// Copyright 2017 The Nomulus 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.dns;

import static google.registry.model.EppResourceUtils.loadByForeignKey;

import google.registry.dns.DnsConstants.TargetType;
import google.registry.model.EppResource;
import google.registry.model.EppResource.ForeignKeyedEppResource;
import google.registry.model.annotations.ExternalMessagingName;
import google.registry.model.domain.DomainBase;
import google.registry.model.host.HostResource;
import google.registry.request.Action;
import google.registry.request.HttpException.BadRequestException;
import google.registry.request.HttpException.NotFoundException;
import google.registry.request.Parameter;
import google.registry.request.auth.Auth;
import google.registry.util.Clock;
import javax.inject.Inject;

/** Action that manually triggers refresh of DNS information. */
@Action(
    service = Action.Service.BACKEND,
    path = "/_dr/dnsRefresh",
    automaticallyPrintOk = true,
    auth = Auth.AUTH_INTERNAL_OR_ADMIN)
public final class RefreshDnsAction implements Runnable {

  private final Clock clock;
  private final DnsQueue dnsQueue;
  private final String domainOrHostName;
  private final TargetType type;

  @Inject
  RefreshDnsAction(
      @Parameter("domainOrHostName") String domainOrHostName,
      @Parameter("type") TargetType type,
      Clock clock,
      DnsQueue dnsQueue) {
    this.domainOrHostName = domainOrHostName;
    this.type = type;
    this.clock = clock;
    this.dnsQueue = dnsQueue;
  }

  @Override
  public void run() {
    if (!domainOrHostName.contains(".")) {
      throw new BadRequestException("URL parameter 'name' must be fully qualified");
    }
    switch (type) {
      case DOMAIN:
        loadAndVerifyExistence(DomainBase.class, domainOrHostName);
        dnsQueue.addDomainRefreshTask(domainOrHostName);
        break;
      case HOST:
        verifyHostIsSubordinate(loadAndVerifyExistence(HostResource.class, domainOrHostName));
        dnsQueue.addHostRefreshTask(domainOrHostName);
        break;
      default:
        throw new BadRequestException("Unsupported type: " + type);
    }
  }

  private <T extends EppResource & ForeignKeyedEppResource>
      T loadAndVerifyExistence(Class<T> clazz, String foreignKey) {
    return loadByForeignKey(clazz, foreignKey, clock.nowUtc())
        .orElseThrow(
            () ->
                new NotFoundException(
                    String.format(
                        "%s %s not found",
                        clazz.getAnnotation(ExternalMessagingName.class).value(),
                        domainOrHostName)));
  }

  private static void verifyHostIsSubordinate(HostResource host) {
    if (!host.isSubordinate()) {
      throw new BadRequestException(
          String.format("%s isn't a subordinate hostname", host.getHostName()));
    }
  }
}
