/*
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 collectors

import (
	"fmt"
	"strings"
	"testing"
	"time"

	"github.com/stretchr/testify/mock"

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/component-base/metrics/testutil"
	statsapi "k8s.io/kubernetes/pkg/kubelet/apis/stats/v1alpha1"
)

type mockSummaryProvider struct {
	mock.Mock
}

func (m *mockSummaryProvider) Get(updateStats bool) (*statsapi.Summary, error) {
	args := m.Called(updateStats)
	return args.Get(0).(*statsapi.Summary), args.Error(1)
}

func (m *mockSummaryProvider) GetCPUAndMemoryStats() (*statsapi.Summary, error) {
	args := m.Called()
	return args.Get(0).(*statsapi.Summary), args.Error(1)
}

func TestCollectResourceMetrics(t *testing.T) {
	testTime := metav1.NewTime(time.Unix(2, 0)) // a static timestamp: 2000
	interestedMetrics := []string{
		"scrape_error",
		"node_cpu_usage_seconds",
		"node_memory_working_set_bytes",
		"container_cpu_usage_seconds",
		"container_memory_working_set_bytes",
	}

	tests := []struct {
		name            string
		summary         *statsapi.Summary
		summaryErr      error
		expectedMetrics string
	}{
		{
			name:       "error getting summary",
			summary:    nil,
			summaryErr: fmt.Errorf("failed to get summary"),
			expectedMetrics: `
				# HELP scrape_error [ALPHA] 1 if there was an error while getting container metrics, 0 otherwise
				# TYPE scrape_error gauge
				scrape_error 1
			`,
		},
		{
			name: "arbitrary node metrics",
			summary: &statsapi.Summary{
				Node: statsapi.NodeStats{
					CPU: &statsapi.CPUStats{
						Time:                 testTime,
						UsageCoreNanoSeconds: uint64Ptr(10000000000),
					},
					Memory: &statsapi.MemoryStats{
						Time:            testTime,
						WorkingSetBytes: uint64Ptr(1000),
					},
				},
			},
			summaryErr: nil,
			expectedMetrics: `
				# HELP node_cpu_usage_seconds [ALPHA] Cumulative cpu time consumed by the node in core-seconds
				# TYPE node_cpu_usage_seconds gauge
				node_cpu_usage_seconds 10 2000
				# HELP node_memory_working_set_bytes [ALPHA] Current working set of the node in bytes
				# TYPE node_memory_working_set_bytes gauge
				node_memory_working_set_bytes 1000 2000
				# HELP scrape_error [ALPHA] 1 if there was an error while getting container metrics, 0 otherwise
				# TYPE scrape_error gauge
				scrape_error 0
			`,
		},
		{
			name: "arbitrary container metrics for different container, pods and namespaces",
			summary: &statsapi.Summary{
				Pods: []statsapi.PodStats{
					{
						PodRef: statsapi.PodReference{
							Name:      "pod_a",
							Namespace: "namespace_a",
						},
						Containers: []statsapi.ContainerStats{
							{
								Name: "container_a",
								CPU: &statsapi.CPUStats{
									Time:                 testTime,
									UsageCoreNanoSeconds: uint64Ptr(10000000000),
								},
								Memory: &statsapi.MemoryStats{
									Time:            testTime,
									WorkingSetBytes: uint64Ptr(1000),
								},
							},
							{
								Name: "container_b",
								CPU: &statsapi.CPUStats{
									Time:                 testTime,
									UsageCoreNanoSeconds: uint64Ptr(10000000000),
								},
								Memory: &statsapi.MemoryStats{
									Time:            testTime,
									WorkingSetBytes: uint64Ptr(1000),
								},
							},
						},
					},
					{
						PodRef: statsapi.PodReference{
							Name:      "pod_b",
							Namespace: "namespace_b",
						},
						Containers: []statsapi.ContainerStats{
							{
								Name: "container_a",
								CPU: &statsapi.CPUStats{
									Time:                 testTime,
									UsageCoreNanoSeconds: uint64Ptr(10000000000),
								},
								Memory: &statsapi.MemoryStats{
									Time:            testTime,
									WorkingSetBytes: uint64Ptr(1000),
								},
							},
						},
					},
				},
			},
			summaryErr: nil,
			expectedMetrics: `
				# HELP scrape_error [ALPHA] 1 if there was an error while getting container metrics, 0 otherwise
				# TYPE scrape_error gauge
				scrape_error 0
				# HELP container_cpu_usage_seconds [ALPHA] Cumulative cpu time consumed by the container in core-seconds
				# TYPE container_cpu_usage_seconds gauge
				container_cpu_usage_seconds{container="container_a",namespace="namespace_a",pod="pod_a"} 10 2000
				container_cpu_usage_seconds{container="container_a",namespace="namespace_b",pod="pod_b"} 10 2000
				container_cpu_usage_seconds{container="container_b",namespace="namespace_a",pod="pod_a"} 10 2000
				# HELP container_memory_working_set_bytes [ALPHA] Current working set of the container in bytes
				# TYPE container_memory_working_set_bytes gauge
				container_memory_working_set_bytes{container="container_a",namespace="namespace_a",pod="pod_a"} 1000 2000
				container_memory_working_set_bytes{container="container_a",namespace="namespace_b",pod="pod_b"} 1000 2000
				container_memory_working_set_bytes{container="container_b",namespace="namespace_a",pod="pod_a"} 1000 2000
			`,
		},
	}

	for _, test := range tests {
		tc := test
		t.Run(tc.name, func(t *testing.T) {
			provider := &mockSummaryProvider{}
			provider.On("GetCPUAndMemoryStats").Return(tc.summary, tc.summaryErr)
			collector := NewResourceMetricsCollector(provider)

			if err := testutil.CustomCollectAndCompare(collector, strings.NewReader(tc.expectedMetrics), interestedMetrics...); err != nil {
				t.Fatal(err)
			}
		})
	}
}

func uint64Ptr(u uint64) *uint64 {
	return &u
}