Merge pull request #3257 from vladyslav-iosdev/#3250

Switch from Gasnow to Etherscan for gas price estimates #3250

AlphaWallet/Gas/Models/GasNowGasPriceEstimator.swift

@@ -2,6 +2,7 @@
 
 import Foundation
 import PromiseKit
+import Alamofire
 
 class GasNowGasPriceEstimator {
     func fetch() -> Promise<GasNowPriceEstimates> {
@@ -11,3 +12,42 @@ class GasNowGasPriceEstimator {
         }
     }
 }
+
+class EtherscanGasPriceEstimator {
+
+    struct EtherscanPriceEstimatesResponse: Decodable {
+        let result: EtherscanPriceEstimates
+    }
+
+    static func supports(server: RPCServer) -> Bool {
+        return server.etherscanGasPriceEstimatesURL != nil
+    }
+
+    func fetch(server: RPCServer) -> Promise<GasNowPriceEstimates> {
+        struct AnyError: Error {}
+        guard let url = server.etherscanGasPriceEstimatesURL else {
+            return .init(error: AnyError())
+        }
+
+        return Alamofire.request(url, method: .get).responseDecodable(EtherscanPriceEstimatesResponse.self).compactMap { response in
+            EtherscanPriceEstimates.bridgeToGasNowPriceEstimates(for: response.result)
+        } 
+    }
+}
+
+fileprivate extension RPCServer {
+    var etherscanGasPriceEstimatesURL: URL? {
+        let apiKeyParameter: String
+        if let apiKey = etherscanApiKey {
+            apiKeyParameter = "&apikey=\(apiKey)"
+        } else {
+            apiKeyParameter = ""
+        }
+        switch self {
+        case .main, .kovan, .ropsten, .rinkeby, .goerli, .binance_smart_chain, .heco, .polygon, .optimistic, .optimisticKovan:
+            return etherscanApiRoot?.appendingQueryString("\("module=gastracker&action=gasoracle")\(apiKeyParameter)")
+        case .artis_sigma1, .artis_tau1, .binance_smart_chain_testnet, .callisto, .poa, .sokol, .classic, .xDai, .heco_testnet, .fantom, .fantom_testnet, .avalanche, .avalanche_testnet, .mumbai_testnet, .cronosTestnet, .custom:
+            return nil
+        }
+    }
+}

AlphaWallet/Gas/Models/GasNowPriceEstimates.swift

@@ -37,4 +37,36 @@ struct GasNowPriceEstimates: Decodable {
         case data
         case code
     }
-}
+}
+
+extension EtherscanPriceEstimates {
+
+    /// Current label in UI    Key to pull gas price from
+    /// - Rapid    "FastGasPrice" * 1.2
+    /// - Fast    "FastGasPrice"
+    /// - Standard/Average    "ProposeGasPrice"
+    /// - Slow    "SafeGasPrice"
+    static func bridgeToGasNowPriceEstimates(for value: EtherscanPriceEstimates) -> GasNowPriceEstimates? {
+        let slow = EtherNumberFormatter.full.number(from: value.safeGasPrice, units: UnitConfiguration.gasPriceUnit)!
+        let standard = EtherNumberFormatter.full.number(from: value.proposeGasPrice, units: UnitConfiguration.gasPriceUnit)!
+        let fastGasPrice = EtherNumberFormatter.full.number(from: value.fastGasPrice, units: UnitConfiguration.gasPriceUnit)!
+
+        guard let slow = Int(slow.description), let standard = Int(standard.description), let fast = Int(fastGasPrice.description) else { return nil }
+        let data = GasNowPriceEstimates.Data(slow: slow, standard: standard, fast: fast, rapid: Int((Double(fast) * 1.2).rounded(.down)))
+        return GasNowPriceEstimates(data: data, code: 1)
+    }
+}
+
+struct EtherscanPriceEstimates: Decodable {
+    enum CodingKeys: String, CodingKey {
+        case fastGasPrice = "FastGasPrice"
+        case proposeGasPrice = "ProposeGasPrice"
+        case safeGasPrice = "SafeGasPrice"
+        case suggestBaseFee = "suggestBaseFee"
+    }
+
+    let fastGasPrice: String
+    let proposeGasPrice: String
+    let safeGasPrice: String
+    let suggestBaseFee: String
+}

AlphaWallet/Settings/Types/RPCServers.swift

@@ -807,7 +807,7 @@ extension RPCServer: Codable {
     }
 }
 
-fileprivate extension URL {
+extension URL {
     //Much better to use URLComponents, but this is much simpler for our use. This probably doesn't percent-escape probably, but we shouldn't need it for the URLs we access here
 	func appendingQueryString(_ queryString: String) -> URL? {
         let urlString = absoluteString

AlphaWallet/Transfer/Controllers/TransactionConfigurator.swift

@@ -209,24 +209,24 @@ class TransactionConfigurator {
     }
 
     static func estimateGasPrice(server: RPCServer) -> Promise<GasEstimates> {
-        switch server {
-        case .main:
-            return firstly {
-                estimateGasPriceForEthMainnetUsingThirdPartyApi()
-            }.recover { _ in
+        if EtherscanGasPriceEstimator.supports(server: server) {
+            return estimateGasPriceForUsingEtherscanApi(server: server).recover { _ in
                 estimateGasPriceForUseRpcNode(server: server)
             }
-        case .xDai:
-            return estimateGasPriceForXDai()
-        case .kovan, .ropsten, .rinkeby, .poa, .sokol, .classic, .callisto, .goerli, .artis_sigma1, .artis_tau1, .binance_smart_chain, .binance_smart_chain_testnet, .custom, .heco, .heco_testnet, .fantom, .fantom_testnet, .avalanche, .avalanche_testnet, .polygon, .mumbai_testnet, .optimistic, .optimisticKovan, .cronosTestnet:
-            return Promise(estimateGasPriceForUseRpcNode(server: server))
+        } else {
+            switch server {
+            case .xDai:
+                return estimateGasPriceForXDai()
+            case .main, .kovan, .ropsten, .rinkeby, .poa, .sokol, .classic, .callisto, .goerli, .artis_sigma1, .artis_tau1, .binance_smart_chain, .binance_smart_chain_testnet, .custom, .heco, .heco_testnet, .fantom, .fantom_testnet, .avalanche, .avalanche_testnet, .polygon, .mumbai_testnet, .optimistic, .optimisticKovan, .cronosTestnet:
+                return Promise(estimateGasPriceForUseRpcNode(server: server))
+            }
         }
     }
 
-    private static func estimateGasPriceForEthMainnetUsingThirdPartyApi() -> Promise<GasEstimates> {
-        let estimator = GasNowGasPriceEstimator()
+    private static func estimateGasPriceForUsingEtherscanApi(server: RPCServer) -> Promise<GasEstimates> {
+        let estimator = EtherscanGasPriceEstimator()
         return firstly {
-            estimator.fetch()
+            estimator.fetch(server: server)
         }.map { estimates in
             GasEstimates(standard: BigInt(estimates.standard), others: [
                 TransactionConfigurationType.slow: BigInt(estimates.slow),
@@ -290,9 +290,11 @@ class TransactionConfigurator {
         }
         switch session.server {
         case .main:
-            if (configurations.standard.gasPrice / BigInt(EthereumUnit.gwei.rawValue)) > Constants.highStandardGasThresholdGwei {
-                return .networkCongested
-            }
+            //NOTE: Suppose that these lines were related to GasNow
+            //if (configurations.standard.gasPrice / BigInt(EthereumUnit.gwei.rawValue)) > Constants.highStandardGasThresholdGwei {
+            //    return .networkCongested
+            //}
+            break
         case .kovan, .ropsten, .rinkeby, .poa, .sokol, .classic, .callisto, .xDai, .goerli, .artis_sigma1, .artis_tau1, .binance_smart_chain, .fantom, .fantom_testnet, .binance_smart_chain_testnet, .custom, .heco, .heco_testnet, .avalanche, .avalanche_testnet, .polygon, .mumbai_testnet, .optimistic, .optimisticKovan, .cronosTestnet:
             break
         }

AlphaWallet/Transfer/ViewControllers/ConfigureTransactionViewController.swift

@@ -240,9 +240,7 @@ class ConfigureTransactionViewController: UIViewController {
             warningIcon.widthAnchor.constraint(equalToConstant: 24),
             warningIcon.widthAnchor.constraint(equalTo: warningIcon.heightAnchor),
 
-            descriptionLabel.widthAnchor.constraint(equalTo: stackView.widthAnchor, constant: -50),
-
-            descriptionLabel.widthAnchor.constraint(equalToConstant: 250),
+            descriptionLabel.widthAnchor.constraint(equalTo: stackView.widthAnchor, constant: -50) 
         ])
 
         var frame = footer.frame