//
//  KeychainUtil.swift
//
//  Created by Rodrigo Busata on 10/07/18.
//

import Foundation

struct KeychainUtil {

    private static let server = Bundle.main.bundleIdentifier!


    static func saveCredentials(username: String, password: String) {
        let password = password.data(using: String.Encoding.utf8)!

        if self.getCredentials(byUsernamre: username) == nil {
            let query: [String: Any] = [kSecClass as String: kSecClassInternetPassword,
                                        kSecAttrServer as String: self.server,
                                        kSecAttrAccount as String: username,
                                        kSecValueData as String: password]

            let status = SecItemAdd(query as CFDictionary, nil)
            if status != errSecSuccess {
                print("Failed on saveCredentials() INSERT")
            }

        } else {
            let query: [String: Any] = [kSecClass as String: kSecClassInternetPassword,
                                        kSecAttrServer as String: self.server,
                                        kSecAttrAccount as String: username]

            let attributes: [String: Any] = [kSecValueData as String: password]

            let status = SecItemUpdate(query as CFDictionary, attributes as CFDictionary)
            if status != errSecSuccess {
                print("Failed on saveCredentials() UPDATE")
            }
        }
    }


    static func getCredentials(byUsernamre username: String) -> String? {
        let query: [String: Any] = [kSecClass as String: kSecClassInternetPassword,
                                    kSecAttrServer as String: self.server,
                                    kSecAttrAccount as String: username,
                                    kSecMatchLimit as String: kSecMatchLimitOne,
                                    kSecReturnAttributes as String: true,
                                    kSecReturnData as String: true]

        var item: CFTypeRef?
        let status = SecItemCopyMatching(query as CFDictionary, &item)
        if status == errSecItemNotFound {
            return nil
        }

        if status != errSecSuccess {
            print("Failed on getCredentials()")
            return nil
        }

        guard let existingItem = item as? [String : Any],
            let passwordData = existingItem[kSecValueData as String] as? Data,
            let password = String(data: passwordData, encoding: String.Encoding.utf8)
            else {
                return nil
        }

        return password
    }
}