// 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.flows.domain;

import static com.google.common.base.Preconditions.checkNotNull;
import static google.registry.flows.FlowUtils.persistEntityChanges;
import static google.registry.flows.FlowUtils.validateClientIsLoggedIn;
import static google.registry.flows.ResourceFlowUtils.denyPendingTransfer;
import static google.registry.flows.ResourceFlowUtils.handlePendingTransferOnDelete;
import static google.registry.flows.ResourceFlowUtils.loadAndVerifyExistence;
import static google.registry.flows.ResourceFlowUtils.updateForeignKeyIndexDeletionTime;
import static google.registry.flows.ResourceFlowUtils.verifyNoDisallowedStatuses;
import static google.registry.flows.ResourceFlowUtils.verifyOptionalAuthInfo;
import static google.registry.flows.ResourceFlowUtils.verifyResourceOwnership;
import static google.registry.flows.domain.DomainFlowUtils.checkAllowedAccessToTld;
import static google.registry.flows.domain.DomainFlowUtils.createCancelingRecords;
import static google.registry.flows.domain.DomainFlowUtils.updateAutorenewRecurrenceEndTime;
import static google.registry.flows.domain.DomainFlowUtils.verifyNotInPredelegation;
import static google.registry.model.eppoutput.Result.Code.SUCCESS;
import static google.registry.model.eppoutput.Result.Code.SUCCESS_WITH_ACTION_PENDING;
import static google.registry.model.ofy.ObjectifyService.ofy;
import static google.registry.model.reporting.DomainTransactionRecord.TransactionReportField.ADD_FIELDS;
import static google.registry.model.reporting.DomainTransactionRecord.TransactionReportField.RENEW_FIELDS;
import static google.registry.pricing.PricingEngineProxy.getDomainRenewCost;
import static google.registry.util.CollectionUtils.nullToEmpty;
import static google.registry.util.CollectionUtils.union;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Sets;
import com.googlecode.objectify.Key;
import google.registry.dns.DnsQueue;
import google.registry.flows.EppException;
import google.registry.flows.EppException.AssociationProhibitsOperationException;
import google.registry.flows.ExtensionManager;
import google.registry.flows.FlowModule.ClientId;
import google.registry.flows.FlowModule.Superuser;
import google.registry.flows.FlowModule.TargetId;
import google.registry.flows.SessionMetadata;
import google.registry.flows.TransactionalFlow;
import google.registry.flows.annotations.ReportingSpec;
import google.registry.flows.custom.DomainDeleteFlowCustomLogic;
import google.registry.flows.custom.DomainDeleteFlowCustomLogic.AfterValidationParameters;
import google.registry.flows.custom.DomainDeleteFlowCustomLogic.BeforeResponseParameters;
import google.registry.flows.custom.DomainDeleteFlowCustomLogic.BeforeResponseReturnData;
import google.registry.flows.custom.DomainDeleteFlowCustomLogic.BeforeSaveParameters;
import google.registry.flows.custom.EntityChanges;
import google.registry.model.ImmutableObject;
import google.registry.model.billing.BillingEvent;
import google.registry.model.domain.DomainResource;
import google.registry.model.domain.DomainResource.Builder;
import google.registry.model.domain.GracePeriod;
import google.registry.model.domain.fee.BaseFee.FeeType;
import google.registry.model.domain.fee.Credit;
import google.registry.model.domain.fee.FeeTransformResponseExtension;
import google.registry.model.domain.fee06.FeeDeleteResponseExtensionV06;
import google.registry.model.domain.fee11.FeeDeleteResponseExtensionV11;
import google.registry.model.domain.fee12.FeeDeleteResponseExtensionV12;
import google.registry.model.domain.metadata.MetadataExtension;
import google.registry.model.domain.rgp.GracePeriodStatus;
import google.registry.model.domain.secdns.SecDnsCreateExtension;
import google.registry.model.domain.superuser.DomainDeleteSuperuserExtension;
import google.registry.model.eppcommon.AuthInfo;
import google.registry.model.eppcommon.ProtocolDefinition.ServiceExtension;
import google.registry.model.eppcommon.StatusValue;
import google.registry.model.eppcommon.Trid;
import google.registry.model.eppinput.EppInput;
import google.registry.model.eppoutput.EppResponse;
import google.registry.model.poll.PendingActionNotificationResponse.DomainPendingActionNotificationResponse;
import google.registry.model.poll.PollMessage;
import google.registry.model.poll.PollMessage.OneTime;
import google.registry.model.registry.Registry;
import google.registry.model.registry.Registry.TldType;
import google.registry.model.reporting.DomainTransactionRecord;
import google.registry.model.reporting.DomainTransactionRecord.TransactionReportField;
import google.registry.model.reporting.HistoryEntry;
import google.registry.model.reporting.IcannReportingTypes.ActivityReportField;
import google.registry.model.transfer.TransferStatus;
import java.util.Collections;
import java.util.Optional;
import java.util.Set;
import javax.annotation.Nullable;
import javax.inject.Inject;
import org.joda.money.Money;
import org.joda.time.DateTime;
import org.joda.time.Duration;

/**
 * An EPP flow that deletes a domain.
 *
 * @error {@link google.registry.flows.EppException.UnimplementedExtensionException}
 * @error {@link google.registry.flows.ResourceFlowUtils.ResourceDoesNotExistException}
 * @error {@link google.registry.flows.ResourceFlowUtils.ResourceNotOwnedException}
 * @error {@link google.registry.flows.exceptions.OnlyToolCanPassMetadataException}
 * @error {@link google.registry.flows.exceptions.ResourceStatusProhibitsOperationException}
 * @error {@link DomainDeleteFlow.DomainToDeleteHasHostsException}
 * @error {@link DomainFlowUtils.BadCommandForRegistryPhaseException}
 * @error {@link DomainFlowUtils.NotAuthorizedForTldException}
 */
@ReportingSpec(ActivityReportField.DOMAIN_DELETE)
public final class DomainDeleteFlow implements TransactionalFlow {

  private static final ImmutableSet<StatusValue> DISALLOWED_STATUSES = ImmutableSet.of(
      StatusValue.CLIENT_DELETE_PROHIBITED,
      StatusValue.PENDING_DELETE,
      StatusValue.SERVER_DELETE_PROHIBITED);

  @Inject ExtensionManager extensionManager;
  @Inject EppInput eppInput;
  @Inject SessionMetadata sessionMetadata;
  @Inject Optional<AuthInfo> authInfo;
  @Inject @ClientId String clientId;
  @Inject @TargetId String targetId;
  @Inject @Superuser boolean isSuperuser;
  @Inject HistoryEntry.Builder historyBuilder;
  @Inject DnsQueue dnsQueue;
  @Inject Trid trid;
  @Inject EppResponse.Builder responseBuilder;
  @Inject DomainDeleteFlowCustomLogic flowCustomLogic;
  @Inject DomainDeleteFlow() {}

  @Override
  public final EppResponse run() throws EppException {
    extensionManager.register(
        MetadataExtension.class, SecDnsCreateExtension.class, DomainDeleteSuperuserExtension.class);
    flowCustomLogic.beforeValidation();
    extensionManager.validate();
    validateClientIsLoggedIn(clientId);
    DateTime now = ofy().getTransactionTime();
    // Loads the target resource if it exists
    DomainResource existingDomain = loadAndVerifyExistence(DomainResource.class, targetId, now);
    Registry registry = Registry.get(existingDomain.getTld());
    verifyDeleteAllowed(existingDomain, registry, now);
    flowCustomLogic.afterValidation(
        AfterValidationParameters.newBuilder().setExistingDomain(existingDomain).build());
    ImmutableSet.Builder<ImmutableObject> entitiesToSave = new ImmutableSet.Builder<>();
    Builder builder;
    if (existingDomain.getStatusValues().contains(StatusValue.PENDING_TRANSFER)) {
      builder =
          denyPendingTransfer(existingDomain, TransferStatus.SERVER_CANCELLED, now).asBuilder();
    } else {
      builder = existingDomain.asBuilder();
    }
    Duration redemptionGracePeriodLength = registry.getRedemptionGracePeriodLength();
    Duration pendingDeleteLength = registry.getPendingDeleteLength();
    Optional<DomainDeleteSuperuserExtension> domainDeleteSuperuserExtension =
        eppInput.getSingleExtension(DomainDeleteSuperuserExtension.class);
    if (domainDeleteSuperuserExtension.isPresent()) {
      redemptionGracePeriodLength =
          Duration.standardDays(
              domainDeleteSuperuserExtension.get().getRedemptionGracePeriodDays());
      pendingDeleteLength =
          Duration.standardDays(domainDeleteSuperuserExtension.get().getPendingDeleteDays());
    }
    boolean inAddGracePeriod =
        existingDomain.getGracePeriodStatuses().contains(GracePeriodStatus.ADD);
    // If the domain is in the Add Grace Period, we delete it immediately.
    // Otherwise, we give it a PENDING_DELETE status.
    Duration durationUntilDelete =
        inAddGracePeriod
            ? Duration.ZERO
            // By default, this should be 30 days of grace, and 5 days of pending delete.
            : redemptionGracePeriodLength.plus(pendingDeleteLength);
    HistoryEntry historyEntry = buildHistoryEntry(
        existingDomain, registry, now, durationUntilDelete, inAddGracePeriod);
    if (durationUntilDelete.equals(Duration.ZERO)) {
      builder.setDeletionTime(now).setStatusValues(null);
    } else {
      DateTime deletionTime = now.plus(durationUntilDelete);
      PollMessage.OneTime deletePollMessage =
          createDeletePollMessage(existingDomain, historyEntry, deletionTime);
      entitiesToSave.add(deletePollMessage);
      builder.setDeletionTime(deletionTime)
          .setStatusValues(ImmutableSet.of(StatusValue.PENDING_DELETE))
          // Clear out all old grace periods and add REDEMPTION, which does not include a key to a
          // billing event because there isn't one for a domain delete.
          .setGracePeriods(ImmutableSet.of(GracePeriod.createWithoutBillingEvent(
              GracePeriodStatus.REDEMPTION,
              now.plus(redemptionGracePeriodLength),
              clientId)))
          .setDeletePollMessage(Key.create(deletePollMessage));
      // Note: The expiration time is unchanged, so if it's before the new deletion time, there will
      // be a "phantom autorenew" where the expiration time advances but no billing event or poll
      // message are produced (since we are ending the autorenew recurrences at "now" below).  For
      // now at least this is working as intended.
    }
    DomainResource newDomain = builder.build();
    updateForeignKeyIndexDeletionTime(newDomain);
    handlePendingTransferOnDelete(existingDomain, newDomain, now, historyEntry);
    // Close the autorenew billing event and poll message. This may delete the poll message.
    updateAutorenewRecurrenceEndTime(existingDomain, now);
    // If there's a pending transfer, the gaining client's autorenew billing
    // event and poll message will already have been deleted in
    // ResourceDeleteFlow since it's listed in serverApproveEntities.
    dnsQueue.addDomainRefreshTask(existingDomain.getFullyQualifiedDomainName());
    // Cancel any grace periods that were still active.
    for (GracePeriod gracePeriod : existingDomain.getGracePeriods()) {
      // No cancellation is written if the grace period was not for a billable event.
      if (gracePeriod.hasBillingEvent()) {
        entitiesToSave.add(
            BillingEvent.Cancellation.forGracePeriod(gracePeriod, historyEntry, targetId));
      }
    }
    entitiesToSave.add(newDomain, historyEntry);
    EntityChanges entityChanges = flowCustomLogic.beforeSave(
        BeforeSaveParameters.newBuilder()
            .setExistingDomain(existingDomain)
            .setNewDomain(newDomain)
            .setHistoryEntry(historyEntry)
            .setEntityChanges(EntityChanges.newBuilder().setSaves(entitiesToSave.build()).build())
            .build());
    persistEntityChanges(entityChanges);
    BeforeResponseReturnData responseData =
        flowCustomLogic.beforeResponse(
            BeforeResponseParameters.newBuilder()
                .setResultCode(
                    newDomain.getDeletionTime().isAfter(now)
                        ? SUCCESS_WITH_ACTION_PENDING
                        : SUCCESS)
                .setResponseExtensions(getResponseExtensions(existingDomain, now))
                .build());
    return responseBuilder
        .setResultFromCode(responseData.resultCode())
        .setExtensions(responseData.responseExtensions())
        .build();
  }

  private void verifyDeleteAllowed(DomainResource existingDomain, Registry registry, DateTime now)
      throws EppException {
    verifyNoDisallowedStatuses(existingDomain, DISALLOWED_STATUSES);
    verifyOptionalAuthInfo(authInfo, existingDomain);
    if (!isSuperuser) {
      verifyResourceOwnership(clientId, existingDomain);
      verifyNotInPredelegation(registry, now);
      checkAllowedAccessToTld(clientId, registry.getTld().toString());
    }
    if (!existingDomain.getSubordinateHosts().isEmpty()) {
      throw new DomainToDeleteHasHostsException();
    }
  }

  private HistoryEntry buildHistoryEntry(
      DomainResource existingResource,
      Registry registry,
      DateTime now,
      Duration durationUntilDelete,
      boolean inAddGracePeriod) {
    // We ignore prober transactions
    if (registry.getTldType() == TldType.REAL) {
      Duration maxGracePeriod = Collections.max(
          ImmutableSet.of(
              registry.getAddGracePeriodLength(),
              registry.getAutoRenewGracePeriodLength(),
              registry.getRenewGracePeriodLength()));
      ImmutableSet<DomainTransactionRecord> cancelledRecords =
          createCancelingRecords(
              existingResource,
              now,
              maxGracePeriod,
              Sets.immutableEnumSet(Sets.union(ADD_FIELDS, RENEW_FIELDS)));
      historyBuilder
          .setDomainTransactionRecords(
              union(
                  cancelledRecords,
                  DomainTransactionRecord.create(
                      existingResource.getTld(),
                      now.plus(durationUntilDelete),
                      inAddGracePeriod
                          ? TransactionReportField.DELETED_DOMAINS_GRACE
                          : TransactionReportField.DELETED_DOMAINS_NOGRACE,
                      1)));
    }
    return historyBuilder
        .setType(HistoryEntry.Type.DOMAIN_DELETE)
        .setModificationTime(now)
        .setParent(Key.create(existingResource))
        .build();
  }

  private OneTime createDeletePollMessage(
      DomainResource existingResource, HistoryEntry historyEntry, DateTime deletionTime) {
    return new PollMessage.OneTime.Builder()
        .setClientId(existingResource.getCurrentSponsorClientId())
        .setEventTime(deletionTime)
        .setMsg("Domain deleted.")
        .setResponseData(ImmutableList.of(
            DomainPendingActionNotificationResponse.create(
                existingResource.getFullyQualifiedDomainName(), true, trid, deletionTime)))
        .setParent(historyEntry)
        .build();
  }

  @Nullable
  private ImmutableList<FeeTransformResponseExtension> getResponseExtensions(
      DomainResource existingDomain, DateTime now) {
    FeeTransformResponseExtension.Builder feeResponseBuilder = getDeleteResponseBuilder();
    if (feeResponseBuilder == null) {
      return ImmutableList.of();
    }
    ImmutableList.Builder<Credit> creditsBuilder = new ImmutableList.Builder<>();
    for (GracePeriod gracePeriod : existingDomain.getGracePeriods()) {
      if (gracePeriod.hasBillingEvent()) {
        Money cost = getGracePeriodCost(gracePeriod, now);
        creditsBuilder.add(Credit.create(
            cost.negated().getAmount(), FeeType.CREDIT, gracePeriod.getType().getXmlName()));
        feeResponseBuilder.setCurrency(checkNotNull(cost.getCurrencyUnit()));
      }
    }
    ImmutableList<Credit> credits = creditsBuilder.build();
    if (credits.isEmpty()) {
      return ImmutableList.of();
    }
    return ImmutableList.of(feeResponseBuilder.setCredits(credits).build());
  }

  private Money getGracePeriodCost(GracePeriod gracePeriod, DateTime now) {
    if (gracePeriod.getType() == GracePeriodStatus.AUTO_RENEW) {
      DateTime autoRenewTime =
          ofy().load().key(checkNotNull(gracePeriod.getRecurringBillingEvent())).now()
              .getRecurrenceTimeOfYear()
                  .getLastInstanceBeforeOrAt(now);
      return getDomainRenewCost(targetId, autoRenewTime, 1);
    }
    return ofy().load().key(checkNotNull(gracePeriod.getOneTimeBillingEvent())).now().getCost();
  }

  @Nullable
  private FeeTransformResponseExtension.Builder getDeleteResponseBuilder() {
    Set<String> uris = nullToEmpty(sessionMetadata.getServiceExtensionUris());
    if (uris.contains(ServiceExtension.FEE_0_12.getUri())) {
      return new FeeDeleteResponseExtensionV12.Builder();
    }
    if (uris.contains(ServiceExtension.FEE_0_11.getUri())) {
      return new FeeDeleteResponseExtensionV11.Builder();
    }
    if (uris.contains(ServiceExtension.FEE_0_6.getUri())) {
      return new FeeDeleteResponseExtensionV06.Builder();
    }
    return null;
  }

  /** Domain to be deleted has subordinate hosts. */
  static class DomainToDeleteHasHostsException extends AssociationProhibitsOperationException {
    public DomainToDeleteHasHostsException() {
      super("Domain to be deleted has subordinate hosts");
    }
  }
}