/**
 * Copyright (C) 2014-2016 LinkedIn Corp. (pinot-core@linkedin.com)
 *
 * 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.linkedin.pinot.client;

import com.ning.http.client.AsyncHttpClient;
import com.ning.http.client.Response;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import org.json.JSONObject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


/**
 * JSON encoded Pinot client transport over AsyncHttpClient.
 */
class JsonAsyncHttpPinotClientTransport implements PinotClientTransport {
  private static final Logger LOGGER = LoggerFactory.getLogger(JsonAsyncHttpPinotClientTransport.class);
  AsyncHttpClient _httpClient = new AsyncHttpClient();

  @Override
  public BrokerResponse executeQuery(String brokerAddress, String query) throws PinotClientException {
    try {
      return executeQueryAsync(brokerAddress, query).get();
    } catch (Exception e) {
      throw new PinotClientException(e);
    }
  }

  @Override
  public Future<BrokerResponse> executeQueryAsync(String brokerAddress, final String query) {
    try {
      final JSONObject json = new JSONObject();
      json.put("pql", query);

      final String url = "http://" + brokerAddress + "/query";

      final Future<Response> response = _httpClient.preparePost(url).setBody(json.toString()).execute();

      return new BrokerResponseFuture(response, query, url);
    } catch (Exception e) {
      throw new PinotClientException(e);
    }
  }

  private static class BrokerResponseFuture implements Future<BrokerResponse> {
    private final Future<Response> _response;
    private final String _query;
    private final String _url;

    public BrokerResponseFuture(Future<Response> response, String query, String url) {
      _response = response;
      _query = query;
      _url = url;
    }

    @Override
    public boolean cancel(boolean mayInterruptIfRunning) {
      return _response.cancel(mayInterruptIfRunning);
    }

    @Override
    public boolean isCancelled() {
      return _response.isCancelled();
    }

    @Override
    public boolean isDone() {
      return _response.isDone();
    }

    @Override
    public BrokerResponse get()
        throws InterruptedException, ExecutionException {
      try {
        return get(1000L, TimeUnit.DAYS);
      } catch (TimeoutException e) {
        LOGGER.error("Caught timeout during synchronous get", e);
        throw new InterruptedException();
      }
    }

    @Override
    public BrokerResponse get(long timeout, TimeUnit unit)
        throws InterruptedException, ExecutionException, TimeoutException {
      try {
        LOGGER.debug("Sending query {} to {}", _query, _url);

        Response httpResponse = _response.get(timeout, unit);

        LOGGER.debug("Completed query, HTTP status is {}", httpResponse.getStatusCode());

        if (httpResponse.getStatusCode() != 200) {
          throw new PinotClientException("Pinot returned HTTP status " + httpResponse.getStatusCode() +
              ", expected 200");
        }

        String responseBody = httpResponse.getResponseBody();
        return BrokerResponse.fromJson(new JSONObject(responseBody));
      } catch (Exception e) {
        throw new ExecutionException(e);
      }
    }
  }
}