// 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.token;

import static google.registry.model.ofy.ObjectifyService.ofy;

import com.google.common.collect.ImmutableMap;
import com.google.common.net.InternetDomainName;
import com.googlecode.objectify.Key;
import google.registry.flows.EppException;
import google.registry.flows.EppException.AssociationProhibitsOperationException;
import google.registry.flows.EppException.ParameterValueSyntaxErrorException;
import google.registry.model.domain.AllocationToken;
import google.registry.model.domain.DomainCommand;
import google.registry.model.registry.Registry;
import google.registry.model.reporting.HistoryEntry;
import java.util.List;
import java.util.function.Function;
import javax.inject.Inject;
import org.joda.time.DateTime;

/** Utility functions for dealing with {@link AllocationToken}s in domain flows. */
public class AllocationTokenFlowUtils {

  final AllocationTokenCustomLogic tokenCustomLogic;

  @Inject
  AllocationTokenFlowUtils(AllocationTokenCustomLogic tokenCustomLogic) {
    this.tokenCustomLogic = tokenCustomLogic;
  }

  /**
   * Verifies that a given allocation token string is valid.
   *
   * @return the loaded {@link AllocationToken} for that string.
   * @throws InvalidAllocationTokenException if the token doesn't exist.
   */
  public AllocationToken verifyToken(
      DomainCommand.Create command, String token, Registry registry, String clientId, DateTime now)
      throws EppException {
    AllocationToken tokenEntity = ofy().load().key(Key.create(AllocationToken.class, token)).now();
    if (tokenEntity == null) {
      throw new InvalidAllocationTokenException();
    }
    if (tokenEntity.isRedeemed()) {
      throw new AlreadyRedeemedAllocationTokenException();
    }
    return tokenCustomLogic.verifyToken(command, tokenEntity, registry, clientId, now);
  }

  /**
   * Checks if the allocation token applies to the given domain names, used for domain checks.
   *
   * @return A map of domain names to domain check error response messages. If a message is present
   *     for a a given domain then it does not validate with this allocation token; domains that do
   *     validate have blank messages (i.e. no error).
   */
  public ImmutableMap<InternetDomainName, String> checkDomainsWithToken(
      List<InternetDomainName> domainNames, String token, String clientId, DateTime now) {
    AllocationToken tokenEntity = ofy().load().key(Key.create(AllocationToken.class, token)).now();
    String globalResult;
    if (tokenEntity == null) {
      globalResult = new InvalidAllocationTokenException().getMessage();
    } else if (tokenEntity.isRedeemed()) {
      globalResult = AlreadyRedeemedAllocationTokenException.ERROR_MSG_SHORT;
    } else {
      globalResult = "";
    }
    ImmutableMap<InternetDomainName, String> checkResults =
        domainNames
            .stream()
            .collect(ImmutableMap.toImmutableMap(Function.identity(), domainName -> globalResult));
    // Only call custom logic if there wasn't a global allocation token error that applies to all
    // check results. The custom logic can only add errors, not override existing errors.
    return globalResult.isEmpty()
        ? tokenCustomLogic.checkDomainsWithToken(checkResults, tokenEntity, clientId, now)
        : checkResults;
  }

  /** Redeems an {@link AllocationToken}, returning the redeemed copy. */
  public AllocationToken redeemToken(
      AllocationToken token, Key<HistoryEntry> redemptionHistoryEntry) {
    return token.asBuilder().setRedemptionHistoryEntry(redemptionHistoryEntry).build();
  }

  /** The allocation token was already redeemed. */
  public static class AlreadyRedeemedAllocationTokenException
      extends AssociationProhibitsOperationException {

    public static final String ERROR_MSG_LONG = "The allocation token was already redeemed";

    /** A short error message fitting within 32 characters for use in domain check responses. */
    public static final String ERROR_MSG_SHORT = "Alloc token was already redeemed";

    public AlreadyRedeemedAllocationTokenException() {
      super(ERROR_MSG_LONG);
    }
  }

  /** The allocation token is invalid. */
  public static class InvalidAllocationTokenException extends ParameterValueSyntaxErrorException {
    public InvalidAllocationTokenException() {
      super("The allocation token is invalid");
    }
  }
}