// Copyright 2018 The Feed Authors.
//
// 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 com.google.android.libraries.feed.api.internal.requestmanager;

import com.google.android.libraries.feed.api.host.logging.RequestReason;
import com.google.android.libraries.feed.common.Result;
import com.google.android.libraries.feed.common.functional.Consumer;
import com.google.search.now.feed.client.StreamDataProto.StreamDataOperation;
import com.google.search.now.feed.client.StreamDataProto.StreamToken;
import com.google.search.now.wire.feed.ConsistencyTokenProto.ConsistencyToken;
import java.util.List;

/**
 * Creates and issues requests to the server.
 *
 * <p>Note: this is the internal version of FeedRequestManager. See {@link RequestManager} for the
 * client version.
 */
public interface FeedRequestManager {
  /**
   * Issues a request for the next page of data. The {@code streamToken} described to the server
   * what the next page means. The{@code token} is used by the server for consistent data across
   * requests. The response will be sent to a {@link Consumer} a set of {@link StreamDataOperation}
   * created by the ProtocolAdapter.
   */
  void loadMore(
      StreamToken streamToken,
      ConsistencyToken token,
      Consumer<Result<List<StreamDataOperation>>> consumer);

  /**
   * Issues a request to refresh the entire feed, with the consumer being called back with the
   * resulting {@link StreamDataOperation}s.
   *
   * @param reason The reason for this refresh.
   */
  void triggerRefresh(
      @RequestReason int reason, Consumer<Result<List<StreamDataOperation>>> consumer);

  /**
   * Issues a request to refresh the entire feed, with the consumer being called back with the
   * resulting {@link StreamDataOperation}s.
   *
   * @param reason The reason for this refresh.
   * @param token Used by the server for consistent data across requests.
   * @param consumer The consumer called after the refresh is performed.
   */
  void triggerRefresh(
      @RequestReason int reason,
      ConsistencyToken token,
      Consumer<Result<List<StreamDataOperation>>> consumer);
}