func (mr *RunCommand) feedRunner(runner *common.RunnerConfig, runners chan *common.RunnerConfig) {
	if !mr.isHealthy(runner.UniqueID()) {
		return
	}

	runners <- runner
}

func (n *GitLabClient) GetBuild(config common.RunnerConfig) (*common.GetBuildResponse, bool) {
	request := common.GetBuildRequest{
		Info:  n.getRunnerVersion(config),
		Token: config.Token,
	}

	var response common.GetBuildResponse
	result, statusText, certificates := n.doJSON(config.RunnerCredentials, "POST", "builds/register.json", 201, &request, &response)

	switch result {
	case 201:
		config.Log().WithFields(logrus.Fields{
			"build":    strconv.Itoa(response.ID),
			"repo_url": response.RepoCleanURL(),
		}).Println("Checking for builds...", "received")
		response.TLSCAChain = certificates
		return &response, true
	case 403:
		config.Log().Errorln("Checking for builds...", "forbidden")
		return nil, false
	case 204, 404:
		config.Log().Debugln("Checking for builds...", "nothing")
		return nil, true
	case clientError:
		config.Log().WithField("status", statusText).Errorln("Checking for builds...", "error")
		return nil, false
	default:
		config.Log().WithField("status", statusText).Warningln("Checking for builds...", "failed")
		return nil, true
	}
}

func (n *GitLabClient) UpdateBuild(config common.RunnerConfig, id int, state common.BuildState, trace *string) common.UpdateState {
	request := common.UpdateBuildRequest{
		Info:  n.getRunnerVersion(config),
		Token: config.Token,
		State: state,
		Trace: trace,
	}

	log := config.Log().WithField("build", id)

	result, statusText, _ := n.doJSON(config.RunnerCredentials, "PUT", fmt.Sprintf("builds/%d.json", id), 200, &request, nil)
	switch result {
	case 200:
		log.Debugln("Submitting build to coordinator...", "ok")
		return common.UpdateSucceeded
	case 404:
		log.Warningln("Submitting build to coordinator...", "aborted")
		return common.UpdateAbort
	case 403:
		log.WithField("status", statusText).Errorln("Submitting build to coordinator...", "forbidden")
		return common.UpdateAbort
	case clientError:
		log.WithField("status", statusText).Errorln("Submitting build to coordinator...", "error")
		return common.UpdateAbort
	default:
		log.WithField("status", statusText).Warningln("Submitting build to coordinator...", "failed")
		return common.UpdateFailed
	}
}

func (c *clientBuildTrace) resendPatch(id int, config common.RunnerConfig, buildCredentials *common.BuildCredentials, tracePatch common.BuildTracePatch) (update common.UpdateState) {
	config.Log().Warningln(id, "Resending trace patch due to range missmatch")

	update = c.client.PatchTrace(config, buildCredentials, tracePatch)
	if update == common.UpdateRangeMissmatch {
		config.Log().Errorln(id, "Appending trace to coordinator...", "failed due to range missmatch")
		update = common.UpdateFailed
	}

	return
}

func (m *machineProvider) updateMachines(machines []string, config *common.RunnerConfig) (data machinesData) {
	data.Runner = config.ShortDescription()

	for _, name := range machines {
		details := m.machineDetails(name, false)
		err := m.updateMachine(config, &data, details)
		if err != nil {
			m.remove(details.Name, err)
		}

		data.Add(details.State)
	}
	return
}

func (mr *RunCommand) processRunner(id int, runner *common.RunnerConfig, runners chan *common.RunnerConfig) (err error) {
	provider := common.GetExecutor(runner.Executor)
	if provider == nil {
		return
	}

	context, err := provider.Acquire(runner)
	if err != nil {
		log.Warningln("Failed to update executor", runner.Executor, "for", runner.ShortDescription(), err)
		return
	}
	defer provider.Release(runner, context)

	// Acquire build slot
	if !mr.buildsHelper.acquire(runner) {
		return
	}
	defer mr.buildsHelper.release(runner)

	// Receive a new build
	buildData, healthy := mr.network.GetBuild(*runner)
	mr.makeHealthy(runner.UniqueID(), healthy)
	if buildData == nil {
		return
	}

	// Make sure to always close output
	buildCredentials := &common.BuildCredentials{
		ID:    buildData.ID,
		Token: buildData.Token,
	}
	trace := mr.network.ProcessBuild(*runner, buildCredentials)
	defer trace.Fail(err)

	// Create a new build
	build := &common.Build{
		GetBuildResponse: *buildData,
		Runner:           runner,
		ExecutorData:     context,
		SystemInterrupt:  mr.abortBuilds,
	}

	// Add build to list of builds to assign numbers
	mr.buildsHelper.addBuild(build)
	defer mr.buildsHelper.removeBuild(build)

	// Process the same runner by different worker again
	// to speed up taking the builds
	select {
	case runners <- runner:
		mr.log().WithField("runner", runner.ShortDescription()).Debugln("Requeued the runner")

	default:
		mr.log().WithField("runner", runner.ShortDescription()).Debugln("Failed to requeue the runner: ")
	}

	// Process a build
	return build.Run(mr.config, trace)
}

func (m *machineProvider) Acquire(config *common.RunnerConfig) (data common.ExecutorData, err error) {
	if config.Machine == nil || config.Machine.MachineName == "" {
		err = fmt.Errorf("Missing Machine options")
		return
	}

	machines, err := m.loadMachines(config)
	if err != nil {
		return
	}

	// Lock updating machines, because two Acquires can be run at the same time
	m.acquireLock.Lock()

	// Update a list of currently configured machines
	machinesData := m.updateMachines(machines, config)

	// Pre-create machines
	m.createMachines(config, &machinesData)

	m.acquireLock.Unlock()

	logrus.WithFields(machinesData.Fields()).
		WithField("runner", config.ShortDescription()).
		WithField("minIdleCount", config.Machine.IdleCount).
		WithField("maxMachines", config.Limit).
		WithField("time", time.Now()).
		Debugln("Docker Machine Details")
	machinesData.writeDebugInformation()

	// Try to find a free machine
	details := m.findFreeMachine(machines...)
	if details != nil {
		data = details
		return
	}

	// If we have a free machines we can process a build
	if config.Machine.IdleCount != 0 && machinesData.Idle == 0 {
		err = errors.New("No free machines that can process builds")
	}
	return
}

func (n *GitLabClient) PatchTrace(config common.RunnerConfig, buildCredentials *common.BuildCredentials, tracePatch common.BuildTracePatch) common.UpdateState {
	id := buildCredentials.ID

	contentRange := fmt.Sprintf("%d-%d", tracePatch.Offset(), tracePatch.Limit())
	headers := make(http.Header)
	headers.Set("Content-Range", contentRange)
	headers.Set("BUILD-TOKEN", buildCredentials.Token)
	uri := fmt.Sprintf("builds/%d/trace.txt", id)
	request := bytes.NewReader(tracePatch.Patch())

	response, err := n.doRaw(config.RunnerCredentials, "PATCH", uri, request, "text/plain", headers)
	if err != nil {
		config.Log().Errorln("Appending trace to coordinator...", "error", err.Error())
		return common.UpdateFailed
	}

	defer response.Body.Close()
	defer io.Copy(ioutil.Discard, response.Body)

	remoteState := response.Header.Get("Build-Status")
	remoteRange := response.Header.Get("Range")
	log := config.Log().WithFields(logrus.Fields{
		"build":        id,
		"sent-log":     contentRange,
		"build-log":    remoteRange,
		"build-status": remoteState,
		"code":         response.StatusCode,
		"status":       response.Status,
	})

	if remoteState == "canceled" {
		log.Warningln("Appending trace to coordinator", "aborted")
		return common.UpdateAbort
	}

	switch response.StatusCode {
	case 202:
		log.Debugln("Appending trace to coordinator...", "ok")
		return common.UpdateSucceeded
	case 404:
		log.Warningln("Appending trace to coordinator...", "not-found")
		return common.UpdateNotFound
	case 406:
		log.Errorln("Appending trace to coordinator...", "forbidden")
		return common.UpdateAbort
	case 416:
		log.Warningln("Appending trace to coordinator...", "range missmatch")

		remoteRange := strings.Split(remoteRange, "-")
		newOffset, _ := strconv.Atoi(remoteRange[1])
		tracePatch.SetNewOffset(newOffset)

		return common.UpdateRangeMissmatch
	case clientError:
		log.Errorln("Appending trace to coordinator...", "error")
		return common.UpdateAbort
	default:
		log.Warningln("Appending trace to coordinator...", "failed")
		return common.UpdateFailed
	}
}

func machineFilter(config *common.RunnerConfig) string {
	return machineFormat(config.ShortDescription(), config.Machine.MachineName)
}