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

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

	go e.ExecuteStage(stage)

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

	var receives = make([]stages.Mediator, 0)
	for {
		receive := <-*monitorCh
		receives = append(receives, receive)
		if receive.Type == "end" {
			log.Debugf("monitorCh closed")
			log.Debugf("monitorCh last received:  %+v\n", receive)
			log.Debugf("----- Execute %v done ------\n\n", name)
			return e.bindReceives(&receives)
		}
		log.Debugf("monitorCh received  %+v\n", receive)
	}
}

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

	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
}

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

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

// 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())

	var result string
	if !e.isUpstreamAnyFailure(mediatorsReceived) || e.Opts.StopOnAnyFailure {
		result = strconv.FormatBool(stage.(stages.Runner).Run())
	} else {
		log.Warnf("Execution is skipped: %v", stage.GetStageName())
		result = "skipped"
	}
	log.Debugf("Stage execution results: %+v, %+v", stage.GetStageName(), result)
	e.Resources.ReportStageResult(stage, result)

	mediator := stages.Mediator{States: make(map[string]string)}
	mediator.States[stage.GetStageName()] = result

	if childStages := stage.GetChildStages(); childStages.Len() > 0 {
		log.Debugf("Execute childstage: %v", childStages)
		e.executeAllChildStages(&childStages, mediator)
		e.waitAllChildStages(&childStages, &stage)
	}

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

	for _, m := range mediatorsReceived {
		*e.MonitorCh <- m
	}
	*e.MonitorCh <- mediator

	e.finalizeMonitorChAfterExecute(mediatorsReceived)
}