import Foundation
import Security

protocol KeychainStoreProtocol {
    func save(_ value: String, for key: String) -> Bool
    func read(for key: String) -> String?
    func delete(for key: String) -> Bool
}

final class KeychainStore: KeychainStoreProtocol {
    func save(_ value: String, for key: String) -> Bool {
        let data = Data(value.utf8)
        let query: [CFString: Any] = [
            kSecClass: kSecClassGenericPassword,
            kSecAttrAccount: key,
            kSecValueData: data
        ]

        SecItemDelete(query as CFDictionary)
        return SecItemAdd(query as CFDictionary, nil) == errSecSuccess
    }

    func read(for key: String) -> String? {
        let query: [CFString: Any] = [
            kSecClass: kSecClassGenericPassword,
            kSecAttrAccount: key,
            kSecReturnData: true,
            kSecMatchLimit: kSecMatchLimitOne
        ]

        var item: CFTypeRef?
        guard SecItemCopyMatching(query as CFDictionary, &item) == errSecSuccess,
              let data = item as? Data else {
            return nil
        }

        return String(data: data, encoding: .utf8)
    }

    func delete(for key: String) -> Bool {
        let query: [CFString: Any] = [
            kSecClass: kSecClassGenericPassword,
            kSecAttrAccount: key
        ]
        return SecItemDelete(query as CFDictionary) == errSecSuccess
    }
}