package azure_data_explorer

import (
	"bufio"
	"bytes"
	"context"
	"encoding/json"
	"io"
	"log"
	"os"
	"strings"
	"testing"
	"time"

	"github.com/Azure/azure-kusto-go/kusto"
	"github.com/Azure/azure-kusto-go/kusto/ingest"
	"github.com/stretchr/testify/require"

	"github.com/influxdata/telegraf"
	telegrafJson "github.com/influxdata/telegraf/plugins/serializers/json"
	"github.com/influxdata/telegraf/testutil"
)

func TestWrite(t *testing.T) {
	testCases := []struct {
		name               string
		inputMetric        []telegraf.Metric
		metricsGrouping    string
		tableName          string
		expected           map[string]interface{}
		expectedWriteError string
		createTables       bool
		ingestionType      string
	}{
		{
			name:            "Valid metric",
			inputMetric:     testutil.MockMetrics(),
			createTables:    true,
			tableName:       "test1",
			metricsGrouping: tablePerMetric,
			expected: map[string]interface{}{
				"metricName": "test1",
				"fields": map[string]interface{}{
					"value": 1.0,
				},
				"tags": map[string]interface{}{
					"tag1": "value1",
				},
				"timestamp": float64(time.Date(2009, time.November, 10, 23, 0, 0, 0, time.UTC).UnixNano() / int64(time.Second)),
			},
		},
		{
			name:            "Don't create tables'",
			inputMetric:     testutil.MockMetrics(),
			createTables:    false,
			tableName:       "test1",
			metricsGrouping: tablePerMetric,
			expected: map[string]interface{}{
				"metricName": "test1",
				"fields": map[string]interface{}{
					"value": 1.0,
				},
				"tags": map[string]interface{}{
					"tag1": "value1",
				},
				"timestamp": float64(time.Date(2009, time.November, 10, 23, 0, 0, 0, time.UTC).UnixNano() / int64(time.Second)),
			},
		},
		{
			name:            "SingleTable metric grouping type",
			inputMetric:     testutil.MockMetrics(),
			createTables:    true,
			tableName:       "test1",
			metricsGrouping: singleTable,
			expected: map[string]interface{}{
				"metricName": "test1",
				"fields": map[string]interface{}{
					"value": 1.0,
				},
				"tags": map[string]interface{}{
					"tag1": "value1",
				},
				"timestamp": float64(time.Date(2009, time.November, 10, 23, 0, 0, 0, time.UTC).UnixNano() / int64(time.Second)),
			},
		},
		{
			name:            "Valid metric managed ingestion",
			inputMetric:     testutil.MockMetrics(),
			createTables:    true,
			tableName:       "test1",
			metricsGrouping: tablePerMetric,
			ingestionType:   managedIngestion,
			expected: map[string]interface{}{
				"metricName": "test1",
				"fields": map[string]interface{}{
					"value": 1.0,
				},
				"tags": map[string]interface{}{
					"tag1": "value1",
				},
				"timestamp": float64(time.Date(2009, time.November, 10, 23, 0, 0, 0, time.UTC).UnixNano() / int64(time.Second)),
			},
		},
	}

	for _, tC := range testCases {
		t.Run(tC.name, func(t *testing.T) {
			serializer, err := telegrafJson.NewSerializer(
				telegrafJson.FormatConfig{
					TimestampUnits: time.Second,
				})
			require.NoError(t, err)

			ingestionType := "queued"
			if tC.ingestionType != "" {
				ingestionType = tC.ingestionType
			}

			localFakeIngestor := &fakeIngestor{}
			plugin := AzureDataExplorer{
				Endpoint:        "someendpoint",
				Database:        "databasename",
				Log:             testutil.Logger{},
				MetricsGrouping: tC.metricsGrouping,
				TableName:       tC.tableName,
				CreateTables:    tC.createTables,
				kustoClient:     kusto.NewMockClient(),
				metricIngestors: map[string]ingest.Ingestor{
					tC.tableName: localFakeIngestor,
				},
				serializer:    serializer,
				IngestionType: ingestionType,
			}

			errorInWrite := plugin.Write(testutil.MockMetrics())

			if tC.expectedWriteError != "" {
				require.EqualError(t, errorInWrite, tC.expectedWriteError)
			} else {
				require.NoError(t, errorInWrite)

				expectedNameOfMetric := tC.expected["metricName"].(string)

				createdFakeIngestor := localFakeIngestor

				require.Equal(t, expectedNameOfMetric, createdFakeIngestor.actualOutputMetric["name"])

				expectedFields := tC.expected["fields"].(map[string]interface{})
				require.Equal(t, expectedFields, createdFakeIngestor.actualOutputMetric["fields"])

				expectedTags := tC.expected["tags"].(map[string]interface{})
				require.Equal(t, expectedTags, createdFakeIngestor.actualOutputMetric["tags"])

				expectedTime := tC.expected["timestamp"].(float64)
				require.Equal(t, expectedTime, createdFakeIngestor.actualOutputMetric["timestamp"])
			}
		})
	}
}

func TestCreateAzureDataExplorerTable(t *testing.T) {
	serializer, _ := telegrafJson.NewSerializer(telegrafJson.FormatConfig{TimestampUnits: time.Second})
	plugin := AzureDataExplorer{
		Endpoint:        "someendpoint",
		Database:        "databasename",
		Log:             testutil.Logger{},
		MetricsGrouping: tablePerMetric,
		TableName:       "test1",
		CreateTables:    false,
		kustoClient:     kusto.NewMockClient(),
		metricIngestors: map[string]ingest.Ingestor{
			"test1": &fakeIngestor{},
		},
		serializer:    serializer,
		IngestionType: queuedIngestion,
	}
	var buf bytes.Buffer
	log.SetOutput(&buf)
	defer func() {
		log.SetOutput(os.Stderr)
	}()

	err := plugin.createAzureDataExplorerTable(context.Background(), "test1")

	output := buf.String()

	if err == nil && !strings.Contains(output, "skipped table creation") {
		t.Logf("FAILED : TestCreateAzureDataExplorerTable:  Should have skipped table creation.")
		t.Fail()
	}
}

func TestWriteWithType(t *testing.T) {
	metricName := "test1"
	fakeClient := kusto.NewMockClient()
	expectedResultMap := map[string]string{metricName: `{"fields":{"value":1},"name":"test1","tags":{"tag1":"value1"},"timestamp":1257894000}`}
	mockMetrics := testutil.MockMetrics()
	// Multi tables
	mockMetricsMulti := []telegraf.Metric{
		testutil.TestMetric(1.0, "test2"),
		testutil.TestMetric(2.0, "test3"),
	}
	expectedResultMap2 := map[string]string{
		"test2": `{"fields":{"value":1.0},"name":"test2","tags":{"tag1":"value1"},"timestamp":1257894000}`,
		"test3": `{"fields":{"value":2.0},"name":"test3","tags":{"tag1":"value1"},"timestamp":1257894000}`,
	}
	// List of tests
	testCases := []struct {
		name                      string
		inputMetric               []telegraf.Metric
		metricsGrouping           string
		tableNameToExpectedResult map[string]string
		expectedWriteError        string
		createTables              bool
		ingestionType             string
	}{
		{
			name:                      "Valid metric",
			inputMetric:               mockMetrics,
			createTables:              true,
			metricsGrouping:           tablePerMetric,
			tableNameToExpectedResult: expectedResultMap,
		},
		{
			name:                      "Don't create tables'",
			inputMetric:               mockMetrics,
			createTables:              false,
			metricsGrouping:           tablePerMetric,
			tableNameToExpectedResult: expectedResultMap,
		},
		{
			name:                      "SingleTable metric grouping type",
			inputMetric:               mockMetrics,
			createTables:              true,
			metricsGrouping:           singleTable,
			tableNameToExpectedResult: expectedResultMap,
		},
		{
			name:                      "Valid metric managed ingestion",
			inputMetric:               mockMetrics,
			createTables:              true,
			metricsGrouping:           tablePerMetric,
			tableNameToExpectedResult: expectedResultMap,
			ingestionType:             managedIngestion,
		},
		{
			name:                      "Table per metric type",
			inputMetric:               mockMetricsMulti,
			createTables:              true,
			metricsGrouping:           tablePerMetric,
			tableNameToExpectedResult: expectedResultMap2,
		},
	}
	for _, testCase := range testCases {
		t.Run(testCase.name, func(t *testing.T) {
			serializer, err := telegrafJson.NewSerializer(telegrafJson.FormatConfig{TimestampUnits: time.Second})
			require.NoError(t, err)
			for tableName, jsonValue := range testCase.tableNameToExpectedResult {
				ingestionType := "queued"
				if testCase.ingestionType != "" {
					ingestionType = testCase.ingestionType
				}
				mockIngestor := &mockIngestor{}
				plugin := AzureDataExplorer{
					Endpoint:        "someendpoint",
					Database:        "databasename",
					Log:             testutil.Logger{},
					IngestionType:   ingestionType,
					MetricsGrouping: testCase.metricsGrouping,
					TableName:       tableName,
					CreateTables:    testCase.createTables,
					kustoClient:     fakeClient,
					metricIngestors: map[string]ingest.Ingestor{
						tableName: mockIngestor,
					},
					serializer: serializer,
				}
				err := plugin.Write(testCase.inputMetric)
				if testCase.expectedWriteError != "" {
					require.EqualError(t, err, testCase.expectedWriteError)
					continue
				}
				require.NoError(t, err)
				createdIngestor := plugin.metricIngestors[tableName]
				if testCase.metricsGrouping == singleTable {
					createdIngestor = plugin.metricIngestors[tableName]
				}
				records := mockIngestor.records[0] // the first element
				require.NotNil(t, createdIngestor)
				require.JSONEq(t, jsonValue, records)
			}
		})
	}
}

func TestInitBlankEndpointData(t *testing.T) {
	plugin := AzureDataExplorer{
		Log:             testutil.Logger{},
		kustoClient:     kusto.NewMockClient(),
		metricIngestors: map[string]ingest.Ingestor{},
	}

	errorInit := plugin.Init()
	require.Error(t, errorInit)
	require.Equal(t, "endpoint configuration cannot be empty", errorInit.Error())
}

type fakeIngestor struct {
	actualOutputMetric map[string]interface{}
}

func (f *fakeIngestor) FromReader(_ context.Context, reader io.Reader, _ ...ingest.FileOption) (*ingest.Result, error) {
	scanner := bufio.NewScanner(reader)
	scanner.Scan()
	firstLine := scanner.Text()
	err := json.Unmarshal([]byte(firstLine), &f.actualOutputMetric)
	if err != nil {
		return nil, err
	}
	return &ingest.Result{}, nil
}

func (f *fakeIngestor) FromFile(_ context.Context, _ string, _ ...ingest.FileOption) (*ingest.Result, error) {
	return &ingest.Result{}, nil
}

func (f *fakeIngestor) Close() error {
	return nil
}

type mockIngestor struct {
	records []string
}

func (m *mockIngestor) FromReader(_ context.Context, reader io.Reader, _ ...ingest.FileOption) (*ingest.Result, error) {
	bufbytes, _ := io.ReadAll(reader)
	metricjson := string(bufbytes)
	m.SetRecords(strings.Split(metricjson, "\n"))
	return &ingest.Result{}, nil
}

func (m *mockIngestor) FromFile(_ context.Context, _ string, _ ...ingest.FileOption) (*ingest.Result, error) {
	return &ingest.Result{}, nil
}

func (m *mockIngestor) SetRecords(records []string) {
	m.records = records
}

// Name receives a copy of Foo since it doesn't need to modify it.
func (m *mockIngestor) Records() []string {
	return m.records
}

func (m *mockIngestor) Close() error {
	return nil
}
