import Foundation
import Security

final class KeychainService {
    static let shared = KeychainService()
    private let service = "app.nightly"
    private let account = "authToken"

    func saveToken(_ token: String) {
        let data = Data(token.utf8)
        let query: [CFString: Any] = [
            kSecClass: kSecClassGenericPassword,
            kSecAttrService: service,
            kSecAttrAccount: account,
            kSecValueData: data
        ]
        SecItemDelete(query as CFDictionary)
        SecItemAdd(query as CFDictionary, nil)
    }

    func getToken() -> String? {
        let query: [CFString: Any] = [
            kSecClass: kSecClassGenericPassword,
            kSecAttrService: service,
            kSecAttrAccount: account,
            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 deleteToken() {
        let query: [CFString: Any] = [
            kSecClass: kSecClassGenericPassword,
            kSecAttrService: service,
            kSecAttrAccount: account
        ]
        SecItemDelete(query as CFDictionary)
    }
}