// Copyright 2015 Prometheus Team
// 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 notify

import (
	"fmt"
	"reflect"
	"testing"
	"time"

	"github.com/prometheus/common/model"
	"golang.org/x/net/context"

	"github.com/prometheus/alertmanager/provider"
	"github.com/prometheus/alertmanager/types"
)

type recordNotifier struct {
	ctx    context.Context
	alerts []*types.Alert
}

func (n *recordNotifier) Notify(ctx context.Context, as ...*types.Alert) error {
	n.ctx = ctx
	n.alerts = append(n.alerts, as...)
	return nil
}

type failNotifier struct{}

func (n *failNotifier) Notify(ctx context.Context, as ...*types.Alert) error {
	return fmt.Errorf("some error")
}

func TestDedupingNotifierHasUpdate(t *testing.T) {
	var (
		n        = &DedupingNotifier{}
		now      = time.Now()
		interval = 100 * time.Minute
	)
	cases := []struct {
		inAlert      *types.Alert
		inNotifyInfo *types.NotifyInfo
		result       bool
	}{
		// A new alert about which there's no previous notification information.
		{
			inAlert: &types.Alert{
				Alert: model.Alert{
					Labels:   model.LabelSet{"alertname": "a"},
					StartsAt: now.Add(-10 * time.Minute),
				},
			},
			inNotifyInfo: nil,
			result:       true,
		},
		// A new alert about which there's no previous notification information.
		// It is already resolved, so there's no use in sending a notification.
		{
			inAlert: &types.Alert{
				Alert: model.Alert{
					Labels:   model.LabelSet{"alertname": "a"},
					StartsAt: now.Add(-10 * time.Minute),
					EndsAt:   now,
				},
			},
			inNotifyInfo: nil,
			result:       false,
		},
		// An alert that has been firing is now resolved for the first time.
		{
			inAlert: &types.Alert{
				Alert: model.Alert{
					Labels:   model.LabelSet{"alertname": "a"},
					StartsAt: now.Add(-10 * time.Minute),
					EndsAt:   now,
				},
			},
			inNotifyInfo: &types.NotifyInfo{
				Alert:     model.LabelSet{"alertname": "a"}.Fingerprint(),
				Resolved:  false,
				Timestamp: now.Add(-time.Minute),
			},
			result: true,
		},
		// A resolved alert for which we have already sent a resolved notification.
		{
			inAlert: &types.Alert{
				Alert: model.Alert{
					Labels:   model.LabelSet{"alertname": "a"},
					StartsAt: now.Add(-10 * time.Minute),
					EndsAt:   now,
				},
			},
			inNotifyInfo: &types.NotifyInfo{
				Alert:     model.LabelSet{"alertname": "a"}.Fingerprint(),
				Resolved:  true,
				Timestamp: now.Add(-time.Minute),
			},
			result: false,
		},
		// An alert that was resolved last time but is now firing again.
		{
			inAlert: &types.Alert{
				Alert: model.Alert{
					Labels:   model.LabelSet{"alertname": "a"},
					StartsAt: now.Add(-3 * time.Minute),
				},
			},
			inNotifyInfo: &types.NotifyInfo{
				Alert:     model.LabelSet{"alertname": "a"}.Fingerprint(),
				Resolved:  true,
				Timestamp: now.Add(-4 * time.Minute),
			},
			result: true,
		},
		// A firing alert about which we already notified. The last notification
		// is less than the repeat interval ago.
		{
			inAlert: &types.Alert{
				Alert: model.Alert{
					Labels:   model.LabelSet{"alertname": "a"},
					StartsAt: now.Add(-10 * time.Minute),
				},
			},
			inNotifyInfo: &types.NotifyInfo{
				Alert:     model.LabelSet{"alertname": "a"}.Fingerprint(),
				Resolved:  false,
				Timestamp: now.Add(-15 * time.Minute),
			},
			result: false,
		},
		// A firing alert about which we already notified. The last notification
		// is more than the repeat interval ago.
		{
			inAlert: &types.Alert{
				Alert: model.Alert{
					Labels:   model.LabelSet{"alertname": "a"},
					StartsAt: now.Add(-10 * time.Minute),
				},
			},
			inNotifyInfo: &types.NotifyInfo{
				Alert:     model.LabelSet{"alertname": "a"}.Fingerprint(),
				Resolved:  false,
				Timestamp: now.Add(-115 * time.Minute),
			},
			result: true,
		},
	}

	for i, c := range cases {
		if n.hasUpdate(c.inAlert, c.inNotifyInfo, now, interval) != c.result {
			t.Errorf("unexpected hasUpdates result for case %d", i)
		}
	}
}

func TestDedupingNotifier(t *testing.T) {
	var (
		record   = &recordNotifier{}
		notifies = provider.NewMemNotifies(provider.NewMemData())
		deduper  = Dedup(notifies, record)
		ctx      = context.Background()
	)
	now := time.Now()

	ctx = WithReceiver(ctx, "name")
	ctx = WithRepeatInterval(ctx, time.Duration(100*time.Minute))
	ctx = WithNow(ctx, now)

	alerts := []*types.Alert{
		{
			Alert: model.Alert{
				Labels: model.LabelSet{"alertname": "0"},
			},
		}, {
			Alert: model.Alert{
				Labels: model.LabelSet{"alertname": "1"},
				EndsAt: now.Add(-5 * time.Minute),
			},
		},
	}

	// Set an initial NotifyInfo to ensure that on notification failure
	// nothing changes.
	nsBefore := []*types.NotifyInfo{
		nil,
		{
			Alert:     alerts[1].Fingerprint(),
			Receiver:  "name",
			Resolved:  false,
			Timestamp: now.Add(-10 * time.Minute),
		},
	}

	if err := notifies.Set(nsBefore...); err != nil {
		t.Fatalf("Setting notifies failed: %s", err)
	}

	deduper.notifier = &failNotifier{}
	if err := deduper.Notify(ctx, alerts...); err == nil {
		t.Fatalf("Fail notifier did not fail")
	}
	// After a failing notify the notifies data must be unchanged.
	nsCur, err := notifies.Get("name", alerts[0].Fingerprint(), alerts[1].Fingerprint())
	if err != nil {
		t.Fatalf("Error getting notify info: %s", err)
	}
	if !reflect.DeepEqual(nsBefore, nsCur) {
		t.Fatalf("Notify info data has changed unexpectedly")
	}

	deduper.notifier = record
	if err := deduper.Notify(ctx, alerts...); err != nil {
		t.Fatalf("Notify failed: %s", err)
	}

	if !reflect.DeepEqual(record.alerts, alerts) {
		t.Fatalf("Expected alerts %v, got %v", alerts, record.alerts)
	}
	nsCur, err = notifies.Get("name", alerts[0].Fingerprint(), alerts[1].Fingerprint())
	if err != nil {
		t.Fatalf("Error getting notifies: %s", err)
	}

	nsAfter := []*types.NotifyInfo{
		{
			Alert:     alerts[0].Fingerprint(),
			Receiver:  "name",
			Resolved:  false,
			Timestamp: now,
		},
		{
			Alert:     alerts[1].Fingerprint(),
			Receiver:  "name",
			Resolved:  true,
			Timestamp: now,
		},
	}

	for i, after := range nsAfter {
		cur := nsCur[i]

		// Hack correct timestamps back in if they are sane.
		if cur != nil && after.Timestamp.IsZero() {
			if cur.Timestamp.Before(now) {
				t.Fatalf("Wrong timestamp for notify %v", cur)
			}
			after.Timestamp = cur.Timestamp
		}

		if !reflect.DeepEqual(after, cur) {
			t.Errorf("Unexpected notifies, expected: %v, got: %v", after, cur)
		}
	}
}

func TestRoutedNotifier(t *testing.T) {
	router := Router{
		"1": &recordNotifier{},
		"2": &recordNotifier{},
		"3": &recordNotifier{},
	}

	for _, route := range []string{"3", "2", "1"} {
		var (
			ctx   = WithReceiver(context.Background(), route)
			alert = &types.Alert{
				Alert: model.Alert{
					Labels: model.LabelSet{"route": model.LabelValue(route)},
				},
			}
		)
		err := router.Notify(ctx, alert)
		if err != nil {
			t.Fatal(err)
		}

		rn := router[route].(*recordNotifier)
		if len(rn.alerts) != 1 && alert != rn.alerts[0] {
			t.Fatalf("Expeceted alert %v, got %v", alert, rn.alerts)
		}
	}
}

func TestSilenceNotifier(t *testing.T) {
	// Mute all label sets that have a "mute" key.
	muter := types.MuteFunc(func(lset model.LabelSet) bool {
		_, ok := lset["mute"]
		return ok
	})

	marker := types.NewMarker()
	record := &recordNotifier{}
	silenceNotifer := Silence(muter, record, marker)

	in := []model.LabelSet{
		{},
		{"test": "set"},
		{"mute": "me"},
		{"foo": "bar", "test": "set"},
		{"foo": "bar", "mute": "me"},
		{},
		{"not": "muted"},
	}
	out := []model.LabelSet{
		{},
		{"test": "set"},
		{"foo": "bar", "test": "set"},
		{},
		{"not": "muted"},
	}

	var inAlerts []*types.Alert
	for _, lset := range in {
		inAlerts = append(inAlerts, &types.Alert{
			Alert: model.Alert{Labels: lset},
		})
	}

	// Set the second alert als previously silenced. It is expected to have
	// the WasSilenced flag set to true afterwards.
	marker.SetSilenced(inAlerts[1].Fingerprint(), 123)

	if err := silenceNotifer.Notify(nil, inAlerts...); err != nil {
		t.Fatalf("Notifying failed: %s", err)
	}

	var got []model.LabelSet
	for i, a := range record.alerts {
		got = append(got, a.Labels)
		if a.WasSilenced != (i == 1) {
			t.Errorf("Expected WasSilenced to be %v for %d, was %v", i == 1, i, a.WasSilenced)
		}
	}

	if !reflect.DeepEqual(got, out) {
		t.Fatalf("Muting failed, expected: %v\ngot %v", out, got)
	}
}

func TestInhibitNotifier(t *testing.T) {
	// Mute all label sets that have a "mute" key.
	muter := types.MuteFunc(func(lset model.LabelSet) bool {
		_, ok := lset["mute"]
		return ok
	})

	marker := types.NewMarker()
	record := &recordNotifier{}
	inhibitNotifer := Inhibit(muter, record, marker)

	in := []model.LabelSet{
		{},
		{"test": "set"},
		{"mute": "me"},
		{"foo": "bar", "test": "set"},
		{"foo": "bar", "mute": "me"},
		{},
		{"not": "muted"},
	}
	out := []model.LabelSet{
		{},
		{"test": "set"},
		{"foo": "bar", "test": "set"},
		{},
		{"not": "muted"},
	}

	var inAlerts []*types.Alert
	for _, lset := range in {
		inAlerts = append(inAlerts, &types.Alert{
			Alert: model.Alert{Labels: lset},
		})
	}

	// Set the second alert as previously inhibited. It is expected to have
	// the WasInhibited flag set to true afterwards.
	marker.SetInhibited(inAlerts[1].Fingerprint(), true)

	if err := inhibitNotifer.Notify(nil, inAlerts...); err != nil {
		t.Fatalf("Notifying failed: %s", err)
	}

	var got []model.LabelSet
	for i, a := range record.alerts {
		got = append(got, a.Labels)
		if a.WasInhibited != (i == 1) {
			t.Errorf("Expected WasInhibited to be %v for %d, was %v", i == 1, i, a.WasInhibited)
		}
	}

	if !reflect.DeepEqual(got, out) {
		t.Fatalf("Muting failed, expected: %v\ngot %v", out, got)
	}
}