feature: Error messaging for send amount too small (#297)

commit 7dace9e2532da36faa84ee2aeb3ca1e8eda42d00 Merge: 305bce9 a04e48d Author: Otto Suess <[email protected]> Date: Thu Nov 14 10:34:26 2019 +0100 Merge branch 'dustEstimateError' of github.com:chitowncrispy/zap-iOS into chitowncrispy-dustEstimateError # Conflicts: # SwiftLnd/Api/Helper/LndApiError.swift # SwiftLnd/Api/Helper/RpcZapHelper.swift commit a04e48d Author: Christopher Pinski <[email protected]> Date: Sat Nov 9 17:49:19 2019 -0600 Created a LoadingError which translates any error from the app to a specific UI state commit 369f379 Author: Christopher Pinski <[email protected]> Date: Thu Oct 31 13:06:08 2019 -0500 Using a result type for the Loadable enum element case commit 31c8d9d Author: Christopher Pinski <[email protected]> Date: Thu Oct 31 09:47:33 2019 -0500 Setting initial value for subtitleText back to nil since we aren't showing an error initially commit 3dabcde Author: Christopher Pinski <[email protected]> Date: Wed Oct 30 23:02:00 2019 -0500 Removing error messaging from fee label commit a5b7658 Author: Christopher Pinski <[email protected]> Date: Fri Oct 25 08:52:26 2019 -0500 Cleaning up code based on PR comments commit 4f3094b Author: Christopher Pinski <[email protected]> Date: Thu Oct 24 20:19:53 2019 -0500 Setting up the primary currency listener only once commit 2b3f895 Author: Christopher Pinski <[email protected]> Date: Thu Oct 24 13:01:42 2019 -0500 Updating the view to show the on chain balance when the user hasn't input any amount commit cfe8917 Author: Christopher Pinski <[email protected]> Date: Wed Oct 23 20:47:51 2019 -0500 Not allowing the user to send if the transaction is dust commit 54986bd Author: Christopher Pinski <[email protected]> Date: Wed Oct 23 20:00:08 2019 -0500 Rebasing PR Co-authored-by: Christopher Pinski <[email protected]>
LN-Zap · Nov 14, 2019 · 8f12a41 · 8f12a41
1 parent 305bce9
commit 8f12a41
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Showing 6 changed files with 78 additions and 28 deletions.
diff --git a/Library/Generated/strings.swift b/Library/Generated/strings.swift
@@ -623,6 +623,8 @@ internal enum L10n {
       internal static let maximumFee = L10n.tr("Localizable", "scene.send.maximum_fee")
       /// Memo:
       internal static let memoHeadline = L10n.tr("Localizable", "scene.send.memo_headline")
+      /// Send amount is too small.
+      internal static let sendAmountTooSmall = L10n.tr("Localizable", "scene.send.send_amount_too_small")
       /// Send
       internal static let sendButton = L10n.tr("Localizable", "scene.send.send_button")
       /// Sending...

diff --git a/Library/Scenes/ModalDetail/Send/LoadingAmountView.swift b/Library/Scenes/ModalDetail/Send/LoadingAmountView.swift
@@ -9,12 +9,18 @@ import Bond
 import Foundation
 import ReactiveKit
 import SwiftBTC
+import SwiftLnd
 
 enum Loadable<E> {
     case loading
     case element(E)
 }
 
+enum LoadingError: Error {
+    case invalidAmount
+    case lndApiError(LndApiError)
+}
+
 final class LoadingAmountView: UIView {
     let amountLabel: UILabel
     let activityIndicator: UIActivityIndicatorView
@@ -29,7 +35,7 @@ final class LoadingAmountView: UIView {
         }
     }
 
-    init(loadable: Observable<Loadable<Satoshi?>>) {
+    init(loadable: Observable<Loadable<Result<Satoshi, LoadingError>>>) {
         amountLabel = UILabel(frame: CGRect.zero)
         activityIndicator = UIActivityIndicatorView(style: .white)
 
@@ -63,25 +69,24 @@ final class LoadingAmountView: UIView {
         fatalError("init(coder:) has not been implemented")
     }
 
-    private func updateLoadable(_ loadable: Loadable<Satoshi?>) {
+    private func updateLoadable(_ loadable: Loadable<Result<Satoshi, LoadingError>>) {
         switch loadable {
         case .loading:
             activityIndicator.isHidden = false
             amountLabel.isHidden = true
-        case .element(let amount):
+        case .element(let result):
             disposable?.dispose()
             amountLabel.isHidden = false
             activityIndicator.isHidden = true
-
-            if let amount = amount {
+
+            switch result {
+            case .success(let amount):
                 disposable = amount
                     .bind(to: amountLabel, currency: Settings.shared.primaryCurrency)
                 disposable?.dispose(in: reactive.bag)
-            } else {
+            case .failure:
                 amountLabel.text = "-"
             }
-
         }
-
     }
 }
diff --git a/Library/Scenes/ModalDetail/Send/SendViewModel.swift b/Library/Scenes/ModalDetail/Send/SendViewModel.swift
@@ -48,7 +48,7 @@ final class SendViewModel: NSObject {
         }
     }
 
-    let fee = Observable<Loadable<Satoshi?>>(.loading)
+    let fee = Observable<Loadable<Result<Satoshi, LoadingError>>>(.loading)
 
     let method: SendMethod
 
@@ -59,6 +59,7 @@ final class SendViewModel: NSObject {
         didSet {
             guard oldValue != amount else { return }
             updateFee()
+            updateSubtitle()
             updateIsUIEnabled()
         }
     }
@@ -68,6 +69,13 @@ final class SendViewModel: NSObject {
             updateFee()
         }
     }
+
+    var isTransactionDust = false {
+        didSet {
+            updateIsUIEnabled()
+            updateSubtitle()
+        }
+    }
 
     var isSending = false {
         didSet {
@@ -118,10 +126,10 @@ final class SendViewModel: NSObject {
 
         updateFee()
         updateIsUIEnabled()
-        updateSubtitle()
+        setupPrimaryCurrencyListener()
     }
 
-    private func updateSubtitle() {
+    private func setupPrimaryCurrencyListener() {
         Settings.shared.primaryCurrency
             .compactMap { [method, maxPaymentAmount] in
                 guard let amount = $0.format(satoshis: maxPaymentAmount) else { return nil }
@@ -137,11 +145,28 @@ final class SendViewModel: NSObject {
             }
             .dispose(in: reactive.bag)
     }
+
+    private func updateSubtitle() {
+        if isTransactionDust && amount ?? 0 > 0 {
+            self.subtitleText.value = L10n.Scene.Send.sendAmountTooSmall
+        } else {
+            guard let amount = Settings.shared.primaryCurrency.value.format(satoshis: maxPaymentAmount) else {
+                return
+            }
+
+            switch method {
+            case .lightning:
+                self.subtitleText.value = L10n.Scene.Send.Subtitle.lightningCanSendBalance(amount)
+            case .onChain:
+                self.subtitleText.value = L10n.Scene.Send.Subtitle.onChainBalance(amount)
+            }
+        }
+    }
 
     private func updateIsUIEnabled() {
-        isSendButtonEnabled.value = isAmountValid && !isSending
+        isSendButtonEnabled.value = isAmountValid && !isSending && !isTransactionDust
         isInputViewEnabled.value = !isSending
-        isSubtitleTextWarning.value = amount ?? 0 > maxPaymentAmount
+        isSubtitleTextWarning.value = amount ?? 0 > maxPaymentAmount || (isTransactionDust && amount ?? 0 > 0)
     }
 
     private var isAmountValid: Bool {
@@ -152,24 +177,36 @@ final class SendViewModel: NSObject {
     private func updateFee() {
         if isAmountValid {
             fee.value = .loading
-            updateIsUIEnabled()
             debounceFetchFee()
         } else {
-            fee.value = .element(nil)
+            fee.value = .element(.failure(.invalidAmount))
         }
     }
 
     private func fetchFee() {
         guard let amount = amount else { return }
 
-        let feeCompletion = { [weak self] (result: (amount: Satoshi, fee: Satoshi?)) -> Void in
+        let feeCompletion = { [weak self] (result: Result<(amount: Satoshi, fee: Satoshi?), LndApiError>) -> Void in
             guard
-                let self = self,
-                result.amount == self.amount
+                let self = self
                 else { return }
-
-            self.fee.value = .element(result.fee)
-            self.updateIsUIEnabled()
+            switch result {
+            case .success(let result):
+                guard
+                    result.amount == self.amount
+                    else { return }
+
+                self.isTransactionDust = false
+                if let fee = result.fee {
+                    self.fee.value = .element(.success(fee))
+                } else {
+                    self.fee.value = .element(.failure(.invalidAmount))
+                }
+            case .failure(let lndApiError):
+                self.isTransactionDust = lndApiError == .transactionOutputIsDust
+                self.fee.value = amount > 0 ? .element(Result.failure(.lndApiError(lndApiError))) : .element(.failure(.invalidAmount))
+                self.updateIsUIEnabled()
+            }
         }
 
         switch method {

diff --git a/Library/Views/OnChainFeeView/OnChainFeeView.swift b/Library/Views/OnChainFeeView/OnChainFeeView.swift
@@ -8,6 +8,7 @@
 import Bond
 import Foundation
 import SwiftBTC
+import SwiftLnd
 
 protocol OnChainFeeViewDelegate: class {
     func confirmationTargetChanged(to confirmationTarget: Int)
@@ -35,7 +36,7 @@ final class OnChainFeeView: UIView {
 
     weak var delegate: OnChainFeeViewDelegate?
 
-    init(loadable: Observable<Loadable<Satoshi?>>) {
+    init(loadable: Observable<Loadable<Result<Satoshi, LoadingError>>>) {
         super.init(frame: .zero)
         setup(loadable: loadable)
     }
@@ -44,7 +45,7 @@ final class OnChainFeeView: UIView {
         fatalError("init(coder:) has not been implemented")
     }
 
-    private func setup(loadable: Observable<Loadable<Satoshi?>>) {
+    private func setup(loadable: Observable<Loadable<Result<Satoshi, LoadingError>>>) {
         Bundle.library.loadNibNamed("OnChainFeeView", owner: self, options: nil)
         addSubview(contentView)
         contentView.frame = self.bounds

diff --git a/Library/en.lproj/Localizable.strings b/Library/en.lproj/Localizable.strings
@@ -156,6 +156,7 @@
 "scene.send.address_headline" = "To:";
 "scene.send.memo_headline" = "Memo:";
 "scene.send.sending" = "Sending...";
+"scene.send.send_amount_too_small" = "Send amount is too small.";
 "scene.send.lightning.title" = "Send Lightning Payment";
 "scene.send.on_chain.title" = "Send On-Chain";
 "scene.send.on_chain.fee" = "Fee:";

diff --git a/Lightning/Services/TransactionService.swift b/Lightning/Services/TransactionService.swift
@@ -38,19 +38,23 @@ public final class TransactionService {
     /// Fee methods can be called multiple times at once. So the completion
     /// includes amount to match on the caller side that the returned result is
     /// for the correct amount.
-    public typealias FeeApiCompletion = ((amount: Satoshi, fee: Satoshi?)) -> Void
+    public typealias FeeApiCompletion = (Result<(amount: Satoshi, fee: Satoshi?), LndApiError>) -> Void
 
     public func lightningFees(for paymentRequest: PaymentRequest, amount: Satoshi, completion: @escaping FeeApiCompletion) {
         api.route(destination: paymentRequest.destination, amount: amount) { result in
             let totalFees = (try? result.get())?.totalFees
-            completion((amount: amount, fee: totalFees))
+            completion(.success((amount: amount, fee: totalFees)))
         }
     }
 
     public func onChainFees(address: BitcoinAddress, amount: Satoshi, confirmationTarget: Int, completion: @escaping FeeApiCompletion) {
-        api.estimateFees(address: address, amount: amount, confirmationTarget: confirmationTarget) {
-            let fees = (try? $0.get())?.total
-            completion((amount: amount, fee: fees))
+        api.estimateFees(address: address, amount: amount, confirmationTarget: confirmationTarget) { result in
+            switch result {
+            case .success(let feeEstimate):
+                completion(.success((amount: amount, fee: feeEstimate.total)))
+            case .failure(let lndApiError):
+                completion(.failure(lndApiError))
+            }
         }
     }