fix upper bound

btcpayserver · Jan 9, 2024 · 49972df · 49972df
1 parent 043cd03
commit 49972df
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Showing 2 changed files with 30 additions and 40 deletions.
diff --git a/BTCPayServer.Tests/ThirdPartyTests.cs b/BTCPayServer.Tests/ThirdPartyTests.cs
@@ -119,9 +119,9 @@ public async Task CanQueryMempoolFeeProvider()
                         })
                         .ToArray());
                 //ENSURE THESE ARE LOGICAL
-                Assert.True(recommendedFees[0].FeeRate >= recommendedFees[1].FeeRate);
-                Assert.True(recommendedFees[1].FeeRate >= recommendedFees[2].FeeRate);
-                Assert.True(recommendedFees[2].FeeRate >= recommendedFees[3].FeeRate);
+                Assert.True(recommendedFees[0].FeeRate >= recommendedFees[1].FeeRate, $"{recommendedFees[0].Target}:{recommendedFees[0].FeeRate} >= {recommendedFees[1].Target}:{recommendedFees[1].FeeRate}");
+                Assert.True(recommendedFees[1].FeeRate >= recommendedFees[2].FeeRate, $"{recommendedFees[1].Target}:{recommendedFees[1].FeeRate} >= {recommendedFees[2].Target}:{recommendedFees[2].FeeRate}");
+                Assert.True(recommendedFees[2].FeeRate >= recommendedFees[3].FeeRate, $"{recommendedFees[2].Target}:{recommendedFees[2].FeeRate} >= {recommendedFees[3].Target}:{recommendedFees[3].FeeRate}");
 
 
 

diff --git a/BTCPayServer/Services/Fees/MempoolSpaceFeeProvider.cs b/BTCPayServer/Services/Fees/MempoolSpaceFeeProvider.cs
@@ -12,12 +12,12 @@
 namespace BTCPayServer.Services.Fees;
 
 public class MempoolSpaceFeeProvider(
-    IMemoryCache MemoryCache,
-    string CacheKey,
-    IHttpClientFactory HttpClientFactory,
-    bool Testnet) : IFeeProvider
+    IMemoryCache memoryCache,
+    string cacheKey,
+    IHttpClientFactory httpClientFactory,
+    bool testnet) : IFeeProvider
 {
-    private string ExplorerLink = Testnet switch
+    private string ExplorerLink = testnet switch
     {
         true => "https://mempool.space/testnet/api/v1/fees/recommended",
         false => "https://mempool.space/api/v1/fees/recommended"
@@ -35,62 +35,52 @@ public async Task<FeeRate> GetFeeRateAsync(int blockTarget = 20)
 
     static FeeRate InterpolateOrBound(Dictionary<int, FeeRate> dictionary, int target)
     {
-        // Get the smallest and largest keys
-        int smallestKey = dictionary.Keys.Min();
-        int largestKey = dictionary.Keys.Max();
-
-        // If the target is outside the range, clamp to the nearest bound
-        if (target <= smallestKey)
-        {
-            return dictionary[smallestKey];
-        }
-        if (target >= largestKey)
-        {
-            return dictionary[largestKey];
-        }
-
         // Find the keys closest to the target for interpolation
-        int key1 = 0, key2 = 0;
-        decimal value1 = 0, value2 = 0;
+        int? k1 = null;
+        int? k2 = null;
 
-        foreach (var key in dictionary.Keys)
+        foreach (int k in dictionary.Keys.Order())
         {
-            if (key < target && (key1 == 0 || key > key1))
+            k1 = k1 is null ? k : k2;
+            k2 = k;
+            if(target < k)
             {
-                key1 = key;
-                value1 = dictionary[key].SatoshiPerByte;
-            }
-            if (key > target && (key2 == 0 || key < key2))
-            {
-                key2 = key;
-                value2 = dictionary[key].SatoshiPerByte;
+                break;
             }
         }
 
+        if (k1 is null)
+        {
+           throw new InvalidOperationException("No fee rate available");
+        }
+
+        var v1 = dictionary[k1!.Value].SatoshiPerByte;
+        var v2 = dictionary[k2!.Value].SatoshiPerByte;
+
         // Linear interpolation formula
-        return new FeeRate(value1 + ((value2 - value1) / (key2 - key1)) * (target - key1));
+        return new FeeRate((decimal) (v1 + (v2 - v1) / (k1 - k2) * (target - k1))!);
     }
 
     public async Task<Dictionary<int, FeeRate>> GetFeeRatesAsync()
     {
         try
         {
-            return  (await  MemoryCache.GetOrCreateAsync(CacheKey, async entry =>
+            return  (await  memoryCache.GetOrCreateAsync(cacheKey, async entry =>
             {
                 entry.AbsoluteExpirationRelativeToNow = TimeSpan.FromMinutes(5);
                 return await GetFeeRatesCore();
             }))!;
         }
         catch (Exception e)
         {
-            MemoryCache.Remove(CacheKey);
+            memoryCache.Remove(cacheKey);
             throw;
         }
     }
 
     protected virtual async Task<Dictionary<int, FeeRate>> GetFeeRatesCore()
     {
-        var client = HttpClientFactory.CreateClient(nameof(MempoolSpaceFeeProvider));
+        var client = httpClientFactory.CreateClient(nameof(MempoolSpaceFeeProvider));
         using var result = await client.GetAsync(ExplorerLink, new CancellationTokenSource(TimeSpan.FromSeconds(10)).Token);
         result.EnsureSuccessStatusCode();
         var recommendedFees = await result.Content.ReadAsAsync<Dictionary<string, decimal>>();
@@ -120,9 +110,9 @@ static FeeRate InterpolateOrBound(Dictionary<int, FeeRate> dictionary, int targe
             }
             else
             {
-                var previous = ordered[i - 1].Value;
+                var previous = feesByBlockTarget[ordered[i - 1].Key];
                 var newValue = RandomizeByPercentage(value.SatoshiPerByte, 10);
-                if (newValue < previous.SatoshiPerByte)
+                if (newValue > previous.SatoshiPerByte)
                 {
                     newValue = previous.SatoshiPerByte;
                 }
@@ -145,7 +135,7 @@ static decimal RandomizeByPercentage(decimal value, int percentage)
         return res switch
         {
             < 1m => 1m,
-            > 850m => 2000m,
+            > 2000m => 2000m,
             _ => res
         };
     }