From 11aec3110014f6c9d2a2f03c632089631d6b057c Mon Sep 17 00:00:00 2001
From: xiaoch05 <xiaoch2010@gmail.com>
Date: Thu, 28 Mar 2024 10:27:13 +0800
Subject: [PATCH] add maxTransferAmount interface

---
 .../aggregation/aggregation.history.graphql   |  1 +
 .../src/aggregation/aggregation.resolver.ts   | 61 +++++++++++++++++++
 apollo/src/graphql.ts                         |  2 +
 3 files changed, 64 insertions(+)

diff --git a/apollo/src/aggregation/aggregation.history.graphql b/apollo/src/aggregation/aggregation.history.graphql
index 8575be29..fc768b02 100644
--- a/apollo/src/aggregation/aggregation.history.graphql
+++ b/apollo/src/aggregation/aggregation.history.graphql
@@ -109,6 +109,7 @@ type Query {
   queryLnBridgeRelayInfos(fromChain: String, toChain: String, version: String, bridge: String, relayer: String, row: Int, page: Int): LnBridgeRelayInfos
   sortedLnBridgeRelayInfos(fromChain: String, toChain: String, version: String, bridge: String, token: String, row: Int, amount: String, decimals: Int): SortedLnBridgeRelayInfos
   queryLnBridgeSupportChains(tokenKey: String): [SupportChains]
+  queryMaxTransfer(fromChain: String, toChain: String, bridge: String, token: String, balance: String): BigInt
 }
 
 type Mutation {
diff --git a/apollo/src/aggregation/aggregation.resolver.ts b/apollo/src/aggregation/aggregation.resolver.ts
index 9d174231..f22ebeaf 100644
--- a/apollo/src/aggregation/aggregation.resolver.ts
+++ b/apollo/src/aggregation/aggregation.resolver.ts
@@ -413,4 +413,65 @@ export class AggregationResolver {
       records: sortedRelayers.sort((l, r) => l.point - r.point).map((item) => item.record),
     };
   }
+
+  /**
+   * For one relayer
+   * userBalance, transferLimitV2(margin), transferLimitV3 baseFee, liquidityFeeRate, protocolFee
+   * suppose user transfer amount is X
+   * then totalFee = X * liquidityFeeRate / 100000 + baseFee + protocolFee
+   * 1. totalFee + X <= userBalance          => X <= (userBalance - baseFee - protocolFee)/(1 + liquidityFeeRate / 100000)
+   * 2. V2: totalFee + X <= transferLimitV2  => X <= (transferLimitV2 - baseFee - protocolFee)/(1 + liquidityFeeRate / 100000)
+   * 3. V3: X <= transferLimitV3             => X <= transferLimitV3
+   */
+  @Query()
+  async queryMaxTransfer(
+    @Args('fromChain') fromChain: string,
+    @Args('toChain') toChain: string,
+    @Args('bridge') bridge: string,
+    @Args('token') token: string,
+    @Args('balance') balance: string,
+  ) {
+    const sendToken = token?.toLowerCase();
+    const baseFilters = { fromChain, toChain, sendToken, bridge };
+
+    const where = {
+      ...baseFilters,
+    };
+
+    const records = await this.aggregationService.queryLnBridgeRelayInfos({
+      skip: 0,
+      where,
+    });
+    var maxTransferAmount = BigInt(0);
+    const now = Math.floor(Date.now() / 1000);
+    const liquidityFeeScale = BigInt(100000);
+    for (const record of records.records) {
+      // offline
+      if (record.heartbeatTimestamp + this.heartbeatTimeout < now || record.paused) {
+        continue;
+      }
+
+      const fixFee = BigInt(record.baseFee) + BigInt(record.protocolFee);
+      const userBalanceRestrict = (BigInt(balance) - fixFee) * liquidityFeeScale / (liquidityFeeScale + BigInt(record.liquidityFeeRate));
+      let limitRestrict = record.version === 'lnv2' ?
+          (BigInt(record.margin) - fixFee) * liquidityFeeScale / (liquidityFeeScale + BigInt(record.liquidityFeeRate)) :
+          BigInt(record.transferLimit);
+
+      try {
+          const softTransferLimit = BigInt(record.softTransferLimit);
+          if (limitRestrict > softTransferLimit && softTransferLimit > 0) {
+              limitRestrict = softTransferLimit;
+          }
+      } catch(e) {
+          console.log(`get softTransferLimit failed ${record.id}, exception: ${e}`);
+          continue;
+      }
+
+      const limit = limitRestrict < userBalanceRestrict ? limitRestrict : userBalanceRestrict;
+      if (maxTransferAmount < limit) {
+          maxTransferAmount = limit;
+      }
+    }
+    return maxTransferAmount;
+  }
 }
diff --git a/apollo/src/graphql.ts b/apollo/src/graphql.ts
index c2fbec0a..b01ee6cc 100644
--- a/apollo/src/graphql.ts
+++ b/apollo/src/graphql.ts
@@ -38,6 +38,8 @@ export abstract class IQuery {
     abstract sortedLnBridgeRelayInfos(fromChain?: Nullable<string>, toChain?: Nullable<string>, version?: Nullable<string>, bridge?: Nullable<string>, token?: Nullable<string>, row?: Nullable<number>, amount?: Nullable<string>, decimals?: Nullable<number>): Nullable<SortedLnBridgeRelayInfos> | Promise<Nullable<SortedLnBridgeRelayInfos>>;
 
     abstract queryLnBridgeSupportChains(tokenKey?: Nullable<string>): Nullable<Nullable<SupportChains>[]> | Promise<Nullable<Nullable<SupportChains>[]>>;
+
+    abstract queryMaxTransfer(fromChain?: Nullable<string>, toChain?: Nullable<string>, bridge?: Nullable<string>, token?: Nullable<string>, balance?: Nullable<string>): Nullable<BigInt> | Promise<Nullable<BigInt>>;
 }
 
 export class HistoryRecord {