[#1028] Runtime switch of lightwalletd servers (#1044)

- comments addressed

modules/Sources/Dependencies/ZcashSDKEnvironment/ZcashSDKEnvironmentInterface.swift

@@ -64,10 +64,12 @@ extension ZcashSDKEnvironment {
                     // remove http:// or https:// from the input if present
                     var input = storedCustomServer
 
-                    if input.contains("https://") {
-                        input = String(input.dropFirst(8))
-                    } else if input.contains("http://") {
-                        input = String(input.dropFirst(7))
+                    let http = "http://"
+                    let https = "https://"
+                    if input.contains(https) {
+                        input = String(input.dropFirst(https.count))
+                    } else if input.contains(http) {
+                        input = String(input.dropFirst(http.count))
                     }
 
                     let split = input.split(separator: ":")

modules/Sources/Dependencies/ZcashSDKEnvironment/ZcashSDKEnvironmentLiveKey.swift

@@ -24,7 +24,8 @@ extension ZcashSDKEnvironment: DependencyKey {
                         // Some endpoint is set by a user so we initialize the SDK with this one
                         return endpoint
                     } else {
-                        // Endpoint failed, fallback to hardcoded mainnet
+                        // Initalization of LightWalletEndpoint failed, fallback to hardcoded one,
+                        // setting the mainnet key to the storage to reflect that
                         userDefaults.setValue(ZcashSDKEnvironment.Servers.mainnet.rawValue, udKey)
                     }
                 }

modules/Sources/Utils/SensitiveData.swift

@@ -82,6 +82,26 @@ extension BlockHeight {
     public var redacted: RedactableBlockHeight { RedactableBlockHeight(self) }
 }
 
+// MARK: - Redactable AccountBalance & SynchronizerState
+
+/// Redactable holder for a block height.
+public struct RedactableAccountBalance: Equatable, Redactable {
+    public let data: AccountBalance?
+
+    public init(_ data: AccountBalance? = nil) { self.data = data }
+}
+
+/// Utility that converts a block height to a redacted counterpart.
+extension AccountBalance {
+    public var redacted: RedactableAccountBalance? { RedactableAccountBalance(self) }
+}
+
+extension SynchronizerState {
+    public var redacted: SynchronizerState {
+        SynchronizerState
+    }
+}
+
 // MARK: - Redactable Int64
 
 /// Redactable holder for an Int64.