feat: add slippage protection

Author: CumpsD

swappy-bot/Commands/DepositAddressProvider.cs

@@ -18,17 +18,20 @@ public static async Task<Result<DepositAddressResponse>> GetDepositAddressAsync(
             AssetInfo assetFrom,
             AssetInfo assetTo,
             string destinationAddress,
-            string refundAddress)
+            string refundAddress,
+            decimal minPrice)
         {
             using var client = httpClientFactory.CreateClient("Broker");
 
-            // TODO: Add minimumPrice, 2% slippage
+            var slippage = minPrice * (98 / 100m);
+            
             var swapRequest =
                 $"swap" +
                 $"?amount={amount}" +
                 $"&sourceAsset={assetFrom.Id}" +
                 $"&destinationAsset={assetTo.Id}" +
                 $"&destinationAddress={destinationAddress}" +
+                $"&minimumPrice={slippage}" +
                 $"&refundAddress={refundAddress}" +
                 $"&retryDurationInBlocks=150" +
                 $"&apiKey={configuration.BrokerApiKey}";

swappy-bot/Commands/QuoteProvider.cs

@@ -68,5 +68,8 @@ public class QuoteResponse
 
         [JsonPropertyName("egressAmount")]
         public decimal EgressAmount { get; set; }
+        
+        [JsonPropertyName("estimatedPrice")]
+        public decimal EstimatedPrice { get; set; }
     }
 }

swappy-bot/Commands/Swap/Swap.cs

@@ -404,6 +404,7 @@ await Context.Channel.SendMessageAsync(
             swapState.QuoteTime = quoteTime;
             swapState.QuoteDeposit = quoteDeposit;
             swapState.QuoteReceive = quoteReceive;
+            swapState.QuoteMinPrice = quote.EstimatedPrice;
             swapState.QuoteRate = quoteRate;
 
             await Context.Channel.SendMessageAsync(
@@ -677,6 +678,7 @@ await Context.Channel.SendMessageAsync(
                 swapState.QuoteTime = quoteTime;
                 swapState.QuoteDeposit = quoteDeposit;
                 swapState.QuoteReceive = quoteReceive;
+                swapState.QuoteMinPrice = quote.EstimatedPrice;
                 swapState.QuoteRate = quoteRate;
             }
 
@@ -785,6 +787,7 @@ await Context.Channel.SendMessageAsync(
             DepositAddressResponse deposit;
             try
             {
+                var swapStateQuoteMinPrice = swapState.QuoteMinPrice;
                 var depositResult = await DepositAddressProvider.GetDepositAddressAsync(
                     _logger,
                     _configuration,
@@ -793,7 +796,8 @@ await Context.Channel.SendMessageAsync(
                     assetFrom,
                     assetTo,
                     swapState.DestinationAddress,
-                    swapState.RefundAddress);
+                    swapState.RefundAddress,
+                    swapStateQuoteMinPrice.Value);
 
                 if (depositResult.IsFailed)
                     throw new Exception("Failed generating deposit address.");

swappy-bot/EntityFramework/SwapState.cs

@@ -21,6 +21,7 @@ public class SwapState
 
         public decimal? QuoteDeposit { get; set; }
         public decimal? QuoteReceive { get; set; }
+        public decimal? QuoteMinPrice { get; set; }
         public string? QuoteRate { get; set; }
         public decimal? QuotePlatformFee { get; set; }
         public decimal? QuoteChainflipFee { get; set; }
@@ -66,6 +67,7 @@ public override void Configure(EntityTypeBuilder<SwapState> builder)
 
             builder.Property(x => x.QuoteDeposit).IsRequired(false).HasPrecision(27, 18);
             builder.Property(x => x.QuoteReceive).IsRequired(false).HasPrecision(27, 18);
+            builder.Property(x => x.QuoteMinPrice).IsRequired(false).HasPrecision(27, 18);
             builder.Property(x => x.QuoteRate).IsRequired(false).HasMaxLength(200);
             builder.Property(x => x.QuotePlatformFee).IsRequired(false).HasPrecision(27, 18);
             builder.Property(x => x.QuoteChainflipFee).IsRequired(false).HasPrecision(27, 18);

swappy-bot/Migrations/20250606130303_AddQuoteMinPrice.Designer.cs

@@ -0,0 +1,30 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace SwappyBot.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddQuoteMinPrice : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<decimal>(
+                name: "quoteminprice",
+                table: "swap_state",
+                type: "numeric(27,18)",
+                precision: 27,
+                scale: 18,
+                nullable: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "quoteminprice",
+                table: "swap_state");
+        }
+    }
+}

swappy-bot/Migrations/20250606130303_AddQuoteMinPrice.cs

@@ -78,6 +78,11 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                         .HasColumnType("numeric(27,18)")
                         .HasColumnName("quotedeposit");
 
+                    b.Property<decimal?>("QuoteMinPrice")
+                        .HasPrecision(27, 18)
+                        .HasColumnType("numeric(27,18)")
+                        .HasColumnName("quoteminprice");
+
                     b.Property<decimal?>("QuotePlatformFee")
                         .HasPrecision(27, 18)
                         .HasColumnType("numeric(27,18)")