package application_insights

import (
	"math"
	"testing"
	"time"

	"github.com/Microsoft/ApplicationInsights-Go/appinsights"

	"github.com/influxdata/telegraf"
	"github.com/influxdata/telegraf/internal"
	"github.com/influxdata/telegraf/metric"
	"github.com/influxdata/telegraf/plugins/outputs/application_insights/mocks"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/mock"
)

func TestConnectFailsIfNoIkey(t *testing.T) {
	assert := assert.New(t)

	transmitter := new(mocks.Transmitter)
	transmitter.On("Close").Return(closed)

	ai := ApplicationInsights{
		transmitter: transmitter,
		// Very long timeout to ensure we do not rely on timeouts for closing the transmitter
		Timeout: internal.Duration{Duration: time.Hour},
	}

	err := ai.Connect()
	assert.Error(err)
}

func TestOutputCloseTimesOut(t *testing.T) {
	assert := assert.New(t)

	transmitter := new(mocks.Transmitter)
	transmitter.On("Close").Return(unfinished)

	ai := ApplicationInsights{
		transmitter: transmitter,
		Timeout:     internal.Duration{Duration: time.Millisecond * 50},
	}

	err := ai.Close()
	assert.NoError(err)
	transmitter.AssertCalled(t, "Close")
}

func TestCloseRemovesDiagMsgListener(t *testing.T) {
	assert := assert.New(t)

	transmitter := new(mocks.Transmitter)
	transmitter.On("Close").Return(closed)

	diagMsgListener := new(mocks.DiagnosticsMessageListener)
	diagMsgListener.On("Remove")

	diagMsgSubscriber := new(mocks.DiagnosticsMessageSubscriber)
	diagMsgSubscriber.
		On("Subscribe", mock.AnythingOfType("appinsights.DiagnosticsMessageHandler")).
		Return(diagMsgListener)

	ai := ApplicationInsights{
		transmitter:             transmitter,
		Timeout:                 internal.Duration{Duration: time.Hour},
		EnableDiagnosticLogging: true,
		diagMsgSubscriber:       diagMsgSubscriber,
		InstrumentationKey:      "1234", // Fake, but necessary to enable tracking
	}

	err := ai.Connect()
	assert.NoError(err)
	diagMsgSubscriber.AssertCalled(t, "Subscribe", mock.AnythingOfType("appinsights.DiagnosticsMessageHandler"))

	err = ai.Close()
	assert.NoError(err)
	transmitter.AssertCalled(t, "Close")
	diagMsgListener.AssertCalled(t, "Remove")
}

func TestAggregateMetricCreated(t *testing.T) {
	tests := []struct {
		name                        string
		fields                      map[string]interface{}
		valueField                  string
		countField                  string
		additionalMetricValueFields []string
	}{
		{"value and count", map[string]interface{}{"value": 16.5, "count": 23}, "value", "count", nil},
		{"value and samples", map[string]interface{}{"value": 16.5, "samples": 23}, "value", "samples", nil},
		{"sum and count", map[string]interface{}{"sum": 16.5, "count": 23}, "sum", "count", nil},
		{"sum and samples", map[string]interface{}{"samples": 23, "sum": 16.5}, "sum", "samples", nil},
		{"value and count, sum is wrong type", map[string]interface{}{"sum": "J23", "value": 16.5, "count": 23}, "value", "count", nil},
		{
			"with aggregates",
			map[string]interface{}{
				"value":  16.5,
				"count":  23,
				"min":    -2.1,
				"max":    34,
				"stddev": 3.4,
			},
			"value",
			"count",
			nil,
		},
		{
			"some aggregates with invalid values",
			map[string]interface{}{
				"value": 16.5,
				"count": 23,
				"min":   "min",
				"max":   []float64{3.4, 5.6},
				"stddev": struct {
					name  string
					value float64
				}{"delta", 7.0},
			},
			"value",
			"count",
			nil,
		},
		{
			"aggregate with additional fields",
			map[string]interface{}{"value": 16.5, "samples": 23, "alpha": -34e12, "bravo": -3, "charlie": "charlie"},
			"value",
			"samples",
			[]string{"alpha", "bravo"},
		},
	}

	for _, tt := range tests {
		tf := func(t *testing.T) {
			assert := assert.New(t)
			now := time.Now().UTC()

			transmitter := new(mocks.Transmitter)
			transmitter.On("Track", mock.Anything)
			metricName := "ShouldBeAggregateMetric"

			m, err := metric.New(
				metricName,
				nil, // tags
				tt.fields,
				now,
			)
			assert.NoError(err)

			ai := ApplicationInsights{
				transmitter:        transmitter,
				InstrumentationKey: "1234", // Fake, but necessary to enable tracking
			}

			err = ai.Connect()
			assert.NoError(err)

			mSet := []telegraf.Metric{m}
			ai.Write(mSet)
			transmitter.AssertNumberOfCalls(t, "Track", 1+len(tt.additionalMetricValueFields))
			var pAggregateTelemetry *appinsights.AggregateMetricTelemetry
			assert.IsType(pAggregateTelemetry, transmitter.Calls[len(transmitter.Calls)-1].Arguments.Get(0), "Expected last telemetry to be AggregateMetricTelemetry")
			aggregateTelemetry := transmitter.Calls[len(transmitter.Calls)-1].Arguments.Get(0).(*appinsights.AggregateMetricTelemetry)
			verifyAggregateTelemetry(assert, m, tt.valueField, tt.countField, aggregateTelemetry)

			verifyAdditionalTelemetry(assert, m, transmitter, tt.additionalMetricValueFields, metricName)
		}

		t.Run(tt.name, tf)
	}
}

func TestSimpleMetricCreated(t *testing.T) {
	tests := []struct {
		name                        string
		fields                      map[string]interface{}
		primaryMetricValueField     string
		additionalMetricValueFields []string
	}{
		{"just a single value field", map[string]interface{}{"value": 16.5}, "value", nil},
		{"single field not named value", map[string]interface{}{"first": 32.9}, "first", nil},
		{"value but no count", map[string]interface{}{"value": 16.5, "other": "bulba"}, "", []string{"value"}},
		{"count but no value", map[string]interface{}{"v1": "v1Val", "count": 23}, "", []string{"count"}},
		{"neither value nor count", map[string]interface{}{"v1": "alpha", "v2": 45.8}, "", []string{"v2"}},
		{"value is of wrong type", map[string]interface{}{"value": "alpha", "count": 15}, "", []string{"count"}},
		{"count is of wrong type", map[string]interface{}{"value": 23.77, "count": 7.5}, "", []string{"count", "value"}},
		{"count is out of range", map[string]interface{}{"value": -98.45e4, "count": math.MaxUint64 - uint64(20)}, "", []string{"value", "count"}},
		{"several additional fields", map[string]interface{}{"alpha": 10, "bravo": "bravo", "charlie": 30, "delta": 40.7}, "", []string{"alpha", "charlie", "delta"}},
	}

	for _, tt := range tests {
		tf := func(t *testing.T) {
			assert := assert.New(t)
			now := time.Now().UTC()

			transmitter := new(mocks.Transmitter)
			transmitter.On("Track", mock.Anything)
			metricName := "ShouldBeSimpleMetric"

			m, err := metric.New(
				metricName,
				nil, // tags
				tt.fields,
				now,
			)
			assert.NoError(err)

			ai := ApplicationInsights{
				transmitter:        transmitter,
				InstrumentationKey: "1234", // Fake, but necessary to enable tracking
			}

			err = ai.Connect()
			assert.NoError(err)

			mSet := []telegraf.Metric{m}
			ai.Write(mSet)

			expectedNumberOfCalls := len(tt.additionalMetricValueFields)
			if tt.primaryMetricValueField != "" {
				expectedNumberOfCalls++
			}

			transmitter.AssertNumberOfCalls(t, "Track", expectedNumberOfCalls)
			if tt.primaryMetricValueField != "" {
				var pMetricTelemetry *appinsights.MetricTelemetry
				assert.IsType(pMetricTelemetry, transmitter.Calls[0].Arguments.Get(0), "First created telemetry should be simple MetricTelemetry")
				metricTelemetry := transmitter.Calls[0].Arguments.Get(0).(*appinsights.MetricTelemetry)

				var expectedTelemetryName string
				if tt.primaryMetricValueField == "value" {
					expectedTelemetryName = m.Name()
				} else {
					expectedTelemetryName = m.Name() + "_" + tt.primaryMetricValueField
				}
				verifySimpleTelemetry(assert, m, tt.primaryMetricValueField, expectedTelemetryName, metricTelemetry)
			}

			verifyAdditionalTelemetry(assert, m, transmitter, tt.additionalMetricValueFields, metricName)
		}

		t.Run(tt.name, tf)
	}
}

func TestTagsAppliedToTelemetry(t *testing.T) {
	tests := []struct {
		name              string
		fields            map[string]interface{}
		tags              map[string]string
		metricValueFields []string
	}{
		{
			"value but no count",
			map[string]interface{}{"value": 16.5, "alpha": 3.5, "bravo": 17},
			map[string]string{"alpha": "a tag is not a field", "charlie": "charlie"},
			[]string{"value", "alpha", "bravo"},
		},
	}

	for _, tt := range tests {
		tf := func(t *testing.T) {
			assert := assert.New(t)
			now := time.Now().UTC()

			transmitter := new(mocks.Transmitter)
			transmitter.On("Track", mock.Anything)
			metricName := "ShouldBeSimpleMetric"

			m, err := metric.New(
				metricName,
				tt.tags,
				tt.fields,
				now,
			)
			assert.NoError(err)

			ai := ApplicationInsights{
				transmitter:        transmitter,
				InstrumentationKey: "1234", // Fake, but necessary to enable tracking
			}

			err = ai.Connect()
			assert.NoError(err)

			mSet := []telegraf.Metric{m}
			ai.Write(mSet)
			transmitter.AssertNumberOfCalls(t, "Track", len(tt.metricValueFields))
			transmitter.AssertCalled(t, "Track", mock.AnythingOfType("*appinsights.MetricTelemetry"))

			// Will verify that all original tags are present in telemetry.Properties map
			verifyAdditionalTelemetry(assert, m, transmitter, tt.metricValueFields, metricName)
		}

		t.Run(tt.name, tf)
	}
}

func TestContextTagsSetOnSimpleTelemetry(t *testing.T) {
	assert := assert.New(t)
	now := time.Now().UTC()

	transmitter := new(mocks.Transmitter)
	transmitter.On("Track", mock.Anything)

	m, err := metric.New(
		"SimpleMetric",
		map[string]string{"kubernetes_container_name": "atcsvc", "kubernetes_pod_name": "bunkie17554"},
		map[string]interface{}{"value": 23.0},
		now,
	)
	assert.NoError(err)

	ai := ApplicationInsights{
		transmitter:        transmitter,
		InstrumentationKey: "1234", // Fake, but necessary to enable tracking
		ContextTagSources: map[string]string{
			"ai.cloud.role":         "kubernetes_container_name",
			"ai.cloud.roleInstance": "kubernetes_pod_name",
			"ai.user.id":            "nonexistent",
		},
	}

	err = ai.Connect()
	assert.NoError(err)

	mSet := []telegraf.Metric{m}
	ai.Write(mSet)
	transmitter.AssertNumberOfCalls(t, "Track", 1)
	metricTelemetry := transmitter.Calls[0].Arguments.Get(0).(*appinsights.MetricTelemetry)
	cloudTags := metricTelemetry.Tags.Cloud()
	assert.Equal("atcsvc", cloudTags.GetRole())
	assert.Equal("bunkie17554", cloudTags.GetRoleInstance())
}

func TestContextTagsSetOnAggregateTelemetry(t *testing.T) {
	assert := assert.New(t)
	now := time.Now().UTC()

	transmitter := new(mocks.Transmitter)
	transmitter.On("Track", mock.Anything)

	m, err := metric.New(
		"AggregateMetric",
		map[string]string{"kubernetes_container_name": "atcsvc", "kubernetes_pod_name": "bunkie17554"},
		map[string]interface{}{"value": 23.0, "count": 5},
		now,
	)
	assert.NoError(err)

	ai := ApplicationInsights{
		transmitter:        transmitter,
		InstrumentationKey: "1234", // Fake, but necessary to enable tracking
		ContextTagSources: map[string]string{
			"ai.cloud.role":         "kubernetes_container_name",
			"ai.cloud.roleInstance": "kubernetes_pod_name",
			"ai.user.id":            "nonexistent",
		},
	}

	err = ai.Connect()
	assert.NoError(err)

	mSet := []telegraf.Metric{m}
	ai.Write(mSet)
	transmitter.AssertNumberOfCalls(t, "Track", 1)
	metricTelemetry := transmitter.Calls[0].Arguments.Get(0).(*appinsights.AggregateMetricTelemetry)
	cloudTags := metricTelemetry.Tags.Cloud()
	assert.Equal("atcsvc", cloudTags.GetRole())
	assert.Equal("bunkie17554", cloudTags.GetRoleInstance())
}

func closed() <-chan struct{} {
	closed := make(chan struct{})
	close(closed)
	return closed
}

func unfinished() <-chan struct{} {
	unfinished := make(chan struct{})
	return unfinished
}

func verifyAggregateTelemetry(
	assert *assert.Assertions,
	metric telegraf.Metric,
	valueField string,
	countField string,
	telemetry *appinsights.AggregateMetricTelemetry,
) {

	verifyAggregateField := func(fieldName string, telemetryValue float64) {
		metricRawFieldValue, found := metric.Fields()[fieldName]
		if !found {
			return
		}

		if _, err := toFloat64(metricRawFieldValue); err == nil {
			assert.EqualValues(metricRawFieldValue, telemetryValue, "Telemetry property %s does not match the metric field", fieldName)
		}
	}
	assert.Equal(metric.Name(), telemetry.Name, "Telemetry name should be the same as metric name")
	assert.EqualValues(metric.Fields()[valueField], telemetry.Value, "Telemetry value does not match metric value field")
	assert.EqualValues(metric.Fields()[countField], telemetry.Count, "Telemetry sample count does not mach metric sample count field")
	verifyAggregateField("min", telemetry.Min)
	verifyAggregateField("max", telemetry.Max)
	verifyAggregateField("stdev", telemetry.StdDev)
	verifyAggregateField("variance", telemetry.Variance)
	assert.Equal(metric.Time(), telemetry.Timestamp, "Telemetry and metric timestamps do not match")
	assertMapContains(assert, metric.Tags(), telemetry.Properties)
}

func verifySimpleTelemetry(
	assert *assert.Assertions,
	metric telegraf.Metric,
	valueField string,
	expectedTelemetryName string,
	telemetry *appinsights.MetricTelemetry,
) {

	assert.Equal(expectedTelemetryName, telemetry.Name, "Telemetry name is not what was expected")
	assert.EqualValues(metric.Fields()[valueField], telemetry.Value, "Telemetry value does not match metric value field")
	assert.Equal(metric.Time(), telemetry.Timestamp, "Telemetry and metric timestamps do not match")
	assertMapContains(assert, metric.Tags(), telemetry.Properties)
}

func verifyAdditionalTelemetry(
	assert *assert.Assertions,
	metric telegraf.Metric,
	transmitter *mocks.Transmitter,
	additionalMetricValueFields []string,
	telemetryNamePrefix string,
) {
	for _, fieldName := range additionalMetricValueFields {
		expectedTelemetryName := telemetryNamePrefix + "_" + fieldName
		telemetry := findTransmittedTelemetry(transmitter, expectedTelemetryName)
		assert.NotNil(telemetry, "Expected telemetry named %s to be created, but could not find it", expectedTelemetryName)
		if telemetry != nil {
			verifySimpleTelemetry(assert, metric, fieldName, expectedTelemetryName, telemetry)
		}
	}
}

func findTransmittedTelemetry(transmitter *mocks.Transmitter, telemetryName string) *appinsights.MetricTelemetry {
	for _, call := range transmitter.Calls {
		telemetry, isMetricTelemetry := call.Arguments.Get(0).(*appinsights.MetricTelemetry)
		if isMetricTelemetry && telemetry.Name == telemetryName {
			return telemetry
		}
	}

	return nil
}

func keys(m map[string]string) []string {
	keys := make([]string, 0, len(m))
	for k := range m {
		keys = append(keys, k)
	}

	return keys
}

func assertMapContains(assert *assert.Assertions, expected, actual map[string]string) {
	if expected == nil && actual == nil {
		return
	}

	assert.NotNil(expected, "Maps not equal: expected is nil but actual is not")
	assert.NotNil(actual, "Maps not equal: actual is nil but expected is not")

	for k, v := range expected {
		av, ok := actual[k]
		assert.True(ok, "Actual map does not contain a value for key '%s'", k)
		assert.Equal(v, av, "The expected value for key '%s' is '%s' but the actual value is '%s", k, v, av)
	}
}