/*
 * Copyright 2013-2014 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
 *
 *      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.springframework.batch.core.jsr.job.flow;

import org.springframework.batch.core.ExitStatus;
import org.springframework.batch.core.JobExecution;
import org.springframework.batch.core.JobExecutionException;
import org.springframework.batch.core.JobInterruptedException;
import org.springframework.batch.core.Step;
import org.springframework.batch.core.configuration.xml.SimpleFlowFactoryBean.DelegateState;
import org.springframework.batch.core.explore.JobExplorer;
import org.springframework.batch.core.job.AbstractJob;
import org.springframework.batch.core.job.flow.Flow;
import org.springframework.batch.core.job.flow.FlowExecutionException;
import org.springframework.batch.core.job.flow.FlowJob;
import org.springframework.batch.core.job.flow.JobFlowExecutor;
import org.springframework.batch.core.job.flow.State;
import org.springframework.batch.core.job.flow.support.state.FlowState;
import org.springframework.batch.core.jsr.job.JsrStepHandler;
import org.springframework.batch.core.jsr.job.flow.support.JsrFlow;
import org.springframework.batch.core.jsr.job.flow.support.state.JsrStepState;
import org.springframework.batch.core.jsr.step.DecisionStep;
import org.springframework.batch.core.launch.NoSuchJobException;
import org.springframework.batch.core.launch.support.ExitCodeMapper;

/**
 * JSR-352 specific extension of the {@link FlowJob}.
 *
 * @author Michael Minella
 * @since 3.0
 */
public class JsrFlowJob extends FlowJob {

	private JobExplorer jobExplorer;

	/**
	 * No arg constructor (invalid state)
	 */
	public JsrFlowJob() {
		super();
	}

	/**
	 * Main constructor
	 *
	 * @param name of the flow
	 */
	public JsrFlowJob(String name) {
		super(name);
	}

	public void setJobExplorer(JobExplorer jobExplorer) {
		this.jobExplorer = jobExplorer;
	}

	/**
	 * @see AbstractJob#doExecute(JobExecution)
	 */
	@Override
	protected void doExecute(final JobExecution execution) throws JobExecutionException {
		try {
			JobFlowExecutor executor = new JsrFlowExecutor(getJobRepository(),
					new JsrStepHandler(getJobRepository(), jobExplorer), execution);

			State startState = ((JsrFlow)flow).getStartState();

			validateFirstStep(startState);

			executor.updateJobExecutionStatus(flow.start(executor).getStatus());
		}
		catch (FlowExecutionException e) {
			if (e.getCause() instanceof JobExecutionException) {
				throw (JobExecutionException) e.getCause();
			}
			throw new JobExecutionException("Flow execution ended unexpectedly", e);
		}
	}

	private void validateFirstStep(State startState)
			throws JobExecutionException {
		while(true) {
			if(startState instanceof DelegateState) {
				startState = ((DelegateState) startState).getState();
			} else if(startState instanceof JsrStepState) {
				String stepName = startState.getName().substring(startState.getName().indexOf(".") + 1, startState.getName().length());
				Step step = ((JsrStepState) startState).getStep(stepName);
				if(step instanceof DecisionStep) {
					throw new JobExecutionException("Decision step is an invalid first step");
				} else {
					break;
				}
			} else if(startState instanceof FlowState){
				Flow firstFlow = ((FlowState) startState).getFlows().iterator().next();
				startState = firstFlow.getStates().iterator().next();
			} else {
				break;
			}
		}
	}

	/**
	 * Default mapping from throwable to {@link ExitStatus}.
	 *
	 * @param ex the cause of the failure
	 * @return an {@link ExitStatus}
	 */
	@Override
	protected ExitStatus getDefaultExitStatusForFailure(Throwable ex, JobExecution execution) {
		if(!ExitStatus.isNonDefaultExitStatus(execution.getExitStatus())) {
			return execution.getExitStatus();
		} else {
			ExitStatus exitStatus;
			if (ex instanceof JobInterruptedException
					|| ex.getCause() instanceof JobInterruptedException) {
				exitStatus = ExitStatus.STOPPED
						.addExitDescription(JobInterruptedException.class.getName());
			} else if (ex instanceof NoSuchJobException
					|| ex.getCause() instanceof NoSuchJobException) {
				exitStatus = new ExitStatus(ExitCodeMapper.NO_SUCH_JOB, ex
						.getClass().getName());
			} else {
				exitStatus = ExitStatus.FAILED.addExitDescription(ex);
			}

			return exitStatus;
		}
	}
}