Connect macOS app to backend device bootstrap

packages/apple/VelodyUtilities/Sources/VelodyUtilities/KeychainService.swift

@@ -1,8 +1,9 @@
 import Foundation
+import Security
 
 public protocol KeychainService: Sendable {
-    func save(_ value: String, forKey key: String) async
-    func loadValue(forKey key: String) async -> String?
+    func save(_ value: String, forKey key: String) async throws
+    func loadValue(forKey key: String) async throws -> String?
 }
 
 public actor MemoryKeychainService: KeychainService {
@@ -10,11 +11,87 @@ public actor MemoryKeychainService: KeychainService {
 
     public init() {}
 
-    public func save(_ value: String, forKey key: String) async {
+    public func save(_ value: String, forKey key: String) async throws {
         storage[key] = value
     }
 
-    public func loadValue(forKey key: String) async -> String? {
+    public func loadValue(forKey key: String) async throws -> String? {
         storage[key]
     }
 }
+
+public enum KeychainServiceError: LocalizedError, Sendable {
+    case invalidValue
+    case unexpectedStatus(OSStatus)
+
+    public var errorDescription: String? {
+        switch self {
+        case .invalidValue:
+            return "The keychain returned invalid data."
+        case let .unexpectedStatus(status):
+            if let message = SecCopyErrorMessageString(status, nil) as String? {
+                return message
+            }
+
+            return "The keychain returned status \(status)."
+        }
+    }
+}
+
+public actor SystemKeychainService: KeychainService {
+    private let service: String
+
+    public init(service: String = "de.diyaa.velody") {
+        self.service = service
+    }
+
+    public func save(_ value: String, forKey key: String) async throws {
+        let query = baseQuery(forKey: key)
+        let deleteStatus = SecItemDelete(query as CFDictionary)
+
+        guard deleteStatus == errSecSuccess || deleteStatus == errSecItemNotFound else {
+            throw KeychainServiceError.unexpectedStatus(deleteStatus)
+        }
+
+        var addQuery = query
+        addQuery[kSecValueData as String] = Data(value.utf8)
+
+        let addStatus = SecItemAdd(addQuery as CFDictionary, nil)
+        guard addStatus == errSecSuccess else {
+            throw KeychainServiceError.unexpectedStatus(addStatus)
+        }
+    }
+
+    public func loadValue(forKey key: String) async throws -> String? {
+        var query = baseQuery(forKey: key)
+        query[kSecReturnData as String] = kCFBooleanTrue
+        query[kSecMatchLimit as String] = kSecMatchLimitOne
+
+        var result: AnyObject?
+        let status = SecItemCopyMatching(query as CFDictionary, &result)
+
+        switch status {
+        case errSecSuccess:
+            guard
+                let data = result as? Data,
+                let value = String(data: data, encoding: .utf8)
+            else {
+                throw KeychainServiceError.invalidValue
+            }
+
+            return value
+        case errSecItemNotFound:
+            return nil
+        default:
+            throw KeychainServiceError.unexpectedStatus(status)
+        }
+    }
+
+    private func baseQuery(forKey key: String) -> [String: Any] {
+        [
+            kSecClass as String: kSecClassGenericPassword,
+            kSecAttrService as String: service,
+            kSecAttrAccount as String: key,
+        ]
+    }
+}