/*
Copyright 2023 The Kubernetes Authors.

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 util

import (
	"strings"
	"testing"
	"time"

	"github.com/stretchr/testify/assert"

	"k8s.io/component-base/metrics/testutil"
	"k8s.io/kubernetes/pkg/kubelet/metrics"
	"k8s.io/utils/clock"
	testingclock "k8s.io/utils/clock/testing"
)

const (
	metricsNameNodeStartupPreKubelet       = "kubelet_node_startup_pre_kubelet_duration_seconds"
	metricsNameNodeStartupPreRegistration  = "kubelet_node_startup_pre_registration_duration_seconds"
	metricsNameNodeStartupRegistration     = "kubelet_node_startup_registration_duration_seconds"
	metricsNameNodeStartupPostRegistration = "kubelet_node_startup_post_registration_duration_seconds"
	metricsNameNodeStartup                 = "kubelet_node_startup_duration_seconds"
)

func TestNodeStartupLatencyNoEvents(t *testing.T) {
	t.Run("metrics registered; no incoming events", func(t *testing.T) {
		metrics.Register()
		defer clearMetrics()

		tracker := &basicNodeStartupLatencyTracker{
			bootTime:         frozenTime.Add(-100 * time.Millisecond),
			kubeletStartTime: frozenTime,
			clock:            clock.RealClock{},
		}

		wants := `
		# HELP kubelet_node_startup_duration_seconds [ALPHA] Duration in seconds of node startup in total.
        # TYPE kubelet_node_startup_duration_seconds gauge
        kubelet_node_startup_duration_seconds 0
        # HELP kubelet_node_startup_post_registration_duration_seconds [ALPHA] Duration in seconds of node startup after registration.
        # TYPE kubelet_node_startup_post_registration_duration_seconds gauge
        kubelet_node_startup_post_registration_duration_seconds 0
        # HELP kubelet_node_startup_pre_kubelet_duration_seconds [ALPHA] Duration in seconds of node startup before kubelet starts.
        # TYPE kubelet_node_startup_pre_kubelet_duration_seconds gauge
        kubelet_node_startup_pre_kubelet_duration_seconds 0
        # HELP kubelet_node_startup_pre_registration_duration_seconds [ALPHA] Duration in seconds of node startup before registration.
        # TYPE kubelet_node_startup_pre_registration_duration_seconds gauge
        kubelet_node_startup_pre_registration_duration_seconds 0
        # HELP kubelet_node_startup_registration_duration_seconds [ALPHA] Duration in seconds of node startup during registration.
        # TYPE kubelet_node_startup_registration_duration_seconds gauge
        kubelet_node_startup_registration_duration_seconds 0
		`
		if err := testutil.GatherAndCompare(metrics.GetGather(), strings.NewReader(wants),
			metricsNameNodeStartupPreKubelet,
			metricsNameNodeStartupPreRegistration,
			metricsNameNodeStartupRegistration,
			metricsNameNodeStartupPostRegistration,
			metricsNameNodeStartup,
		); err != nil {
			t.Error(err)
		}

		assert.Equal(t, frozenTime.Add(-100*time.Millisecond), tracker.bootTime)
		assert.Equal(t, frozenTime, tracker.kubeletStartTime)
		assert.True(t, tracker.firstRegistrationAttemptTime.IsZero())
		assert.True(t, tracker.firstRegisteredNewNodeTime.IsZero())
		assert.True(t, tracker.firstNodeReadyTime.IsZero())
	})
}

func TestRecordAllTimestamps(t *testing.T) {
	t.Run("all timestamps are recorded", func(t *testing.T) {
		metrics.Register()
		defer clearMetrics()

		fakeClock := testingclock.NewFakeClock(frozenTime)
		tracker := &basicNodeStartupLatencyTracker{
			bootTime:         frozenTime.Add(-100 * time.Millisecond),
			kubeletStartTime: frozenTime,
			clock:            fakeClock,
		}

		fakeClock.Step(800 * time.Millisecond)
		tracker.RecordAttemptRegisterNode()

		assert.Equal(t, frozenTime.Add(800*time.Millisecond), tracker.firstRegistrationAttemptTime)

		fakeClock.Step(400 * time.Millisecond)
		tracker.RecordRegisteredNewNode()

		assert.Equal(t, frozenTime.Add(1200*time.Millisecond), tracker.firstRegisteredNewNodeTime)

		fakeClock.Step(1100 * time.Millisecond)
		tracker.RecordNodeReady()

		assert.Equal(t, frozenTime.Add(2300*time.Millisecond), tracker.firstNodeReadyTime)

		wants := `
		# HELP kubelet_node_startup_duration_seconds [ALPHA] Duration in seconds of node startup in total.
        # TYPE kubelet_node_startup_duration_seconds gauge
        kubelet_node_startup_duration_seconds 2.4
        # HELP kubelet_node_startup_post_registration_duration_seconds [ALPHA] Duration in seconds of node startup after registration.
        # TYPE kubelet_node_startup_post_registration_duration_seconds gauge
        kubelet_node_startup_post_registration_duration_seconds 1.1
        # HELP kubelet_node_startup_pre_kubelet_duration_seconds [ALPHA] Duration in seconds of node startup before kubelet starts.
        # TYPE kubelet_node_startup_pre_kubelet_duration_seconds gauge
        kubelet_node_startup_pre_kubelet_duration_seconds 0.1
        # HELP kubelet_node_startup_pre_registration_duration_seconds [ALPHA] Duration in seconds of node startup before registration.
        # TYPE kubelet_node_startup_pre_registration_duration_seconds gauge
        kubelet_node_startup_pre_registration_duration_seconds 0.8
        # HELP kubelet_node_startup_registration_duration_seconds [ALPHA] Duration in seconds of node startup during registration.
        # TYPE kubelet_node_startup_registration_duration_seconds gauge
        kubelet_node_startup_registration_duration_seconds 0.4
		`
		if err := testutil.GatherAndCompare(metrics.GetGather(), strings.NewReader(wants),
			metricsNameNodeStartupPreKubelet,
			metricsNameNodeStartupPreRegistration,
			metricsNameNodeStartupRegistration,
			metricsNameNodeStartupPostRegistration,
			metricsNameNodeStartup,
		); err != nil {
			t.Error(err)
		}
	})
}

func TestRecordAttemptRegister(t *testing.T) {
	t.Run("record attempt register node", func(t *testing.T) {
		metrics.Register()
		defer clearMetrics()

		fakeClock := testingclock.NewFakeClock(frozenTime)
		tracker := &basicNodeStartupLatencyTracker{
			bootTime:         frozenTime.Add(-100 * time.Millisecond),
			kubeletStartTime: frozenTime,
			clock:            fakeClock,
		}

		fakeClock.Step(600 * time.Millisecond)
		tracker.RecordAttemptRegisterNode()

		assert.Equal(t, frozenTime.Add(600*time.Millisecond), tracker.firstRegistrationAttemptTime)
		assert.True(t, tracker.firstRegisteredNewNodeTime.IsZero())
		assert.True(t, tracker.firstNodeReadyTime.IsZero())

		wants := `
		# HELP kubelet_node_startup_duration_seconds [ALPHA] Duration in seconds of node startup in total.
        # TYPE kubelet_node_startup_duration_seconds gauge
        kubelet_node_startup_duration_seconds 0
        # HELP kubelet_node_startup_post_registration_duration_seconds [ALPHA] Duration in seconds of node startup after registration.
        # TYPE kubelet_node_startup_post_registration_duration_seconds gauge
        kubelet_node_startup_post_registration_duration_seconds 0
        # HELP kubelet_node_startup_pre_kubelet_duration_seconds [ALPHA] Duration in seconds of node startup before kubelet starts.
        # TYPE kubelet_node_startup_pre_kubelet_duration_seconds gauge
        kubelet_node_startup_pre_kubelet_duration_seconds 0
        # HELP kubelet_node_startup_pre_registration_duration_seconds [ALPHA] Duration in seconds of node startup before registration.
        # TYPE kubelet_node_startup_pre_registration_duration_seconds gauge
        kubelet_node_startup_pre_registration_duration_seconds 0
        # HELP kubelet_node_startup_registration_duration_seconds [ALPHA] Duration in seconds of node startup during registration.
        # TYPE kubelet_node_startup_registration_duration_seconds gauge
        kubelet_node_startup_registration_duration_seconds 0
				`
		if err := testutil.GatherAndCompare(metrics.GetGather(), strings.NewReader(wants),
			metricsNameNodeStartupPreKubelet,
			metricsNameNodeStartupPreRegistration,
			metricsNameNodeStartupRegistration,
			metricsNameNodeStartupPostRegistration,
			metricsNameNodeStartup,
		); err != nil {
			t.Error(err)
		}
	})
}

func TestRecordAttemptRegisterTwice(t *testing.T) {
	t.Run("record attempt register node twice", func(t *testing.T) {
		metrics.Register()
		defer clearMetrics()

		fakeClock := testingclock.NewFakeClock(frozenTime)
		tracker := &basicNodeStartupLatencyTracker{
			bootTime:         frozenTime.Add(-100 * time.Millisecond),
			kubeletStartTime: frozenTime,
			clock:            fakeClock,
		}

		fakeClock.Step(600 * time.Millisecond)
		tracker.RecordAttemptRegisterNode()

		fakeClock.Step(300 * time.Millisecond)
		tracker.RecordAttemptRegisterNode()

		assert.Equal(t, frozenTime.Add(600*time.Millisecond), tracker.firstRegistrationAttemptTime)
		assert.True(t, tracker.firstRegisteredNewNodeTime.IsZero())
		assert.True(t, tracker.firstNodeReadyTime.IsZero())
	})
}

func TestSkippingRecordRegisteredNewNode(t *testing.T) {
	t.Run("record register new node twice", func(t *testing.T) {
		metrics.Register()
		defer clearMetrics()

		fakeClock := testingclock.NewFakeClock(frozenTime)
		tracker := &basicNodeStartupLatencyTracker{
			bootTime:         frozenTime.Add(-100 * time.Millisecond),
			kubeletStartTime: frozenTime,
			clock:            fakeClock,
		}

		fakeClock.Step(100 * time.Millisecond)
		tracker.RecordAttemptRegisterNode()

		fakeClock.Step(500 * time.Millisecond)
		tracker.RecordRegisteredNewNode()

		fakeClock.Step(300 * time.Millisecond)
		tracker.RecordRegisteredNewNode()

		assert.Equal(t, frozenTime.Add(600*time.Millisecond), tracker.firstRegisteredNewNodeTime)

		wants := `
		# HELP kubelet_node_startup_duration_seconds [ALPHA] Duration in seconds of node startup in total.
        # TYPE kubelet_node_startup_duration_seconds gauge
        kubelet_node_startup_duration_seconds 0
        # HELP kubelet_node_startup_post_registration_duration_seconds [ALPHA] Duration in seconds of node startup after registration.
        # TYPE kubelet_node_startup_post_registration_duration_seconds gauge
        kubelet_node_startup_post_registration_duration_seconds 0
        # HELP kubelet_node_startup_pre_kubelet_duration_seconds [ALPHA] Duration in seconds of node startup before kubelet starts.
        # TYPE kubelet_node_startup_pre_kubelet_duration_seconds gauge
        kubelet_node_startup_pre_kubelet_duration_seconds 0.1
        # HELP kubelet_node_startup_pre_registration_duration_seconds [ALPHA] Duration in seconds of node startup before registration.
        # TYPE kubelet_node_startup_pre_registration_duration_seconds gauge
        kubelet_node_startup_pre_registration_duration_seconds 0.1
        # HELP kubelet_node_startup_registration_duration_seconds [ALPHA] Duration in seconds of node startup during registration.
        # TYPE kubelet_node_startup_registration_duration_seconds gauge
        kubelet_node_startup_registration_duration_seconds 0.5
		`
		if err := testutil.GatherAndCompare(metrics.GetGather(), strings.NewReader(wants),
			metricsNameNodeStartupPreKubelet,
			metricsNameNodeStartupPreRegistration,
			metricsNameNodeStartupRegistration,
			metricsNameNodeStartupPostRegistration,
			metricsNameNodeStartup,
		); err != nil {
			t.Error(err)
		}
	})

	t.Run("record register new node without previous step", func(t *testing.T) {
		metrics.Register()
		defer clearMetrics()

		fakeClock := testingclock.NewFakeClock(frozenTime)
		tracker := &basicNodeStartupLatencyTracker{
			bootTime:         frozenTime.Add(-100 * time.Millisecond),
			kubeletStartTime: frozenTime,
			clock:            fakeClock,
		}

		fakeClock.Step(700 * time.Millisecond)
		tracker.RecordRegisteredNewNode()

		assert.True(t, tracker.firstRegisteredNewNodeTime.IsZero())

		wants := `
		# HELP kubelet_node_startup_duration_seconds [ALPHA] Duration in seconds of node startup in total.
        # TYPE kubelet_node_startup_duration_seconds gauge
        kubelet_node_startup_duration_seconds 0
        # HELP kubelet_node_startup_post_registration_duration_seconds [ALPHA] Duration in seconds of node startup after registration.
        # TYPE kubelet_node_startup_post_registration_duration_seconds gauge
        kubelet_node_startup_post_registration_duration_seconds 0
        # HELP kubelet_node_startup_pre_kubelet_duration_seconds [ALPHA] Duration in seconds of node startup before kubelet starts.
        # TYPE kubelet_node_startup_pre_kubelet_duration_seconds gauge
        kubelet_node_startup_pre_kubelet_duration_seconds 0
        # HELP kubelet_node_startup_pre_registration_duration_seconds [ALPHA] Duration in seconds of node startup before registration.
        # TYPE kubelet_node_startup_pre_registration_duration_seconds gauge
        kubelet_node_startup_pre_registration_duration_seconds 0
        # HELP kubelet_node_startup_registration_duration_seconds [ALPHA] Duration in seconds of node startup during registration.
        # TYPE kubelet_node_startup_registration_duration_seconds gauge
        kubelet_node_startup_registration_duration_seconds 0
		`
		if err := testutil.GatherAndCompare(metrics.GetGather(), strings.NewReader(wants),
			metricsNameNodeStartupPreKubelet,
			metricsNameNodeStartupPreRegistration,
			metricsNameNodeStartupRegistration,
			metricsNameNodeStartupPostRegistration,
			metricsNameNodeStartup,
		); err != nil {
			t.Error(err)
		}
	})
}

func TestSkippingRecordNodeReady(t *testing.T) {
	t.Run("record node ready twice", func(t *testing.T) {
		metrics.Register()
		defer clearMetrics()

		fakeClock := testingclock.NewFakeClock(frozenTime)
		tracker := &basicNodeStartupLatencyTracker{
			bootTime:         frozenTime.Add(-100 * time.Millisecond),
			kubeletStartTime: frozenTime,
			clock:            fakeClock,
		}

		fakeClock.Step(100 * time.Millisecond)
		tracker.RecordAttemptRegisterNode()

		fakeClock.Step(200 * time.Millisecond)
		tracker.RecordRegisteredNewNode()

		fakeClock.Step(300 * time.Millisecond)
		tracker.RecordNodeReady()

		fakeClock.Step(700 * time.Millisecond)
		tracker.RecordNodeReady()

		assert.Equal(t, frozenTime.Add(600*time.Millisecond), tracker.firstNodeReadyTime)

		wants := `
		# HELP kubelet_node_startup_duration_seconds [ALPHA] Duration in seconds of node startup in total.
        # TYPE kubelet_node_startup_duration_seconds gauge
        kubelet_node_startup_duration_seconds 0.7
        # HELP kubelet_node_startup_post_registration_duration_seconds [ALPHA] Duration in seconds of node startup after registration.
        # TYPE kubelet_node_startup_post_registration_duration_seconds gauge
        kubelet_node_startup_post_registration_duration_seconds 0.3
        # HELP kubelet_node_startup_pre_kubelet_duration_seconds [ALPHA] Duration in seconds of node startup before kubelet starts.
        # TYPE kubelet_node_startup_pre_kubelet_duration_seconds gauge
        kubelet_node_startup_pre_kubelet_duration_seconds 0.1
        # HELP kubelet_node_startup_pre_registration_duration_seconds [ALPHA] Duration in seconds of node startup before registration.
        # TYPE kubelet_node_startup_pre_registration_duration_seconds gauge
        kubelet_node_startup_pre_registration_duration_seconds 0.1
        # HELP kubelet_node_startup_registration_duration_seconds [ALPHA] Duration in seconds of node startup during registration.
        # TYPE kubelet_node_startup_registration_duration_seconds gauge
        kubelet_node_startup_registration_duration_seconds 0.2
		`
		if err := testutil.GatherAndCompare(metrics.GetGather(), strings.NewReader(wants),
			metricsNameNodeStartupPreKubelet,
			metricsNameNodeStartupPreRegistration,
			metricsNameNodeStartupRegistration,
			metricsNameNodeStartupPostRegistration,
			metricsNameNodeStartup,
		); err != nil {
			t.Error(err)
		}
	})

	t.Run("record node ready without previous step", func(t *testing.T) {
		metrics.Register()
		defer clearMetrics()

		fakeClock := testingclock.NewFakeClock(frozenTime)
		tracker := &basicNodeStartupLatencyTracker{
			bootTime:         frozenTime.Add(-100 * time.Millisecond),
			kubeletStartTime: frozenTime,
			clock:            fakeClock,
		}

		fakeClock.Step(100 * time.Millisecond)
		tracker.RecordAttemptRegisterNode()

		fakeClock.Step(700 * time.Millisecond)
		tracker.RecordNodeReady()

		assert.True(t, tracker.firstNodeReadyTime.IsZero())

		wants := `
		# HELP kubelet_node_startup_duration_seconds [ALPHA] Duration in seconds of node startup in total.
        # TYPE kubelet_node_startup_duration_seconds gauge
        kubelet_node_startup_duration_seconds 0
        # HELP kubelet_node_startup_post_registration_duration_seconds [ALPHA] Duration in seconds of node startup after registration.
        # TYPE kubelet_node_startup_post_registration_duration_seconds gauge
        kubelet_node_startup_post_registration_duration_seconds 0
        # HELP kubelet_node_startup_pre_kubelet_duration_seconds [ALPHA] Duration in seconds of node startup before kubelet starts.
        # TYPE kubelet_node_startup_pre_kubelet_duration_seconds gauge
        kubelet_node_startup_pre_kubelet_duration_seconds 0
        # HELP kubelet_node_startup_pre_registration_duration_seconds [ALPHA] Duration in seconds of node startup before registration.
        # TYPE kubelet_node_startup_pre_registration_duration_seconds gauge
        kubelet_node_startup_pre_registration_duration_seconds 0
        # HELP kubelet_node_startup_registration_duration_seconds [ALPHA] Duration in seconds of node startup during registration.
        # TYPE kubelet_node_startup_registration_duration_seconds gauge
        kubelet_node_startup_registration_duration_seconds 0
		`
		if err := testutil.GatherAndCompare(metrics.GetGather(), strings.NewReader(wants),
			metricsNameNodeStartupPreKubelet,
			metricsNameNodeStartupPreRegistration,
			metricsNameNodeStartupRegistration,
			metricsNameNodeStartupPostRegistration,
			metricsNameNodeStartup,
		); err != nil {
			t.Error(err)
		}
	})
}

func clearMetrics() {
	metrics.NodeStartupPreKubeletDuration.Set(0)
	metrics.NodeStartupPreRegistrationDuration.Set(0)
	metrics.NodeStartupRegistrationDuration.Set(0)
	metrics.NodeStartupPostRegistrationDuration.Set(0)
	metrics.NodeStartupDuration.Set(0)
}