// Copyright 2022 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import Foundation

/// Utility class for constructing Google Sign In credentials.
@available(iOS 13, tvOS 13, macOS 10.15, macCatalyst 13, watchOS 7, *)
@objc(FIRGoogleAuthProvider) open class GoogleAuthProvider: NSObject {
  /// A string constant identifying the Google identity provider.
  @objc public static let id = "google.com"

  /// Creates an `AuthCredential` for a Google sign in.
  /// - Parameter idToken: The ID Token from Google.
  /// - Parameter accessToken: The Access Token from Google.
  /// - Returns: An AuthCredential containing the Google credentials.
  @objc open class func credential(withIDToken idToken: String,
                                   accessToken: String) -> AuthCredential {
    return GoogleAuthCredential(withIDToken: idToken, accessToken: accessToken)
  }

  @available(*, unavailable)
  @objc override public init() {
    fatalError("This class is not meant to be initialized.")
  }
}

@available(iOS 13, tvOS 13, macOS 10.15, macCatalyst 13, watchOS 7, *)
@objc(FIRGoogleAuthCredential) class GoogleAuthCredential: AuthCredential, NSSecureCoding {
  let idToken: String
  let accessToken: String

  init(withIDToken idToken: String, accessToken: String) {
    self.idToken = idToken
    self.accessToken = accessToken
    super.init(provider: GoogleAuthProvider.id)
  }

  override func prepare(_ request: VerifyAssertionRequest) {
    request.providerIDToken = idToken
    request.providerAccessToken = accessToken
  }

  // MARK: Secure Coding

  static var supportsSecureCoding = true

  func encode(with coder: NSCoder) {
    coder.encode(idToken, forKey: "idToken")
    coder.encode(accessToken, forKey: "accessToken")
  }

  required init?(coder: NSCoder) {
    guard let idToken = coder.decodeObject(of: NSString.self, forKey: "idToken") as? String,
          let accessToken = coder.decodeObject(of: NSString.self, forKey: "accessToken") as? String
    else {
      return nil
    }
    self.idToken = idToken
    self.accessToken = accessToken
    super.init(provider: GoogleAuthProvider.id)
  }
}