content: /*
   * 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 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 org.apache.camel.component.slack;
  
  import java.io.IOException;
  import java.util.Collections;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Queue;
  
  import com.slack.api.Slack;
  import com.slack.api.SlackConfig;
  import com.slack.api.methods.SlackApiException;
  import com.slack.api.methods.response.conversations.ConversationsHistoryResponse;
  import com.slack.api.methods.response.conversations.ConversationsListResponse;
  import com.slack.api.model.Conversation;
  import com.slack.api.model.Message;
  import com.slack.api.util.http.SlackHttpClient;
  import org.apache.camel.AsyncCallback;
  import org.apache.camel.Exchange;
  import org.apache.camel.ExchangePropertyKey;
  import org.apache.camel.Processor;
  import org.apache.camel.RuntimeCamelException;
  import org.apache.camel.component.slack.helper.SlackHelper;
  import org.apache.camel.support.ScheduledBatchPollingConsumer;
  import org.apache.camel.util.CastUtils;
  import org.apache.camel.util.ObjectHelper;
  
  public class SlackConsumer extends ScheduledBatchPollingConsumer {
  
      public static final long DEFAULT_CONSUMER_DELAY = 10 * 1000L;
  
      private static final int CONVERSATIONS_LIST_LIMIT = 200;
      private final SlackEndpoint slackEndpoint;
      private Slack slack;
      private String timestamp;
      private String channelId;
  
      public SlackConsumer(SlackEndpoint endpoint, Processor processor) {
          super(endpoint, processor);
          this.slackEndpoint = endpoint;
      }
  
      @Override
      protected void doStart() throws Exception {
          SlackConfig config = SlackHelper.createSlackConfig(slackEndpoint.getServerUrl());
          SlackHttpClient client = new SlackHttpClient();
          this.slack = Slack.getInstance(config, client);
          this.channelId = getChannelId(slackEndpoint.getChannel(), null);
          super.doStart();
      }
  
      @Override
      protected void doStop() throws Exception {
          super.doStop();
          if (slack != null) {
              slack.close();
          }
      }
  
      @Override
      protected int poll() throws Exception {
          // Maximum limit is 1000. Slack recommends no more than 200 results at a time.
          // https://api.slack.com/methods/conversations.history
          // We set the limit to 1 the first call to set the timestamp of the last message of the history
          ConversationsHistoryResponse response = slack.methods(slackEndpoint.getToken()).conversationsHistory(req -> req
                  .channel(channelId)
                  .oldest(timestamp)
                  .limit(timestamp != null ? Integer.parseInt(slackEndpoint.getMaxResults()) : 1));
  
          if (!response.isOk()) {
              throw new RuntimeCamelException("API request conversations.history to Slack failed: " + response);
          }
  
          // okay we have some response from slack so lets mark the consumer as ready
          forceConsumerAsReady();
  
          Queue<Exchange> exchanges = createExchanges(response.getMessages());
          return processBatch(CastUtils.cast(exchanges));
      }
  
      private Queue<Exchange> createExchanges(final List<Message> list) {
          Queue<Exchange> answer = new LinkedList<>();
          if (ObjectHelper.isNotEmpty(list)) {
              if (slackEndpoint.isNaturalOrder()) {
                  for (int i = list.size() - 1; i >= 0; i--) {
                      Message message = list.get(i);
                      if (i == 0) {
                          timestamp = message.getTs();
                      }
                      Exchange exchange = createExchange(message);
                      answer.add(exchange);
                  }
              } else {
                  for (int i = 0; i < list.size(); i++) {
                      Message message = list.get(i);
                      if (i == 0) {
                          timestamp = message.getTs();
                      }
                      Exchange exchange = createExchange(message);
                      answer.add(exchange);
                  }
              }
          }
          return answer;
      }
  
      @Override
      public int processBatch(Queue<Object> exchanges) throws Exception {
          int total = exchanges.size();
  
          for (int index = 0; index < total && isBatchAllowed(); index++) {
              // only loop if we are started (allowed to run)
              final Exchange exchange = ObjectHelper.cast(Exchange.class, exchanges.poll());
              // add current index and total as properties
              exchange.setProperty(ExchangePropertyKey.BATCH_INDEX, index);
              exchange.setProperty(ExchangePropertyKey.BATCH_SIZE, total);
              exchange.setProperty(ExchangePropertyKey.BATCH_COMPLETE, index == total - 1);
  
              // update pending number of exchanges
              pendingExchanges = total - index - 1;
  
              // use default consumer callback
              AsyncCallback cb = defaultConsumerCallback(exchange, true);
              getAsyncProcessor().process(exchange, cb);
          }
  
          return total;
      }
  
      private String getChannelId(final String channel, final String cursor) {
          try {
              // Maximum limit is 1000. Slack recommends no more than 200 results at a time.
              // https://api.slack.com/methods/conversations.list
              ConversationsListResponse response = slack.methods(slackEndpoint.getToken()).conversationsList(req -> req
                      .types(Collections.singletonList(slackEndpoint.getConversationType()))
                      .cursor(cursor)
                      .limit(CONVERSATIONS_LIST_LIMIT));
  
              if (!response.isOk()) {
                  throw new RuntimeCamelException("API request conversations.list to Slack failed: " + response);
              }
  
              return response.getChannels().stream()
                      .filter(it -> it.getName().equals(channel))
                      .map(Conversation::getId)
                      .findFirst().orElseGet(() -> {
                          if (ObjectHelper.isEmpty(response.getResponseMetadata().getNextCursor())) {
                              throw new RuntimeCamelException(String.format("Channel %s not found", channel));
                          }
                          return getChannelId(channel, response.getResponseMetadata().getNextCursor());
                      });
          } catch (IOException | SlackApiException e) {
              throw new RuntimeCamelException("API request conversations.list to Slack failed", e);
          }
      }
  
      private Exchange createExchange(Message object) {
          Exchange exchange = createExchange(true);
          exchange.getIn().setBody(object);
          return exchange;
      }
  }
  