/*
 * 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.beam.examples;

import org.apache.beam.sdk.options.Description;

import org.apache.beam.sdk.Pipeline;
import org.apache.beam.sdk.extensions.gcp.options.GcpOptions;
import org.apache.beam.sdk.io.gcp.pubsub.PubsubIO;
import org.apache.beam.sdk.io.gcp.pubsub.PubsubOptions;
import org.apache.beam.sdk.options.PipelineOptions;
import org.apache.beam.sdk.options.PipelineOptionsFactory;
import org.apache.beam.sdk.transforms.Combine;
import org.apache.beam.sdk.transforms.Count;
import org.apache.beam.sdk.transforms.MapElements;
import org.apache.beam.sdk.transforms.windowing.AfterProcessingTime;
import org.apache.beam.sdk.transforms.windowing.FixedWindows;
import org.apache.beam.sdk.transforms.windowing.Repeatedly;
import org.apache.beam.sdk.transforms.windowing.Window;
import org.apache.beam.sdk.values.PCollection;
import org.apache.beam.sdk.values.TypeDescriptors;
import org.joda.time.Duration;
import org.apache.beam.sdk.options.Default;
import org.apache.beam.sdk.options.Validation.Required;
import java.util.Date;

public class Pubsub {

  public interface TestOptions extends PipelineOptions {

    /**
     * By default, this example reads from a public dataset containing the text of King Lear. Set
     * this option to choose a different input file or glob.
     */
    @Description("Path of the file to read from")
    @Default.String("gs://apache-beam-samples/shakespeare/kinglear.txt")
    String getInputFile();

    void setInputFile(String value);

    /** Set this required option to specify where to write the output. */
    @Description("Path of the file to write to")
    @Required
    String getOutput();

    void setOutput(String value);
  }

  /**
   * Send a Number to the PubSub topic one at a time... without quick updates. 2 mssages will fire ,
   * one wont.
   */
  public static void main(String[] args) {

    //GcpOptions options = PipelineOptionsFactory.create().as(PubsubOptions.class);
    TestOptions options =
        PipelineOptionsFactory.fromArgs(args).withValidation().as(TestOptions.class);
    //options.setProject("amordkov-user-project-test");

    Pipeline p = Pipeline.create(options);

    // Read
    PCollection<String> blah =
        p.apply(
            PubsubIO.readStrings().fromSubscription("projects/amordkov-user-project-test/subscriptions/slow-input"));


    // Output what we read
    blah.apply(print("Received incoming message at "));

    // Do an actual aggregation
    blah.apply(MapElements.into(TypeDescriptors.longs()).via(Long::valueOf))
        .apply(Window.into(FixedWindows.of(Duration.standardSeconds(10))))
        .apply(Combine.globally(Count.<Long>combineFn()).withoutDefaults())
        .apply(
            print(
                "Watermark trigger fired at "));

    // Do an actual aggregation without watermark trigger but process trigger
    blah.apply(MapElements.into(TypeDescriptors.longs()).via(Long::valueOf))
        .apply(
            Window.<Long>into(FixedWindows.of(Duration.standardSeconds(10)))
                .triggering(Repeatedly.forever(AfterProcessingTime.pastFirstElementInPane()))
                .withAllowedLateness(Duration.ZERO)
                .discardingFiredPanes())
        .apply(Combine.globally(Count.<Long>combineFn()).withoutDefaults())
        .apply(print("Processing time trigger fired at "));

    p.run();
  }

  public static <T> MapElements<T, String> print(String message) {
    return MapElements.into(TypeDescriptors.strings())
        .<T>via(
            x -> {
              System.out.println(message + (new Date()) + ", value = " + x);
              return "";
            });
  }
}