/*
 * Copyright 2016-2019 the original author or authors.
 *
 * 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
 *
 *      https://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 io.spring.cloud;

import java.util.Arrays;
import java.util.List;

import org.springframework.batch.core.Job;
import org.springframework.batch.core.Step;
import org.springframework.batch.core.StepContribution;
import org.springframework.batch.core.configuration.annotation.EnableBatchProcessing;
import org.springframework.batch.core.configuration.annotation.JobBuilderFactory;
import org.springframework.batch.core.configuration.annotation.StepBuilderFactory;
import org.springframework.batch.core.scope.context.ChunkContext;
import org.springframework.batch.core.step.tasklet.Tasklet;
import org.springframework.batch.item.ItemProcessor;
import org.springframework.batch.item.ItemWriter;
import org.springframework.batch.item.support.ListItemReader;
import org.springframework.batch.repeat.RepeatStatus;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.task.configuration.EnableTask;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@EnableTask
@SpringBootApplication
@EnableBatchProcessing
public class BatchEventsApplication {

	public static void main(String[] args) {
		SpringApplication.run(BatchEventsApplication.class, args);
	}

	@Configuration
	public static class JobConfiguration {

		private static final int DEFAULT_CHUNK_COUNT = 3;

		@Autowired
		private JobBuilderFactory jobBuilderFactory;

		@Autowired
		private StepBuilderFactory stepBuilderFactory;

		@Bean
		public Step step1() {
			return this.stepBuilderFactory.get("step1")
				.tasklet(new Tasklet() {
					@Override
					public RepeatStatus execute(StepContribution contribution, ChunkContext chunkContext) throws Exception {
						System.out.println("Tasklet has run");
						return RepeatStatus.FINISHED;
					}
				}).build();
		}

		@Bean
		public Step step2() {
			return this.stepBuilderFactory.get("step2")
				.<String, String>chunk(DEFAULT_CHUNK_COUNT)
				.reader(new ListItemReader<>(Arrays.asList("1", "2", "3", "4", "5", "6")))
				.processor(new ItemProcessor<String, String>() {
					@Override
					public String process(String item) throws Exception {
						return String.valueOf(Integer.parseInt(item) * -1);
					}
				})
				.writer(new ItemWriter<String>() {
					@Override
					public void write(List<? extends String> items) throws Exception {
						for (String item : items) {
							System.out.println(">> " + item);
						}
					}
				}).build();
		}

		@Bean
		public Job job() {
			return this.jobBuilderFactory.get("job")
				.start(step1())
				.next(step2())
				.build();
		}
	}
}
