/*
 * MIT License
 *
 * Copyright (c) 2020-present Cloudogu GmbH and Contributors
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

package sonia.scm.repository;

import com.github.legman.Subscribe;
import sonia.scm.HandlerEventType;
import sonia.scm.event.ScmEventBus;

import javax.inject.Inject;
import java.util.Collection;
import java.util.Optional;
import java.util.stream.Collectors;

import static sonia.scm.ContextEntry.ContextBuilder.entity;
import static sonia.scm.NotFoundException.notFound;

public class DefaultNamespaceManager implements NamespaceManager {

  private final RepositoryManager repositoryManager;
  private final NamespaceDao dao;
  private final ScmEventBus eventBus;

  @Inject
  public DefaultNamespaceManager(RepositoryManager repositoryManager, NamespaceDao dao, ScmEventBus eventBus) {
    this.repositoryManager = repositoryManager;
    this.dao = dao;
    this.eventBus = eventBus;
  }

  @Override
  public Optional<Namespace> get(String namespace) {
    return repositoryManager
      .getAllNamespaces()
      .stream()
      .filter(n -> n.equals(namespace))
      .map(this::createNamespaceForName)
      .findFirst();
  }

  @Override
  public Collection<Namespace> getAll() {
    return repositoryManager
      .getAllNamespaces()
      .stream()
      .map(this::createNamespaceForName)
      .collect(Collectors.toList());
  }

  @Override
  public void modify(Namespace namespace) {
    NamespacePermissions.permissionWrite().check();
    Namespace oldNamespace = get(namespace.getNamespace())
      .orElseThrow(() -> notFound(entity(Namespace.class, namespace.getNamespace())));
    fireEvent(HandlerEventType.BEFORE_MODIFY, namespace, oldNamespace);
    dao.add(namespace);
    fireEvent(HandlerEventType.MODIFY, namespace, oldNamespace);
  }

  @Subscribe
  public void cleanupDeletedNamespaces(RepositoryEvent repositoryEvent) {
    if (namespaceRelevantChange(repositoryEvent)) {
      Collection<String> allNamespaces = repositoryManager.getAllNamespaces();
      String oldNamespace = getOldNamespace(repositoryEvent);
      if (!allNamespaces.contains(oldNamespace)) {
        dao.delete(oldNamespace);
      }
    }
  }

  public boolean namespaceRelevantChange(RepositoryEvent repositoryEvent) {
    HandlerEventType eventType = repositoryEvent.getEventType();
    return eventType == HandlerEventType.DELETE
      || eventType == HandlerEventType.MODIFY && !repositoryEvent.getItem().getNamespace().equals(repositoryEvent.getOldItem().getNamespace());
  }

  public String getOldNamespace(RepositoryEvent repositoryEvent) {
    if (repositoryEvent.getEventType() == HandlerEventType.DELETE) {
      return repositoryEvent.getItem().getNamespace();
    } else {
      return repositoryEvent.getOldItem().getNamespace();
    }
  }

  private Namespace createNamespaceForName(String namespace) {
    if (NamespacePermissions.permissionRead().isPermitted()) {
      return dao.get(namespace)
        .map(Namespace::clone)
        .orElse(new Namespace(namespace));
    } else {
      return new Namespace(namespace);
    }
  }

  protected void fireEvent(HandlerEventType event, Namespace namespace, Namespace oldNamespace) {
    eventBus.post(new NamespaceModificationEvent(event, namespace, oldNamespace));
  }
}
