#4: Create Security Service

SolardVPNCommunityCoreiOS/SOLARdVPNCommunityCoreiOS/Services/SecurityService/SecurityService.swift

@@ -0,0 +1,73 @@
+//
+//  SecurityService.swift
+//  SOLARdVPNCommunityCoreiOS
+//
+//  Created by Lika Vorobeva on 05.10.2022.
+//
+
+import Foundation
+import SentinelWallet
+import HDWallet
+import SwiftKeychainWrapper
+
+enum SecurityServiceError: Error {
+    case emptyInput
+    case invalidInput
+}
+
+private struct Constants {
+    let key = "password"
+    let mnemonicsCount = 24
+}
+private let constants = Constants()
+
+final public class SecurityService: SecurityServiceType {
+    private let keychain: KeychainWrapper
+
+    public init(
+        keychain: KeychainWrapper = .init(
+            serviceName: "SecurityService",
+            accessGroup: "group.ee.solarlabs.community-core.ios"
+        )
+    ) {
+        self.keychain = keychain
+    }
+
+    public func save(mnemonics: [String], for account: String) -> Bool {
+        let mnemonicString = mnemonics.joined(separator: " ")
+        return keychain.set(
+            mnemonicString,
+            forKey: account.sha1(),
+            withAccessibility: .afterFirstUnlockThisDeviceOnly
+        )
+    }
+
+    public func loadMnemonics(for account: String) -> [String]? {
+        keychain
+            .string(forKey: account.sha1())?
+            .trimmingCharacters(in: .whitespacesAndNewlines)
+            .components(separatedBy: " ")
+    }
+
+    public func mnemonicsExists(for account: String) -> Bool {
+        keychain.hasValue(forKey: account.sha1())
+    }
+
+    public func restore(from mnemonics: [String]) -> Result<String, Error> {
+        guard !mnemonics.isEmpty else {
+            return .failure(SecurityServiceError.emptyInput)
+        }
+
+        guard
+            mnemonics.count == constants.mnemonicsCount, mnemonics.allSatisfy({ WordList.english.words.contains($0) })
+        else {
+            return .failure(SecurityServiceError.invalidInput)
+        }
+
+        guard let restoredAddress = restoreAddress(for: mnemonics) else {
+            return .failure(SecurityServiceError.invalidInput)
+        }
+
+        return .success(restoredAddress)
+    }
+}