/*
Copyright 2019 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 noderesources

import (
	"context"
	"testing"

	"github.com/google/go-cmp/cmp"

	v1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/util/validation/field"
	"k8s.io/klog/v2/ktesting"
	fwk "k8s.io/kube-scheduler/framework"
	"k8s.io/kubernetes/pkg/scheduler/apis/config"
	"k8s.io/kubernetes/pkg/scheduler/backend/cache"
	"k8s.io/kubernetes/pkg/scheduler/framework"
	plfeature "k8s.io/kubernetes/pkg/scheduler/framework/plugins/feature"
	"k8s.io/kubernetes/pkg/scheduler/framework/runtime"
	st "k8s.io/kubernetes/pkg/scheduler/testing"
	tf "k8s.io/kubernetes/pkg/scheduler/testing/framework"
)

func TestMostAllocatedScoringStrategy(t *testing.T) {
	tests := []struct {
		name           string
		requestedPod   *v1.Pod
		nodes          []*v1.Node
		existingPods   []*v1.Pod
		expectedScores fwk.NodeScoreList
		resources      []config.ResourceSpec
		wantErrs       field.ErrorList
		wantStatusCode fwk.Code
	}{
		{
			// Node1 scores (used resources) on 0-MaxNodeScore scale
			// CPU Score: (0 * MaxNodeScore)  / 4000 = 0
			// Memory Score: (0 * MaxNodeScore) / 10000 = 0
			// Node1 Score: (0 + 0) / 2 = 0
			// Node2 scores (used resources) on 0-MaxNodeScore scale
			// CPU Score: (0 * MaxNodeScore) / 4000 = 0
			// Memory Score: (0 * MaxNodeScore) / 10000 = 0
			// Node2 Score: (0 + 0) / 2 = 0
			name:         "nothing scheduled, nothing requested",
			requestedPod: st.MakePod().Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node1").Capacity(map[v1.ResourceName]string{"cpu": "4000", "memory": "10000"}).Obj(),
				st.MakeNode().Name("node2").Capacity(map[v1.ResourceName]string{"cpu": "4000", "memory": "10000"}).Obj(),
			},
			existingPods:   nil,
			expectedScores: []fwk.NodeScore{{Name: "node1", Score: fwk.MinNodeScore}, {Name: "node2", Score: fwk.MinNodeScore}},
			resources:      defaultResources,
		},
		{
			// Node1 scores on 0-MaxNodeScore scale
			// CPU Score: (3000 * MaxNodeScore) / 4000 = 75
			// Memory Score: (5000 * MaxNodeScore) / 10000 = 50
			// Node1 Score: (75 + 50) / 2 = 62
			// Node2 scores on 0-MaxNodeScore scale
			// CPU Score: (3000 * MaxNodeScore) / 6000 = 50
			// Memory Score: (5000 * MaxNodeScore) / 10000 = 50
			// Node2 Score: (50 + 50) / 2 = 50
			name: "nothing scheduled, resources requested, differently sized nodes",
			requestedPod: st.MakePod().
				Req(map[v1.ResourceName]string{"cpu": "1000", "memory": "2000"}).
				Req(map[v1.ResourceName]string{"cpu": "2000", "memory": "3000"}).
				Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node1").Capacity(map[v1.ResourceName]string{"cpu": "4000", "memory": "10000"}).Obj(),
				st.MakeNode().Name("node2").Capacity(map[v1.ResourceName]string{"cpu": "6000", "memory": "10000"}).Obj(),
			},
			existingPods:   nil,
			expectedScores: []fwk.NodeScore{{Name: "node1", Score: 62}, {Name: "node2", Score: 50}},
			resources:      defaultResources,
		},
		{
			name: "Resources not set, pods scheduled with error",
			requestedPod: st.MakePod().
				Req(map[v1.ResourceName]string{"cpu": "1000", "memory": "2000"}).
				Req(map[v1.ResourceName]string{"cpu": "2000", "memory": "3000"}).
				Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node1").Capacity(map[v1.ResourceName]string{"cpu": "4000", "memory": "10000"}).Obj(),
				st.MakeNode().Name("node2").Capacity(map[v1.ResourceName]string{"cpu": "6000", "memory": "10000"}).Obj(),
			},
			existingPods:   nil,
			expectedScores: []fwk.NodeScore{{Name: "node1", Score: fwk.MinNodeScore}, {Name: "node2", Score: fwk.MinNodeScore}},
			resources:      nil,
			wantStatusCode: fwk.Error,
		},
		{
			// Node1 scores on 0-MaxNodeScore scale
			// CPU Score: (6000 * MaxNodeScore) / 10000 = 60
			// Memory Score: (0 * MaxNodeScore) / 20000 = 0
			// Node1 Score: (60 + 0) / 2 = 30
			// Node2 scores on 0-MaxNodeScore scale
			// CPU Score: (6000 * MaxNodeScore) / 10000 = 60
			// Memory Score: (5000 * MaxNodeScore) / 20000 = 25
			// Node2 Score: (60 + 25) / 2 = 42
			name:         "no resources requested, pods scheduled with resources",
			requestedPod: st.MakePod().Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node1").Capacity(map[v1.ResourceName]string{"cpu": "10000", "memory": "20000"}).Obj(),
				st.MakeNode().Name("node2").Capacity(map[v1.ResourceName]string{"cpu": "10000", "memory": "20000"}).Obj(),
			},
			existingPods: []*v1.Pod{
				st.MakePod().Node("node1").Req(map[v1.ResourceName]string{"cpu": "3000", "memory": "0"}).Obj(),
				st.MakePod().Node("node1").Req(map[v1.ResourceName]string{"cpu": "3000", "memory": "0"}).Obj(),
				st.MakePod().Node("node2").Req(map[v1.ResourceName]string{"cpu": "3000", "memory": "0"}).Obj(),
				st.MakePod().Node("node2").Req(map[v1.ResourceName]string{"cpu": "3000", "memory": "5000"}).Obj(),
			},
			expectedScores: []fwk.NodeScore{{Name: "node1", Score: 30}, {Name: "node2", Score: 42}},
			resources:      defaultResources,
		},
		{
			// Node1 scores on 0-MaxNodeScore scale
			// CPU Score: (6000 * MaxNodeScore) / 10000 = 60
			// Memory Score: (5000 * MaxNodeScore) / 20000 = 25
			// Node1 Score: (60 + 25) / 2 = 42
			// Node2 scores on 0-MaxNodeScore scale
			// CPU Score: (6000 * MaxNodeScore) / 10000 = 60
			// Memory Score: (10000 * MaxNodeScore) / 20000 = 50
			// Node2 Score: (60 + 50) / 2 = 55
			name: "resources requested, pods scheduled with resources",
			requestedPod: st.MakePod().
				Req(map[v1.ResourceName]string{"cpu": "1000", "memory": "2000"}).
				Req(map[v1.ResourceName]string{"cpu": "2000", "memory": "3000"}).
				Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node1").Capacity(map[v1.ResourceName]string{"cpu": "10000", "memory": "20000"}).Obj(),
				st.MakeNode().Name("node2").Capacity(map[v1.ResourceName]string{"cpu": "10000", "memory": "20000"}).Obj(),
			},
			existingPods: []*v1.Pod{
				st.MakePod().Node("node1").Req(map[v1.ResourceName]string{"cpu": "3000", "memory": "0"}).Obj(),
				st.MakePod().Node("node2").Req(map[v1.ResourceName]string{"cpu": "3000", "memory": "5000"}).Obj(),
			},
			expectedScores: []fwk.NodeScore{{Name: "node1", Score: 42}, {Name: "node2", Score: 55}},
			resources:      defaultResources,
		},
		{
			// Node1 scores on 0-MaxNodeScore scale
			// CPU Score: 5000 * MaxNodeScore / 5000 return 100
			// Memory Score: (9000 * MaxNodeScore) / 10000 = 90
			// Node1 Score: (100 + 90) / 2 = 95
			// Node2 scores on 0-MaxNodeScore scale
			// CPU Score: (5000 * MaxNodeScore) / 10000 = 50
			// Memory Score: 9000 * MaxNodeScore / 9000 return 100
			// Node2 Score: (50 + 100) / 2 = 75
			name: "resources requested equal node capacity",
			requestedPod: st.MakePod().
				Req(map[v1.ResourceName]string{"cpu": "2000", "memory": "4000"}).
				Req(map[v1.ResourceName]string{"cpu": "3000", "memory": "5000"}).
				Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node1").Capacity(map[v1.ResourceName]string{"cpu": "5000", "memory": "10000"}).Obj(),
				st.MakeNode().Name("node2").Capacity(map[v1.ResourceName]string{"cpu": "10000", "memory": "9000"}).Obj(),
			},
			existingPods:   nil,
			expectedScores: []fwk.NodeScore{{Name: "node1", Score: 95}, {Name: "node2", Score: 75}},
			resources:      defaultResources,
		},
		{
			// CPU Score: (3000 *100) / 4000 = 75
			// Memory Score: (5000 *100) / 10000 = 50
			// Node1 Score: (75 * 1 + 50 * 2) / (1 + 2) = 58
			// CPU Score: (3000 *100) / 6000 = 50
			// Memory Score: (5000 *100) / 10000 = 50
			// Node2 Score: (50 * 1 + 50 * 2) / (1 + 2) = 50
			name: "nothing scheduled, resources requested, differently sized nodes",
			requestedPod: st.MakePod().
				Req(map[v1.ResourceName]string{"cpu": "1000", "memory": "2000"}).
				Req(map[v1.ResourceName]string{"cpu": "2000", "memory": "3000"}).
				Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node1").Capacity(map[v1.ResourceName]string{"cpu": "4000", "memory": "10000"}).Obj(),
				st.MakeNode().Name("node2").Capacity(map[v1.ResourceName]string{"cpu": "6000", "memory": "10000"}).Obj(),
			},
			existingPods:   nil,
			expectedScores: []fwk.NodeScore{{Name: "node1", Score: 58}, {Name: "node2", Score: 50}},
			resources: []config.ResourceSpec{
				{Name: "memory", Weight: 2},
				{Name: "cpu", Weight: 1},
			},
		},
		{
			// Node1 scores on 0-MaxNodeScore scale
			// CPU Fraction: 300 / 250 = 100%
			// Memory Fraction: 600 / 1000 = 60%
			// Node1 Score: (100 + 60) / 2 = 80
			// Node2 scores on 0-MaxNodeScore scale
			// CPU Fraction: 100 / 250 = 40%
			// Memory Fraction: 200 / 1000 = 20%
			// Node2 Score: (20 + 40) / 2 = 30
			name:         "no resources requested, pods scheduled, nonzero request for resource",
			requestedPod: st.MakePod().Container("container").Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node1").Capacity(map[v1.ResourceName]string{"cpu": "250m", "memory": "1000Mi"}).Obj(),
				st.MakeNode().Name("node2").Capacity(map[v1.ResourceName]string{"cpu": "250m", "memory": "1000Mi"}).Obj(),
			},
			existingPods: []*v1.Pod{
				st.MakePod().Node("node1").Container("container").Obj(),
				st.MakePod().Node("node1").Container("container").Obj(),
			},
			expectedScores: []fwk.NodeScore{{Name: "node1", Score: 80}, {Name: "node2", Score: 30}},
			resources:      defaultResources,
		},
		{
			// resource with negative weight is not allowed
			name: "resource with negative weight",
			requestedPod: st.MakePod().
				Req(map[v1.ResourceName]string{"cpu": "1000", "memory": "2000"}).
				Req(map[v1.ResourceName]string{"cpu": "2000", "memory": "3000"}).
				Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node2").Capacity(map[v1.ResourceName]string{"cpu": "4000", "memory": "10000"}).Obj(),
			},
			resources: []config.ResourceSpec{
				{Name: "memory", Weight: -1},
				{Name: "cpu", Weight: 1},
			},
			wantErrs: field.ErrorList{
				&field.Error{
					Type:  field.ErrorTypeInvalid,
					Field: "scoringStrategy.resources[0].weight",
				},
			},
		},
		{
			// resource with zero weight is not allowed
			name: "resource with zero weight",
			requestedPod: st.MakePod().
				Req(map[v1.ResourceName]string{"cpu": "1000", "memory": "2000"}).
				Req(map[v1.ResourceName]string{"cpu": "2000", "memory": "3000"}).
				Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node2").Capacity(map[v1.ResourceName]string{"cpu": "4000", "memory": "10000"}).Obj(),
			},
			resources: []config.ResourceSpec{
				{Name: "memory", Weight: 1},
				{Name: "cpu", Weight: 0},
			},
			wantErrs: field.ErrorList{
				&field.Error{
					Type:  field.ErrorTypeInvalid,
					Field: "scoringStrategy.resources[1].weight",
				},
			},
		},
		{
			// resource weight should be less than MaxNodeScore
			name: "resource weight larger than MaxNodeScore",
			requestedPod: st.MakePod().
				Req(map[v1.ResourceName]string{"cpu": "1000", "memory": "2000"}).
				Req(map[v1.ResourceName]string{"cpu": "2000", "memory": "3000"}).
				Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node2").Capacity(map[v1.ResourceName]string{"cpu": "4000", "memory": "10000"}).Obj(),
			},
			resources: []config.ResourceSpec{
				{Name: "memory", Weight: 101},
			},
			wantErrs: field.ErrorList{
				&field.Error{
					Type:  field.ErrorTypeInvalid,
					Field: "scoringStrategy.resources[0].weight",
				},
			},
		},
		{
			// Bypass extended resource if the pod does not request.
			// For both nodes: cpuScore and memScore are 50
			// Given that extended resource score are intentionally bypassed,
			// the final scores are:
			// - node1: (50 + 50) / 2 = 50
			// - node2: (50 + 50) / 2 = 50
			name: "bypass extended resource if the pod does not request",
			requestedPod: st.MakePod().
				Req(map[v1.ResourceName]string{"cpu": "1000", "memory": "2000"}).
				Req(map[v1.ResourceName]string{"cpu": "2000", "memory": "3000"}).
				Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node1").Capacity(map[v1.ResourceName]string{"cpu": "6000", "memory": "10000"}).Obj(),
				st.MakeNode().Name("node2").Capacity(map[v1.ResourceName]string{"cpu": "6000", "memory": "10000", v1.ResourceName(extendedRes): "4"}).Obj(),
			},
			resources:      extendedResourceSet,
			existingPods:   nil,
			expectedScores: []fwk.NodeScore{{Name: "node1", Score: 50}, {Name: "node2", Score: 50}},
		},
		{
			// Honor extended resource if the pod requests.
			// For both nodes: cpuScore and memScore are 50.
			// In terms of extended resource score:
			// - node1 get: 2 / 4 * 100 = 50
			// - node2 get: 2 / 10 * 100 = 20
			// So the final scores are:
			// - node1: (50 + 50 + 50) / 3 = 50
			// - node2: (50 + 50 + 20) / 3 = 40
			name: "honor extended resource if the pod request",
			requestedPod: st.MakePod().Node("node1").
				Req(map[v1.ResourceName]string{"cpu": "3000", "memory": "5000", v1.ResourceName(extendedRes): "2"}).
				Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node1").Capacity(map[v1.ResourceName]string{"cpu": "6000", "memory": "10000", v1.ResourceName(extendedRes): "4"}).Obj(),
				st.MakeNode().Name("node2").Capacity(map[v1.ResourceName]string{"cpu": "6000", "memory": "10000", v1.ResourceName(extendedRes): "10"}).Obj(),
			},
			resources:      extendedResourceSet,
			existingPods:   nil,
			expectedScores: []fwk.NodeScore{{Name: "node1", Score: 50}, {Name: "node2", Score: 40}},
		},
		{
			// If the node doesn't have a resource
			// CPU Score: (3000 * 100) / 6000 = 50
			// Memory Score: (4000 * 100) / 10000 = 40
			// Node1 Score: (50 * 1 + 40 * 1) / (1 + 1) = 45
			// Node2 Score: (50 * 1 + 40 * 1) / (1 + 1) = 45
			name: "if the node doesn't have a resource",
			requestedPod: st.MakePod().Node("node1").
				Req(map[v1.ResourceName]string{"cpu": "3000", "memory": "4000"}).
				Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node1").Capacity(map[v1.ResourceName]string{"cpu": "6000", "memory": "10000"}).Obj(),
				st.MakeNode().Name("node2").Capacity(map[v1.ResourceName]string{"cpu": "6000", "memory": "10000", v1.ResourceName(extendedRes): "4"}).Obj(),
			},
			expectedScores: []fwk.NodeScore{{Name: "node1", Score: 45}, {Name: "node2", Score: 45}},
			resources: []config.ResourceSpec{
				{Name: extendedRes, Weight: 2},
				{Name: string(v1.ResourceCPU), Weight: 1},
				{Name: string(v1.ResourceMemory), Weight: 1},
			},
		},
	}

	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			_, ctx := ktesting.NewTestContext(t)
			ctx, cancel := context.WithCancel(ctx)
			defer cancel()

			state := framework.NewCycleState()
			snapshot := cache.NewSnapshot(test.existingPods, test.nodes)
			fh, _ := runtime.NewFramework(ctx, nil, nil, runtime.WithSnapshotSharedLister(snapshot))

			p, err := NewFit(ctx,
				&config.NodeResourcesFitArgs{
					ScoringStrategy: &config.ScoringStrategy{
						Type:      config.MostAllocated,
						Resources: test.resources,
					},
				}, fh, plfeature.Features{})

			if diff := cmp.Diff(test.wantErrs.ToAggregate(), err, ignoreBadValueDetail); diff != "" {
				t.Fatalf("got err (-want,+got):\n%s", diff)
			}
			if err != nil {
				return
			}

			status := p.(fwk.PreScorePlugin).PreScore(ctx, state, test.requestedPod, tf.BuildNodeInfos(test.nodes))
			if !status.IsSuccess() {
				t.Errorf("PreScore is expected to return success, but didn't. Got status: %v", status)
			}

			var gotScores fwk.NodeScoreList
			for _, n := range test.nodes {
				nodeInfo, err := snapshot.Get(n.Name)
				if err != nil {
					t.Errorf("failed to get node %q from snapshot: %v", n.Name, err)
				}
				score, status := p.(fwk.ScorePlugin).Score(ctx, state, test.requestedPod, nodeInfo)
				if status.Code() != test.wantStatusCode {
					t.Errorf("unexpected status code, want: %v, got: %v", test.wantStatusCode, status.Code())
				}
				gotScores = append(gotScores, fwk.NodeScore{Name: n.Name, Score: score})
			}

			if diff := cmp.Diff(test.expectedScores, gotScores); diff != "" {
				t.Errorf("Unexpected scores (-want,+got):\n%s", diff)
			}
		})
	}
}
