Add AccountsService

Encrypted Ink/Ethereum/AccountsService.swift

@@ -1,19 +1,62 @@
 // Copyright © 2021 Encrypted Ink. All rights reserved.
 
 import Foundation
+import Web3Swift
 
 struct AccountsService {
     
+    private static let keychainKey = "EncryptedInkStorage"
+    
+    static func addAccount(privateKey: String) -> Account? {
+        guard
+            let addressBytes = try? EthPrivateKey(hex: privateKey).address().value()
+        else {
+            return nil
+        }
+        let address = addressBytes.toPrefixedHexString()
+        let account = Account(privateKey: privateKey, address: address)
+        var accounts = getAccounts()
+        guard !accounts.contains(where: { $0.address == address }) else { return nil }
+        accounts.append(account)
+        saveInKeychain(accounts: accounts)
+        return account
+    }
+    
+    static func removeAccount(_ account: Account) {
+        var accounts = getAccounts()
+        accounts.removeAll(where: {$0.address == account.address })
+        
+        saveInKeychain(accounts: accounts)
+    }
+    
     static func getAccounts() -> [Account] {
-        return []
+        return loadAccountsFromKeychain() ?? []
     }
     
-    func removeAccount(_ account: Account) {
+    private static func saveInKeychain(accounts: [Account]) {
+        guard let data = try? JSONEncoder().encode(accounts) else { return }
+        let query = [kSecClass as String: kSecClassGenericPassword as String,
+                     kSecAttrAccount as String: keychainKey,
+                     kSecValueData as String: data] as [String: Any]
 
+        SecItemDelete(query as CFDictionary)
+        SecItemAdd(query as CFDictionary, nil)
     }
     
-    func addAccount(privateKey: String) -> Account? {
+    private static func loadAccountsFromKeychain() -> [Account]? {
-        return nil
+        guard let returnDataQueryValue = kCFBooleanTrue else { return nil }
-    }
+        let query = [kSecClass as String: kSecClassGenericPassword,
+                     kSecAttrAccount as String: keychainKey,
+                     kSecReturnData as String: returnDataQueryValue,
+                     kSecMatchLimit as String: kSecMatchLimitOne] as [String: Any]
 
+        var dataTypeRef: AnyObject?
+        let status: OSStatus = SecItemCopyMatching(query as CFDictionary, &dataTypeRef)
+        if status == noErr, let data = dataTypeRef as? Data {
+            let accounts = try? JSONDecoder().decode([Account].self, from: data)
+            return accounts
+        } else {
+            return nil
+        }
+    }
 }

Encrypted Ink/Ethereum/Ethereum.swift

@@ -13,7 +13,7 @@ struct Transaction {
     let contractCall: String
 }
 
-struct Account {
+struct Account: Codable {
     let privateKey: String
     let address: String
 }