// 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.feedstore.internal;

import com.google.android.libraries.feed.common.functional.Committer;
import com.google.android.libraries.feed.common.logging.Logger;
import com.google.android.libraries.feed.host.storage.CommitResult;
import com.google.android.libraries.feed.internalapi.store.UploadableActionMutation;
import com.google.search.now.feed.client.StreamDataProto.StreamUploadableAction;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

/** Implementation of {@link UploadableActionMutation} */
public final class FeedUploadableActionMutation implements UploadableActionMutation {
  private static final String TAG = "FeedUploadableActionMutation";

  private final Map<String, FeedUploadableActionChanges> actions = new HashMap<>();
  private final Committer<CommitResult, Map<String, FeedUploadableActionChanges>> committer;

  FeedUploadableActionMutation(
      Committer<CommitResult, Map<String, FeedUploadableActionChanges>> committer) {
    this.committer = committer;
  }

  @Override
  public UploadableActionMutation upsert(StreamUploadableAction action, String contentId) {
    /*@Nullable*/ FeedUploadableActionChanges actionsForId = actions.get(contentId);
    if (actionsForId == null) {
      actionsForId = new FeedUploadableActionChanges();
    }
    actionsForId.upsertAction(action);
    actions.put(contentId, actionsForId);
    Logger.i(TAG, "Added action %d", action);
    return this;
  }

  @Override
  public UploadableActionMutation remove(StreamUploadableAction action, String contentId) {
    /*@Nullable*/ FeedUploadableActionChanges actionsForId = actions.get(contentId);
    if (actionsForId == null) {
      actionsForId = new FeedUploadableActionChanges();
    }
    actionsForId.removeAction(action);
    actions.put(contentId, actionsForId);
    Logger.i(TAG, "Added action %d", action);
    return this;
  }

  @Override
  public CommitResult commit() {
    return committer.commit(actions);
  }

  public static class FeedUploadableActionChanges {
    private final Set<StreamUploadableAction> upsertActions;
    private final Set<StreamUploadableAction> removeActions;

    FeedUploadableActionChanges() {
      this.upsertActions = new HashSet<>();
      this.removeActions = new HashSet<>();
    }

    void upsertAction(StreamUploadableAction action) {
      upsertActions.add(action);
      removeActions.remove(action);
    }

    void removeAction(StreamUploadableAction action) {
      removeActions.add(action);
      upsertActions.remove(action);
    }

    public Set<StreamUploadableAction> upsertActions() {
      return upsertActions;
    }

    public Set<StreamUploadableAction> removeActions() {
      return removeActions;
    }
  }
}