/*
Copyright 2021 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 metrics

import (
	"strings"
	"sync"
	"testing"

	"github.com/prometheus/client_golang/prometheus/testutil"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	apimachineryversion "k8s.io/apimachinery/pkg/version"
)

func TestEnableHiddenMetrics(t *testing.T) {
	resetMetricsGlobalState(t)

	currentVersion := apimachineryversion.Info{
		Major:      "1",
		Minor:      "17",
		GitVersion: "v1.17.1-alpha-1.12345",
	}

	var tests = []struct {
		name           string
		fqName         string
		counter        *Counter
		mustRegister   bool
		expectedMetric string
	}{
		{
			name:   "hide by register",
			fqName: "hidden_metric_register",
			counter: NewCounter(&CounterOpts{
				Name:              "hidden_metric_register",
				Help:              "counter help",
				StabilityLevel:    STABLE,
				DeprecatedVersion: "1.14.0",
			}),
			mustRegister: false,
			expectedMetric: `
				# HELP hidden_metrics_total [BETA] The count of hidden metrics.
                # TYPE hidden_metrics_total counter
                hidden_metrics_total 1
				# HELP hidden_metric_register [STABLE] (Deprecated since 1.14.0) counter help
				# TYPE hidden_metric_register counter
				hidden_metric_register 1
				`,
		},
		{
			name:   "hide by must register",
			fqName: "hidden_metric_must_register",
			counter: NewCounter(&CounterOpts{
				Name:              "hidden_metric_must_register",
				Help:              "counter help",
				StabilityLevel:    STABLE,
				DeprecatedVersion: "1.14.0",
			}),
			mustRegister: true,
			expectedMetric: `
				# HELP hidden_metric_must_register [STABLE] (Deprecated since 1.14.0) counter help
				# TYPE hidden_metric_must_register counter
				hidden_metric_must_register 1
				# HELP hidden_metrics_total [BETA] The count of hidden metrics.
                # TYPE hidden_metrics_total counter
                hidden_metrics_total 2
				`,
		},
	}

	for _, test := range tests {
		tc := test
		t.Run(tc.name, func(t *testing.T) {
			registry := newKubeRegistry(currentVersion)
			registry.MustRegister(hiddenMetricsTotal)
			if tc.mustRegister {
				registry.MustRegister(tc.counter)
			} else {
				_ = registry.Register(tc.counter)
			}

			tc.counter.Inc() // no-ops, because counter hasn't been initialized
			if err := testutil.GatherAndCompare(registry, strings.NewReader(""), tc.fqName); err != nil {
				t.Fatal(err)
			}

			SetShowHidden()
			defer func() {
				showHiddenOnce = sync.Once{}
				showHidden.Store(false)
			}()

			tc.counter.Inc()
			if err := testutil.GatherAndCompare(registry, strings.NewReader(tc.expectedMetric), tc.fqName, hiddenMetricsTotal.Name); err != nil {
				t.Fatal(err)
			}
		})
	}
}

func TestEnableHiddenStableCollector(t *testing.T) {
	var currentVersion = apimachineryversion.Info{
		Major:      "1",
		Minor:      "17",
		GitVersion: "v1.17.0-alpha-1.12345",
	}
	var normal = NewDesc("test_enable_hidden_custom_metric_normal", "this is a normal metric", []string{"name"}, nil, STABLE, "")
	var hiddenA = NewDesc("test_enable_hidden_custom_metric_hidden_a", "this is the hidden metric A", []string{"name"}, nil, STABLE, "1.14.0")
	var hiddenB = NewDesc("test_enable_hidden_custom_metric_hidden_b", "this is the hidden metric B", []string{"name"}, nil, STABLE, "1.14.0")

	var tests = []struct {
		name                      string
		descriptors               []*Desc
		metricNames               []string
		expectMetricsBeforeEnable string
		expectMetricsAfterEnable  string
	}{
		{
			name:        "all hidden",
			descriptors: []*Desc{hiddenA, hiddenB},
			metricNames: []string{"test_enable_hidden_custom_metric_hidden_a",
				"test_enable_hidden_custom_metric_hidden_b"},
			expectMetricsBeforeEnable: "",
			expectMetricsAfterEnable: `
        		# HELP test_enable_hidden_custom_metric_hidden_a [STABLE] (Deprecated since 1.14.0) this is the hidden metric A
        		# TYPE test_enable_hidden_custom_metric_hidden_a gauge
        		test_enable_hidden_custom_metric_hidden_a{name="value"} 1
        		# HELP test_enable_hidden_custom_metric_hidden_b [STABLE] (Deprecated since 1.14.0) this is the hidden metric B
        		# TYPE test_enable_hidden_custom_metric_hidden_b gauge
        		test_enable_hidden_custom_metric_hidden_b{name="value"} 1
			`,
		},
		{
			name:        "partial hidden",
			descriptors: []*Desc{normal, hiddenA, hiddenB},
			metricNames: []string{"test_enable_hidden_custom_metric_normal",
				"test_enable_hidden_custom_metric_hidden_a",
				"test_enable_hidden_custom_metric_hidden_b"},
			expectMetricsBeforeEnable: `
        		# HELP test_enable_hidden_custom_metric_normal [STABLE] this is a normal metric
        		# TYPE test_enable_hidden_custom_metric_normal gauge
        		test_enable_hidden_custom_metric_normal{name="value"} 1
			`,
			expectMetricsAfterEnable: `
        		# HELP test_enable_hidden_custom_metric_normal [STABLE] this is a normal metric
        		# TYPE test_enable_hidden_custom_metric_normal gauge
        		test_enable_hidden_custom_metric_normal{name="value"} 1
        		# HELP test_enable_hidden_custom_metric_hidden_a [STABLE] (Deprecated since 1.14.0) this is the hidden metric A
        		# TYPE test_enable_hidden_custom_metric_hidden_a gauge
        		test_enable_hidden_custom_metric_hidden_a{name="value"} 1
        		# HELP test_enable_hidden_custom_metric_hidden_b [STABLE] (Deprecated since 1.14.0) this is the hidden metric B
        		# TYPE test_enable_hidden_custom_metric_hidden_b gauge
        		test_enable_hidden_custom_metric_hidden_b{name="value"} 1
			`,
		},
	}

	for _, test := range tests {
		tc := test
		t.Run(tc.name, func(t *testing.T) {
			registry := newKubeRegistry(currentVersion)
			customCollector := newTestCustomCollector(tc.descriptors...)
			registry.CustomMustRegister(customCollector)

			if err := testutil.GatherAndCompare(registry, strings.NewReader(tc.expectMetricsBeforeEnable), tc.metricNames...); err != nil {
				t.Fatalf("before enable test failed: %v", err)
			}

			SetShowHidden()
			defer func() {
				showHiddenOnce = sync.Once{}
				showHidden.Store(false)
			}()

			if err := testutil.GatherAndCompare(registry, strings.NewReader(tc.expectMetricsAfterEnable), tc.metricNames...); err != nil {
				t.Fatalf("after enable test failed: %v", err)
			}

			// refresh descriptors to share with cases.
			for _, d := range tc.descriptors {
				d.ClearState()
			}
		})
	}
}

func TestShowHiddenMetric(t *testing.T) {
	resetMetricsGlobalState(t)

	registry := newKubeRegistry(apimachineryversion.Info{
		Major:      "1",
		Minor:      "15",
		GitVersion: "v1.15.0-alpha-1.12345",
	})

	expectedMetricCount := 0
	registry.MustRegister(alphaHiddenCounter)

	ms, err := registry.Gather()
	require.NoError(t, err, "Gather failed %v", err)
	assert.Lenf(t, ms, expectedMetricCount, "Got %v metrics, Want: %v metrics", len(ms), expectedMetricCount)

	showHidden.Store(true)
	registry.MustRegister(NewCounter(
		&CounterOpts{
			Namespace:         "some_namespace",
			Name:              "test_alpha_show_hidden_counter",
			Subsystem:         "subsystem",
			StabilityLevel:    ALPHA,
			Help:              "counter help",
			DeprecatedVersion: "1.14.0",
		},
	))
	expectedMetricCount = 1

	ms, err = registry.Gather()
	require.NoError(t, err, "Gather failed %v", err)
	assert.Lenf(t, ms, expectedMetricCount, "Got %v metrics, Want: %v metrics", len(ms), expectedMetricCount)
}

func TestDisabledMetrics(t *testing.T) {
	resetMetricsGlobalState(t)

	o := NewOptions()
	o.DisabledMetrics = []string{"should_be_disabled", "should_be_disabled"} // should be deduplicated (disabled_metrics_total == 1)
	currentVersion := apimachineryversion.Info{
		Major:      "1",
		Minor:      "17",
		GitVersion: "v1.17.1-alpha-1.12345",
	}
	registry := newKubeRegistry(currentVersion)
	registry.MustRegister(disabledMetricsTotal)
	o.Apply()
	disabledMetric := NewCounterVec(&CounterOpts{
		Name: "should_be_disabled",
		Help: "this metric should be disabled",
	}, []string{"label"})
	// gauges cannot be reset
	enabledMetric := NewGauge(&GaugeOpts{
		Name: "should_be_enabled",
		Help: "this metric should not be disabled",
	})

	registry.MustRegister(disabledMetric)
	registry.MustRegister(enabledMetric)
	disabledMetric.WithLabelValues("one").Inc()
	disabledMetric.WithLabelValues("two").Inc()
	disabledMetric.WithLabelValues("two").Inc()
	enabledMetric.Inc()

	enabledMetricOutput := `# HELP disabled_metrics_total [BETA] The count of disabled metrics.
		# TYPE disabled_metrics_total counter
        disabled_metrics_total 1
        # HELP should_be_enabled [ALPHA] this metric should not be disabled
        # TYPE should_be_enabled gauge
        should_be_enabled 1
`
	if err := testutil.GatherAndCompare(registry, strings.NewReader(enabledMetricOutput), "should_be_disabled", "should_be_enabled", disabledMetricsTotal.Name); err != nil {
		t.Fatal(err)
	}
}