import Foundation
import Security

final class LicenseStore {
    private let keychainService = "com.xuqm.license"
    private let defaults: UserDefaults

    init() {
        defaults = UserDefaults(suiteName: "xuqm_license") ?? .standard
    }

    var token: String? {
        get { keychainGet("token") }
        set { keychainSet("token", value: newValue) }
    }

    var deviceId: String? {
        get { keychainGet("deviceId") }
        set { keychainSet("deviceId", value: newValue) }
    }

    var status: String? {
        get { defaults.string(forKey: "status") }
        set { defaults.set(newValue, forKey: "status") }
    }

    // Stored as Double (milliseconds since epoch) to match Android's currentTimeMillis
    var statusTime: Double {
        get { defaults.double(forKey: "statusTime") }
        set { defaults.set(newValue, forKey: "statusTime") }
    }

    var appKey: String? {
        get { defaults.string(forKey: "appKey") }
        set { defaults.set(newValue, forKey: "appKey") }
    }

    func clear() {
        token = nil
        deviceId = nil
        status = nil
        statusTime = 0
        appKey = nil
    }

    private func keychainGet(_ key: String) -> String? {
        let query: [CFString: Any] = [
            kSecClass: kSecClassGenericPassword,
            kSecAttrService: keychainService,
            kSecAttrAccount: key,
            kSecReturnData: true,
            kSecMatchLimit: kSecMatchLimitOne,
        ]
        var result: AnyObject?
        guard SecItemCopyMatching(query as CFDictionary, &result) == errSecSuccess,
              let data = result as? Data else { return nil }
        return String(data: data, encoding: .utf8)
    }

    private func keychainSet(_ key: String, value: String?) {
        guard let value else { keychainDelete(key); return }
        let data = Data(value.utf8)
        let query: [CFString: Any] = [
            kSecClass: kSecClassGenericPassword,
            kSecAttrService: keychainService,
            kSecAttrAccount: key,
        ]
        if SecItemCopyMatching(query as CFDictionary, nil) == errSecSuccess {
            SecItemUpdate(query as CFDictionary, [kSecValueData: data] as CFDictionary)
        } else {
            var item = query
            item[kSecValueData] = data
            SecItemAdd(item as CFDictionary, nil)
        }
    }

    private func keychainDelete(_ key: String) {
        let query: [CFString: Any] = [
            kSecClass: kSecClassGenericPassword,
            kSecAttrService: keychainService,
            kSecAttrAccount: key,
        ]
        SecItemDelete(query as CFDictionary)
    }
}