": "pnpm@9.4.0",
-  "version": "3.0.0",
+  "version": "3.0.1",
   "license": "MIT",
   "main": "dist/index.js",
   "typings": "dist/index.d.ts",
diff --git a/src/alexSDK.ts b/src/alexSDK.ts
index 99c8e1c..3d1d4ac 100644
--- a/src/alexSDK.ts
+++ b/src/alexSDK.ts
@@ -13,6 +13,7 @@ import { fromEntries } from './utils/utils';
 import type { AMMRoute } from './utils/ammRouteResolver';
 import {
   broadcastSponsoredTx,
+  getSponsorData,
   requiredStxAmountForSponsorTx,
   runSponsoredSpotTx,
   SponsoredTxError,
@@ -174,6 +175,16 @@ export class AlexSDK {
     );
   }
 
+  /**
+   * Check if the sponsor service is available.
+   * 
+   * @returns {Promise<boolean>} - A promise that resolves to true if the sponsor service is available, false otherwise.
+   */
+  async isSponsoredTxServiceAvailable(): Promise<boolean> {
+    const { status } = await getSponsorData();
+    return status === 'ok';
+  }
+
   /**
    * Get the amount of destination currency that will be received when swapping from one currency to another
    * in the context of sponsor tx.
@@ -195,7 +206,9 @@ export class AlexSDK {
     const sponsorFeeAmount =
       from === Currency.STX
         ? stxAmount
-        : await this.getAmountTo(Currency.STX, stxAmount, from);
+        : await this.getAmountTo(Currency.STX, BigInt(1e8), from).then(
+          (x) => (x * stxAmount) / BigInt(1e8)
+        );
     if (sponsorFeeAmount > fromAmount) {
       return BigInt(0);
     }
@@ -269,7 +282,9 @@ export class AlexSDK {
     const sponsorFeeAmount =
       currencyX === Currency.STX
         ? stxAmount
-        : await this.getAmountTo(Currency.STX, stxAmount, currencyX);
+        : await this.getAmountTo(Currency.STX, BigInt(1e8), currencyX).then(
+          (x) => (x * stxAmount) / BigInt(1e8)
+        );
     if (sponsorFeeAmount > fromAmount) {
       throw new SponsoredTxError(
         SponsoredTxErrorCode.insufficient_funds,
diff --git a/src/config.ts b/src/config.ts
index 2e85ba2..c43ac54 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -6,4 +6,5 @@ export const configs = {
   STACKS_API_HOST: 'https://api.hiro.so',
   READONLY_CALL_API_HOST: 'https://stacks-node.alexlab.co',
   SPONSORED_TX_EXECUTOR: 'https://api.stxer.xyz/sponsor/execute',
+  SPONSORED_TX_STATUS: 'https://api.stxer.xyz/sponsor/status',
 };
diff --git a/src/helpers/SponsorTxHelper.ts b/src/helpers/SponsorTxHelper.ts
index 4e1d0e7..ce2980e 100644
--- a/src/helpers/SponsorTxHelper.ts
+++ b/src/helpers/SponsorTxHelper.ts
@@ -11,13 +11,26 @@ import { hasLength } from '../utils/arrayHelper';
 import { transferFactory } from '../utils/postConditions';
 import { composeTx, type TxToBroadCast } from './SwapHelper';
 
+let sponsorData: Promise<{ status: 'ok' | string, perRouteFee: bigint }> | undefined;
+
+export function getSponsorData(): Promise<{ status: 'ok' | string, perRouteFee: bigint }> {
+  if (sponsorData == null) {
+    sponsorData = fetch(configs.SPONSORED_TX_STATUS, {
+      method: 'GET',
+      mode: 'cors',
+    }).then(res => res.json()).then(data => ({ status: data.status, perRouteFee: BigInt(data.per_route_fee) }));
+  }
+  return sponsorData;
+}
+
 export const requiredStxAmountForSponsorTx = async (
   _from: Currency,
   _to: Currency,
   customRoute: AMMRoute
 ): Promise<bigint> => {
-  const feePerSegment = 0.05 * 1e8;
-  return BigInt(Math.floor(customRoute.length * feePerSegment));
+  // we need to convert the fee to the same unit as the amount
+  const feePerSegment = await getSponsorData().then(data => data.perRouteFee * BigInt(1e8) / BigInt(1e6));
+  return BigInt(customRoute.length) * feePerSegment;
 };
 
 export function runSponsoredSpotTx(
@@ -62,11 +75,16 @@ export function runSponsoredSpotTx(
         fee: feeAmount,
       },
       [
-        transfer(stxAddress, currencyX, totalAmount),
+        transfer(
+          stxAddress,
+          currencyX,
+          totalAmount,
+          FungibleConditionCode.LessEqual
+        ),
         transfer(
           AlexVault,
           currencyY,
-          minDy,
+          BigInt(0),
           FungibleConditionCode.GreaterEqual
         ),
       ]
@@ -89,7 +107,12 @@ export function runSponsoredSpotTx(
         fee: feeAmount,
       },
       [
-        transfer(stxAddress, currencyX, totalAmount),
+        transfer(
+          stxAddress,
+          currencyX,
+          totalAmount,
+          FungibleConditionCode.LessEqual
+        ),
         transfer(
           AlexVault,
           segment1.neighbour,
@@ -105,7 +128,7 @@ export function runSponsoredSpotTx(
         transfer(
           AlexVault,
           currencyY,
-          minDy,
+          BigInt(0),
           FungibleConditionCode.GreaterEqual
         ),
       ]
@@ -158,7 +181,7 @@ export function runSponsoredSpotTx(
         transfer(
           AlexVault,
           currencyY,
-          minDy,
+          BigInt(0),
           FungibleConditionCode.GreaterEqual
         ),
       ]
@@ -225,7 +248,7 @@ export function runSponsoredSpotTx(
         transfer(
           AlexVault,
           currencyY,
-          minDy,
+          BigInt(0),
           FungibleConditionCode.GreaterEqual
         ),
       ]