/*
 * Copyright (C) 2015 Simon Vig Therkildsen
 *
 * 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 net.simonvt.cathode.remote;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import net.simonvt.cathode.jobqueue.JobFailedException;
import okhttp3.Headers;
import retrofit2.Call;
import retrofit2.Response;
import timber.log.Timber;

public abstract class PagedCallJob<T> extends ErrorHandlerJob<List<T>> {

  private static final String HEADER_PAGE_COUNT = "x-pagination-page-count";

  public PagedCallJob() {
  }

  public PagedCallJob(int flags) {
    super(flags);
  }

  @Override public final void perform() {
    List<T> results = new ArrayList<>();
    List<T> result;

    try {
      int page = 1;
      int pageCount = 0;
      do {
        Call<List<T>> call = getCall(page);
        Response<List<T>> response = call.execute();
        if (!response.isSuccessful()) {
          error(response);

          throw new JobFailedException("Failed job: " + key());
        }

        Headers headers = response.headers();
        String pageCountStr = headers.get(HEADER_PAGE_COUNT);
        if (pageCountStr != null) {
          pageCount = Integer.valueOf(pageCountStr);
        }

        result = response.body();
        results.addAll(result);
        page++;
      } while (page <= pageCount);

      handleResponse(results);
    } catch (IOException e) {
      Timber.d(e, "Job failed: %s", key());
      throw new JobFailedException(e);
    }
  }

  public abstract Call<List<T>> getCall(int page);

  public abstract void handleResponse(List<T> response);
}