/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 *
 *   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 org.apache.streams.facebook.provider.page;

import org.apache.streams.config.ComponentConfigurator;
import org.apache.streams.config.StreamsConfiguration;
import org.apache.streams.config.StreamsConfigurator;
import org.apache.streams.core.StreamsDatum;
import org.apache.streams.facebook.FacebookConfiguration;
import org.apache.streams.facebook.FacebookPageFeedProviderConfiguration;
import org.apache.streams.facebook.FacebookPageProviderConfiguration;
import org.apache.streams.facebook.provider.FacebookDataCollector;
import org.apache.streams.facebook.provider.FacebookProvider;
import org.apache.streams.jackson.StreamsJacksonMapper;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
import com.google.common.util.concurrent.Uninterruptibles;
import com.typesafe.config.Config;
import com.typesafe.config.ConfigFactory;
import com.typesafe.config.ConfigParseOptions;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.PrintStream;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.TimeUnit;

/**
 * Streams Provider which collects Page Profiles in the ID List contained in the
 * FacebookConfiguration object
 *
 * <p></p>
 * To use from command line,
 *
 * <p></p>
 * Launch using:
 *
 * <p></p>
 * mvn exec:java -Dexec.mainClass=org.apache.streams.facebook.provider.page.FacebookPageProvider -Dexec.args="application.conf pages.json"
 *
 * <p></p>
 * Supply (at least) the following required configuration in application.conf:
 *
 * <p>
 *   facebook.oauth.appId
 *   facebook.oauth.appSecret
 *   facebook.oauth.userAccessToken
 * </p>
 */
public class FacebookPageProvider extends FacebookProvider {

  public static final String STREAMS_ID = "FacebookPageProvider";

  private static final Logger LOGGER = LoggerFactory.getLogger(FacebookPageProvider.class);

  private static ObjectMapper MAPPER = StreamsJacksonMapper.getInstance();

  private FacebookPageProviderConfiguration configuration;

  public FacebookPageProvider() {
    super.configuration = new ComponentConfigurator<>(FacebookPageFeedProviderConfiguration.class).detectConfiguration();
  }

  public FacebookPageProvider(FacebookPageProviderConfiguration configuration) {
    super(configuration);
  }

  @VisibleForTesting
  BlockingQueue<StreamsDatum> getQueue() {
    return super.datums;
  }

  @Override
  protected FacebookDataCollector getDataCollector() {
    return new FacebookPageDataCollector(super.datums, super.configuration);
  }

  /**
   * Run FacebookPageProvider from command line.
   * @param args configfile outfile
   * @throws Exception Exception
   */
  public static void main(String[] args) throws Exception {

    Preconditions.checkArgument(args.length >= 2);

    String configfile = args[0];
    String outfile = args[1];

    File confFile = new File(configfile);
    assert (confFile.exists());

    Config conf = ConfigFactory.parseFileAnySyntax(confFile, ConfigParseOptions.defaults().setAllowMissing(false));
    StreamsConfigurator.addConfig(conf);

    StreamsConfiguration streamsConfiguration = StreamsConfigurator.detectConfiguration();
    FacebookPageProviderConfiguration config = new ComponentConfigurator<>(FacebookPageProviderConfiguration.class).detectConfiguration();
    FacebookPageProvider provider = new FacebookPageProvider(config);

    PrintStream outStream = new PrintStream(new BufferedOutputStream(new FileOutputStream(outfile)));
    provider.prepare(config);
    provider.startStream();
    do {
      Uninterruptibles.sleepUninterruptibly(streamsConfiguration.getBatchFrequencyMs(), TimeUnit.MILLISECONDS);
      for (StreamsDatum datum : provider.readCurrent()) {
        String json;
        try {
          json = MAPPER.writeValueAsString(datum.getDocument());
          outStream.println(json);
        } catch (JsonProcessingException ex) {
          System.err.println(ex.getMessage());
        }
      }
    }
    while ( provider.isRunning());
    provider.cleanUp();
    outStream.flush();
  }
}
