/*
 * ToroDB
 * Copyright © 2014 8Kdata Technology (www.8kdata.com)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

package com.torodb.mongodb.repl.topology;

import com.eightkdata.mongowp.OpTime;
import com.google.common.net.HostAndPort;
import com.torodb.mongodb.repl.SyncSourceProvider;
import com.torodb.mongodb.repl.exceptions.NoSyncSourceFoundException;

import java.util.Optional;
import java.util.function.Supplier;

import javax.inject.Inject;
import javax.inject.Singleton;

/**
 *
 */
@Singleton
public class TopologySyncSourceProvider implements SyncSourceProvider {

  private final TopologyService topologyService;

  @Inject
  public TopologySyncSourceProvider(TopologyService topologyService) {
    this.topologyService = topologyService;
  }

  @Override
  public HostAndPort newSyncSource() throws NoSyncSourceFoundException {
    return newSyncSource(Optional.empty(), NoSyncSourceFoundException::new);
  }

  @Override
  public HostAndPort newSyncSource(OpTime lastFetchedOpTime)
      throws NoSyncSourceFoundException {
    return newSyncSource(
        Optional.of(lastFetchedOpTime),
        () -> new NoSyncSourceFoundException(lastFetchedOpTime)
    );
  }

  private HostAndPort newSyncSource(Optional<OpTime> minOpTime,
      Supplier<NoSyncSourceFoundException> exSupplier)
      throws NoSyncSourceFoundException {
    return topologyService.chooseNewSyncSource(minOpTime)
        .join()
        .orElseThrow(exSupplier);
  }

  @Override
  public boolean shouldChangeSyncSource() {
    return topologyService.shouldChangeSyncSource()
        .join();
  }

  @Override
  public Optional<HostAndPort> getLastUsedSyncSource() {
    return topologyService.getLastUsedSyncSource().join();
  }

}