// 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.rde;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkState;

import com.google.appengine.tools.cloudstorage.GcsFilename;
import com.googlecode.objectify.Key;
import com.googlecode.objectify.Work;
import google.registry.config.ConfigModule.Config;
import google.registry.gcs.GcsUtils;
import google.registry.model.contact.ContactResource;
import google.registry.model.index.EppResourceIndex;
import google.registry.model.index.ForeignKeyIndex;
import google.registry.model.ofy.Ofy;
import google.registry.model.registrar.Registrar;
import google.registry.model.registry.Registry;
import google.registry.model.registry.Registry.RegistryNotFoundException;
import google.registry.model.registry.Registry.TldState;
import google.registry.util.Clock;
import google.registry.util.FormattingLogger;
import google.registry.xjc.rderegistrar.XjcRdeRegistrar;
import java.io.IOException;
import java.io.InputStream;
import javax.inject.Inject;
import javax.xml.bind.JAXBException;
import javax.xml.stream.XMLStreamException;
import org.joda.time.DateTime;

/**
 * Utility functions for escrow file import.
 */
public class RdeImportUtils {

  private static final FormattingLogger logger = FormattingLogger.getLoggerForCallerClass();

  private final Ofy ofy;
  private final Clock clock;
  private final String escrowBucketName;
  private final GcsUtils gcsUtils;

  @Inject
  public RdeImportUtils(
      Ofy ofy, Clock clock, @Config("rdeImportBucket") String escrowBucketName, GcsUtils gcsUtils) {
    this.ofy = ofy;
    this.clock = clock;
    this.gcsUtils = gcsUtils;
    this.escrowBucketName = escrowBucketName;
  }

  /**
   * Imports a contact from an escrow file.
   *
   * <p>The contact will only be imported if it has not been previously imported.
   *
   * <p>If the contact is imported, {@link ForeignKeyIndex} and {@link EppResourceIndex} are also
   * created.
   *
   * @return true if the contact was created or updated, false otherwise.
   */
  public boolean importContact(final ContactResource resource) {
    return ofy.transact(
        new Work<Boolean>() {
          @Override
          public Boolean run() {
            ContactResource existing = ofy.load().key(Key.create(resource)).now();
            if (existing == null) {
              ForeignKeyIndex<ContactResource> existingForeignKeyIndex =
                  ForeignKeyIndex.load(
                      ContactResource.class, resource.getContactId(), clock.nowUtc());
              // foreign key index should not exist, since existing contact was not found.
              checkState(
                  existingForeignKeyIndex == null,
                  String.format(
                      "New contact resource has existing foreign key index. "
                          + "contactId=%s, repoId=%s",
                      resource.getContactId(), resource.getRepoId()));
              ofy.save().entity(resource);
              ofy.save().entity(ForeignKeyIndex.create(resource, resource.getDeletionTime()));
              ofy.save().entity(EppResourceIndex.create(Key.create(resource)));
              logger.infofmt(
                  "Imported contact resource - ROID=%s, id=%s",
                  resource.getRepoId(), resource.getContactId());
              return true;
            } else if (!existing.getRepoId().equals(resource.getRepoId())) {
              logger.warningfmt(
                  "Existing contact with same contact id but different ROID. "
                      + "contactId=%s, existing ROID=%s, new ROID=%s",
                  resource.getContactId(), existing.getRepoId(), resource.getRepoId());
            }
            return false;
          }
        });
  }

  /**
   * Validates an escrow file for import.
   *
   * <p>Before an escrow file is imported into the registry, the following conditions must be met:
   *
   * <ul>
   * <li>The TLD must already exist in the registry
   * <li>The TLD must be in the PREDELEGATION state
   * <li>Each registrar must already exist in the registry
   * <li>Each IDN table referenced must already exist in the registry
   * </ul>
   *
   * <p>If any of the above conditions is not true, an {@link IllegalStateException} will be thrown.
   *
   * @param escrowFilePath Path to the escrow file to validate
   * @throws IOException If the escrow file cannot be read
   * @throws IllegalArgumentException if the escrow file cannot be imported
   */
  public void validateEscrowFileForImport(String escrowFilePath) throws IOException {
    // TODO (wolfgang): Add validation method for IDN tables
    try (InputStream input =
        gcsUtils.openInputStream(new GcsFilename(escrowBucketName, escrowFilePath))) {
      try {
        RdeParser parser = new RdeParser(input);
        // validate that tld exists and is in PREDELEGATION state
        String tld = parser.getHeader().getTld();
        try {
          Registry registry = Registry.get(tld);
          TldState currentState = registry.getTldState(DateTime.now());
          checkArgument(
              currentState == TldState.PREDELEGATION,
              String.format("Tld '%s' is in state %s and cannot be imported", tld, currentState));
        } catch (RegistryNotFoundException e) {
          throw new IllegalArgumentException(
              String.format("Tld '%s' not found in the registry", tld));
        }
        // validate that all registrars exist
        while (parser.nextRegistrar()) {
          XjcRdeRegistrar registrar = parser.getRegistrar();
          if (Registrar.loadByClientId(registrar.getId()) == null) {
            throw new IllegalArgumentException(
                String.format("Registrar '%s' not found in the registry", registrar.getId()));
          }
        }
      } catch (XMLStreamException | JAXBException e) {
        throw new IllegalArgumentException(
            String.format("Invalid XML file: '%s'", escrowFilePath), e);
      }
    }
  }
}