Show warnings for high/low/congested gas prices in actionsheet for transaction confirmation and editing gas option screen

AlphaWallet/Assets.xcassets/gasWarning.imageset/Contents.json

@@ -0,0 +1,21 @@
+{
+  "images" : [
+    {
+      "filename" : "gasWarning.pdf",
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

AlphaWallet/Localization/en.lproj/Localizable.strings

@@ -500,6 +500,15 @@
 "transactionConfiguration.Type.average.time" = "< 5 min";
 "transactionConfiguration.Type.fast.time" = "< 2 min";
 "transactionConfiguration.Type.rapid.time" = "ASAP";
+"transactionConfiguration.gasPrice.tooHigh.short" = "High Price";
+"transactionConfiguration.gasPrice.tooLow.short" = "Low Price";
+"transactionConfiguration.gasPrice.tooHigh.long" = "High Gas Price Warning!";
+"transactionConfiguration.gasPrice.tooLow.long" = "Gas Price Might Be Too Low";
+
+"transactionConfiguration.gasPrice.tooHigh.description" = "You set a really high gas price. Please make sure this is not a mistake. AlphaWallet uses gasnow.org";
+"transactionConfiguration.gasPrice.tooLow.description" = "Gas price is set below the 'slow' speed. Your transaction may take a long time to be written or may never be written.";
+"transactionConfiguration.gasPrice.congested.description" = "The Ethereum blockchain network is very congested now. Fees might be higher than usual.
+You can check the latest gas price on gasnow.org";
 "transactionConfirmation.Row.title.ens" = "ENS";
 "transactionConfirmation.Row.title.wallet" = "Wallet Address";
 "transactionConfirmation.Send.Section.Gas.title" = "Gas";

AlphaWallet/Localization/es.lproj/Localizable.strings

@@ -500,6 +500,15 @@
 "transactionConfiguration.Type.average.time" = "< 5 min";
 "transactionConfiguration.Type.fast.time" = "< 2 min";
 "transactionConfiguration.Type.rapid.time" = "ASAP";
+"transactionConfiguration.gasPrice.tooHigh.short" = "High Price";
+"transactionConfiguration.gasPrice.tooLow.short" = "Low Price";
+"transactionConfiguration.gasPrice.tooHigh.long" = "High Gas Price Warning!";
+"transactionConfiguration.gasPrice.tooLow.long" = "Gas Price Might Be Too Low";
+
+"transactionConfiguration.gasPrice.tooHigh.description" = "You set a really high gas price. Please make sure this is not a mistake. AlphaWallet uses gasnow.org";
+"transactionConfiguration.gasPrice.tooLow.description" = "Gas price is set below the 'slow' speed. Your transaction may take a long time to be written or may never be written.";
+"transactionConfiguration.gasPrice.congested.description" = "The Ethereum blockchain network is very congested now. Fees might be higher than usual.
+You can check the latest gas price on gasnow.org";
 "transactionConfirmation.Row.title.ens" = "ENS";
 "transactionConfirmation.Row.title.wallet" = "Wallet Address";
 "transactionConfirmation.Send.Section.Gas.title" = "Gas";

AlphaWallet/Localization/ja.lproj/Localizable.strings

@@ -500,6 +500,15 @@
 "transactionConfiguration.Type.average.time" = "< 5 min";
 "transactionConfiguration.Type.fast.time" = "< 2 min";
 "transactionConfiguration.Type.rapid.time" = "ASAP";
+"transactionConfiguration.gasPrice.tooHigh.short" = "High Price";
+"transactionConfiguration.gasPrice.tooLow.short" = "Low Price";
+"transactionConfiguration.gasPrice.tooHigh.long" = "High Gas Price Warning!";
+"transactionConfiguration.gasPrice.tooLow.long" = "Gas Price Might Be Too Low";
+
+"transactionConfiguration.gasPrice.tooHigh.description" = "You set a really high gas price. Please make sure this is not a mistake. AlphaWallet uses gasnow.org";
+"transactionConfiguration.gasPrice.tooLow.description" = "Gas price is set below the 'slow' speed. Your transaction may take a long time to be written or may never be written.";
+"transactionConfiguration.gasPrice.congested.description" = "The Ethereum blockchain network is very congested now. Fees might be higher than usual.
+You can check the latest gas price on gasnow.org";
 "transactionConfirmation.Row.title.ens" = "ENS";
 "transactionConfirmation.Row.title.wallet" = "Wallet Address";
 "transactionConfirmation.Send.Section.Gas.title" = "Gas";

AlphaWallet/Localization/ko.lproj/Localizable.strings

@@ -500,6 +500,15 @@
 "transactionConfiguration.Type.average.time" = "< 5 min";
 "transactionConfiguration.Type.fast.time" = "< 2 min";
 "transactionConfiguration.Type.rapid.time" = "ASAP";
+"transactionConfiguration.gasPrice.tooHigh.short" = "High Price";
+"transactionConfiguration.gasPrice.tooLow.short" = "Low Price";
+"transactionConfiguration.gasPrice.tooHigh.long" = "High Gas Price Warning!";
+"transactionConfiguration.gasPrice.tooLow.long" = "Gas Price Might Be Too Low";
+
+"transactionConfiguration.gasPrice.tooHigh.description" = "You set a really high gas price. Please make sure this is not a mistake. AlphaWallet uses gasnow.org";
+"transactionConfiguration.gasPrice.tooLow.description" = "Gas price is set below the 'slow' speed. Your transaction may take a long time to be written or may never be written.";
+"transactionConfiguration.gasPrice.congested.description" = "The Ethereum blockchain network is very congested now. Fees might be higher than usual.
+You can check the latest gas price on gasnow.org";
 "transactionConfirmation.Row.title.ens" = "ENS";
 "transactionConfirmation.Row.title.wallet" = "Wallet Address";
 "transactionConfirmation.Send.Section.Gas.title" = "Gas";

AlphaWallet/Localization/zh-Hans.lproj/Localizable.strings

@@ -500,6 +500,15 @@
 "transactionConfiguration.Type.average.time" = "< 5 min";
 "transactionConfiguration.Type.fast.time" = "< 2 min";
 "transactionConfiguration.Type.rapid.time" = "ASAP";
+"transactionConfiguration.gasPrice.tooHigh.short" = "High Price";
+"transactionConfiguration.gasPrice.tooLow.short" = "Low Price";
+"transactionConfiguration.gasPrice.tooHigh.long" = "High Gas Price Warning!";
+"transactionConfiguration.gasPrice.tooLow.long" = "Gas Price Might Be Too Low";
+
+"transactionConfiguration.gasPrice.tooHigh.description" = "You set a really high gas price. Please make sure this is not a mistake. AlphaWallet uses gasnow.org";
+"transactionConfiguration.gasPrice.tooLow.description" = "Gas price is set below the 'slow' speed. Your transaction may take a long time to be written or may never be written.";
+"transactionConfiguration.gasPrice.congested.description" = "The Ethereum blockchain network is very congested now. Fees might be higher than usual.
+You can check the latest gas price on gasnow.org";
 "transactionConfirmation.Row.title.ens" = "ENS";
 "transactionConfirmation.Row.title.wallet" = "Wallet Address";
 "transactionConfirmation.Send.Section.Gas.title" = "Gas";

AlphaWallet/Settings/Types/Constants.swift

@@ -125,6 +125,7 @@ public struct Constants {
     static let ENSRegistrarGoerli = ENSRegistrarAddress
 
     static let gasNowEndpointBaseUrl = "https://www.gasnow.org"
+    static let highStandardGasThresholdGwei = BigInt(55)
 
     //Misc
     public static let etherReceivedNotificationIdentifier = "etherReceivedNotificationIdentifier"

AlphaWallet/Transfer/Controllers/TransactionConfigurator.swift

@@ -15,6 +15,41 @@ protocol TransactionConfiguratorDelegate: class {
 }
 
 class TransactionConfigurator {
+    enum GasPriceWarning {
+        case tooHighCustomGasPrice
+        case networkCongested
+        case tooLowCustomGasPrice
+
+        var shortTitle: String {
+            switch self {
+            case .tooHighCustomGasPrice, .networkCongested:
+                return R.string.localizable.transactionConfigurationGasPriceTooHighShort()
+            case .tooLowCustomGasPrice:
+                return R.string.localizable.transactionConfigurationGasPriceTooLowShort()
+            }
+        }
+
+        var longTitle: String {
+            switch self {
+            case .tooHighCustomGasPrice, .networkCongested:
+                return R.string.localizable.transactionConfigurationGasPriceTooHighLong()
+            case .tooLowCustomGasPrice:
+                return R.string.localizable.transactionConfigurationGasPriceTooLowLong()
+            }
+        }
+
+        var description: String {
+            switch self {
+            case .tooHighCustomGasPrice:
+                return R.string.localizable.transactionConfigurationGasPriceTooHighDescription()
+            case .networkCongested:
+                return R.string.localizable.transactionConfigurationGasPriceCongestedDescription()
+            case .tooLowCustomGasPrice:
+                return R.string.localizable.transactionConfigurationGasPriceTooLowDescription()
+            }
+        }
+    }
+
     private let account: AlphaWallet.Address
 
     private var isGasLimitSpecifiedByTransaction: Bool {
@@ -62,6 +97,10 @@ class TransactionConfigurator {
         }
     }
 
+    var gasPriceWarning: GasPriceWarning? {
+        gasPriceWarning(forConfiguration: currentConfiguration)
+    }
+
     init(session: WalletSession, transaction: UnconfirmedTransaction) {
         self.session = session
         self.account = session.account.address
@@ -185,6 +224,25 @@ class TransactionConfigurator {
         }
     }
 
+    func gasPriceWarning(forConfiguration configuration: TransactionConfiguration) -> GasPriceWarning? {
+        if let fastestConfig = configurations.fastestThirdPartyConfiguration, configuration.gasPrice > fastestConfig.gasPrice {
+            return .tooHighCustomGasPrice
+        }
+        //Conversion to gwei is needed so we that 17 (entered) is equal to 17.1 (fetched). Because 17.1 is displayed as "17" in the UI and might confuse the user if it's not treated as equal
+        if let slowestConfig = configurations.slowestThirdPartyConfiguration, (configuration.gasPrice / BigInt(EthereumUnit.gwei.rawValue)) < (slowestConfig.gasPrice / BigInt(EthereumUnit.gwei.rawValue)) {
+            return .tooLowCustomGasPrice
+        }
+        switch session.server {
+        case .main:
+            if (configurations.standard.gasPrice / BigInt(EthereumUnit.gwei.rawValue)) > Constants.highStandardGasThresholdGwei {
+                return .networkCongested
+            }
+        case .kovan, .ropsten, .rinkeby, .poa, .sokol, .classic, .callisto, .xDai, .goerli, .artis_sigma1, .artis_tau1, .binance_smart_chain, .binance_smart_chain_testnet, .custom:
+            break
+        }
+        return nil
+    }
+
     private static func computeDefaultGasPrice(server: RPCServer, transaction: UnconfirmedTransaction) -> BigInt {
         switch server {
         case .xDai:

AlphaWallet/Transfer/Types/TransactionConfiguration.swift

@@ -50,6 +50,11 @@ enum TransactionConfigurationType: Int, CaseIterable {
     case rapid
     case custom
 
+    static var sortedThirdPartyFastestFirst: [TransactionConfigurationType] {
+        //We intentionally do not include `.standard`
+        [.rapid, .fast, .slow]
+    }
+
     var title: String {
         switch self {
         case .standard:

AlphaWallet/Transfer/Types/TransactionConfigurations.swift

@@ -12,6 +12,24 @@ struct TransactionConfigurations {
         others.keys + [.standard, .custom]
     }
 
+    var fastestThirdPartyConfiguration: TransactionConfiguration? {
+        for each in TransactionConfigurationType.sortedThirdPartyFastestFirst {
+            if let config = others[each] {
+                return config
+            }
+        }
+        return nil
+    }
+
+    var slowestThirdPartyConfiguration: TransactionConfiguration? {
+        for each in TransactionConfigurationType.sortedThirdPartyFastestFirst.reversed() {
+            if let config = others[each] {
+                return config
+            }
+        }
+        return nil
+    }
+
     subscript(configurationType: TransactionConfigurationType) -> TransactionConfiguration? {
         get {
             switch configurationType {

AlphaWallet/Transfer/ViewControllers/ConfigureTransactionViewController.swift

@@ -27,7 +27,7 @@ class ConfigureTransactionViewController: UIViewController {
         let tableView = UITableView()
         tableView.register(GasSpeedTableViewCell.self)
         tableView.registerHeaderFooterView(GasSpeedTableViewHeaderView.self)
-        tableView.tableFooterView = createTableInformationFooter()
+        tableView.tableFooterView = createTableFooter()
         tableView.separatorStyle = .none
         tableView.allowsSelection = true
         return tableView
@@ -102,6 +102,8 @@ class ConfigureTransactionViewController: UIViewController {
         updatedViewModel.configurations = configurator.configurations
         viewModel = updatedViewModel
         recalculateTotalFeeForCustomGas()
+        showGasPriceWarning()
+        tableView.tableFooterView = createTableFooter()
         tableView.reloadData()
     }
 
@@ -153,13 +155,21 @@ class ConfigureTransactionViewController: UIViewController {
         })
     }
 
-    private func createTableInformationFooter() -> UIView {
+    private func createTableFooter() -> UIView {
+        if let gasPriceWarning = viewModel.gasPriceWarning {
+            return createTableFooterForGasPriceWarning(gasPriceWarning)
+        } else {
+            return createTableFooterForGasInformation()
+        }
+    }
+
+    private func createTableFooterForGasInformation() -> UIView {
         let footer = UIView(frame: .init(x: 0, y: 0, width: 0, height: 100))
         let label = UILabel()
         label.translatesAutoresizingMaskIntoConstraints = false
         label.textAlignment = .center
         label.numberOfLines = 0
-        label.font = Fonts.regular(size: 12)
+        label.font = Fonts.regular(size: 15)
         label.textColor = R.color.dove()
         label.text = R.string.localizable.transactionConfirmationFeeFooterText()
         footer.addSubview(label)
@@ -169,12 +179,84 @@ class ConfigureTransactionViewController: UIViewController {
         return footer
     }
 
+    private func createTableFooterForGasPriceWarning(_ gasPriceWarning: TransactionConfigurator.GasPriceWarning) -> UIView {
+        let footer = UIView(frame: .init(x: 0, y: 0, width: 0, height: 0))
+
+        let background = UIView()
+        background.translatesAutoresizingMaskIntoConstraints = false
+        background.backgroundColor = .init(red: 255, green: 235, blue: 234)
+        background.borderColor = .init(red: 252, green: 187, blue: 183)
+        background.cornerRadius = 8
+        background.borderWidth = 1
+        footer.addSubview(background)
+
+        let warningIcon = UIImageView(image: R.image.gasWarning())
+        warningIcon.translatesAutoresizingMaskIntoConstraints = false
+
+        let titleLabel = UILabel()
+        titleLabel.textAlignment = .center
+        titleLabel.font = Fonts.semibold(size: 20)
+        titleLabel.textColor = R.color.danger()
+        titleLabel.text = gasPriceWarning.longTitle
+
+        let descriptionLabel = UITextView()
+        descriptionLabel.backgroundColor = .clear
+        descriptionLabel.textColor = R.color.dove()
+        descriptionLabel.textAlignment = .center
+        descriptionLabel.isEditable = false
+        descriptionLabel.isSelectable = true
+        descriptionLabel.isUserInteractionEnabled = true
+        descriptionLabel.isScrollEnabled = false
+        descriptionLabel.dataDetectorTypes = .link
+        descriptionLabel.font = Fonts.regular(size: 15)
+        descriptionLabel.text = gasPriceWarning.description
+
+        let row0 = [warningIcon, titleLabel].asStackView(axis: .horizontal, spacing: 6)
+        let row1 = descriptionLabel
+
+        let stackView = [
+            row0,
+            row1,
+        ].asStackView(axis: .vertical, spacing: 6, alignment: .center)
+        stackView.translatesAutoresizingMaskIntoConstraints = false
+        footer.addSubview(stackView)
+
+        NSLayoutConstraint.activate([
+            background.anchorsConstraint(to: footer, margin: 16),
+
+            stackView.anchorsConstraint(to: background, edgeInsets: UIEdgeInsets(top: 16, left: 0, bottom: 16, right: 16)),
+
+            warningIcon.widthAnchor.constraint(equalToConstant: 24),
+            warningIcon.widthAnchor.constraint(equalTo: warningIcon.heightAnchor),
+
+            descriptionLabel.widthAnchor.constraint(equalTo: stackView.widthAnchor, constant: -50),
+
+            descriptionLabel.widthAnchor.constraint(equalToConstant: 250),
+        ])
+
+        var frame = footer.frame
+        frame.size.height = footer.systemLayoutSizeFitting(footer.frame.size).height
+        footer.frame = frame
+
+        return footer
+    }
+
     private func recalculateTotalFeeForCustomGas() {
         cells.totalFee.value = viewModel.gasViewModel.feeText
         let configurationTypes = viewModel.configurationTypes
         if let indexPath = configurationTypes.index(of: .custom).flatMap { IndexPath(row: $0, section: ConfigureTransactionViewModel.Section.configurationTypes.rawValue) }, let cell = tableView.cellForRow(at: indexPath) as? GasSpeedTableViewCell {
             cell.configure(viewModel: viewModel.gasSpeedViewModel(indexPath: indexPath))
         }
+        showGasPriceWarning()
+        tableView.tableFooterView = createTableFooter()
+    }
+
+    private func showGasPriceWarning() {
+        if viewModel.gasPriceWarning == nil {
+            cells.gasPrice.textField.status = .none
+        } else {
+            cells.gasPrice.textField.status = .error("")
+        }
     }
 
     @objc private func saveButtonSelected(_ sender: UIBarButtonItem) {
@@ -212,6 +294,12 @@ class ConfigureTransactionViewController: UIViewController {
                 cells.nonce.textField.status = .error(ConfigureTransactionError.nonceNotPositiveNumber.localizedDescription)
             }
 
+            if viewModel.gasPriceWarning == nil {
+                cells.gasPrice.textField.status = .none
+            } else {
+                cells.gasPrice.textField.status = .error("")
+            }
+
             guard canSave else {
                 tableView.reloadData()
                 return

AlphaWallet/Transfer/ViewModels/ConfigureTransactionViewModel.swift

@@ -4,10 +4,17 @@ import Foundation
 import BigInt
 
 struct ConfigureTransactionViewModel {
+    private let server: RPCServer
+    private let ethPrice: Subscribable<Double>
+    private let transactionType: TransactionType
+    private let configurator: TransactionConfigurator
+    private let currencyRate: CurrencyRate?
+    private let fullFormatter = EtherNumberFormatter.full
+    private var totalFee: BigInt {
+        return configurationToEdit.gasPrice * configurationToEdit.gasLimit
+    }
+
     var selectedConfigurationType: TransactionConfigurationType
-    let server: RPCServer
-    let ethPrice: Subscribable<Double>
-    let transactionType: TransactionType
     var configurationToEdit: EditedTransactionConfiguration {
         didSet {
             configurations.custom = configurationToEdit.configuration
@@ -19,30 +26,14 @@ struct ConfigureTransactionViewModel {
             configurationTypes = ConfigureTransactionViewModel.sortedConfigurationTypes(fromConfigurations: configurations)
         }
     }
-    let currencyRate: CurrencyRate?
-
-    init(server: RPCServer, configurator: TransactionConfigurator, ethPrice: Subscribable<Double>, currencyRate: CurrencyRate?) {
-        self.server = server
-        self.ethPrice = ethPrice
-        let configurations = configurator.configurations
-        self.configurationTypes = ConfigureTransactionViewModel.sortedConfigurationTypes(fromConfigurations: configurations)
-        self.configurations = configurations
-        self.currencyRate = currencyRate
-        transactionType = configurator.transaction.transactionType
-        selectedConfigurationType = configurator.selectedConfigurationType
-        configurationToEdit = EditedTransactionConfiguration(configuration: configurator.configurations.custom)
+    var gasPriceWarning: TransactionConfigurator.GasPriceWarning? {
+        configurator.gasPriceWarning(forConfiguration: configurationToEdit.configuration)
     }
 
-    private let fullFormatter = EtherNumberFormatter.full
-
     var gasViewModel: GasViewModel {
         return GasViewModel(fee: totalFee, symbol: server.symbol, currencyRate: currencyRate, formatter: fullFormatter)
     }
 
-    private var totalFee: BigInt {
-        return configurationToEdit.gasPrice * configurationToEdit.gasLimit
-    }
-
     var backgroundColor: UIColor {
         return R.color.alabaster()!
     }
@@ -60,20 +51,6 @@ struct ConfigureTransactionViewModel {
         }
     }
 
-    static func sortedConfigurationTypes(fromConfigurations configurations: TransactionConfigurations) -> [TransactionConfigurationType] {
-        let available = configurations.types
-        let all: [TransactionConfigurationType] = [.slow, .standard, .fast, .rapid, .custom]
-        return all.filter { available.contains($0) }
-    }
-
-    func gasSpeedViewModel(indexPath: IndexPath) -> GasSpeedTableViewCellViewModel {
-        let configurationType = configurationTypes[indexPath.row]
-        let isSelected = selectedConfigurationType == configurationType
-        let configuration = configurations[configurationType]!
-        //TODO if subscribable price are resolved or changes, will be good to refresh, but not essential
-        return .init(configuration: configuration, configurationType: configurationType, cryptoToDollarRate: ethPrice.value, symbol: server.symbol, title: configurationType.title, isSelected: isSelected)
-    }
-
     var gasLimitSliderViewModel: SliderTableViewCellViewModel {
         return .init(
             value: configurationToEdit.gasLimitRawValue,
@@ -109,17 +86,6 @@ struct ConfigureTransactionViewModel {
         return .init(placeholder: placeholder, value: gasViewModel.feeText, allowEditing: false)
     }
 
-    func numberOfRowsInSections(in section: Int) -> Int {
-        switch sections[section] {
-        case .configurationTypes:
-            return configurationTypes.count
-        case .gasPrice:
-            return 1
-        case .gasLimit:
-            return gasLimitRows.count
-        }
-    }
-
     var sections: [Section] {
         switch selectedConfigurationType {
         case .standard, .slow, .fast, .rapid:
@@ -159,6 +125,44 @@ struct ConfigureTransactionViewModel {
             case totalFee
         }
     }
+
+    init(server: RPCServer, configurator: TransactionConfigurator, ethPrice: Subscribable<Double>, currencyRate: CurrencyRate?) {
+        self.server = server
+        self.ethPrice = ethPrice
+        let configurations = configurator.configurations
+        self.configurationTypes = ConfigureTransactionViewModel.sortedConfigurationTypes(fromConfigurations: configurations)
+        self.configurator = configurator
+        self.configurations = configurations
+        self.currencyRate = currencyRate
+        transactionType = configurator.transaction.transactionType
+        selectedConfigurationType = configurator.selectedConfigurationType
+        configurationToEdit = EditedTransactionConfiguration(configuration: configurator.configurations.custom)
+    }
+
+    static func sortedConfigurationTypes(fromConfigurations configurations: TransactionConfigurations) -> [TransactionConfigurationType] {
+        let available = configurations.types
+        let all: [TransactionConfigurationType] = [.slow, .standard, .fast, .rapid, .custom]
+        return all.filter { available.contains($0) }
+    }
+
+    func gasSpeedViewModel(indexPath: IndexPath) -> GasSpeedTableViewCellViewModel {
+        let configurationType = configurationTypes[indexPath.row]
+        let isSelected = selectedConfigurationType == configurationType
+        let configuration = configurations[configurationType]!
+        //TODO if subscribable price are resolved or changes, will be good to refresh, but not essential
+        return .init(configuration: configuration, configurationType: configurationType, cryptoToDollarRate: ethPrice.value, symbol: server.symbol, title: configurationType.title, isSelected: isSelected)
+    }
+
+    func numberOfRowsInSections(in section: Int) -> Int {
+        switch sections[section] {
+        case .configurationTypes:
+            return configurationTypes.count
+        case .gasPrice:
+            return 1
+        case .gasLimit:
+            return gasLimitRows.count
+        }
+    }
 }
 
 private let numberValueFormatter: NumberFormatter = {
@@ -172,4 +176,4 @@ extension String {
     var numberValue: NSNumber? {
         return numberValueFormatter.number(from: self)
     }
-}
+}

AlphaWallet/Transfer/ViewModels/GasSpeedTableViewCellViewModel.swift

@@ -30,7 +30,7 @@ struct GasSpeedTableViewCellViewModel {
 
     private var gasPriceString: String {
         let price = configuration.gasPrice / BigInt(EthereumUnit.gwei.rawValue)
-        return "\(R.string.localizable.configureTransactionHeaderGasPrice()): \(price) Gwei"
+        return "\(R.string.localizable.configureTransactionHeaderGasPrice()): \(price) \(EthereumUnit.gwei.name)"
     }
 
     private var estimatedTime: String? {

AlphaWallet/Transfer/ViewModels/TransactionConfirmationTableHeaderViewModel.swift

@@ -8,11 +8,16 @@
 import UIKit
 
 struct TransactionConfirmationHeaderViewModel {
+    enum Title {
+        case normal(String?)
+        case warning(String)
+    }
 
     let title: String?
-    var headerName: String?
-    var details: String?
+    let headerName: String?
+    let details: String?
     var configuration: TransactionConfirmationHeaderView.Configuration
+    let isWarning: Bool
     var chevronImage: UIImage? {
         let image = configuration.isOpened ? R.image.expand() : R.image.not_expand()
         return image?.withRenderingMode(.alwaysTemplate)
@@ -56,4 +61,18 @@ struct TransactionConfirmationHeaderViewModel {
     var backgroundColor: UIColor {
         return Colors.appBackground
     }
+
+    init(title: Title, headerName: String?, details: String? = nil, configuration: TransactionConfirmationHeaderView.Configuration) {
+        switch title {
+        case .normal(let title):
+            self.title = title
+            self.isWarning = false
+        case .warning(let title):
+            self.title = title
+            self.isWarning = true
+        }
+        self.headerName = headerName
+        self.details = details
+        self.configuration = configuration
+    }
 }

AlphaWallet/Transfer/ViewModels/TransactionConfirmationViewModel.swift

@@ -229,14 +229,18 @@ extension TransactionConfirmationViewModel {
             switch sections[section] {
             case .balance:
                 let title = R.string.localizable.tokenTransactionConfirmationDefault()
-                return .init(title: balance ?? title, headerName: headerName, details: newBalance, configuration: configuration)
+                return .init(title: .normal(balance ?? title), headerName: headerName, details: newBalance, configuration: configuration)
             case .gas:
                 let gasFee = gasFeeString(withConfigurator: configurator, cryptoToDollarRate: cryptoToDollarRate)
-                return .init(title: configurationTitle, headerName: headerName, details: gasFee, configuration: configuration)
+                if let warning = configurator.gasPriceWarning {
+                    return .init(title: .warning(warning.shortTitle), headerName: headerName, details: gasFee, configuration: configuration)
+                } else {
+                    return .init(title: .normal(configurationTitle), headerName: headerName, details: gasFee, configuration: configuration)
+                }
             case .amount:
-                return .init(title: formattedAmountValue, headerName: headerName, configuration: configuration)
+                return .init(title: .normal(formattedAmountValue), headerName: headerName, configuration: configuration)
             case .recipient:
-                return .init(title: recipientResolver.value, headerName: headerName, configuration: configuration)
+                return .init(title: .normal(recipientResolver.value), headerName: headerName, configuration: configuration)
             }
         }
     }
@@ -311,11 +315,15 @@ extension TransactionConfirmationViewModel {
             switch sections[section] {
             case .gas:
                 let gasFee = gasFeeString(withConfigurator: configurator, cryptoToDollarRate: cryptoToDollarRate)
-                return .init(title: configurationTitle, headerName: headerName, details: gasFee, configuration: configuration)
+                if let warning = configurator.gasPriceWarning {
+                    return .init(title: .warning(warning.shortTitle), headerName: headerName, details: gasFee, configuration: configuration)
+                } else {
+                    return .init(title: .normal(configurationTitle), headerName: headerName, details: gasFee, configuration: configuration)
+                }
             case .amount:
-                return .init(title: formattedAmountValue, headerName: headerName, configuration: configuration)
+                return .init(title: .normal(formattedAmountValue), headerName: headerName, configuration: configuration)
             case .function(let functionCallMetaData):
-                return .init(title: functionCallMetaData.name, headerName: headerName, configuration: configuration)
+                return .init(title: .normal(functionCallMetaData.name), headerName: headerName, configuration: configuration)
             }
         }
 
@@ -384,13 +392,17 @@ extension TransactionConfirmationViewModel {
             switch sections[section] {
             case .gas:
                 let gasFee = gasFeeString(withConfigurator: configurator, cryptoToDollarRate: cryptoToDollarRate)
-                return .init(title: configurationTitle, headerName: headerName, details: gasFee, configuration: configuration)
+                if let warning = configurator.gasPriceWarning {
+                    return .init(title: .warning(warning.shortTitle), headerName: headerName, details: gasFee, configuration: configuration)
+                } else {
+                    return .init(title: .normal(configurationTitle), headerName: headerName, details: gasFee, configuration: configuration)
+                }
             case .contract:
-                return .init(title: address.truncateMiddle, headerName: headerName, configuration: configuration)
+                return .init(title: .normal(address.truncateMiddle), headerName: headerName, configuration: configuration)
             case .function:
-                return .init(title: functionCallMetaData.name, headerName: headerName, configuration: configuration)
+                return .init(title: .normal(functionCallMetaData.name), headerName: headerName, configuration: configuration)
             case .amount:
-                return .init(title: formattedAmountValue, headerName: headerName, configuration: configuration)
+                return .init(title: .normal(formattedAmountValue), headerName: headerName, configuration: configuration)
             }
         }
 
@@ -475,7 +487,11 @@ extension TransactionConfirmationViewModel {
             switch sections[section] {
             case .gas:
                 let gasFee = gasFeeString(withConfigurator: configurator, cryptoToDollarRate: cryptoToDollarRate)
-                return .init(title: configurationTitle, headerName: headerName, details: gasFee, configuration: configuration)
+                if let warning = configurator.gasPriceWarning {
+                    return .init(title: .warning(warning.shortTitle), headerName: headerName, details: gasFee, configuration: configuration)
+                } else {
+                    return .init(title: .normal(configurationTitle), headerName: headerName, details: gasFee, configuration: configuration)
+                }
             case .tokenId:
                 let tokenId = configurator.transaction.tokenId.flatMap({ String($0) })
                 let title: String
@@ -488,9 +504,9 @@ extension TransactionConfirmationViewModel {
                 } else {
                     title = tokenId ?? ""
                 }
-                return .init(title: title, headerName: headerName, configuration: configuration)
+                return .init(title: .normal(title), headerName: headerName, configuration: configuration)
             case .recipient:
-                return .init(title: recipientResolver.value, headerName: headerName, configuration: configuration)
+                return .init(title: .normal(recipientResolver.value), headerName: headerName, configuration: configuration)
             }
         }
     }
@@ -548,7 +564,11 @@ extension TransactionConfirmationViewModel {
             let headerName = sections[section].title
             switch sections[section] {
             case .gas:
-                return .init(title: configurationTitle, headerName: headerName, configuration: configuration)
+                if let warning = configurator.gasPriceWarning {
+                    return .init(title: .warning(warning.shortTitle), headerName: headerName, configuration: configuration)
+                } else {
+                    return .init(title: .normal(configurationTitle), headerName: headerName, configuration: configuration)
+                }
             case .amount:
                 let cryptoToDollarSymbol = Constants.Currency.usd
                 let nativeCryptoSymbol = configurator.session.server.symbol
@@ -560,9 +580,9 @@ extension TransactionConfirmationViewModel {
                 } else {
                     formattedAmountValue = "\(nativeCryptoPrice) \(nativeCryptoSymbol)"
                 }
-                return .init(title: formattedAmountValue, headerName: headerName, configuration: configuration)
+                return .init(title: .normal(formattedAmountValue), headerName: headerName, configuration: configuration)
             case .numberOfTokens:
-                return .init(title: String(numberOfTokens), headerName: headerName, configuration: configuration)
+                return .init(title: .normal(String(numberOfTokens)), headerName: headerName, configuration: configuration)
             }
         }
     }

AlphaWallet/Transfer/Views/TransactionConfirmationHeaderView.swift

@@ -33,14 +33,17 @@ class TransactionConfirmationHeaderView: UIView {
 
     private let titleLabel: UILabel = {
         let label = UILabel()
-        label.translatesAutoresizingMaskIntoConstraints = false
         label.numberOfLines = 0
         return label
     }()
 
+    private let warningIcon: UIImageView = {
+        let imageView = UIImageView(image: R.image.gasWarning())
+        return imageView
+    }()
+
     private let detailsLabel: UILabel = {
         let label = UILabel()
-        label.translatesAutoresizingMaskIntoConstraints = false
         label.numberOfLines = 0
 
         return label
@@ -48,7 +51,6 @@ class TransactionConfirmationHeaderView: UIView {
 
     private lazy var chevronView: UIView = {
         let view = UIView()
-        view.translatesAutoresizingMaskIntoConstraints = false
         view.addSubview(chevronImageView)
 
         return view
@@ -86,9 +88,12 @@ class TransactionConfirmationHeaderView: UIView {
         separatorLine.translatesAutoresizingMaskIntoConstraints = false
         separatorLine.backgroundColor = R.color.mercury()
 
+        titleLabel.setContentCompressionResistancePriority(.required, for: .horizontal)
+        let titleRow = [warningIcon, titleLabel].asStackView(axis: .horizontal, spacing: 6)
+
         let col0 = nameLabel
         let col1 = [
-            titleLabel,
+            titleRow,
             detailsLabel
         ].asStackView(axis: .vertical, alignment: .leading)
         col1.translatesAutoresizingMaskIntoConstraints = false
@@ -125,6 +130,9 @@ class TransactionConfirmationHeaderView: UIView {
 
             titleLabel.centerYAnchor.constraint(equalTo: nameLabel.centerYAnchor),
 
+            warningIcon.widthAnchor.constraint(equalToConstant: 24),
+            warningIcon.widthAnchor.constraint(equalTo: warningIcon.heightAnchor),
+
             col1.leadingAnchor.constraint(equalTo: nameLabel.trailingAnchor, constant: ScreenChecker().isNarrowScreen ? 8 : 16),
             col1.trailingAnchor.constraint(equalTo: contents.trailingAnchor),
             col1.topAnchor.constraint(lessThanOrEqualTo: nameLabel.topAnchor),
@@ -153,6 +161,9 @@ class TransactionConfirmationHeaderView: UIView {
         chevronView.isHidden = viewModel.configuration.shouldHideChevron
 
         chevronImageView.image = viewModel.chevronImage
+
+        warningIcon.isHidden = !viewModel.isWarning
+
         titleLabel.alpha = viewModel.titleAlpha
 
         titleLabel.attributedText = viewModel.titleAttributedString