package scheduler

import (
	"fmt"
	"strings"
	"testing"

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/runtime"
	dynamicfake "k8s.io/client-go/dynamic/fake"
	"k8s.io/client-go/kubernetes/fake"
	"k8s.io/component-base/metrics/testutil"

	workv1alpha2 "github.com/karmada-io/karmada/pkg/apis/work/v1alpha2"
	karmadafake "github.com/karmada-io/karmada/pkg/generated/clientset/versioned/fake"
	"github.com/karmada-io/karmada/pkg/scheduler/metrics"
)

const incomingBindingMetricsName = "queue_incoming_bindings_total"

type trigger func(scheduler *Scheduler, obj interface{})

var (
	addBinding = func(scheduler *Scheduler, obj interface{}) {
		scheduler.onResourceBindingAdd(obj)
	}
	updateBinding = func(scheduler *Scheduler, obj interface{}) {
		scheduler.onResourceBindingUpdate(nil, obj)
	}
	policyChanged = func(scheduler *Scheduler, obj interface{}) {
		rb := obj.(*workv1alpha2.ResourceBinding)
		scheduler.onResourceBindingRequeue(rb, metrics.PolicyChanged)
	}
	crbPolicyChanged = func(scheduler *Scheduler, obj interface{}) {
		crb := obj.(*workv1alpha2.ClusterResourceBinding)
		scheduler.onClusterResourceBindingRequeue(crb, metrics.PolicyChanged)
	}
	clusterChanged = func(scheduler *Scheduler, obj interface{}) {
		rb := obj.(*workv1alpha2.ResourceBinding)
		scheduler.onResourceBindingRequeue(rb, metrics.ClusterChanged)
	}
	crbClusterChanged = func(scheduler *Scheduler, obj interface{}) {
		crb := obj.(*workv1alpha2.ClusterResourceBinding)
		scheduler.onClusterResourceBindingRequeue(crb, metrics.ClusterChanged)
	}
	scheduleAttemptSuccess = func(scheduler *Scheduler, obj interface{}) {
		scheduler.handleErr(nil, obj)
	}
	scheduleAttemptFailure = func(scheduler *Scheduler, obj interface{}) {
		scheduler.handleErr(fmt.Errorf("schedule attempt failure"), obj)
	}
)

func TestIncomingBindingMetrics(t *testing.T) {
	dynamicClient := dynamicfake.NewSimpleDynamicClient(runtime.NewScheme())
	karmadaClient := karmadafake.NewSimpleClientset()
	kubeClient := fake.NewSimpleClientset()

	sche, err := NewScheduler(dynamicClient, karmadaClient, kubeClient)
	if err != nil {
		t.Errorf("create scheduler error: %s", err)
	}

	var rbInfos = make([]*workv1alpha2.ResourceBinding, 0, 3)
	var crbInfos = make([]*workv1alpha2.ClusterResourceBinding, 0, 3)
	for i := 1; i <= 3; i++ {
		rb := &workv1alpha2.ResourceBinding{
			ObjectMeta: metav1.ObjectMeta{
				Name:       fmt.Sprintf("test-rb-%d", i),
				Namespace:  "bar",
				Generation: 1,
			},
		}
		rbInfos = append(rbInfos, rb)
	}

	for i := 1; i <= 3; i++ {
		crb := &workv1alpha2.ClusterResourceBinding{
			ObjectMeta: metav1.ObjectMeta{
				Name: fmt.Sprintf("test-rb-%d", i),
			},
		}
		crbInfos = append(crbInfos, crb)
	}

	rbTests := []struct {
		name        string
		crbInvolved bool
		trigger     trigger
		want        string
	}{
		{
			name:        "add resourceBinding",
			crbInvolved: false,
			trigger:     addBinding,
			want: `
			# HELP karmada_scheduler_queue_incoming_bindings_total Number of bindings added to scheduling queues by event type.
			# TYPE karmada_scheduler_queue_incoming_bindings_total counter
			karmada_scheduler_queue_incoming_bindings_total{event="BindingAdd"} 3
`,
		},
		{
			name:        "update resourceBinding",
			crbInvolved: false,
			trigger:     updateBinding,
			want: `
			# HELP karmada_scheduler_queue_incoming_bindings_total Number of bindings added to scheduling queues by event type.
			# TYPE karmada_scheduler_queue_incoming_bindings_total counter
			karmada_scheduler_queue_incoming_bindings_total{event="BindingUpdate"} 3
`,
		},
		{
			name:        "policy associated with resourceBinding changed",
			crbInvolved: false,
			trigger:     policyChanged,
			want: `
			# HELP karmada_scheduler_queue_incoming_bindings_total Number of bindings added to scheduling queues by event type.
			# TYPE karmada_scheduler_queue_incoming_bindings_total counter
			karmada_scheduler_queue_incoming_bindings_total{event="PolicyChanged"} 3
`,
		},
		{
			name:        "policy associated with clusterResourceBinding changed",
			crbInvolved: true,
			trigger:     crbPolicyChanged,
			want: `
			# HELP karmada_scheduler_queue_incoming_bindings_total Number of bindings added to scheduling queues by event type.
			# TYPE karmada_scheduler_queue_incoming_bindings_total counter
			karmada_scheduler_queue_incoming_bindings_total{event="PolicyChanged"} 3
`,
		},
		{
			name:        "cluster which matches the existing propagationPolicy changed",
			crbInvolved: false,
			trigger:     clusterChanged,
			want: `
			# HELP karmada_scheduler_queue_incoming_bindings_total Number of bindings added to scheduling queues by event type.
			# TYPE karmada_scheduler_queue_incoming_bindings_total counter
			karmada_scheduler_queue_incoming_bindings_total{event="ClusterChanged"} 3
`,
		},
		{
			name:        "cluster which matches the existing clusterPropagationPolicy changed",
			crbInvolved: true,
			trigger:     crbClusterChanged,
			want: `
			# HELP karmada_scheduler_queue_incoming_bindings_total Number of bindings added to scheduling queues by event type.
			# TYPE karmada_scheduler_queue_incoming_bindings_total counter
			karmada_scheduler_queue_incoming_bindings_total{event="ClusterChanged"} 3
`,
		},
		{
			name:        "schedule attempt success",
			crbInvolved: false,
			trigger:     scheduleAttemptSuccess,
			want:        ``,
		},
		{
			name:        "schedule attempt failure",
			crbInvolved: false,
			trigger:     scheduleAttemptFailure,
			want: `
			# HELP karmada_scheduler_queue_incoming_bindings_total Number of bindings added to scheduling queues by event type.
			# TYPE karmada_scheduler_queue_incoming_bindings_total counter
			karmada_scheduler_queue_incoming_bindings_total{event="ScheduleAttemptFailure"} 3
`,
		},
	}

	for _, test := range rbTests {
		t.Run(test.name, func(t *testing.T) {
			metrics.SchedulerQueueIncomingBindings.Reset()
			if test.crbInvolved {
				for _, crbInfo := range crbInfos {
					test.trigger(sche, crbInfo)
				}
			} else {
				for _, rbInfo := range rbInfos {
					test.trigger(sche, rbInfo)
				}
			}
			metricName := metrics.SchedulerSubsystem + "_" + incomingBindingMetricsName
			if err := testutil.CollectAndCompare(metrics.SchedulerQueueIncomingBindings, strings.NewReader(test.want), metricName); err != nil {
				t.Errorf("unexpected collecting result:\n%s", err)
			}
		})
	}
}