import Foundation
import Security

public final class TokenStore: @unchecked Sendable {

    private let service = "com.xuqm.sdk.token"
    private let account = "auth_token"

    public init() {}

    public func save(_ token: String) {
        delete()

        guard let data = token.data(using: .utf8) else { return }

        let query: [String: Any] = [
            kSecClass as String: kSecClassGenericPassword,
            kSecAttrService as String: service,
            kSecAttrAccount as String: account,
            kSecValueData as String: data,
            kSecAttrAccessible as String: kSecAttrAccessibleAfterFirstUnlock,
        ]

        SecItemAdd(query as CFDictionary, nil)
    }

    public func get() -> String? {
        let query: [String: Any] = [
            kSecClass as String: kSecClassGenericPassword,
            kSecAttrService as String: service,
            kSecAttrAccount as String: account,
            kSecReturnData as String: true,
            kSecMatchLimit as String: kSecMatchLimitOne,
        ]

        var item: CFTypeRef?
        let status = SecItemCopyMatching(query as CFDictionary, &item)
        guard status == errSecSuccess, let data = item as? Data else {
            return nil
        }
        return String(data: data, encoding: .utf8)
    }

    public func clear() {
        delete()
    }

    private func delete() {
        let query: [String: Any] = [
            kSecClass as String: kSecClassGenericPassword,
            kSecAttrService as String: service,
            kSecAttrAccount as String: account,
        ]
        SecItemDelete(query as CFDictionary)
    }
}