Merge pull request #276 from synonymdev/fix/lnurl-min-send-ceil

Fix/lnurl minSendable edge case when msats are not divisable by 1000

Author: piotr-iohk

Bitkit/Utilities/LightningAmountConversion.swift

@@ -0,0 +1,18 @@
+import Foundation
+
+enum LightningAmountConversion {
+    /// Lightning amounts are commonly expressed in millisatoshis (msat).
+    ///
+    /// The UI and amount input operate in whole sats. When converting a minimum bound to sats we must round up:
+    /// `100500 msat` means the minimum payable amount is `101 sat` (not `100 sat`).
+    static func satsCeil(fromMsats msats: UInt64) -> UInt64 {
+        let quotient = msats / Env.msatsPerSat
+        let remainder = msats % Env.msatsPerSat
+        return remainder == 0 ? quotient : quotient + 1
+    }
+
+    /// Converts msats → sats by rounding down (safe for maximum bounds).
+    static func satsFloor(fromMsats msats: UInt64) -> UInt64 {
+        msats / Env.msatsPerSat
+    }
+}

Bitkit/ViewModels/AppViewModel.swift

@@ -253,8 +253,8 @@ extension AppViewModel {
         }
 
         var normalizedData = data
-        normalizedData.minSendable = max(1, normalizedData.minSendable / Env.msatsPerSat)
-        normalizedData.maxSendable = max(normalizedData.minSendable, normalizedData.maxSendable / Env.msatsPerSat)
+        normalizedData.minSendable = max(1, LightningAmountConversion.satsCeil(fromMsats: normalizedData.minSendable))
+        normalizedData.maxSendable = max(normalizedData.minSendable, LightningAmountConversion.satsFloor(fromMsats: normalizedData.maxSendable))
 
         // Check if user has enough lightning balance to pay the minimum amount
         let lightningBalance = lightningService.balances?.totalLightningBalanceSats ?? 0
@@ -292,8 +292,8 @@ extension AppViewModel {
         }
 
         var normalizedData = data
-        let minSats = max(1, minMsats / Env.msatsPerSat)
-        let maxSats = max(minSats, maxMsats / Env.msatsPerSat)
+        let minSats = max(1, LightningAmountConversion.satsCeil(fromMsats: minMsats))
+        let maxSats = max(minSats, LightningAmountConversion.satsFloor(fromMsats: maxMsats))
         normalizedData.minWithdrawable = minSats
         normalizedData.maxWithdrawable = maxSats
 

Bitkit/Views/Wallets/Sheets/BoostSheet.swift

@@ -389,7 +389,8 @@ struct BoostSheet: View {
             app.toast(
                 type: .success,
                 title: t("wallet__boost_success_title"),
-                description: t("wallet__boost_success_msg")
+                description: t("wallet__boost_success_msg"),
+                accessibilityIdentifier: "BoostSuccessToast"
             )
 
             Logger.info("Boost transaction completed successfully, hiding sheet", context: "BoostSheet.performBoost")
@@ -408,8 +409,9 @@ struct BoostSheet: View {
 
             app.toast(
                 type: .error,
-                title: t("wallet__boost_error"),
-                description: error.localizedDescription
+                title: t("wallet__boost_error_title"),
+                description: t("wallet__boost_error_msg"),
+                accessibilityIdentifier: "BoostFailureToast"
             )
 
             throw error

BitkitTests/LightningAmountConversionTests.swift

@@ -0,0 +1,20 @@
+@testable import Bitkit
+import XCTest
+
+final class LightningAmountConversionTests: XCTestCase {
+    func testSatsCeilRoundsUpWhenNotDivisibleBy1000() {
+        XCTAssertEqual(LightningAmountConversion.satsCeil(fromMsats: 100_500), 101)
+        XCTAssertEqual(LightningAmountConversion.satsCeil(fromMsats: 1500), 2)
+    }
+
+    func testSatsCeilKeepsExactSatAmounts() {
+        XCTAssertEqual(LightningAmountConversion.satsCeil(fromMsats: 100_000), 100)
+        XCTAssertEqual(LightningAmountConversion.satsCeil(fromMsats: 0), 0)
+    }
+
+    func testSatsFloorRoundsDown() {
+        XCTAssertEqual(LightningAmountConversion.satsFloor(fromMsats: 100_999), 100)
+        XCTAssertEqual(LightningAmountConversion.satsFloor(fromMsats: 100_000), 100)
+        XCTAssertEqual(LightningAmountConversion.satsFloor(fromMsats: 0), 0)
+    }
+}