package discovery

import (
	"errors"
	"testing"
	"time"

	clientmodel "github.com/prometheus/client_golang/model"

	"github.com/prometheus/prometheus/config"
	"github.com/prometheus/prometheus/retrieval/discovery/marathon"
)

var marathonValidLabel = map[string]string{"prometheus": "yes"}

func newTestDiscovery(client marathon.AppListClient) (chan *config.TargetGroup, *MarathonDiscovery) {
	ch := make(chan *config.TargetGroup)
	md := NewMarathonDiscovery(&config.MarathonSDConfig{
		Servers: []string{"http://localhost:8080"},
	})
	md.client = client
	return ch, md
}

func TestMarathonSDHandleError(t *testing.T) {
	var errTesting = errors.New("testing failure")
	ch, md := newTestDiscovery(func(url string) (*marathon.AppList, error) {
		return nil, errTesting
	})
	go func() {
		select {
		case tg := <-ch:
			t.Fatalf("Got group: %s", tg)
		default:
		}
	}()
	err := md.updateServices(ch)
	if err != errTesting {
		t.Fatalf("Expected error: %s", err)
	}
}

func TestMarathonSDEmptyList(t *testing.T) {
	ch, md := newTestDiscovery(func(url string) (*marathon.AppList, error) {
		return &marathon.AppList{}, nil
	})
	go func() {
		select {
		case tg := <-ch:
			t.Fatalf("Got group: %v", tg)
		default:
		}
	}()
	err := md.updateServices(ch)
	if err != nil {
		t.Fatalf("Got error: %s", err)
	}
}

func marathonTestAppList(labels map[string]string, runningTasks int) *marathon.AppList {
	task := marathon.Task{
		ID:    "test-task-1",
		Host:  "mesos-slave1",
		Ports: []uint32{31000},
	}
	docker := marathon.DockerContainer{Image: "repo/image:tag"}
	container := marathon.Container{Docker: docker}
	app := marathon.App{
		ID:           "test-service",
		Tasks:        []marathon.Task{task},
		RunningTasks: runningTasks,
		Labels:       labels,
		Container:    container,
	}
	return &marathon.AppList{
		Apps: []marathon.App{app},
	}
}

func TestMarathonSDSendGroup(t *testing.T) {
	ch, md := newTestDiscovery(func(url string) (*marathon.AppList, error) {
		return marathonTestAppList(marathonValidLabel, 1), nil
	})
	go func() {
		select {
		case tg := <-ch:
			if tg.Source != "test-service" {
				t.Fatalf("Wrong target group name: %s", tg.Source)
			}
			if len(tg.Targets) != 1 {
				t.Fatalf("Wrong number of targets: %v", tg.Targets)
			}
			tgt := tg.Targets[0]
			if tgt[clientmodel.AddressLabel] != "mesos-slave1:31000" {
				t.Fatalf("Wrong target address: %s", tgt[clientmodel.AddressLabel])
			}
		default:
			t.Fatal("Did not get a target group.")
		}
	}()
	err := md.updateServices(ch)
	if err != nil {
		t.Fatalf("Got error: %s", err)
	}
}

func TestMarathonSDNoLabel(t *testing.T) {
	ch, md := newTestDiscovery(func(url string) (*marathon.AppList, error) {
		return marathonTestAppList(map[string]string{}, 1), nil
	})
	go func() {
		select {
		case tg := <-ch:
			t.Fatalf("Got group: %s", tg)
		default:
		}
	}()
	err := md.updateServices(ch)
	if err != nil {
		t.Fatalf("Got error: %s", err)
	}
}

func TestMarathonSDNotRunning(t *testing.T) {
	ch, md := newTestDiscovery(func(url string) (*marathon.AppList, error) {
		return marathonTestAppList(marathonValidLabel, 0), nil
	})
	go func() {
		select {
		case tg := <-ch:
			t.Fatalf("Got group: %s", tg)
		default:
		}
	}()
	err := md.updateServices(ch)
	if err != nil {
		t.Fatalf("Got error: %s", err)
	}
}

func TestMarathonSDRemoveApp(t *testing.T) {
	ch, md := newTestDiscovery(func(url string) (*marathon.AppList, error) {
		return marathonTestAppList(marathonValidLabel, 1), nil
	})
	go func() {
		up1 := <-ch
		up2 := <-ch
		if up2.Source != up1.Source {
			t.Fatalf("Source is different: %s", up2)
			if len(up2.Targets) > 0 {
				t.Fatalf("Got a non-empty target set: %s", up2.Targets)
			}
		}
	}()
	err := md.updateServices(ch)
	if err != nil {
		t.Fatalf("Got error on first update: %s", err)
	}

	md.client = func(url string) (*marathon.AppList, error) {
		return marathonTestAppList(marathonValidLabel, 0), nil
	}
	err = md.updateServices(ch)
	if err != nil {
		t.Fatalf("Got error on second update: %s", err)
	}
}

func TestMarathonSDSources(t *testing.T) {
	_, md := newTestDiscovery(func(url string) (*marathon.AppList, error) {
		return marathonTestAppList(marathonValidLabel, 1), nil
	})
	sources := md.Sources()
	if len(sources) != 1 {
		t.Fatalf("Wrong number of sources: %s", sources)
	}
}

func TestMarathonSDRunAndStop(t *testing.T) {
	ch, md := newTestDiscovery(func(url string) (*marathon.AppList, error) {
		return marathonTestAppList(marathonValidLabel, 1), nil
	})
	md.refreshInterval = time.Millisecond * 10

	go func() {
		select {
		case <-ch:
			md.Stop()
		case <-time.After(md.refreshInterval * 3):
			md.Stop()
			t.Fatalf("Update took too long.")
		}
	}()
	md.Run(ch)
	select {
	case <-ch:
	default:
		t.Fatalf("Channel not closed.")
	}
}