/*
    * Copyright 2009-2010 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.admin.jmx;
  
  import java.util.Collection;
  import java.util.Date;
  
  import org.springframework.batch.admin.domain.StepExecutionHistory;
  import org.springframework.batch.admin.service.JobService;
  import org.springframework.batch.core.StepExecution;
  import org.springframework.jmx.export.annotation.ManagedResource;
  
  @ManagedResource
  public class SimpleStepExecutionMetrics implements StepExecutionMetrics {
  
  	private final JobService jobService;
  
  	private final String stepName;
  
  	private final String jobName;
  
  	public SimpleStepExecutionMetrics(JobService jobService, String jobName, String stepName) {
  		this.jobService = jobService;
  		this.jobName = jobName;
  		this.stepName = stepName;
  	}
  
  	public int getExecutionCount() {
  		return jobService.countStepExecutionsForStep(jobName, stepName);
  	}
  
  	public int getFailureCount() {
  		int count = 0;
  		int start = 0;
  		int pageSize = 100;
  		Collection<StepExecution> stepExecutions;
  		do {
  			stepExecutions = jobService.listStepExecutionsForStep(jobName, stepName, start, pageSize);
  			start += pageSize;
  			for (StepExecution stepExecution : stepExecutions) {
  				if (stepExecution.getStatus().isUnsuccessful()) {
  					count++;
  				}
  			}
  		} while (!stepExecutions.isEmpty());
  		return count;
  	}
  
  	public double getLatestDuration() {
  		StepExecution stepExecution = getLatestStepExecution(stepName);
  		if (stepExecution==null) {
  			return 0;
  		}
  		Date endTime = stepExecution.getEndTime();
  		return (endTime != null ? endTime.getTime() : System.currentTimeMillis())
  				- stepExecution.getStartTime().getTime();
  	}
  
  	public double getMeanDuration() {
  		StepExecutionHistory history = computeHistory(stepName);
  		return history.getDuration().getMean();
  	}
  
  	public double getMaxDuration() {
  		StepExecutionHistory history = computeHistory(stepName);
  		return history.getDuration().getMax();
  	}
  
  	public int getLatestReadCount() {
  		StepExecution stepExecution = getLatestStepExecution(stepName);
  		return stepExecution == null ? 0 : stepExecution.getReadCount();
  	}
  
  	public int getLatestWriteCount() {
  		StepExecution stepExecution = getLatestStepExecution(stepName);
  		return stepExecution == null ? 0 : stepExecution.getWriteCount();
  	}
  
  	public int getLatestFilterCount() {
  		StepExecution stepExecution = getLatestStepExecution(stepName);
  		return stepExecution == null ? 0 : stepExecution.getFilterCount();
  	}
  
  	public int getLatestSkipCount() {
  		StepExecution stepExecution = getLatestStepExecution(stepName);
  		return stepExecution == null ? 0 : stepExecution.getSkipCount();
 	}
 
 	public int getLatestCommitCount() {
 		StepExecution stepExecution = getLatestStepExecution(stepName);
 		return stepExecution == null ? 0 : stepExecution.getCommitCount();
 	}
 
 	public int getLatestRollbackCount() {
 		StepExecution stepExecution = getLatestStepExecution(stepName);
 		return stepExecution == null ? 0 : stepExecution.getRollbackCount();
 	}
 
 	public long getLatestExecutionId() {
 		StepExecution stepExecution = getLatestStepExecution(stepName);
 		return stepExecution == null ? -1 : stepExecution.getId();
 	}
 
 	public String getLatestStatus() {
 		StepExecution stepExecution = getLatestStepExecution(stepName);
 		return stepExecution == null ? "NON" : stepExecution.getStatus().toString();
 	}
 
 	public String getLatestExitCode() {
 		StepExecution stepExecution = getLatestStepExecution(stepName);
 		return stepExecution == null ? "NONE" : stepExecution.getExitStatus().getExitCode();
 	}
 
 	public String getLatestExitDescription() {
 		StepExecution stepExecution = getLatestStepExecution(stepName);
 		return stepExecution == null ? "" : stepExecution.getExitStatus().getExitDescription();
 	}
 
 	private StepExecutionHistory computeHistory(String stepName) {
 		// Running average over last 10 executions...
 		return computeHistory(stepName, 10);
 	}
 
 	private StepExecution getLatestStepExecution(String stepName) {
 		// On the cautious side: grab the last 4 executions by ID and look for
 		// the one that was last started...
 		Collection<StepExecution> stepExecutions = jobService.listStepExecutionsForStep(jobName, stepName, 0, 4);
 		if (stepExecutions.isEmpty()) {
 			return null;
 		}
 		long lastUpdated = 0L;
 		StepExecution result = null;
 		for (StepExecution stepExecution : stepExecutions) {
 			long updated = stepExecution.getStartTime().getTime();
 			if (updated > lastUpdated) {
 				result = stepExecution;
 				lastUpdated = updated;
 			}
 		}
 		return result;
 	}
 
 	private StepExecutionHistory computeHistory(String stepName, int total) {
 		StepExecutionHistory stepExecutionHistory = new StepExecutionHistory(stepName);
 		for (StepExecution stepExecution : jobService.listStepExecutionsForStep(jobName, stepName, 0, total)) {
 			stepExecutionHistory.append(stepExecution);
 		}
 		return stepExecutionHistory;
 	}
 
 }