// Copyright 2016 The Domain Registry Authors. All Rights Reserved.
//
// 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.

package google.registry.flows;

import static com.google.appengine.api.users.UserServiceFactory.getUserService;
import static com.google.common.base.MoreObjects.toStringHelper;
import static com.google.common.base.Strings.nullToEmpty;

import com.google.appengine.api.users.User;
import com.google.common.annotations.VisibleForTesting;
import google.registry.flows.EppException.AuthenticationErrorException;
import google.registry.model.registrar.Registrar;
import google.registry.model.registrar.RegistrarContact;
import javax.annotation.Nullable;

/** Credentials provided by {@link com.google.appengine.api.users.UserService}. */
public class GaeUserCredentials implements TransportCredentials {

  final User gaeUser;

  @VisibleForTesting
  public GaeUserCredentials(@Nullable User gaeUser) {
    this.gaeUser = gaeUser;
  }

  @Override
  public void validate(Registrar registrar, String ignoredPassword)
      throws AuthenticationErrorException {
    if (gaeUser == null) {
      throw new UserNotLoggedInException();
    }
    // Allow admins to act as any registrar.
    if (getUserService().isUserAdmin()) {
      return;
    }
    // Check Registrar's contacts to see if any are associated with this gaeUserId.
    final String gaeUserId = gaeUser.getUserId();
    for (RegistrarContact rc : registrar.getContacts()) {
      if (gaeUserId.equals(rc.getGaeUserId())) {
        return;
      }
    }
    throw new BadGaeUserIdException(gaeUser);
  }

  @Override
  public String toString() {
    return toStringHelper(getClass())
        .add("gaeUser", gaeUser)
        .toString();
  }

  /** User is not logged in as a GAE user. */
  public static class UserNotLoggedInException extends AuthenticationErrorException {
    public UserNotLoggedInException() {
      super("User is not logged in");
    }
  }

  /** GAE user id is not allowed to login as requested registrar. */
  public static class BadGaeUserIdException extends AuthenticationErrorException {
    public BadGaeUserIdException(User user) {
      super(
          "User id is not allowed to login as requested registrar: "
              + (nullToEmpty(user.getEmail())));
    }
  }
}