func (e *Engine) waitCloseOutputCh(stage stages.Stage) {
	for {
		receive, ok := <-*stage.GetOutputCh()
		if !ok {
			log.Debugf("outputCh closed")
			break
		}
		log.Debugf("outputCh received  %+v\n", receive)
	}
}

//Execute executes a stage using the supplied mediator
func (e *Engine) Execute(stage stages.Stage, mediator stages.Mediator) stages.Mediator {
	mediator.Type = "start"
	name := stage.GetStageName()
	log.Debugf("----- Execute %v start ------\n", name)

	go func() {
		*stage.GetInputCh() <- mediator
		close(*stage.GetInputCh())
	}()

	go e.ExecuteStage(stage)
	e.waitCloseOutputCh(stage)
	return e.waitMonitorChFinalized(name)
}

func execute(stage stages.Stage) stages.Mediator {
	mon := make(chan stages.Mediator)
	e := &Engine{
		MonitorCh: &mon,
		Resources: &pipelines.Resources{
			Reporter: &messengers.FakeMessenger{},
		},
		EnvVariables: config.NewEnvVariables(),
	}

	go e.ExecuteStage(stage)

	mediator := stages.Mediator{States: make(map[string]string), Type: "start"}
	go func() {
		*stage.GetInputCh() <- mediator
		close(*stage.GetInputCh())
	}()

	for {
		_, ok := <-*stage.GetOutputCh()
		if !ok {
			break
		}
	}

	var m stages.Mediator
	acm := stages.Mediator{States: make(map[string]string)}
	for {
		m = <-mon
		for k, v := range m.States {
			acm.States[k] = v
		}
		if m.Type == "end" {
			break
		}
	}
	return acm
}

// ExecuteStage executes the supplied stage
func (e *Engine) ExecuteStage(stage stages.Stage) {
	log.Debug("Receiving input")
	mediatorsReceived := e.receiveInputs(stage.GetInputCh())

	log.Debugf("Received input size: %v", len(mediatorsReceived))
	log.Debugf("Mediator received: %+v", mediatorsReceived)
	log.Debugf("Execute as parent: %+v", stage)
	log.Debugf("Execute as parent name %+v", stage.GetStageName())

	mediator := stages.Mediator{States: make(map[string]string)}
	mediator.States[stage.GetStageName()] = e.executeStage(stage, mediatorsReceived)
	e.executeChildStages(&stage, &mediator)

	log.Debugf("Sending output of stage: %+v %v", stage.GetStageName(), mediator)
	*stage.GetOutputCh() <- mediator
	close(*stage.GetOutputCh())
	log.Debugf("Closed output of stage: %+v", stage.GetStageName())

	e.finalizeMonitorChAfterExecute(mediatorsReceived, mediator)
}

func (e *Engine) executeStage(stage stages.Stage, received []stages.Mediator) string {
	var result string
	if !e.isUpstreamAnyFailure(received) || e.Opts.StopOnAnyFailure {
		result = strconv.FormatBool(stage.(stages.Runner).Run())
		e.EnvVariables.ExportSpecialVariable("__OUT[\""+stage.GetStageName()+"\"]", stage.GetOutResult())
		e.EnvVariables.ExportSpecialVariable("__ERR[\""+stage.GetStageName()+"\"]", stage.GetErrResult())
		e.EnvVariables.ExportSpecialVariable("__RESULT[\""+stage.GetStageName()+"\"]", result)
	} else {
		log.Warnf("Execution is skipped: %v", stage.GetStageName())
		result = "skipped"
	}
	e.Resources.ReportStageResult(stage, result)
	log.Debugf("Stage execution results: %+v, %+v", stage.GetStageName(), result)
	return result
}

// ReportStageResult throw the results of specified stage to the messenger services.
func (resources *Resources) ReportStageResult(stage stages.Stage, resultStr string) {
	name := stage.GetStageName()
	if !resources.Reporter.Suppress("result") {
		if resultStr == "true" {
			resources.Reporter.Post(
				fmt.Sprintf("[%s][RESULT] Succeeded", name))
		} else if resultStr == "skipped" {
			resources.Reporter.Post(
				fmt.Sprintf("[%s][RESULT] Skipped", name))
		} else {
			resources.Reporter.Post(
				fmt.Sprintf("[%s][RESULT] Failed", name))
		}
	}

	if stage.GetStageOpts().ReportingFullOutput {
		if out := stage.GetOutResult(); (len(out) > 0) && (!resources.Reporter.Suppress("stdout")) {
			resources.Reporter.Post(
				fmt.Sprintf("[%s][STDOUT] %s", name, stage.GetOutResult()))
		}
		if err := stage.GetErrResult(); len(err) > 0 && (!resources.Reporter.Suppress("stderr")) {
			resources.Reporter.Post(
				fmt.Sprintf("[%s][STDERR] %s", name, stage.GetErrResult()))
		}
	}
}

func (e *Engine) executeStage(stage stages.Stage, received []stages.Mediator, mediator stages.Mediator) string {
	var result string
	if !e.isUpstreamAnyFailure(received) || e.Opts.StopOnAnyFailure {
		result = strconv.FormatBool(stage.(stages.Runner).Run())
		e.EnvVariables.ExportSpecialVariable("__OUT[\""+stage.GetStageName()+"\"]", stage.GetOutResult())
		e.EnvVariables.ExportSpecialVariable("__ERR[\""+stage.GetStageName()+"\"]", stage.GetErrResult())
		e.EnvVariables.ExportSpecialVariable("__COMBINED[\""+stage.GetStageName()+"\"]", stage.GetCombinedResult())
		e.EnvVariables.ExportSpecialVariable("__RESULT[\""+stage.GetStageName()+"\"]", result)
		e.executeChildStages(&stage, &mediator)
	} else {
		log.Warnf("Execution is skipped: %v", stage.GetStageName())
		if childStages := stage.GetChildStages(); childStages.Len() > 0 {
			for childStage := childStages.Front(); childStage != nil; childStage = childStage.Next() {
				log.Warnf("Execution of child stage is skipped: %v", childStage.Value.(stages.Stage).GetStageName())
			}
		}
		result = "skipped"
	}
	if !stage.GetSuppressAll() {
		e.Resources.ReportStageResult(stage, result)
	}
	log.Debugf("Stage execution results: %+v, %+v", stage.GetStageName(), result)
	return result
}