package regex

import (
	"sync"
	"testing"
	"time"

	"github.com/stretchr/testify/require"

	"github.com/influxdata/telegraf"
	"github.com/influxdata/telegraf/metric"
	"github.com/influxdata/telegraf/testutil"
)

func newM1() telegraf.Metric {
	return testutil.MustMetric(
		"access_log",
		map[string]string{
			"verb":      "GET",
			"resp_code": "200",
		},
		map[string]interface{}{
			"request": "/users/42/",
		},
		time.Now(),
	)
}

func newM2() telegraf.Metric {
	return testutil.MustMetric(
		"access_log",
		map[string]string{
			"verb":      "GET",
			"resp_code": "200",
		},
		map[string]interface{}{
			"request":       "/api/search/?category=plugins&q=regex&sort=asc",
			"ignore_number": int64(200),
			"ignore_bool":   true,
		},
		time.Now(),
	)
}

func newUUIDTags() telegraf.Metric {
	m1 := metric.New("access_log",
		map[string]string{
			"compound": "other-18cb0b46-73b8-4084-9fc4-5105f32a8a68",
			"simple":   "d60be57c-2f43-4e4f-a68a-4ca8204bae41",
			"control":  "not_uuid",
		},
		map[string]interface{}{
			"request": "/users/42/",
		},
		time.Now(),
	)
	return m1
}

func TestFieldConversions(t *testing.T) {
	tests := []struct {
		message        string
		converter      converter
		expectedFields map[string]interface{}
	}{
		{
			message: "Should change existing field",
			converter: converter{
				Key:         "request",
				Pattern:     "^/users/\\d+/$",
				Replacement: "/users/{id}/",
			},
			expectedFields: map[string]interface{}{
				"request": "/users/{id}/",
			},
		},
		{
			message: "Should add new field",
			converter: converter{
				Key:         "request",
				Pattern:     "^/users/\\d+/$",
				Replacement: "/users/{id}/",
				ResultKey:   "normalized_request",
			},
			expectedFields: map[string]interface{}{
				"request":            "/users/42/",
				"normalized_request": "/users/{id}/",
			},
		},
	}

	for _, tt := range tests {
		t.Run(tt.message, func(t *testing.T) {
			regex := Regex{
				Fields: []converter{tt.converter},
				Log:    testutil.Logger{},
			}
			require.NoError(t, regex.Init())

			processed := regex.Apply(newM1())

			expectedTags := map[string]string{
				"verb":      "GET",
				"resp_code": "200",
			}

			require.Equal(t, tt.expectedFields, processed[0].Fields(), tt.message)
			require.Equal(t, expectedTags, processed[0].Tags(), "Should not change tags")
			require.Equal(t, "access_log", processed[0].Name(), "Should not change name")
		})
	}
}

func TestTagConversions(t *testing.T) {
	tests := []struct {
		message      string
		converter    converter
		expectedTags map[string]string
	}{
		{
			message: "Should change existing tag",
			converter: converter{
				Key:         "resp_code",
				Pattern:     "^(\\d)\\d\\d$",
				Replacement: "${1}xx",
			},
			expectedTags: map[string]string{
				"verb":      "GET",
				"resp_code": "2xx",
			},
		},
		{
			message: "Should append to existing tag",
			converter: converter{
				Key:         "verb",
				Pattern:     "^(.*)$",
				Replacement: " (${1})",
				ResultKey:   "resp_code",
				Append:      true,
			},
			expectedTags: map[string]string{
				"verb":      "GET",
				"resp_code": "200 (GET)",
			},
		},
		{
			message: "Should add new tag",
			converter: converter{
				Key:         "resp_code",
				Pattern:     "^(\\d)\\d\\d$",
				Replacement: "${1}xx",
				ResultKey:   "resp_code_group",
			},
			expectedTags: map[string]string{
				"verb":            "GET",
				"resp_code":       "200",
				"resp_code_group": "2xx",
			},
		},
	}

	for _, test := range tests {
		regex := Regex{
			Tags: []converter{test.converter},
			Log:  testutil.Logger{},
		}
		require.NoError(t, regex.Init())

		processed := regex.Apply(newM1())

		expectedFields := map[string]interface{}{
			"request": "/users/42/",
		}

		require.Equal(t, expectedFields, processed[0].Fields(), test.message, "Should not change fields")
		require.Equal(t, test.expectedTags, processed[0].Tags(), test.message)
		require.Equal(t, "access_log", processed[0].Name(), "Should not change name")
	}
}

func TestMetricNameConversions(t *testing.T) {
	inputTemplate := []telegraf.Metric{
		testutil.MustMetric(
			"access_log",
			map[string]string{
				"verb":      "GET",
				"resp_code": "200",
			},
			map[string]interface{}{
				"request": "/users/42/",
			},
			time.Unix(1627646243, 0),
		),
		testutil.MustMetric(
			"access_log",
			map[string]string{
				"verb":      "GET",
				"resp_code": "200",
			},
			map[string]interface{}{
				"request":       "/api/search/?category=plugins&q=regex&sort=asc",
				"ignore_number": int64(200),
				"ignore_bool":   true,
			},
			time.Unix(1627646253, 0),
		),
		testutil.MustMetric(
			"error_log",
			map[string]string{
				"verb":      "GET",
				"resp_code": "404",
			},
			map[string]interface{}{
				"request":       "/api/search/?category=plugins&q=regex&sort=asc",
				"ignore_number": int64(404),
				"ignore_flag":   true,
				"error_message": "request too silly",
			},
			time.Unix(1627646263, 0),
		),
	}

	tests := []struct {
		name      string
		converter converter
		expected  []telegraf.Metric
	}{
		{
			name: "Should change metric name",
			converter: converter{
				Pattern:     "^(\\w+)_log$",
				Replacement: "${1}",
			},
			expected: []telegraf.Metric{
				testutil.MustMetric(
					"access",
					map[string]string{
						"verb":      "GET",
						"resp_code": "200",
					},
					map[string]interface{}{
						"request": "/users/42/",
					},
					time.Unix(1627646243, 0),
				),
				testutil.MustMetric(
					"access",
					map[string]string{
						"verb":      "GET",
						"resp_code": "200",
					},
					map[string]interface{}{
						"request":       "/api/search/?category=plugins&q=regex&sort=asc",
						"ignore_number": int64(200),
						"ignore_bool":   true,
					},
					time.Unix(1627646253, 0),
				),
				testutil.MustMetric(
					"error",
					map[string]string{
						"verb":      "GET",
						"resp_code": "404",
					},
					map[string]interface{}{
						"request":       "/api/search/?category=plugins&q=regex&sort=asc",
						"ignore_number": int64(404),
						"ignore_flag":   true,
						"error_message": "request too silly",
					},
					time.Unix(1627646263, 0),
				),
			},
		},
	}

	for _, test := range tests {
		// Copy the inputs as they will be modified by the processor
		input := make([]telegraf.Metric, 0, len(inputTemplate))
		for _, m := range inputTemplate {
			input = append(input, m.Copy())
		}

		t.Run(test.name, func(t *testing.T) {
			regex := Regex{
				MetricRename: []converter{test.converter},
				Log:          testutil.Logger{},
			}
			require.NoError(t, regex.Init())

			actual := regex.Apply(input...)
			testutil.RequireMetricsEqual(t, test.expected, actual)
		})
	}
}

func TestFieldRenameConversions(t *testing.T) {
	inputTemplate := []telegraf.Metric{
		testutil.MustMetric(
			"access_log",
			map[string]string{
				"verb":      "GET",
				"resp_code": "200",
			},
			map[string]interface{}{
				"request": "/users/42/",
			},
			time.Unix(1627646243, 0),
		),
		testutil.MustMetric(
			"access_log",
			map[string]string{
				"verb":      "GET",
				"resp_code": "200",
			},
			map[string]interface{}{
				"request":       "/api/search/?category=plugins&q=regex&sort=asc",
				"ignore_number": int64(200),
				"ignore_bool":   true,
			},
			time.Unix(1627646253, 0),
		),
		testutil.MustMetric(
			"error_log",
			map[string]string{
				"verb":      "GET",
				"resp_code": "404",
			},
			map[string]interface{}{
				"request":       "/api/search/?category=plugins&q=regex&sort=asc",
				"ignore_number": int64(404),
				"ignore_flag":   true,
				"error_message": "request too silly",
			},
			time.Unix(1627646263, 0),
		),
	}

	tests := []struct {
		name      string
		converter converter
		expected  []telegraf.Metric
	}{
		{
			name: "Should change field name",
			converter: converter{
				Pattern:     "^(?:ignore|error)_(\\w+)$",
				Replacement: "result_${1}",
			},
			expected: []telegraf.Metric{
				testutil.MustMetric(
					"access_log",
					map[string]string{
						"verb":      "GET",
						"resp_code": "200",
					},
					map[string]interface{}{
						"request": "/users/42/",
					},
					time.Unix(1627646243, 0),
				),
				testutil.MustMetric(
					"access_log",
					map[string]string{
						"verb":      "GET",
						"resp_code": "200",
					},
					map[string]interface{}{
						"request":       "/api/search/?category=plugins&q=regex&sort=asc",
						"result_number": int64(200),
						"result_bool":   true,
					},
					time.Unix(1627646253, 0),
				),
				testutil.MustMetric(
					"error_log",
					map[string]string{
						"verb":      "GET",
						"resp_code": "404",
					},
					map[string]interface{}{
						"request":        "/api/search/?category=plugins&q=regex&sort=asc",
						"result_number":  int64(404),
						"result_flag":    true,
						"result_message": "request too silly",
					},
					time.Unix(1627646263, 0),
				),
			},
		},
		{
			name: "Should keep existing field name",
			converter: converter{
				Pattern:     "^(?:ignore|error)_(\\w+)$",
				Replacement: "request",
			},
			expected: []telegraf.Metric{
				testutil.MustMetric(
					"access_log",
					map[string]string{
						"verb":      "GET",
						"resp_code": "200",
					},
					map[string]interface{}{
						"request": "/users/42/",
					},
					time.Unix(1627646243, 0),
				),
				testutil.MustMetric(
					"access_log",
					map[string]string{
						"verb":      "GET",
						"resp_code": "200",
					},
					map[string]interface{}{
						"request":       "/api/search/?category=plugins&q=regex&sort=asc",
						"ignore_number": int64(200),
						"ignore_bool":   true,
					},
					time.Unix(1627646253, 0),
				),
				testutil.MustMetric(
					"error_log",
					map[string]string{
						"verb":      "GET",
						"resp_code": "404",
					},
					map[string]interface{}{
						"request":       "/api/search/?category=plugins&q=regex&sort=asc",
						"ignore_number": int64(404),
						"ignore_flag":   true,
						"error_message": "request too silly",
					},
					time.Unix(1627646263, 0),
				),
			},
		},
		{
			name: "Should overwrite existing field name",
			converter: converter{
				Pattern:     "^ignore_bool$",
				Replacement: "request",
				ResultKey:   "overwrite",
			},
			expected: []telegraf.Metric{
				testutil.MustMetric(
					"access_log",
					map[string]string{
						"verb":      "GET",
						"resp_code": "200",
					},
					map[string]interface{}{
						"request": "/users/42/",
					},
					time.Unix(1627646243, 0),
				),
				testutil.MustMetric(
					"access_log",
					map[string]string{
						"verb":      "GET",
						"resp_code": "200",
					},
					map[string]interface{}{
						"ignore_number": int64(200),
						"request":       true,
					},
					time.Unix(1627646253, 0),
				),
				testutil.MustMetric(
					"error_log",
					map[string]string{
						"verb":      "GET",
						"resp_code": "404",
					},
					map[string]interface{}{
						"request":       "/api/search/?category=plugins&q=regex&sort=asc",
						"ignore_number": int64(404),
						"ignore_flag":   true,
						"error_message": "request too silly",
					},
					time.Unix(1627646263, 0),
				),
			},
		},
	}

	for _, test := range tests {
		// Copy the inputs as they will be modified by the processor
		input := make([]telegraf.Metric, 0, len(inputTemplate))
		for _, m := range inputTemplate {
			input = append(input, m.Copy())
		}

		t.Run(test.name, func(t *testing.T) {
			regex := Regex{
				FieldRename: []converter{test.converter},
				Log:         testutil.Logger{},
			}
			require.NoError(t, regex.Init())

			actual := regex.Apply(input...)
			testutil.RequireMetricsEqual(t, test.expected, actual)
		})
	}
}

func TestTagRenameConversions(t *testing.T) {
	inputTemplate := []telegraf.Metric{
		testutil.MustMetric(
			"access_log",
			map[string]string{
				"verb":      "GET",
				"resp_code": "200",
			},
			map[string]interface{}{
				"request": "/users/42/",
			},
			time.Unix(1627646243, 0),
		),
		testutil.MustMetric(
			"access_log",
			map[string]string{
				"verb":      "GET",
				"resp_code": "200",
			},
			map[string]interface{}{
				"request":       "/api/search/?category=plugins&q=regex&sort=asc",
				"ignore_number": int64(200),
				"ignore_bool":   true,
			},
			time.Unix(1627646253, 0),
		),
		testutil.MustMetric(
			"error_log",
			map[string]string{
				"verb":      "GET",
				"resp_code": "404",
			},
			map[string]interface{}{
				"request":       "/api/search/?category=plugins&q=regex&sort=asc",
				"ignore_number": int64(404),
				"ignore_flag":   true,
				"error_message": "request too silly",
			},
			time.Unix(1627646263, 0),
		),
	}

	tests := []struct {
		name      string
		converter converter
		expected  []telegraf.Metric
	}{
		{
			name: "Should change tag name",
			converter: converter{
				Pattern:     "^resp_(\\w+)$",
				Replacement: "${1}",
			},
			expected: []telegraf.Metric{
				testutil.MustMetric(
					"access_log",
					map[string]string{
						"verb": "GET",
						"code": "200",
					},
					map[string]interface{}{
						"request": "/users/42/",
					},
					time.Unix(1627646243, 0),
				),
				testutil.MustMetric(
					"access_log",
					map[string]string{
						"verb": "GET",
						"code": "200",
					},
					map[string]interface{}{
						"request":       "/api/search/?category=plugins&q=regex&sort=asc",
						"ignore_number": int64(200),
						"ignore_bool":   true,
					},
					time.Unix(1627646253, 0),
				),
				testutil.MustMetric(
					"error_log",
					map[string]string{
						"verb": "GET",
						"code": "404",
					},
					map[string]interface{}{
						"request":       "/api/search/?category=plugins&q=regex&sort=asc",
						"ignore_number": int64(404),
						"ignore_flag":   true,
						"error_message": "request too silly",
					},
					time.Unix(1627646263, 0),
				),
			},
		},
		{
			name: "Should keep existing tag name",
			converter: converter{
				Pattern:     "^resp_(\\w+)$",
				Replacement: "verb",
			},
			expected: []telegraf.Metric{
				testutil.MustMetric(
					"access_log",
					map[string]string{
						"verb":      "GET",
						"resp_code": "200",
					},
					map[string]interface{}{
						"request": "/users/42/",
					},
					time.Unix(1627646243, 0),
				),
				testutil.MustMetric(
					"access_log",
					map[string]string{
						"verb":      "GET",
						"resp_code": "200",
					},
					map[string]interface{}{
						"request":       "/api/search/?category=plugins&q=regex&sort=asc",
						"ignore_number": int64(200),
						"ignore_bool":   true,
					},
					time.Unix(1627646253, 0),
				),
				testutil.MustMetric(
					"error_log",
					map[string]string{
						"verb":      "GET",
						"resp_code": "404",
					},
					map[string]interface{}{
						"request":       "/api/search/?category=plugins&q=regex&sort=asc",
						"ignore_number": int64(404),
						"ignore_flag":   true,
						"error_message": "request too silly",
					},
					time.Unix(1627646263, 0),
				),
			},
		},
		{
			name: "Should overwrite existing tag name",
			converter: converter{
				Pattern:     "^resp_(\\w+)$",
				Replacement: "verb",
				ResultKey:   "overwrite",
			},
			expected: []telegraf.Metric{
				testutil.MustMetric(
					"access_log",
					map[string]string{
						"verb": "200",
					},
					map[string]interface{}{
						"request": "/users/42/",
					},
					time.Unix(1627646243, 0),
				),
				testutil.MustMetric(
					"access_log",
					map[string]string{
						"verb": "200",
					},
					map[string]interface{}{
						"request":       "/api/search/?category=plugins&q=regex&sort=asc",
						"ignore_number": int64(200),
						"ignore_bool":   true,
					},
					time.Unix(1627646253, 0),
				),
				testutil.MustMetric(
					"error_log",
					map[string]string{
						"verb": "404",
					},
					map[string]interface{}{
						"request":       "/api/search/?category=plugins&q=regex&sort=asc",
						"ignore_number": int64(404),
						"ignore_flag":   true,
						"error_message": "request too silly",
					},
					time.Unix(1627646263, 0),
				),
			},
		},
	}

	for _, test := range tests {
		// Copy the inputs as they will be modified by the processor
		input := make([]telegraf.Metric, 0, len(inputTemplate))
		for _, m := range inputTemplate {
			input = append(input, m.Copy())
		}

		t.Run(test.name, func(t *testing.T) {
			regex := Regex{
				TagRename: []converter{test.converter},
				Log:       testutil.Logger{},
			}
			require.NoError(t, regex.Init())

			actual := regex.Apply(input...)
			testutil.RequireMetricsEqual(t, test.expected, actual)
		})
	}
}

func TestMultipleConversions(t *testing.T) {
	regex := Regex{
		Tags: []converter{
			{
				Key:         "resp_code",
				Pattern:     "^(\\d)\\d\\d$",
				Replacement: "${1}xx",
				ResultKey:   "resp_code_group",
			},
			{
				Key:         "resp_code_group",
				Pattern:     "2xx",
				Replacement: "OK",
				ResultKey:   "resp_code_text",
			},
		},
		Fields: []converter{
			{
				Key:         "request",
				Pattern:     "^/api(?P<method>/[\\w/]+)\\S*",
				Replacement: "${method}",
				ResultKey:   "method",
			},
			{
				Key:         "request",
				Pattern:     ".*category=(\\w+).*",
				Replacement: "${1}",
				ResultKey:   "search_category",
			},
		},
		Log: testutil.Logger{},
	}
	require.NoError(t, regex.Init())

	processed := regex.Apply(newM2())

	expectedFields := map[string]interface{}{
		"request":         "/api/search/?category=plugins&q=regex&sort=asc",
		"method":          "/search/",
		"search_category": "plugins",
		"ignore_number":   int64(200),
		"ignore_bool":     true,
	}
	expectedTags := map[string]string{
		"verb":            "GET",
		"resp_code":       "200",
		"resp_code_group": "2xx",
		"resp_code_text":  "OK",
	}

	require.Equal(t, expectedFields, processed[0].Fields())
	require.Equal(t, expectedTags, processed[0].Tags())
}

func TestNamedGroups(t *testing.T) {
	regex := Regex{
		Tags: []converter{
			{
				Key:     "resp_code",
				Pattern: "^(?P<resp_code_group>\\d)\\d\\d$",
			},
		},
		Fields: []converter{
			{
				Key:     "request",
				Pattern: `^/api/(?P<method>\w+)[/?].*category=(?P<search_category>\w+)&(?:.*)`,
			},
		},
		Log: testutil.Logger{},
	}
	require.NoError(t, regex.Init())

	input := testutil.MustMetric(
		"access_log",
		map[string]string{
			"verb":      "GET",
			"resp_code": "200",
		},
		map[string]interface{}{
			"request":       "/api/search/?category=plugins&q=regex&sort=asc",
			"ignore_number": int64(200),
			"ignore_bool":   true,
		},
		time.Unix(1695243874, 0),
	)

	expected := []telegraf.Metric{
		metric.New(
			"access_log",
			map[string]string{
				"verb":            "GET",
				"resp_code":       "200",
				"resp_code_group": "2",
			},
			map[string]interface{}{
				"request":         "/api/search/?category=plugins&q=regex&sort=asc",
				"method":          "search",
				"search_category": "plugins",
				"ignore_number":   int64(200),
				"ignore_bool":     true,
			},
			time.Unix(1695243874, 0),
		),
	}
	actual := regex.Apply(input)
	testutil.RequireMetricsEqual(t, expected, actual)
}

func TestNoMatches(t *testing.T) {
	tests := []struct {
		message        string
		converter      converter
		expectedFields map[string]interface{}
	}{
		{
			message: "Should not change anything if there is no field with given key",
			converter: converter{
				Key:         "not_exists",
				Pattern:     "\\.*",
				Replacement: "x",
			},
			expectedFields: map[string]interface{}{
				"request": "/users/42/",
			},
		},
		{
			message: "Should not change anything if regex doesn't match",
			converter: converter{
				Key:         "request",
				Pattern:     "not_match",
				Replacement: "x",
			},
			expectedFields: map[string]interface{}{
				"request": "/users/42/",
			},
		},
		{
			message: "Should not emit new tag/field when result_key given but regex doesn't match",
			converter: converter{
				Key:         "request",
				Pattern:     "not_match",
				Replacement: "x",
				ResultKey:   "new_field",
			},
			expectedFields: map[string]interface{}{
				"request": "/users/42/",
			},
		},
	}

	for _, test := range tests {
		regex := Regex{
			Fields: []converter{test.converter},
			Log:    testutil.Logger{},
		}
		require.NoError(t, regex.Init())

		processed := regex.Apply(newM1())

		require.Equal(t, test.expectedFields, processed[0].Fields(), test.message)
	}
}

func BenchmarkConversions(b *testing.B) {
	regex := Regex{
		Tags: []converter{
			{
				Key:         "resp_code",
				Pattern:     "^(\\d)\\d\\d$",
				Replacement: "${1}xx",
				ResultKey:   "resp_code_group",
			},
		},
		Fields: []converter{
			{
				Key:         "request",
				Pattern:     "^/users/\\d+/$",
				Replacement: "/users/{id}/",
			},
		},
		Log: testutil.Logger{},
	}
	require.NoError(b, regex.Init())

	for n := 0; n < b.N; n++ {
		processed := regex.Apply(newM1())
		_ = processed
	}
}

func TestAnyTagConversion(t *testing.T) {
	tests := []struct {
		message      string
		converter    converter
		expectedTags map[string]string
	}{
		{
			message: "Should change existing tag",
			converter: converter{
				Key:         "*",
				Pattern:     "[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}",
				Replacement: "{UUID}",
			},
			expectedTags: map[string]string{
				"compound": "other-{UUID}",
				"simple":   "{UUID}",
				"control":  "not_uuid",
			},
		},
	}

	for _, test := range tests {
		regex := Regex{
			Tags: []converter{test.converter},
			Log:  testutil.Logger{},
		}
		require.NoError(t, regex.Init())

		processed := regex.Apply(newUUIDTags())

		expectedFields := map[string]interface{}{
			"request": "/users/42/",
		}

		require.Equal(t, expectedFields, processed[0].Fields(), test.message, "Should not change fields")
		require.Equal(t, test.expectedTags, processed[0].Tags(), test.message)
		require.Equal(t, "access_log", processed[0].Name(), "Should not change name")
	}
}

func TestAnyFieldConversion(t *testing.T) {
	tests := []struct {
		message        string
		converter      converter
		expectedFields map[string]interface{}
	}{
		{
			message: "Should change existing fields",
			converter: converter{
				Key:         "*",
				Pattern:     "[0-9]{4}",
				Replacement: "{ID}",
			},
			expectedFields: map[string]interface{}{
				"counter": int64(42),
				"id":      "{ID}",
				"user_id": "{ID}",
				"status":  "1",
				"request": "/users/{ID}/",
			},
		},
	}

	for _, test := range tests {
		regex := Regex{
			Fields: []converter{test.converter},
			Log:    testutil.Logger{},
		}
		require.NoError(t, regex.Init())

		input := metric.New("access_log",
			map[string]string{},
			map[string]interface{}{
				"counter": int64(42),
				"id":      "1234",
				"user_id": "2300",
				"status":  "1",
				"request": "/users/2300/",
			},
			time.Now(),
		)

		processed := regex.Apply(input)

		require.Empty(t, processed[0].Tags(), test.message, "Should not change tags")
		require.Equal(t, test.expectedFields, processed[0].Fields(), test.message)
		require.Equal(t, "access_log", processed[0].Name(), "Should not change name")
	}
}

func TestTrackedMetricNotLost(t *testing.T) {
	now := time.Now()

	// Setup raw input and expected output
	inputRaw := testutil.MustMetric(
		"access_log",
		map[string]string{
			"verb":      "GET",
			"resp_code": "200",
		},
		map[string]interface{}{
			"request":       "/api/search/?category=plugins&q=regex&sort=asc",
			"ignore_number": int64(200),
			"ignore_bool":   true,
		},
		now,
	)

	expected := []telegraf.Metric{
		metric.New(
			"access_log",
			map[string]string{
				"verb":            "GET",
				"resp_code":       "200",
				"resp_code_group": "2xx",
				"resp_code_text":  "OK",
			},
			map[string]interface{}{
				"request":         "/api/search/?category=plugins&q=regex&sort=asc",
				"method":          "/search/",
				"search_category": "plugins",
				"ignore_number":   int64(200),
				"ignore_bool":     true,
			},
			now,
		),
	}

	// Create fake notification for testing
	var mu sync.Mutex
	delivered := make([]telegraf.DeliveryInfo, 0, 1)
	notify := func(di telegraf.DeliveryInfo) {
		mu.Lock()
		defer mu.Unlock()
		delivered = append(delivered, di)
	}

	// Convert raw input to tracking metric
	input, _ := metric.WithTracking(inputRaw, notify)

	// Prepare and start the plugin
	regex := Regex{
		Tags: []converter{
			{
				Key:         "resp_code",
				Pattern:     "^(\\d)\\d\\d$",
				Replacement: "${1}xx",
				ResultKey:   "resp_code_group",
			},
			{
				Key:         "resp_code_group",
				Pattern:     "2xx",
				Replacement: "OK",
				ResultKey:   "resp_code_text",
			},
		},
		Fields: []converter{
			{
				Key:         "request",
				Pattern:     "^/api(?P<method>/[\\w/]+)\\S*",
				Replacement: "${method}",
				ResultKey:   "method",
			},
			{
				Key:         "request",
				Pattern:     ".*category=(\\w+).*",
				Replacement: "${1}",
				ResultKey:   "search_category",
			},
		},
		Log: testutil.Logger{},
	}
	require.NoError(t, regex.Init())

	// Process expected metrics and compare with resulting metrics
	actual := regex.Apply(input)
	testutil.RequireMetricsEqual(t, expected, actual)

	// Simulate output acknowledging delivery
	for _, m := range actual {
		m.Accept()
	}

	// Check delivery
	require.Eventuallyf(t, func() bool {
		mu.Lock()
		defer mu.Unlock()
		return len(delivered) == 1
	}, time.Second, 100*time.Millisecond, "%d delivered but %d expected", len(delivered), len(expected))
}