SharedWebCredentialsManager.swift

//
//  SharedWebCredentialsManager.swift
//  Keychain
//
//  Created by Mohammad Alatrash on 6/14/18.
//

import Foundation

enum SharedWebCredentialsManagerError: Error {
    case noCredentialsFound
    case generatePasswordFailed
    case saveFailed(String)
    case deleteFailed(String)
}

class SharedWebCredentialsManager {

    static let shared = SharedWebCredentialsManager()
    let domain: String = "www.domain.com"

    func request(_ completion: (String?, String?, SharedWebCredentialsManagerError?) -> Void) {
        SecRequestSharedWebCredential(domain as CFString, nil) { (credentials, error) in
            guard let credentials = credentials, CFArrayGetCount(credentials) > 0 else {
                completion(nil, nil, SharedWebCredentialsManagerError.noCredentialsFound)
                return
            }

            let credential = CFArrayGetValueAtIndex(credentials, 0)
            let credentialDict = unsafeBitCast(credential, to: CFDictionary.self)
            let unsafeAccount = CFDictionaryGetValue(credentialDict, Unmanaged.passUnretained(kSecAttrAccount).toOpaque())
            let account = unsafeBitCast(unsafeAccount, to: CFString.self) as String
            let unsafePassword = CFDictionaryGetValue(credentialDict, Unmanaged.passUnretained(kSecSharedPassword).toOpaque())
            let password = unsafeBitCast(unsafePassword, to: CFString.self) as String

            completion(account, password, nil)
        }
    }

    func save(account: String, password: String, completion: ((Bool, SharedWebCredentialsManagerError?) -> Void)? = nil) {
        SecAddSharedWebCredential(domain as CFString, account as CFString, password as CFString?) { error in
            guard let error = error else {
                completion?(true, nil)
                return
            }
            let errorDescription = CFErrorCopyDescription(error) as String
            let saveFailedError = SharedWebCredentialsManagerError.saveFailed(errorDescription)
            completion?(false, saveFailedError)
        }
    }

    func delete(account: String, completion: ((Bool, SharedWebCredentialsManagerError?) -> Void)? = nil) -> Promise<Bool> {
        SecAddSharedWebCredential(domain as CFString, account as CFString, nil) { error in
            guard let error = error else {
                completion?(true, nil)
                return
            }

            let errorDescription = CFErrorCopyDescription(error) as String
            let deleteFailedError = SharedWebCredentialsManagerError.saveFailed(errorDescription)
            completion?(true, deleteFailedError)
        }
    }

    func generatePassword(_ completion: ((String?, SharedWebCredentialsManagerError?) -> Void)? = nil) {
        guard let password = SecCreateSharedWebCredentialPassword() as String? else {
            completion?(nil, SharedWebCredentialsManagerError.generatePasswordFailed)
            return
        }
        completion?(password, nil)
    }
}