insights-go/insights_test.go

package insights

import (
	"bytes"
	"errors"
	"fmt"
	"io"
	"net/http"
	"net/http/httptest"
	"net/url"
	"os"
	"path/filepath"
	"reflect"
	"regexp"
	"strings"
	"sync"
	"sync/atomic"
	"testing"
	"time"

	json "github.com/goccy/go-json"
	"github.com/google/go-cmp/cmp"
	"github.com/google/go-cmp/cmp/cmpopts"
	"github.com/stretchr/testify/require"
)

// Helper type used to implement the io.Reader interface on function values.
type readFunc func([]byte) (int, error)

func (f readFunc) Read(b []byte) (int, error) { return f(b) }

// Helper type used to implement the http.RoundTripper interface on function
// values.
type roundTripperFunc func(*http.Request) (*http.Response, error)

func (f roundTripperFunc) RoundTrip(r *http.Request) (*http.Response, error) { return f(r) }

func (f roundTripperFunc) CancelRequest(r *http.Request) {}

// Instances of this type are used to mock the client callbacks in unit tests.
type testCallback struct {
	success func(APIMessage)
	failure func(APIMessage, error)
}

func (c testCallback) Success(m APIMessage) {
	if c.success != nil {
		c.success(m)
	}
}

func (c testCallback) Failure(m APIMessage, e error) {
	if c.failure != nil {
		c.failure(m, e)
	}
}

// Instances of this type are used to mock the client logger in unit tests.
type testLogger struct {
	logf   func(string, ...any)
	errorf func(string, ...any)
}

func (l testLogger) Debugf(format string, args ...any) {
	if l.logf != nil {
		l.logf(format, args...)
	}
}

func (l testLogger) Logf(format string, args ...any) {
	if l.logf != nil {
		l.logf(format, args...)
	}
}

func (l testLogger) Warnf(format string, args ...any) {
	if l.logf != nil {
		l.logf(format, args...)
	}
}

func (l testLogger) Errorf(format string, args ...any) {
	if l.errorf != nil {
		l.errorf(format, args...)
	}
}

func TestNewWithConfig_LogsErrorForBlankAPIKeyAfterTrim(t *testing.T) {
	var logged string

	client, err := NewWithConfig(" \n\t ", Config{
		Logger: testLogger{
			logf: t.Logf,
			errorf: func(format string, args ...any) {
				logged = fmt.Sprintf(format, args...)
			},
		},
	})
	require.NoError(t, err)
	require.NotNil(t, client)
	defer client.Close()

	require.Contains(t, logged, "apiKey is empty after trimming whitespace")
	require.Contains(t, logged, ErrSDKDisabled.Error())
}

func TestNew_BlankAPIKeyReturnsNoopClient(t *testing.T) {
	client := New(" \n\t ")
	require.NotNil(t, client)

	_, ok := client.(*noopClient)
	require.True(t, ok)
	require.ErrorIs(t, client.Enqueue(Capture{}), ErrSDKDisabled)

	isEnabled, err := client.IsFeatureEnabled(FeatureFlagPayload{})
	require.ErrorIs(t, err, ErrSDKDisabled)
	require.Equal(t, false, isEnabled)

	flag, err := client.GetFeatureFlag(FeatureFlagPayload{})
	require.ErrorIs(t, err, ErrSDKDisabled)
	require.Equal(t, false, flag)

	result, err := client.GetFeatureFlagResult(FeatureFlagPayload{})
	require.ErrorIs(t, err, ErrSDKDisabled)
	require.NotNil(t, result)
	require.False(t, result.Enabled)

	payload, err := client.GetFeatureFlagPayload(FeatureFlagPayload{})
	require.ErrorIs(t, err, ErrSDKDisabled)
	require.Empty(t, payload)

	allFlags, err := client.GetAllFlags(FeatureFlagPayloadNoKey{})
	require.ErrorIs(t, err, ErrSDKDisabled)
	require.Empty(t, allFlags)

	evaluations, err := client.EvaluateFlags(EvaluateFlagsPayload{})
	require.ErrorIs(t, err, ErrSDKDisabled)
	require.NotNil(t, evaluations)
	require.Empty(t, evaluations.Keys())

	require.ErrorIs(t, client.ReloadFeatureFlags(), ErrSDKDisabled)
	require.ErrorIs(t, client.Close(), ErrSDKDisabled)
	require.ErrorIs(t, client.Close(), ErrSDKDisabled)
}

func TestNewWithConfig_BlankAPIKeyReturnsNoopClientWithoutRequests(t *testing.T) {
	var requests atomic.Int64
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		requests.Add(1)
		w.WriteHeader(http.StatusOK)
	}))
	defer server.Close()

	var successes atomic.Int64
	var failures atomic.Int64
	client, err := NewWithConfig(" \n\t ", Config{
		Endpoint:       server.URL,
		PersonalApiKey: "personal-api-key",
		BatchSize:      1,
		Interval:       time.Millisecond,
		Callback: testCallback{
			success: func(APIMessage) { successes.Add(1) },
			failure: func(APIMessage, error) { failures.Add(1) },
		},
	})
	require.NoError(t, err)
	require.NotNil(t, client)
	_, ok := client.(*noopClient)
	require.True(t, ok)

	require.ErrorIs(t, client.Enqueue(Capture{DistinctId: "test-user", Event: "test-event"}), ErrSDKDisabled)
	isEnabled, err := client.IsFeatureEnabled(FeatureFlagPayload{Key: "test-flag", DistinctId: "test-user"})
	require.ErrorIs(t, err, ErrSDKDisabled)
	require.Equal(t, false, isEnabled)
	allFlags, err := client.GetAllFlags(FeatureFlagPayloadNoKey{DistinctId: "test-user"})
	require.ErrorIs(t, err, ErrSDKDisabled)
	require.Empty(t, allFlags)
	remoteConfigPayload, err := client.GetRemoteConfigPayload("test-flag")
	require.ErrorIs(t, err, ErrSDKDisabled)
	require.Empty(t, remoteConfigPayload)
	require.ErrorIs(t, client.Close(), ErrSDKDisabled)

	require.Zero(t, requests.Load())
	require.Zero(t, successes.Load())
	require.Zero(t, failures.Load())
}

func TestNewWithConfig_BlankAPIKeyWithPersonalAPIKeyReturnsNoopClient(t *testing.T) {
	var requests atomic.Int64
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		requests.Add(1)
		w.WriteHeader(http.StatusOK)
	}))
	defer server.Close()

	client, err := NewWithConfig(" \n\t ", Config{
		Endpoint:       server.URL,
		PersonalApiKey: "personal-api-key",
		BatchSize:      1,
		Interval:       time.Millisecond,
	})
	require.NoError(t, err)
	require.NotNil(t, client)
	_, ok := client.(*noopClient)
	require.True(t, ok)

	require.ErrorIs(t, client.Enqueue(Capture{DistinctId: "test-user", Event: "test-event"}), ErrSDKDisabled)
	isEnabled, err := client.IsFeatureEnabled(FeatureFlagPayload{Key: "test-flag", DistinctId: "test-user"})
	require.ErrorIs(t, err, ErrSDKDisabled)
	require.Equal(t, false, isEnabled)
	remoteConfigPayload, err := client.GetRemoteConfigPayload("test-flag")
	require.ErrorIs(t, err, ErrSDKDisabled)
	require.Empty(t, remoteConfigPayload)
	require.ErrorIs(t, client.Close(), ErrSDKDisabled)

	require.Zero(t, requests.Load())
}

func TestNewWithConfig_TrimsWhitespaceSensitiveInputsInRequests(t *testing.T) {
	var (
		mu                sync.Mutex
		batchAPIKey       string
		remoteConfigToken string
		remoteConfigAuth  string
	)

	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		switch {
		case strings.Contains(r.URL.Path, "/flags/definitions"):
			if got := r.Header.Get("Authorization"); got != "Bearer test-personal-key" {
				t.Errorf("Expected Authorization header 'Bearer test-personal-key', got %q", got)
			}
			w.Header().Set("Content-Type", "application/json")
			_, _ = w.Write([]byte(`{"flags": [], "group_type_mapping": {}}`))
		case r.URL.Path == "/batch/":
			body, err := io.ReadAll(r.Body)
			if err != nil {
				t.Errorf("Failed to read batch body: %v", err)
				w.WriteHeader(http.StatusInternalServerError)
				return
			}

			var payload struct {
				ApiKey string `json:"api_key"`
			}
			if err := json.Unmarshal(body, &payload); err != nil {
				t.Errorf("Failed to parse batch body: %v", err)
				w.WriteHeader(http.StatusInternalServerError)
				return
			}

			mu.Lock()
			batchAPIKey = payload.ApiKey
			mu.Unlock()
			w.WriteHeader(http.StatusOK)
		case strings.Contains(r.URL.Path, "/remote_config"):
			mu.Lock()
			remoteConfigToken = r.URL.Query().Get("token")
			remoteConfigAuth = r.Header.Get("Authorization")
			mu.Unlock()
			w.Header().Set("Content-Type", "application/json")
			_, _ = w.Write([]byte(`"ok"`))
		default:
			t.Errorf("Unexpected request to %s", r.URL.Path)
			w.WriteHeader(http.StatusNotFound)
		}
	}))
	defer server.Close()

	client, err := NewWithConfig(" \n test-api-key\t ", Config{
		PersonalApiKey: " \ttest-personal-key\n ",
		Endpoint:       " \n" + server.URL + "\t ",
		BatchSize:      1,
	})
	require.NoError(t, err)

	payload, err := client.GetRemoteConfigPayload("test-flag")
	require.NoError(t, err)
	require.Equal(t, "ok", payload)

	require.NoError(t, client.Enqueue(Capture{DistinctId: "test-user", Event: "test-event"}))
	require.NoError(t, client.Close())

	mu.Lock()
	defer mu.Unlock()
	require.Equal(t, "test-api-key", batchAPIKey)
	require.Equal(t, "test-api-key", remoteConfigToken)
	require.Equal(t, "Bearer test-personal-key", remoteConfigAuth)
}

var _ Message = (*testErrorMessage)(nil)

// Instances of this type are used to force message validation errors in unit
// tests.
type testErrorMessage struct{}
type testAPIErrorMessage struct{}

func (m testErrorMessage) internal() {
}

func (m testErrorMessage) Validate() error { return testError }

func (m testErrorMessage) APIfy() APIMessage {
	return testAPIErrorMessage{}
}

var (
	// A control error returned by mock functions to emulate a failure.
	//lint:ignore ST1012 variable name is fine :D
	testError = errors.New("test error")

	// HTTP transport that always succeeds.
	testTransportOK = roundTripperFunc(func(r *http.Request) (*http.Response, error) {
		return &http.Response{
			Status:     http.StatusText(http.StatusOK),
			StatusCode: http.StatusOK,
			Proto:      r.Proto,
			ProtoMajor: r.ProtoMajor,
			ProtoMinor: r.ProtoMinor,
			Body:       io.NopCloser(strings.NewReader("")),
			Request:    r,
		}, nil
	})

	testTransportFeatureFlagsOK = roundTripperFunc(func(r *http.Request) (*http.Response, error) {
		var body string
		if strings.HasPrefix(r.URL.Path, "/flags/definitions") {
			body = fixture("feature_flag/test-simple-flag.json")
		}
		return &http.Response{
			Status:     http.StatusText(http.StatusOK),
			StatusCode: http.StatusOK,
			Proto:      r.Proto,
			ProtoMajor: r.ProtoMajor,
			ProtoMinor: r.ProtoMinor,
			Body:       io.NopCloser(strings.NewReader(body)),
			Request:    r,
		}, nil
	})

	// HTTP transport that sleeps for a little while and eventually succeeds.
	testTransportDelayed = roundTripperFunc(func(r *http.Request) (*http.Response, error) {
		time.Sleep(10 * time.Millisecond)
		return testTransportOK.RoundTrip(r)
	})

	// HTTP transport that always returns a 400.
	testTransportBadRequest = roundTripperFunc(func(r *http.Request) (*http.Response, error) {
		return &http.Response{
			Status:     http.StatusText(http.StatusBadRequest),
			StatusCode: http.StatusBadRequest,
			Proto:      r.Proto,
			ProtoMajor: r.ProtoMajor,
			ProtoMinor: r.ProtoMinor,
			Body:       io.NopCloser(strings.NewReader("")),
			Request:    r,
		}, nil
	})

	// HTTP transport that always returns a 400 with an erroring body reader.
	testTransportBodyError = roundTripperFunc(func(r *http.Request) (*http.Response, error) {
		return &http.Response{
			Status:     http.StatusText(http.StatusBadRequest),
			StatusCode: http.StatusBadRequest,
			Proto:      r.Proto,
			ProtoMajor: r.ProtoMajor,
			ProtoMinor: r.ProtoMinor,
			Body:       io.NopCloser(readFunc(func(b []byte) (int, error) { return 0, testError })),
			Request:    r,
		}, nil
	})

	// HTTP transport that always return an error.
	testTransportError = roundTripperFunc(func(r *http.Request) (*http.Response, error) {
		return nil, testError
	})
)

func fixture(name string) string {
	f, err := os.Open(filepath.Join("fixtures", name))
	if err != nil {
		panic(err)
	}
	defer f.Close()
	b, err := io.ReadAll(f)
	if err != nil {
		panic(err)
	}
	return string(b)
}

func assertPayloadEqual(t *testing.T, expected, actual string) {
	t.Helper()

	sysCtx := getSystemContext().ToProperties()

	var expectedJSON, actualJSON map[string]any
	require.NoError(t, json.Unmarshal([]byte(expected), &expectedJSON))
	require.NoError(t, json.Unmarshal([]byte(actual), &actualJSON))

	batch, ok := actualJSON["batch"].([]any)
	require.True(t, ok, "actual JSON missing 'batch' array")
	for i, item := range batch {
		event, ok := item.(map[string]any)
		if !ok {
			continue
		}
		props, ok := event["properties"].(map[string]any)
		if !ok {
			continue
		}
		for key := range sysCtx {
			if _, exists := props[key]; !exists {
				t.Errorf("batch[%d] missing %s in properties", i, key)
			}
		}
	}

	knownSysCtxKeys := map[string]struct{}{
		"$os":         {},
		"$os_version": {},
		"$os_distro":  {},
		"$go_version": {},
	}
	opt := cmpopts.IgnoreMapEntries(func(k string, v any) bool {
		_, ok := knownSysCtxKeys[k]
		return ok
	})
	if diff := cmp.Diff(expectedJSON, actualJSON, opt); diff != "" {
		t.Errorf("payload mismatch (-expected +actual):\n%s", diff)
	}
}

func mockTime() time.Time {
	// time.Unix(0, 0) fails on Circle
	return time.Date(2009, time.November, 10, 23, 0, 0, 0, time.UTC)
}

func mockServer() (chan []byte, *httptest.Server) {
	done := make(chan []byte, 1)

	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		buf := bytes.NewBuffer(nil)
		io.Copy(buf, r.Body)

		var v any
		err := json.Unmarshal(buf.Bytes(), &v)
		if err != nil {
			panic(err)
		}

		b, err := json.MarshalIndent(v, "", "  ")
		if err != nil {
			panic(err)
		}

		done <- b
	}))

	return done, server
}

func ExampleCapture() {
	body, server := mockServer()
	defer server.Close()

	client, _ := NewWithConfig("Csyjlnlun3OzyNJAafdlv", Config{
		Endpoint:  server.URL,
		BatchSize: 1,
		now:       mockTime,
	})
	defer client.Close()

	client.Enqueue(Capture{
		Uuid:       "00000000-0000-0000-0000-000000000000",
		Event:      "Download",
		DistinctId: "123456",
		Properties: Properties{
			"application": "Insights Go",
			"version":     "1.0.0",
		},
		SendFeatureFlags: SendFeatureFlags(false),
	})

	fmt.Printf("%s\n", <-body)
	// Output:
	// {
	//   "api_key": "Csyjlnlun3OzyNJAafdlv",
	//   "batch": [
	//     {
	//       "distinct_id": "123456",
	//       "event": "Download",
	//       "library": "insights-go",
	//       "library_version": "1.0.0",
	//       "properties": {
	//         "$geoip_disable": true,
	//         "$lib": "insights-go",
	//         "$lib_version": "1.0.0",
	//         "application": "Insights Go",
	//         "platform": "macos",
	//         "version": "1.0.0"
	//       },
	//       "send_feature_flags": false,
	//       "timestamp": "2009-11-10T23:00:00Z",
	//       "type": "capture",
	//       "uuid": "00000000-0000-0000-0000-000000000000"
	//     }
	//   ]
	// }
}

func TestCaptureNoProperties(t *testing.T) {
	defer func() {
		// Ensure that the test doesn't panic.
		if recover() != nil {
			t.Error("shouldnt have panicked when merging properties into nil properties")
		}
	}()

	_, server := mockServer()
	defer server.Close()

	client, _ := NewWithConfig("Csyjlnlun3OzyNJAafdlv", Config{
		Endpoint:               server.URL,
		BatchSize:              1,
		now:                    mockTime,
		DefaultEventProperties: NewProperties().Set("service", "api"),
	})
	defer client.Close()

	client.Enqueue(Capture{
		Event:            "Download",
		DistinctId:       "123456",
		SendFeatureFlags: SendFeatureFlags(false),
	})
}

func TestEnqueue(t *testing.T) {
	exception := Exception{
		Uuid:         "00000000-0000-0000-0000-000000000004",
		DistinctId:   "my-user-id",
		Timestamp:    time.Date(2025, 8, 11, 20, 43, 37, 0, time.UTC),
		DisableGeoIP: true,
		ExceptionList: []ExceptionItem{
			{
				Type:  "Exception Title",
				Value: "Exception Description",
				Stacktrace: &ExceptionStacktrace{
					Type: "raw",
					Frames: []StackFrame{
						{
							Filename:  "/Users/Developer/insights-go/examples/main.go",
							LineNo:    56,
							Function:  "main.main",
							InApp:     true,
							Synthetic: false,
							Platform:  "go",
						},
					},
				},
			},
		},
	}
	f, tv := false, true
	tests := map[string]struct {
		ref          string
		msg          Message
		disableGeoIP *bool
	}{
		"alias": {
			strings.TrimSpace(fixture("test-enqueue-alias.json")),
			Alias{Uuid: "00000000-0000-0000-0000-000000000001", Alias: "A", DistinctId: "B"},
			&tv,
		},

		"identify": {
			strings.TrimSpace(fixture("test-enqueue-identify.json")),
			Identify{
				Uuid:       "00000000-0000-0000-0000-000000000002",
				DistinctId: "B",
				Properties: Properties{"email": "[email protected]"},
			},
			&tv,
		},
		"identify-default-geoip": {
			strings.TrimSpace(fixture("test-enqueue-identify.json")),
			Identify{
				Uuid:       "00000000-0000-0000-0000-000000000002",
				DistinctId: "B",
				Properties: Properties{"email": "[email protected]"},
			},
			nil,
		},

		"groupIdentify": {
			strings.TrimSpace(fixture("test-enqueue-group-identify.json")),
			GroupIdentify{
				Uuid:       "00000000-0000-0000-0000-000000000003",
				DistinctId: "$organization_id:5",
				Type:       "organization",
				Key:        "id:5",
				Properties: Properties{},
			},
			&tv,
		},

		"capture": {
			strings.TrimSpace(fixture("test-enqueue-capture.json")),
			Capture{
				Uuid:       "00000000-0000-0000-0000-000000000010",
				Event:      "Download",
				DistinctId: "123456",
				Properties: Properties{
					"application": "Insights Go",
					"version":     "1.0.0",
				},
				SendFeatureFlags: SendFeatureFlags(false),
			},
			&f,
		},

		"captureWithDisableGeoIP": {
			strings.TrimSpace(fixture("test-enqueue-capture-with-disable-geoip.json")),
			Capture{
				Uuid:       "00000000-0000-0000-0000-000000000011",
				Event:      "Download",
				DistinctId: "123456",
				Properties: Properties{
					"application": "Insights Go",
					"version":     "1.0.0",
				},
				SendFeatureFlags: SendFeatureFlags(false),
			},
			&tv,
		},

		"exception": {
			strings.TrimSpace(fixture("test-enqueue-exception.json")),
			exception,
			&tv,
		},

		"*alias": {
			strings.TrimSpace(fixture("test-enqueue-alias.json")),
			&Alias{Uuid: "00000000-0000-0000-0000-000000000001", Alias: "A", DistinctId: "B"},
			&tv,
		},

		"*identify": {
			strings.TrimSpace(fixture("test-enqueue-identify.json")),
			&Identify{
				Uuid:       "00000000-0000-0000-0000-000000000002",
				DistinctId: "B",
				Properties: Properties{"email": "[email protected]"},
			},
			&tv,
		},

		"*groupIdentify": {
			strings.TrimSpace(fixture("test-enqueue-group-identify.json")),
			&GroupIdentify{
				Uuid:       "00000000-0000-0000-0000-000000000003",
				DistinctId: "$organization_id:5",
				Type:       "organization",
				Key:        "id:5",
				Properties: Properties{},
			},
			&tv,
		},

		"*capture": {
			strings.TrimSpace(fixture("test-enqueue-capture-with-uuid.json")),
			&Capture{
				Uuid:       "11111111-1111-1111-1111-111111111111",
				Event:      "Download",
				DistinctId: "123456",
				Properties: Properties{
					"application": "Insights Go",
					"version":     "1.0.0",
				},
				SendFeatureFlags: SendFeatureFlags(false),
			},
			&tv,
		},

		"*exception": {
			strings.TrimSpace(fixture("test-enqueue-exception.json")),
			&exception,
			&tv,
		},
	}

	body, server := mockServer()
	defer server.Close()

	for name, test := range tests {
		t.Run(name, func(t *testing.T) {
			client, _ := NewWithConfig("Csyjlnlun3OzyNJAafdlv", Config{
				Endpoint:     server.URL,
				Verbose:      true,
				Logger:       toLogger(t),
				BatchSize:    1,
				now:          mockTime,
				DisableGeoIP: test.disableGeoIP,
			})
			defer client.Close()

			if err := client.Enqueue(test.msg); err != nil {
				t.Error(err)
				return
			}

			assertPayloadEqual(t, test.ref, string(<-body))
		})
	}
}

// TestEnqueue_UUID_PreSupplied verifies that user-provided UUIDs are preserved
// on outgoing events for all message types.
func TestEnqueue_UUID_PreSupplied(t *testing.T) {
	tests := []struct {
		name string
		msg  Message
		uuid string
	}{
		{
			name: "Capture",
			msg:  Capture{Uuid: "user-provided-uuid-capture", Event: "test", DistinctId: "user1"},
			uuid: "user-provided-uuid-capture",
		},
		{
			name: "Alias",
			msg:  Alias{Uuid: "user-provided-uuid-alias", Alias: "new", DistinctId: "user1"},
			uuid: "user-provided-uuid-alias",
		},
		{
			name: "Identify",
			msg:  Identify{Uuid: "user-provided-uuid-identify", DistinctId: "user1"},
			uuid: "user-provided-uuid-identify",
		},
		{
			name: "GroupIdentify",
			msg:  GroupIdentify{Uuid: "user-provided-uuid-group", Type: "company", Key: "acme"},
			uuid: "user-provided-uuid-group",
		},
		{
			name: "Exception",
			msg: Exception{
				Uuid:       "user-provided-uuid-exception",
				DistinctId: "user1",
				ExceptionList: []ExceptionItem{
					{Type: "Error", Value: "test error"},
				},
			},
			uuid: "user-provided-uuid-exception",
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			body, server := mockServer()
			defer server.Close()

			cli, _ := NewWithConfig("test-key", Config{
				Endpoint:  server.URL,
				BatchSize: 1,
				now:       mockTime,
			})
			defer cli.Close()

			err := cli.Enqueue(tt.msg)
			require.NoError(t, err)

			// Read the body sent to the server
			select {
			case res := <-body:
				require.Contains(t, string(res), tt.uuid,
					"pre-supplied UUID should be preserved in request body")
			case <-time.After(time.Second):
				t.Fatal("timeout waiting for request")
			}
		})
	}
}

// TestEnqueue_UUID_AutoGenerated verifies that UUIDs are auto-generated when
// not provided by the user for all message types.
func TestEnqueue_UUID_AutoGenerated(t *testing.T) {
	// UUID v4 format regex: 8-4-4-4-12 hex characters
	uuidPattern := regexp.MustCompile(`[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}`)

	tests := []struct {
		name string
		msg  Message
	}{
		{
			name: "Capture",
			msg:  Capture{Event: "test", DistinctId: "user1"},
		},
		{
			name: "Alias",
			msg:  Alias{Alias: "new", DistinctId: "user1"},
		},
		{
			name: "Identify",
			msg:  Identify{DistinctId: "user1"},
		},
		{
			name: "GroupIdentify",
			msg:  GroupIdentify{Type: "company", Key: "acme"},
		},
		{
			name: "Exception",
			msg: Exception{
				DistinctId: "user1",
				ExceptionList: []ExceptionItem{
					{Type: "Error", Value: "test error"},
				},
			},
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			body, server := mockServer()
			defer server.Close()

			cli, _ := NewWithConfig("test-key", Config{
				Endpoint:  server.URL,
				BatchSize: 1,
				now:       mockTime,
			})
			defer cli.Close()

			err := cli.Enqueue(tt.msg)
			require.NoError(t, err)

			// Read the body sent to the server
			select {
			case res := <-body:
				resStr := string(res)
				// Verify a valid UUID was generated
				matches := uuidPattern.FindAllString(resStr, -1)
				require.NotEmpty(t, matches,
					"auto-generated UUID should be present in request body")
				// Verify it's not empty string
				require.NotContains(t, resStr, `"uuid":""`,
					"UUID should not be empty")
			case <-time.After(time.Second):
				t.Fatal("timeout waiting for request")
			}
		})
	}
}

var _ Message = (*customMessage)(nil)

type customMessage struct {
}
type customAPIMessage struct {
}

func (c *customMessage) internal() {
}

func (c *customMessage) Validate() error {
	return nil
}

func (c *customMessage) APIfy() APIMessage {
	return customAPIMessage{}
}

func TestEnqueuingCustomTypeFails(t *testing.T) {
	client := New("0123456789")
	err := client.Enqueue(&customMessage{})
	require.Error(t, err)
	require.EqualError(t, err, "messages with custom types cannot be enqueued: *insights.customMessage",
		"invalid/missing error when queuing unsupported message")
}

func TestCaptureWithInterval(t *testing.T) {
	const interval = 100 * time.Millisecond
	var ref = strings.TrimSpace(fixture("test-interval-capture.json"))

	body, server := mockServer()
	defer server.Close()

	t0 := time.Now()

	client, _ := NewWithConfig("Csyjlnlun3OzyNJAafdlv", Config{
		Endpoint: server.URL,
		Interval: interval,
		Verbose:  true,
		Logger:   toLogger(t),
		now:      mockTime,
	})
	defer client.Close()

	client.Enqueue(Capture{
		Uuid:       "00000000-0000-0000-0000-000000000012",
		Event:      "Download",
		DistinctId: "123456",
		Properties: Properties{
			"application": "Insights Go",
			"version":     "1.0.0",
		},
		SendFeatureFlags: SendFeatureFlags(false),
	})

	// Will flush in 100 milliseconds
	assertPayloadEqual(t, ref, string(<-body))

	if t1 := time.Now(); t1.Sub(t0) < interval {
		t.Error("the flushing interval is too short:", interval)
	}
}

func TestCaptureWithTimestamp(t *testing.T) {
	var ref = strings.TrimSpace(fixture("test-timestamp-capture.json"))

	body, server := mockServer()
	defer server.Close()

	client, _ := NewWithConfig("Csyjlnlun3OzyNJAafdlv", Config{
		Endpoint:  server.URL,
		Verbose:   true,
		Logger:    toLogger(t),
		BatchSize: 1,
		now:       mockTime,
	})
	defer client.Close()

	client.Enqueue(Capture{
		Uuid:       "00000000-0000-0000-0000-000000000013",
		Event:      "Download",
		DistinctId: "123456",
		Properties: Properties{
			"application": "Insights Go",
			"version":     "1.0.0",
		},
		SendFeatureFlags: SendFeatureFlags(false),
		Timestamp:        time.Date(2015, time.July, 10, 23, 0, 0, 0, time.UTC),
	})

	assertPayloadEqual(t, ref, string(<-body))
}

func TestCaptureWithDefaultProperties(t *testing.T) {
	var ref = strings.TrimSpace(fixture("test-merge-capture.json"))

	body, server := mockServer()
	defer server.Close()

	client, _ := NewWithConfig("Csyjlnlun3OzyNJAafdlv", Config{
		Endpoint:               server.URL,
		Verbose:                true,
		DefaultEventProperties: NewProperties().Set("service", "api"),
		Logger:                 toLogger(t),
		BatchSize:              1,
		now:                    mockTime,
	})
	defer client.Close()

	client.Enqueue(Capture{
		Uuid:       "00000000-0000-0000-0000-000000000014",
		Event:      "Download",
		DistinctId: "123456",
		Properties: Properties{
			"application": "Insights Go",
			"version":     "1.0.0",
		},
		SendFeatureFlags: SendFeatureFlags(false),
		Timestamp:        time.Date(2015, time.July, 10, 23, 0, 0, 0, time.UTC),
	})

	assertPayloadEqual(t, ref, string(<-body))
}

func TestCaptureMany(t *testing.T) {
	var ref = strings.TrimSpace(fixture("test-many-capture.json"))

	body, server := mockServer()
	defer server.Close()

	client, _ := NewWithConfig("Csyjlnlun3OzyNJAafdlv", Config{
		Endpoint:  server.URL,
		Verbose:   true,
		Logger:    toLogger(t),
		BatchSize: 3,
		now:       mockTime,
	})
	defer client.Close()

	// UUIDs for the first batch (3 events) - remaining 2 events will be in a second batch
	uuids := []string{
		"00000000-0000-0000-0000-000000000015",
		"00000000-0000-0000-0000-000000000016",
		"00000000-0000-0000-0000-000000000017",
		"00000000-0000-0000-0000-000000000018",
		"00000000-0000-0000-0000-000000000019",
	}
	for i := range 5 {
		client.Enqueue(Capture{
			Uuid:       uuids[i],
			Event:      "Download",
			DistinctId: "123456",
			Properties: Properties{
				"application": "Insights Go",
				"version":     i,
			},
			SendFeatureFlags: SendFeatureFlags(false),
		})
	}

	assertPayloadEqual(t, ref, string(<-body))
}

func TestClientCloseTwice(t *testing.T) {
	client := New("0123456789")
	require.NoError(t, client.Close())
	require.EqualError(t, client.Close(), ErrClosed.Error())
	require.EqualError(t, client.Enqueue(Capture{DistinctId: "1", Event: "A"}), ErrClosed.Error())
}

func TestClientConfigError(t *testing.T) {
	client, err := NewWithConfig("0123456789", Config{
		Interval: -1 * time.Second,
	})
	require.Error(t, err, "no error returned when creating a client with an invalid config")
	require.ErrorAs(t, err, &ConfigError{}, "invalid error type returned when creating a client with an invalid config")
	require.Nil(t, client)
}

func TestClientWithPersonalApiKeyClosing(t *testing.T) {
	client, err := NewWithConfig("123", Config{
		PersonalApiKey: "123",
		Transport:      testTransportFeatureFlagsOK,
	})
	require.NoError(t, err)
	require.NoError(t, client.Close())
}

func TestClientEnqueueError(t *testing.T) {
	client := New("0123456789")
	defer client.Close()

	if err := client.Enqueue(testErrorMessage{}); err != testError {
		t.Error("invlaid error returned when queueing an invalid message:", err)
	}
}

func TestClientCallback(t *testing.T) {
	reschan := make(chan bool, 1)
	errchan := make(chan error, 1)

	client, _ := NewWithConfig("0123456789", Config{
		Logger: testLogger{t.Logf, t.Logf},
		Callback: testCallback{
			func(m APIMessage) { reschan <- true },
			func(m APIMessage, e error) { errchan <- e },
		},
		Transport: testTransportOK,
	})

	client.Enqueue(Capture{
		DistinctId: "A",
		Event:      "B",
	})
	client.Close()

	select {
	case <-reschan:
	case err := <-errchan:
		t.Error("failure callback triggered:", err)
	}
}

func TestClientMarshalMessageError(t *testing.T) {
	errchan := make(chan error, 1)

	client, _ := NewWithConfig("0123456789", Config{
		Logger: testLogger{t.Logf, t.Logf},
		Callback: testCallback{
			nil,
			func(m APIMessage, e error) { errchan <- e },
		},
		Transport: testTransportOK,
	})

	// Functions cannot be serializable, this should break the JSON marshaling
	// and trigger the failure callback.
	client.Enqueue(Capture{
		DistinctId: "A",
		Event:      "B",
		Properties: Properties{"invalid": func() {}},
	})
	client.Close()

	if err := <-errchan; err == nil {
		t.Error("failure callback not triggered for unserializable message")

	} else if _, ok := err.(*json.UnsupportedTypeError); !ok {
		t.Errorf("invalid error type returned by unserializable message: %T", err)
	}
}

func TestClientErrorWithMalformedEndpoint(t *testing.T) {
	_, err := NewWithConfig("0123456789", Config{
		Endpoint:  "://localhost:80", // Malformed endpoint URL.
		Logger:    testLogger{t.Logf, t.Logf},
		Transport: testTransportOK,
	})

	require.ErrorContains(t, err, "invalid endpoint")
}

func TestClientRoundTripperError(t *testing.T) {
	t.Parallel()
	errchan := make(chan error, 1)

	client, _ := NewWithConfig("0123456789", Config{
		Logger: testLogger{t.Logf, t.Logf},
		Callback: testCallback{
			nil,
			func(m APIMessage, e error) { errchan <- e },
		},
		Transport: testTransportError,
	})

	client.Enqueue(Capture{DistinctId: "A", Event: "B"})
	client.Close()

	if err := <-errchan; err == nil {
		t.Error("failure callback not triggered for an invalid request")

	} else if e, ok := err.(*url.Error); !ok {
		t.Errorf("invalid error returned by round tripper: %T: %s", err, err)

	} else if e.Err != testError {
		t.Errorf("invalid error returned by round tripper: %T: %s", e.Err, e.Err)
	}
}

func TestClientRetryError(t *testing.T) {
	errchan := make(chan error, 1)

	client, _ := NewWithConfig("0123456789", Config{
		Logger: testLogger{t.Logf, t.Logf},
		Callback: testCallback{
			nil,
			func(m APIMessage, e error) { errchan <- e },
		},
		Transport: roundTripperFunc(func(r *http.Request) (*http.Response, error) {
			return nil, testError
		}),
		BatchSize:  1,
		RetryAfter: func(i int) time.Duration { return time.Millisecond },
	})

	client.Enqueue(Capture{DistinctId: "A", Event: "B"})

	// Each retry should happen ~1 millisecond, this should give enough time to
	// the test to trigger the failure callback.
	time.Sleep(50 * time.Millisecond)

	if err := <-errchan; err == nil {
		t.Error("failure callback not triggered for a retry falure")

	} else if e, ok := err.(*url.Error); !ok {
		t.Errorf("invalid error returned by round tripper: %T: %s", err, err)

	} else if e.Err != testError {
		t.Errorf("invalid error returned by round tripper: %T: %s", e.Err, e.Err)
	}

	client.Close()
}

func TestClientResponse400(t *testing.T) {
	t.Parallel()
	errchan := make(chan error, 1)

	client, _ := NewWithConfig("0123456789", Config{
		Logger: testLogger{t.Logf, t.Logf},
		Callback: testCallback{
			nil,
			func(m APIMessage, e error) { errchan <- e },
		},
		// This HTTP transport always return 400's.
		Transport: testTransportBadRequest,
	})

	client.Enqueue(Capture{DistinctId: "A", Event: "B"})
	client.Close()

	if err := <-errchan; err == nil {
		t.Error("failure callback not triggered for a 400 response")
	}
}

func TestClientResponseBodyError(t *testing.T) {
	t.Parallel()
	errchan := make(chan error, 1)

	client, _ := NewWithConfig("0123456789", Config{
		Logger: testLogger{t.Logf, t.Logf},
		Callback: testCallback{
			nil,
			func(m APIMessage, e error) { errchan <- e },
		},
		// This HTTP transport always return 400's with an erroring body.
		Transport: testTransportBodyError,
	})

	client.Enqueue(Capture{DistinctId: "A", Event: "B"})
	client.Close()

	if err := <-errchan; err == nil {
		t.Error("failure callback not triggered for a 400 response")

	} else if err != testError {
		t.Errorf("invalid error returned by erroring response body: %T: %s", err, err)
	}
}

func TestClientWorkerPool(t *testing.T) {
	successCount := atomic.Int32{}

	client, err := NewWithConfig("0123456789", Config{
		Logger: testLogger{t.Logf, t.Logf},
		Callback: testCallback{
			func(m APIMessage) { successCount.Add(1) },
			func(m APIMessage, e error) { t.Errorf("unexpected failure: %v", e) },
		},
		Transport: testTransportDelayed,
		// Use single worker with small batch size to test sequential processing
		BatchSize:           1,
		MaxEnqueuedRequests: 1,
	})
	require.NoError(t, err)

	// Both messages should succeed with the worker pool (they queue up)
	require.NoError(t, client.Enqueue(Capture{DistinctId: "A", Event: "B"}))
	require.NoError(t, client.Enqueue(Capture{DistinctId: "A", Event: "B"}))
	require.NoError(t, client.Close())

	if successCount.Load() != 2 {
		t.Errorf("expected 2 successful callbacks, got %d", successCount.Load())
	}
}

func TestFeatureFlagsWithNoPersonalApiKey(t *testing.T) {
	// silence Errorf by tossing them in channel and not reading back
	errchan := make(chan error, 1)
	defer close(errchan)

	var logged []string
	client, err := NewWithConfig("Csyjlnlun3OzyNJAafdlv", Config{
		PersonalApiKey: " \n\t ",
		Logger: testLogger{
			logf: func(format string, args ...any) {
				logged = append(logged, fmt.Sprintf(format, args...))
			},
			errorf: t.Logf,
		},
		Callback: testCallback{
			func(m APIMessage) {},
			func(m APIMessage, e error) { errchan <- e },
		},
	})
	require.NoError(t, err)

	require.ErrorIs(t, client.ReloadFeatureFlags(), ErrNoPersonalAPIKey)

	payload, err := client.GetRemoteConfigPayload("test-flag")
	require.ErrorIs(t, err, ErrNoPersonalAPIKey)
	require.Empty(t, payload)

	localFlag, err := client.GetFeatureFlag(FeatureFlagPayload{
		Key:                 "test-flag",
		DistinctId:          "test-user",
		OnlyEvaluateLocally: true,
	})
	require.ErrorIs(t, err, ErrNoPersonalAPIKey)
	require.Nil(t, localFlag)

	localFlags, err := client.GetAllFlags(FeatureFlagPayloadNoKey{
		DistinctId:          "test-user",
		OnlyEvaluateLocally: true,
	})
	require.ErrorIs(t, err, ErrNoPersonalAPIKey)
	require.Nil(t, localFlags)

	localEvaluations, err := client.EvaluateFlags(EvaluateFlagsPayload{
		DistinctId:          "test-user",
		OnlyEvaluateLocally: true,
	})
	require.ErrorIs(t, err, ErrNoPersonalAPIKey)
	require.NotNil(t, localEvaluations)
	require.Empty(t, localEvaluations.Keys())

	joinedLogs := strings.Join(logged, "\n")
	require.Contains(t, joinedLogs, "PostHog personal_api_key is not configured; ReloadFeatureFlags requires a PersonalApiKey.")
	require.Contains(t, joinedLogs, "PostHog personal_api_key is not configured; GetRemoteConfigPayload requires a PersonalApiKey.")
	require.Contains(t, joinedLogs, "PostHog personal_api_key is not configured; GetFeatureFlagResult requires a PersonalApiKey.")
	require.Contains(t, joinedLogs, "PostHog personal_api_key is not configured; GetAllFlags requires a PersonalApiKey.")
	require.Contains(t, joinedLogs, "PostHog personal_api_key is not configured; EvaluateFlags requires a PersonalApiKey.")
}

func TestFeatureFlagPublicMethodsKeepDistinctIDConfigError(t *testing.T) {
	client, err := NewWithConfig("test-api-key", Config{})
	require.NoError(t, err)
	defer client.Close()

	_, err = client.IsFeatureEnabled(FeatureFlagPayload{Key: "test-flag"})
	assertDistinctIDConfigError(t, err)

	_, err = client.GetFeatureFlag(FeatureFlagPayload{Key: "test-flag"})
	assertDistinctIDConfigError(t, err)

	_, err = client.GetFeatureFlagResult(FeatureFlagPayload{Key: "test-flag"})
	assertDistinctIDConfigError(t, err)

	_, err = client.GetFeatureFlagPayload(FeatureFlagPayload{Key: "test-flag"})
	assertDistinctIDConfigError(t, err)

	_, err = client.GetAllFlags(FeatureFlagPayloadNoKey{})
	assertDistinctIDConfigError(t, err)
}

func assertDistinctIDConfigError(t *testing.T, err error) {
	t.Helper()
	var configErr ConfigError
	require.ErrorAs(t, err, &configErr)
	require.Equal(t, "DistinctId required", configErr.Reason)
	require.Equal(t, "Distinct Id", configErr.Field)
}

func TestIsFeatureEnabled(t *testing.T) {
	tests := []struct {
		name           string
		flagConfig     FeatureFlagPayload
		mockResponse   string
		expectedResult any
		expectedError  string
	}{
		{
			name: "Feature flag is enabled",
			flagConfig: FeatureFlagPayload{
				Key:        "test-flag",
				DistinctId: "user123",
			},
			mockResponse:   `{"featureFlags": {"test-flag": true}}`,
			expectedResult: true,
		},
		{
			name: "Feature flag is disabled",
			flagConfig: FeatureFlagPayload{
				Key:        "test-flag",
				DistinctId: "user456",
			},
			mockResponse:   `{"featureFlags": {"test-flag": false}}`,
			expectedResult: false,
		},
		{
			name: "Feature flag is a string 'true'",
			flagConfig: FeatureFlagPayload{
				Key:        "test-flag",
				DistinctId: "user789",
			},
			mockResponse:   `{"featureFlags": {"test-flag": "true"}}`,
			expectedResult: "true",
		},
		{
			name: "Feature flag is a string 'false'",
			flagConfig: FeatureFlagPayload{
				Key:        "test-flag",
				DistinctId: "user101",
			},
			mockResponse:   `{"featureFlags": {"test-flag": "false"}}`,
			expectedResult: "false",
		},
		{
			name: "Feature flag is a variant string",
			flagConfig: FeatureFlagPayload{
				Key:        "test-flag",
				DistinctId: "user202",
			},
			mockResponse:   `{"featureFlags": {"test-flag": "variant-a"}}`,
			expectedResult: "variant-a",
		},
		{
			name: "Feature flag doesn't exist",
			flagConfig: FeatureFlagPayload{
				Key:        "non-existent-flag",
				DistinctId: "user303",
			},
			mockResponse:   `{"featureFlags": {}}`,
			expectedResult: false,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				if r.URL.Path == "/flags/" {
					w.WriteHeader(http.StatusOK)
					w.Write([]byte(tt.mockResponse))
				} else {
					t.Errorf("Unexpected request to %s", r.URL.Path)
				}
			}))
			defer server.Close()

			client, _ := NewWithConfig("test-api-key", Config{
				Endpoint: server.URL,
			})

			result, err := client.IsFeatureEnabled(tt.flagConfig)

			if tt.expectedError != "" {
				if err == nil || !strings.Contains(err.Error(), tt.expectedError) {
					t.Errorf("Expected error containing '%s', got '%v'", tt.expectedError, err)
				}
			} else {
				if err != nil {
					t.Errorf("Unexpected error: %v", err)
				}
				if result != tt.expectedResult {
					t.Errorf("Expected result %v, got %v", tt.expectedResult, result)
				}
			}
		})
	}
}

func TestDeviceIdInFlagsRequest(t *testing.T) {
	t.Run("GetFeatureFlag passes device_id when provided", func(t *testing.T) {
		var requestData FlagsRequestData
		server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			if r.URL.Path == "/flags" || r.URL.Path == "/flags/" {
				body, _ := io.ReadAll(r.Body)
				json.Unmarshal(body, &requestData)
				w.Write([]byte(`{"featureFlags": {"test-flag": true}}`))
			}
		}))
		defer server.Close()

		client, _ := NewWithConfig("test-api-key", Config{
			Endpoint: server.URL,
		})
		defer client.Close()

		deviceId := "test-device-123"
		_, err := client.GetFeatureFlag(FeatureFlagPayload{
			Key:        "test-flag",
			DistinctId: "user-123",
			DeviceId:   &deviceId,
		})

		if err != nil {
			t.Errorf("Expected no error, got: %v", err)
		}
		if requestData.DeviceId == nil {
			t.Error("Expected device_id to be set in request, got nil")
		} else if *requestData.DeviceId != "test-device-123" {
			t.Errorf("Expected device_id 'test-device-123', got: %s", *requestData.DeviceId)
		}
	})

	t.Run("GetFeatureFlag omits device_id when nil", func(t *testing.T) {
		var receivedBody string
		server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			if r.URL.Path == "/flags" || r.URL.Path == "/flags/" {
				body, _ := io.ReadAll(r.Body)
				receivedBody = string(body)
				w.Write([]byte(`{"featureFlags": {"test-flag": true}}`))
			}
		}))
		defer server.Close()

		client, _ := NewWithConfig("test-api-key", Config{
			Endpoint: server.URL,
		})
		defer client.Close()

		_, err := client.GetFeatureFlag(FeatureFlagPayload{
			Key:        "test-flag",
			DistinctId: "user-123",
		})

		if err != nil {
			t.Errorf("Expected no error, got: %v", err)
		}
		if strings.Contains(receivedBody, "device_id") {
			t.Errorf("Expected request to NOT contain device_id when nil, got: %s", receivedBody)
		}
	})

	t.Run("GetAllFlags passes device_id when provided", func(t *testing.T) {
		var requestData FlagsRequestData
		server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			if r.URL.Path == "/flags" || r.URL.Path == "/flags/" {
				body, _ := io.ReadAll(r.Body)
				json.Unmarshal(body, &requestData)
				w.Write([]byte(`{"featureFlags": {"test-flag": true}}`))
			}
		}))
		defer server.Close()

		client, _ := NewWithConfig("test-api-key", Config{
			Endpoint: server.URL,
		})
		defer client.Close()

		deviceId := "test-device-456"
		_, err := client.GetAllFlags(FeatureFlagPayloadNoKey{
			DistinctId: "user-123",
			DeviceId:   &deviceId,
		})

		if err != nil {
			t.Errorf("Expected no error, got: %v", err)
		}
		if requestData.DeviceId == nil {
			t.Error("Expected device_id to be set in request, got nil")
		} else if *requestData.DeviceId != "test-device-456" {
			t.Errorf("Expected device_id 'test-device-456', got: %s", *requestData.DeviceId)
		}
	})

	t.Run("GetFeatureFlagPayload passes device_id when provided", func(t *testing.T) {
		var requestData FlagsRequestData
		server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			if r.URL.Path == "/flags" || r.URL.Path == "/flags/" {
				body, _ := io.ReadAll(r.Body)
				json.Unmarshal(body, &requestData)
				w.Write([]byte(`{"featureFlags": {"test-flag": true}, "featureFlagPayloads": {"test-flag": "payload-value"}}`))
			}
		}))
		defer server.Close()

		client, _ := NewWithConfig("test-api-key", Config{
			Endpoint: server.URL,
		})
		defer client.Close()

		deviceId := "test-device-789"
		_, err := client.GetFeatureFlagPayload(FeatureFlagPayload{
			Key:        "test-flag",
			DistinctId: "user-123",
			DeviceId:   &deviceId,
		})

		if err != nil {
			t.Errorf("Expected no error, got: %v", err)
		}
		if requestData.DeviceId == nil {
			t.Error("Expected device_id to be set in request, got nil")
		} else if *requestData.DeviceId != "test-device-789" {
			t.Errorf("Expected device_id 'test-device-789', got: %s", *requestData.DeviceId)
		}
	})

	t.Run("Capture SendFeatureFlagsOptions passes device_id when provided", func(t *testing.T) {
		var requestData FlagsRequestData
		received := make(chan struct{})
		server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			switch {
			case r.URL.Path == "/flags" || r.URL.Path == "/flags/":
				body, _ := io.ReadAll(r.Body)
				if err := json.Unmarshal(body, &requestData); err != nil {
					t.Errorf("Failed to parse request body: %v", err)
				}
				close(received)
				w.Write([]byte(`{"featureFlags": {"test-flag": true}}`))
			case strings.HasPrefix(r.URL.Path, "/flags/definitions"):
				w.WriteHeader(http.StatusOK)
				w.Write([]byte(`{"flags":[]}`))
			case strings.HasPrefix(r.URL.Path, "/batch"):
				w.WriteHeader(http.StatusOK)
				w.Write([]byte(`{}`))
			default:
				t.Errorf("Unexpected request to %s", r.URL.Path)
			}
		}))
		defer server.Close()

		client, _ := NewWithConfig("test-api-key", Config{
			Endpoint:       server.URL,
			PersonalApiKey: "personal-key",
			BatchSize:      1,
			now:            mockTime,
		})
		defer client.Close()

		deviceId := "test-device-456"
		err := client.Enqueue(Capture{
			Event:      "test_event",
			DistinctId: "test_user",
			SendFeatureFlags: &SendFeatureFlagsOptions{
				DeviceId: &deviceId,
			},
		})
		if err != nil {
			t.Fatal(err)
		}

		select {
		case <-received:
		case <-time.After(2 * time.Second):
			t.Fatal("Timed out waiting for flags request")
		}

		if requestData.DeviceId == nil {
			t.Error("Expected device_id to be set in request, got nil")
		} else if *requestData.DeviceId != "test-device-456" {
			t.Errorf("Expected device_id 'test-device-456', got: %s", *requestData.DeviceId)
		}
	})
}

func TestGetFeatureFlagPayloadWithNoPersonalApiKey(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path == "/flags" || r.URL.Path == "/flags/" {
			w.Write([]byte(fixture("test-flags-v3.json")))
		} else if !strings.HasPrefix(r.URL.Path, "/batch") {
			t.Errorf("client called an endpoint it shouldn't have: %s", r.URL.Path)
		}
	}))
	defer server.Close()

	client, _ := NewWithConfig("Csyjlnlun3OzyNJAafdlv", Config{
		Endpoint: server.URL,
		Logger:   testLogger{t.Logf, t.Logf},
		Callback: testCallback{
			func(m APIMessage) {},
			func(m APIMessage, e error) {},
		},
	})
	defer client.Close()

	// Test GetFeatureFlagPayload single scenario
	payload, err := client.GetFeatureFlagPayload(FeatureFlagPayload{
		Key:        "enabled-flag",
		DistinctId: "test-user",
	})

	if err != nil {
		t.Errorf("Expected no error, got: %v", err)
	}

	// Check that the flag payload is as expected (should match the value in the fixture)
	expectedPayload := "{\"foo\": 1}"
	if payload != expectedPayload {
		t.Errorf("Expected flag payload %v, got: %v", expectedPayload, payload)
	}

	// Test a bunch of GetFeatureFlagPayload scenarios
	tests := []struct {
		name          string
		flagConfig    FeatureFlagPayload
		mockResponse  string
		expectedValue string
		expectedError string
	}{
		{
			name: "Flag exists and there is a payload",
			flagConfig: FeatureFlagPayload{
				Key:        "test-flag",
				DistinctId: "user123",
			},
			mockResponse:  `{"featureFlags": {"test-flag": true}, "featureFlagPayloads": {"test-flag": "{\"test\": 1}"}}`,
			expectedValue: "{\"test\": 1}",
		},
		{
			name: "Flag exists and payload object is not present",
			flagConfig: FeatureFlagPayload{
				Key:        "test-flag",
				DistinctId: "user123",
			},
			mockResponse:  `{"featureFlags": {"test-flag": false}}`,
			expectedValue: "",
		},
		{
			name: "Flag exists and there is no payload",
			flagConfig: FeatureFlagPayload{
				Key:        "test-flag",
				DistinctId: "user123",
			},
			mockResponse:  `{"featureFlags": {"test-flag": false}, "featureFlagPayloads": {}}`,
			expectedValue: "",
		},

		{
			name: "Flag doesn't exist",
			flagConfig: FeatureFlagPayload{
				Key:        "non-existent-flag",
				DistinctId: "user123",
			},
			mockResponse:  `{"featureFlags": {"other-flag": true}}`,
			expectedValue: "",
		},
		{
			name: "Empty response",
			flagConfig: FeatureFlagPayload{
				Key:        "test-flag",
				DistinctId: "user123",
			},
			mockResponse:  `{}`,
			expectedValue: "",
		},
		{
			name: "Invalid JSON response",
			flagConfig: FeatureFlagPayload{
				Key:        "test-flag",
				DistinctId: "user123",
			},
			mockResponse:  `{invalid-json}`,
			expectedError: "error parsing response from /flags/",
		},
		{
			name: "Non-200 status code",
			flagConfig: FeatureFlagPayload{
				Key:        "test-flag",
				DistinctId: "user123",
			},
			mockResponse:  ``,
			expectedError: "unexpected status code from /flags/: 500",
		},
		{
			name: "With groups and properties",
			flagConfig: FeatureFlagPayload{
				Key:        "test-flag",
				DistinctId: "user123",
				Groups: Groups{
					"company": "test-company",
				},
				PersonProperties: Properties{
					"plan": "enterprise",
				},
				GroupProperties: map[string]Properties{
					"company": {
						"size": "large",
					},
				},
			},
			mockResponse:  `{"featureFlags": {"test-flag": "enterprise-variant"}, "featureFlagPayloads": {"test-flag": "{\"test\": 3}"}}`,
			expectedValue: "{\"test\": 3}",
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				// Check request method and path
				if r.Method != "POST" || r.URL.Path != "/flags/" {
					t.Errorf("Expected POST /flags/, got %s %s", r.Method, r.URL.Path)
				}

				// Check headers
				if r.Header.Get("Content-Type") != "application/json" {
					t.Errorf("Expected Content-Type: application/json, got %s", r.Header.Get("Content-Type"))
				}
				if !strings.HasPrefix(r.Header.Get("User-Agent"), "insights-go/") {
					t.Errorf("Unexpected User-Agent: %s", r.Header.Get("User-Agent"))
				}

				// Check request body
				body, _ := io.ReadAll(r.Body)
				var requestData FlagsRequestData
				json.Unmarshal(body, &requestData)
				if requestData.DistinctId != tt.flagConfig.DistinctId {
					t.Errorf("Expected distinctId %s, got %s", tt.flagConfig.DistinctId, requestData.DistinctId)
				}

				// Send mock response
				if tt.expectedError == "unexpected status code from /flags/: 500" {
					w.WriteHeader(http.StatusInternalServerError)
				} else {
					w.WriteHeader(http.StatusOK)
					w.Write([]byte(tt.mockResponse))
				}
			}))
			defer server.Close()

			client, _ := NewWithConfig("test-api-key", Config{
				Endpoint: server.URL,
			})

			value, err := client.GetFeatureFlagPayload(tt.flagConfig)

			if tt.expectedError != "" {
				if err == nil || !strings.Contains(err.Error(), tt.expectedError) {
					t.Errorf("Expected error containing '%s', got '%v'", tt.expectedError, err)
				}
			} else {
				if err != nil {
					t.Errorf("Unexpected error: %v", err)
				}
				if value != tt.expectedValue {
					t.Errorf("Expected value %v, got %v", tt.expectedValue, value)
				}
			}
		})
	}
}

func TestGetFeatureFlagWithNoPersonalApiKey(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path == "/flags" || r.URL.Path == "/flags/" {
			w.Write([]byte(fixture("test-flags-v3.json")))
		} else if !strings.HasPrefix(r.URL.Path, "/batch") {
			t.Errorf("client called an endpoint it shouldn't have: %s", r.URL.Path)
		}
	}))
	defer server.Close()

	// Capture events via callback
	var capturedEvent *CaptureInApi
	var mu sync.Mutex
	eventCaptured := make(chan struct{}, 1)

	client, _ := NewWithConfig("Csyjlnlun3OzyNJAafdlv", Config{
		Endpoint:  server.URL,
		BatchSize: 1, // Send immediately
		Logger:    testLogger{t.Logf, t.Logf},
		Callback: testCallback{
			func(m APIMessage) {
				if capture, ok := m.(CaptureInApi); ok {
					mu.Lock()
					capturedEvent = &capture
					mu.Unlock()
					select {
					case eventCaptured <- struct{}{}:
					default:
					}
				}
			},
			func(m APIMessage, e error) {},
		},
	})
	defer client.Close()

	// Test GetFeatureFlag single scenario
	flagValue, err := client.GetFeatureFlag(FeatureFlagPayload{
		Key:        "beta-feature",
		DistinctId: "test-user",
	})

	if err != nil {
		t.Errorf("Expected no error, got: %v", err)
	}

	// Check that the flag value is as expected (should match the value in the fixture)
	expectedValue := "decide-fallback-value"
	if flagValue != expectedValue {
		t.Errorf("Expected flag value %v, got: %v", expectedValue, flagValue)
	}

	// Wait for event to be captured
	select {
	case <-eventCaptured:
	case <-time.After(time.Second):
		t.Fatal("Timed out waiting for captured event")
	}

	mu.Lock()
	lastEvent := capturedEvent
	mu.Unlock()

	if lastEvent == nil || lastEvent.Event != "$feature_flag_called" {
		t.Errorf("Expected a $feature_flag_called event, got: %v", lastEvent)
	}

	// Check that the properties of the captured event match the response from /flags
	if lastEvent != nil {
		if lastEvent.Properties["$feature_flag"] != "beta-feature" {
			t.Errorf("Expected feature flag key 'beta-feature', got: %v", lastEvent.Properties["$feature_flag"])
		}
		if lastEvent.Properties["$feature_flag_response"] != expectedValue {
			t.Errorf("Expected feature flag response %v, got: %v", expectedValue, lastEvent.Properties["$feature_flag_response"])
		}
		if lastEvent.Properties["locally_evaluated"] != false {
			t.Errorf("Expected locally_evaluated to be false for remote evaluation, got: %v", lastEvent.Properties["locally_evaluated"])
		}
	}

	// Test a bunch of GetFeatureFlag scenarios
	tests := []struct {
		name          string
		flagConfig    FeatureFlagPayload
		mockResponse  string
		expectedValue any
		expectedError string
	}{
		{
			name: "Flag exists and is true",
			flagConfig: FeatureFlagPayload{
				Key:        "test-flag",
				DistinctId: "user123",
			},
			mockResponse:  `{"featureFlags": {"test-flag": true}}`,
			expectedValue: true,
		},
		{
			name: "Flag exists and is false",
			flagConfig: FeatureFlagPayload{
				Key:        "test-flag",
				DistinctId: "user123",
			},
			mockResponse:  `{"featureFlags": {"test-flag": false}}`,
			expectedValue: false,
		},
		{
			name: "Flag exists with string value",
			flagConfig: FeatureFlagPayload{
				Key:        "test-flag",
				DistinctId: "user123",
			},
			mockResponse:  `{"featureFlags": {"test-flag": "variant-a"}}`,
			expectedValue: "variant-a",
		},
		{
			name: "Flag doesn't exist",
			flagConfig: FeatureFlagPayload{
				Key:        "non-existent-flag",
				DistinctId: "user123",
			},
			mockResponse:  `{"featureFlags": {"other-flag": true}}`,
			expectedValue: false,
		},
		{
			name: "Empty response",
			flagConfig: FeatureFlagPayload{
				Key:        "test-flag",
				DistinctId: "user123",
			},
			mockResponse:  `{}`,
			expectedValue: false,
		},
		{
			name: "Invalid JSON response",
			flagConfig: FeatureFlagPayload{
				Key:        "test-flag",
				DistinctId: "user123",
			},
			mockResponse:  `{invalid-json}`,
			expectedError: "error parsing response from /flags/",
		},
		{
			name: "Non-200 status code",
			flagConfig: FeatureFlagPayload{
				Key:        "test-flag",
				DistinctId: "user123",
			},
			mockResponse:  ``,
			expectedError: "unexpected status code from /flags/: 500",
		},
		{
			name: "With groups and properties",
			flagConfig: FeatureFlagPayload{
				Key:        "test-flag",
				DistinctId: "user123",
				Groups: Groups{
					"company": "test-company",
				},
				PersonProperties: Properties{
					"plan": "enterprise",
				},
				GroupProperties: map[string]Properties{
					"company": {
						"size": "large",
					},
				},
			},
			mockResponse:  `{"featureFlags": {"test-flag": "enterprise-variant"}}`,
			expectedValue: "enterprise-variant",
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				// Check request method and path
				if r.Method != "POST" || r.URL.Path != "/flags/" {
					t.Errorf("Expected POST /flags/, got %s %s", r.Method, r.URL.Path)
				}

				// Check headers
				if r.Header.Get("Content-Type") != "application/json" {
					t.Errorf("Expected Content-Type: application/json, got %s", r.Header.Get("Content-Type"))
				}
				if !strings.HasPrefix(r.Header.Get("User-Agent"), "insights-go/") {
					t.Errorf("Unexpected User-Agent: %s", r.Header.Get("User-Agent"))
				}

				// Check request body
				body, _ := io.ReadAll(r.Body)
				var requestData FlagsRequestData
				json.Unmarshal(body, &requestData)
				if requestData.DistinctId != tt.flagConfig.DistinctId {
					t.Errorf("Expected distinctId %s, got %s", tt.flagConfig.DistinctId, requestData.DistinctId)
				}

				// Send mock response
				if tt.expectedError == "unexpected status code from /flags/: 500" {
					w.WriteHeader(http.StatusInternalServerError)
				} else {
					w.WriteHeader(http.StatusOK)
					w.Write([]byte(tt.mockResponse))
				}
			}))
			defer server.Close()

			client, _ := NewWithConfig("test-api-key", Config{
				Endpoint: server.URL,
			})

			value, err := client.GetFeatureFlag(tt.flagConfig)

			if tt.expectedError != "" {
				if err == nil || !strings.Contains(err.Error(), tt.expectedError) {
					t.Errorf("Expected error containing '%s', got '%v'", tt.expectedError, err)
				}
			} else {
				if err != nil {
					t.Errorf("Unexpected error: %v", err)
				}
				if value != tt.expectedValue {
					t.Errorf("Expected value %v, got %v", tt.expectedValue, value)
				}
			}
		})
	}
}

func TestGetAllFeatureFlagsWithNoPersonalApiKey(t *testing.T) {
	tests := []struct {
		name          string
		flagConfig    FeatureFlagPayloadNoKey
		mockResponse  string
		expectedFlags map[string]any
		expectedError string
	}{
		{
			name: "Multiple feature flags",
			flagConfig: FeatureFlagPayloadNoKey{
				DistinctId: "user123",
			},
			mockResponse: `{
				"featureFlags": {
					"flag1": true,
					"flag2": false,
					"flag3": "variant-a"
				}
			}`,
			expectedFlags: map[string]any{
				"flag1": true,
				"flag2": false,
				"flag3": "variant-a",
			},
		},
		{
			name: "No feature flags",
			flagConfig: FeatureFlagPayloadNoKey{
				DistinctId: "user456",
			},
			mockResponse: `{
				"featureFlags": {}
			}`,
			expectedFlags: map[string]any{},
		},
		{
			name: "Invalid JSON response",
			flagConfig: FeatureFlagPayloadNoKey{
				DistinctId: "user789",
			},
			mockResponse:  `{invalid-json}`,
			expectedError: "error parsing response from /flags/",
		},
		{
			name: "Non-200 status code",
			flagConfig: FeatureFlagPayloadNoKey{
				DistinctId: "user101",
			},
			mockResponse:  ``,
			expectedError: "unexpected status code from /flags/: 500",
		},
		{
			name: "With groups and properties",
			flagConfig: FeatureFlagPayloadNoKey{
				DistinctId: "user102",
				Groups: Groups{
					"company": "test-company",
				},
				PersonProperties: Properties{
					"plan": "enterprise",
				},
				GroupProperties: map[string]Properties{
					"company": {
						"size": "large",
					},
				},
			},
			mockResponse: `{
				"featureFlags": {
					"enterprise_flag": true,
					"company_size_flag": "large"
				}
			}`,
			expectedFlags: map[string]any{
				"enterprise_flag":   true,
				"company_size_flag": "large",
			},
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				// Check request method and path
				if r.Method != "POST" || r.URL.Path != "/flags/" {
					t.Errorf("Expected POST /flags/, got %s %s", r.Method, r.URL.Path)
				}

				// Check headers
				if r.Header.Get("Content-Type") != "application/json" {
					t.Errorf("Expected Content-Type: application/json, got %s", r.Header.Get("Content-Type"))
				}
				if !strings.HasPrefix(r.Header.Get("User-Agent"), "insights-go/") {
					t.Errorf("Unexpected User-Agent: %s", r.Header.Get("User-Agent"))
				}

				// Check request body
				body, _ := io.ReadAll(r.Body)
				var requestData FlagsRequestData
				json.Unmarshal(body, &requestData)
				if requestData.DistinctId != tt.flagConfig.DistinctId {
					t.Errorf("Expected distinctId %s, got %s", tt.flagConfig.DistinctId, requestData.DistinctId)
				}

				// Send mock response
				if tt.expectedError == "unexpected status code from /flags/: 500" {
					w.WriteHeader(http.StatusInternalServerError)
				} else {
					w.WriteHeader(http.StatusOK)
					w.Write([]byte(tt.mockResponse))
				}
			}))
			defer server.Close()

			client, _ := NewWithConfig("test-api-key", Config{
				Endpoint: server.URL,
				// Note: No PersonalApiKey is set, so it will fall back to using the flags endpoint
			})

			flags, err := client.GetAllFlags(tt.flagConfig)

			if tt.expectedError != "" {
				if err == nil || !strings.Contains(err.Error(), tt.expectedError) {
					t.Errorf("Expected error containing '%s', got '%v'", tt.expectedError, err)
				}
			} else {
				if err != nil {
					t.Errorf("Unexpected error: %v", err)
				}
				if !reflect.DeepEqual(flags, tt.expectedFlags) {
					t.Errorf("Expected flags %v, got %v", tt.expectedFlags, flags)
				}
			}
		})
	}
}

func TestGetFeatureFlagPayloadWithPersonalKey(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path == "/flags" || r.URL.Path == "/flags/" {
			t.Fatal("expected local evaluations endpoint to be called")
		}
		w.Write([]byte(fixture("test-api-feature-flag.json")))
	}))
	defer server.Close()

	client, _ := NewWithConfig("Csyjlnlun3OzyNJAafdlv", Config{
		PersonalApiKey: "some very secret key",
		Endpoint:       server.URL,
	})
	defer client.Close()

	payload, checkErr := client.GetFeatureFlagPayload(
		FeatureFlagPayload{
			Key:        "simpleFlag",
			DistinctId: "hey",
		},
	)

	expectedPayload := "{\"test\": 1}"

	if checkErr != nil || payload != expectedPayload {
		t.Errorf("expected payload %v, got %v", expectedPayload, payload)
	}
}

func TestGetFeatureFlagPayloadWithPersonalKey_LocalComputationFailure(t *testing.T) {
	apiCalls := 0
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if apiCalls == 0 && (r.URL.Path == "/flags" || r.URL.Path == "/flags/") {
			t.Fatal("expected local evaluations endpoint to be called first")
		} else if apiCalls == 1 && strings.HasPrefix(r.URL.Path, "/flags/definitions") {
			t.Fatal("expected flags endpoint to be called second")
		}

		if strings.HasPrefix(r.URL.Path, "/flags/definitions") {
			w.Write([]byte(fixture("test-api-feature-flag.json")))
		} else {
			w.Write([]byte(fixture("test-flags-v3.json")))
		}
		apiCalls++
	}))
	defer server.Close()

	client, _ := NewWithConfig("Csyjlnlun3OzyNJAafdlv", Config{
		PersonalApiKey: "some very secret key",
		Endpoint:       server.URL,
	})
	defer client.Close()

	payload, checkErr := client.GetFeatureFlagPayload(
		FeatureFlagPayload{
			Key:        "continuation-flag",
			DistinctId: "hey",
		},
	)
	if checkErr != nil {
		t.Error("expected no error, got", checkErr)
	}

	expectedPayload := "{\"foo\": \"bar\"}"

	if payload != expectedPayload {
		t.Errorf("expected payload %v, got %v", expectedPayload, payload)
	}
}

func TestSimpleFlagOld(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Write([]byte(fixture("test-api-feature-flag.json")))
	}))
	defer server.Close()

	client, _ := NewWithConfig("Csyjlnlun3OzyNJAafdlv", Config{
		PersonalApiKey: "some very secret key",
		Endpoint:       server.URL,
	})
	defer client.Close()

	isEnabled, checkErr := client.IsFeatureEnabled(
		FeatureFlagPayload{
			Key:        "simpleFlag",
			DistinctId: "hey",
		},
	)

	if checkErr != nil || isEnabled != true {
		t.Errorf("simple flag with null rollout percentage should be on for everyone")
	}
}

func TestSimpleFlagCalculation(t *testing.T) {
	require.True(t, checkIfSimpleFlagEnabled("a", "b", 42))
	require.False(t, checkIfSimpleFlagEnabled("a", "b", 40))
}

func TestComplexFlag(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path == "/flags" || r.URL.Path == "/flags/" {
			w.Write([]byte(fixture("test-flags-v3.json")))
		} else if strings.HasPrefix(r.URL.Path, "/flags/definitions") {
			w.Write([]byte(fixture("test-api-feature-flag.json")))
		} else if !strings.HasPrefix(r.URL.Path, "/batch") {
			t.Errorf("client called an endpoint it shouldn't have")
		}
	}))
	defer server.Close()

	client, _ := NewWithConfig("Csyjlnlun3OzyNJAafdlv", Config{
		PersonalApiKey: "some very secret key",
		Endpoint:       server.URL,
	})
	defer client.Close()

	isEnabled, checkErr := client.IsFeatureEnabled(
		FeatureFlagPayload{
			Key:        "enabled-flag",
			DistinctId: "hey",
		},
	)

	if checkErr != nil || isEnabled != true {
		t.Errorf("flag listed in /flags/ response should be marked as enabled")
	}

	flagValue, valueErr := client.GetFeatureFlag(
		FeatureFlagPayload{
			Key:        "enabled-flag",
			DistinctId: "hey",
		},
	)

	if valueErr != nil || flagValue != true {
		t.Errorf("flag listed in /flags/ response should be true")
	}

	payload, valueErr := client.GetFeatureFlagPayload(
		FeatureFlagPayload{
			Key:        "enabled-flag",
			DistinctId: "hey",
		},
	)

	if valueErr != nil || payload != "{\"test\": 1}" {
		t.Errorf(`flag listed in /flags/ response should be "{\"test\": 1}"`)
	}
}

func TestMultiVariateFlag(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path == "/flags" || r.URL.Path == "/flags/" {
			w.Write([]byte(fixture("test-flags-v3.json")))
		} else if strings.HasPrefix(r.URL.Path, "/flags/definitions") {
			w.Write([]byte("{}"))
		} else if !strings.HasPrefix(r.URL.Path, "/batch") {
			t.Errorf("client called an endpoint it shouldn't have")
		}
	}))
	defer server.Close()

	client, _ := NewWithConfig("Csyjlnlun3OzyNJAafdlv", Config{
		PersonalApiKey: "some very secret key",
		Endpoint:       server.URL,
	})
	defer client.Close()

	isEnabled, checkErr := client.IsFeatureEnabled(
		FeatureFlagPayload{
			Key:        "multi-variate-flag",
			DistinctId: "hey",
		},
	)

	if checkErr != nil || isEnabled == false {
		t.Errorf("flag listed in /flags/ response should be marked as enabled")
	}

	flagValue, err := client.GetFeatureFlag(
		FeatureFlagPayload{
			Key:        "multi-variate-flag",
			DistinctId: "hey",
		},
	)

	if err != nil || flagValue != "hello" {
		t.Errorf("flag listed in /flags/ response should have value 'hello'")
	}

	payload, err := client.GetFeatureFlagPayload(
		FeatureFlagPayload{
			Key:        "multi-variate-flag",
			DistinctId: "hey",
		},
	)

	if err != nil || payload != "this is the payload" {
		t.Errorf("flag listed in /flags/ response should have value 'this is the payload'")
	}
}

func TestDisabledFlag(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path == "/flags" || r.URL.Path == "/flags/" {
			w.Write([]byte(fixture("test-flags-v3.json")))
		} else if strings.HasPrefix(r.URL.Path, "/flags/definitions") {
			w.Write([]byte("{}"))
		} else if !strings.HasPrefix(r.URL.Path, "/batch") {
			t.Errorf("client called an endpoint it shouldn't have")
		}
	}))
	defer server.Close()

	client, _ := NewWithConfig("Csyjlnlun3OzyNJAafdlv", Config{
		PersonalApiKey: "some very secret key",
		Endpoint:       server.URL,
	})
	defer client.Close()

	isEnabled, checkErr := client.IsFeatureEnabled(
		FeatureFlagPayload{
			Key:        "disabled-flag",
			DistinctId: "hey",
		},
	)

	if checkErr != nil || isEnabled == true {
		t.Errorf("flag listed in /flags/ response should be marked as disabled")
	}

	flagValue, err := client.GetFeatureFlag(
		FeatureFlagPayload{
			Key:        "disabled-flag",
			DistinctId: "hey",
		},
	)

	if err != nil || flagValue != false {
		t.Errorf("flag listed in /flags/ response should have value 'false'")
	}

	payload, err := client.GetFeatureFlagPayload(
		FeatureFlagPayload{
			Key:        "disabled-flag",
			DistinctId: "hey",
		},
	)

	if err != nil || payload != "" {
		t.Errorf("flag listed in /flags/ response should have value ''")
	}
}

func TestCaptureSendFlags(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Write([]byte(fixture("test-api-feature-flag.json")))
	}))
	defer server.Close()

	client, _ := NewWithConfig("Csyjlnlun3OzyNJAafdlv", Config{
		Endpoint:  server.URL,
		Verbose:   true,
		Logger:    toLogger(t),
		BatchSize: 1,
		now:       mockTime,

		PersonalApiKey: "some very secret key",
	})
	defer client.Close()

	// Without this call client.Close hangs forever
	// Ref: https://github.com/hanzoai/insights-go/issues/28
	client.IsFeatureEnabled(
		FeatureFlagPayload{
			Key:        "simpleFlag",
			DistinctId: "hey",
		},
	)

	err := client.Enqueue(Capture{
		Event:            "Download",
		DistinctId:       "123456",
		SendFeatureFlags: SendFeatureFlags(true),
	})

	if err != nil {
		t.Fatal(err)
	}
}

func TestCaptureSendFeatureFlagsOptions(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Write([]byte(fixture("test-api-feature-flag.json")))
	}))
	defer server.Close()

	client, _ := NewWithConfig("Csyjlnlun3OzyNJAafdlv", Config{
		Endpoint:  server.URL,
		Verbose:   true,
		Logger:    toLogger(t),
		BatchSize: 1,
		now:       mockTime,

		PersonalApiKey: "some very secret key",
	})
	defer client.Close()

	// Test with SendFeatureFlagsOptions struct
	t.Run("SendFeatureFlagsOptions with PersonProperties", func(t *testing.T) {
		err := client.Enqueue(Capture{
			Event:      "test_event",
			DistinctId: "test_user",
			SendFeatureFlags: &SendFeatureFlagsOptions{
				PersonProperties: NewProperties().Set("plan", "premium"),
			},
		})
		if err != nil {
			t.Fatal(err)
		}
	})

	t.Run("SendFeatureFlagsOptions with GroupProperties", func(t *testing.T) {
		err := client.Enqueue(Capture{
			Event:      "test_event",
			DistinctId: "test_user",
			SendFeatureFlags: &SendFeatureFlagsOptions{
				GroupProperties: map[string]Properties{
					"company": NewProperties().Set("name", "Hanzo AI"),
				},
			},
		})
		if err != nil {
			t.Fatal(err)
		}
	})

	t.Run("SendFeatureFlagsOptions with OnlyEvaluateLocally", func(t *testing.T) {
		err := client.Enqueue(Capture{
			Event:      "test_event",
			DistinctId: "test_user",
			SendFeatureFlags: &SendFeatureFlagsOptions{
				OnlyEvaluateLocally: true,
				PersonProperties:    NewProperties().Set("plan", "premium"),
			},
		})
		if err != nil {
			t.Fatal(err)
		}
	})

	t.Run("SendFeatureFlags with nil should not crash", func(t *testing.T) {
		err := client.Enqueue(Capture{
			Event:            "test_event",
			DistinctId:       "test_user",
			SendFeatureFlags: nil,
		})
		if err != nil {
			t.Fatal(err)
		}
	})

	t.Run("SendFeatureFlags backwards compatibility with bool", func(t *testing.T) {
		err := client.Enqueue(Capture{
			Event:            "test_event",
			DistinctId:       "test_user",
			SendFeatureFlags: SendFeatureFlags(true),
		})
		if err != nil {
			t.Fatal(err)
		}

		err = client.Enqueue(Capture{
			Event:            "test_event",
			DistinctId:       "test_user",
			SendFeatureFlags: SendFeatureFlags(false),
		})
		if err != nil {
			t.Fatal(err)
		}
	})
}

func TestSendFeatureFlagsHelperMethods(t *testing.T) {
	t.Run("shouldSendFeatureFlags with bool true", func(t *testing.T) {
		capture := Capture{SendFeatureFlags: SendFeatureFlags(true)}
		if !capture.shouldSendFeatureFlags() {
			t.Error("Expected shouldSendFeatureFlags to return true for bool true")
		}
	})

	t.Run("shouldSendFeatureFlags with bool false", func(t *testing.T) {
		capture := Capture{SendFeatureFlags: SendFeatureFlags(false)}
		if capture.shouldSendFeatureFlags() {
			t.Error("Expected shouldSendFeatureFlags to return false for bool false")
		}
	})

	t.Run("shouldSendFeatureFlags with nil", func(t *testing.T) {
		capture := Capture{SendFeatureFlags: nil}
		if capture.shouldSendFeatureFlags() {
			t.Error("Expected shouldSendFeatureFlags to return false for nil")
		}
	})

	t.Run("shouldSendFeatureFlags with SendFeatureFlagsOptions", func(t *testing.T) {
		capture := Capture{SendFeatureFlags: &SendFeatureFlagsOptions{}}
		if !capture.shouldSendFeatureFlags() {
			t.Error("Expected shouldSendFeatureFlags to return true for non-nil options")
		}
	})

	t.Run("getFeatureFlagsOptions with bool", func(t *testing.T) {
		capture := Capture{SendFeatureFlags: SendFeatureFlags(true)}
		if capture.getFeatureFlagsOptions() != nil {
			t.Error("Expected getFeatureFlagsOptions to return nil for bool")
		}
	})

	t.Run("getFeatureFlagsOptions with SendFeatureFlagsOptions", func(t *testing.T) {
		opts := &SendFeatureFlagsOptions{OnlyEvaluateLocally: true}
		capture := Capture{SendFeatureFlags: opts}
		result := capture.getFeatureFlagsOptions()
		if result != opts {
			t.Error("Expected getFeatureFlagsOptions to return the same options")
		}
		if !result.OnlyEvaluateLocally {
			t.Error("Expected OnlyEvaluateLocally to be true")
		}
	})

	t.Run("getFeatureFlagsOptions with nil", func(t *testing.T) {
		capture := Capture{SendFeatureFlags: nil}
		if capture.getFeatureFlagsOptions() != nil {
			t.Error("Expected getFeatureFlagsOptions to return nil for nil")
		}
	})
}

func TestFeatureFlagQuotaLimits(t *testing.T) {
	t.Run("flags endpoint quota limited", func(t *testing.T) {
		server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			if r.URL.Path == "/flags" || r.URL.Path == "/flags/" {
				w.WriteHeader(http.StatusOK)
				w.Write([]byte(`{
					"featureFlags": {"test-flag": true},
					"featureFlagPayloads": {"test-flag": "test-payload"},
					"quota_limited": ["feature_flags"]
				}`))
			}
		}))
		defer server.Close()

		client, _ := NewWithConfig("test-api-key", Config{
			Endpoint: server.URL,
		})
		defer client.Close()

		// Test GetFeatureFlag
		value, err := client.GetFeatureFlag(FeatureFlagPayload{
			Key:        "test-flag",
			DistinctId: "user123",
		})
		if err != nil {
			t.Error("Expected no error, got", err)
		}
		if value != false {
			t.Error("Expected false when quota limited, got", value)
		}

		// Test GetFeatureFlagPayload
		payload, err := client.GetFeatureFlagPayload(FeatureFlagPayload{
			Key:        "test-flag",
			DistinctId: "user123",
		})
		if err != nil {
			t.Error("Expected no error, got", err)
		}
		if payload != "" {
			t.Error("Expected empty string when quota limited, got", payload)
		}

		// Test GetAllFlags
		flags, err := client.GetAllFlags(FeatureFlagPayloadNoKey{
			DistinctId: "user123",
		})
		if err != nil {
			t.Error("Expected no error, got", err)
		}
		if len(flags) != 0 {
			t.Error("Expected empty map when quota limited, got", flags)
		}
	})

	t.Run("local evaluation endpoint quota limited", func(t *testing.T) {
		server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			if strings.HasPrefix(r.URL.Path, "/flags/definitions") {
				w.WriteHeader(http.StatusPaymentRequired)
				w.Write([]byte(`{
					"type": "quota_limited",
					"detail": "You have exceeded your feature flag request quota",
					"code": "payment_required"
				}`))
			} else if r.URL.Path == "/flags" || r.URL.Path == "/flags/" {
				// Mock the flags endpoint as well since it's used as fallback
				w.WriteHeader(http.StatusOK)
				w.Write([]byte(`{
					"featureFlags": {},
					"featureFlagPayloads": {}
				}`))
			}
		}))
		defer server.Close()

		client, _ := NewWithConfig("test-api-key", Config{
			PersonalApiKey: "test-personal-key",
			Endpoint:       server.URL,
		})
		defer client.Close()

		// Test GetFeatureFlag
		value, err := client.GetFeatureFlag(FeatureFlagPayload{
			Key:        "test-flag",
			DistinctId: "user123",
		})
		if err != nil {
			t.Error("Expected no error, got", err)
		}
		if value != false {
			t.Error("Expected false when quota limited, got", value)
		}

		// Test GetFeatureFlagPayload
		payload, err := client.GetFeatureFlagPayload(FeatureFlagPayload{
			Key:        "test-flag",
			DistinctId: "user123",
		})
		if err != nil {
			t.Error("Expected no error, got", err)
		}
		if payload != "" {
			t.Error("Expected empty string when quota limited, got", payload)
		}

		// Test GetAllFlags
		flags, err := client.GetAllFlags(FeatureFlagPayloadNoKey{
			DistinctId: "user123",
		})
		if err != nil {
			t.Error("Expected no error, got", err)
		}
		if len(flags) != 0 {
			t.Error("Expected empty map when quota limited, got", flags)
		}
	})
}

func TestClient_GetRemoteConfigPayload_IncludesTokenParameter(t *testing.T) {
	t.Run("includes project API key token in remote config URL", func(t *testing.T) {
		var remoteConfigCalled bool
		server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			// Handle the initial feature flag definitions request
			if strings.Contains(r.URL.Path, "/flags/definitions") {
				w.Header().Set("Content-Type", "application/json")
				w.Write([]byte(`{"flags": [], "group_type_mapping": {}}`))
				return
			}

			// Handle the remote config request
			if strings.Contains(r.URL.Path, "/remote_config") {
				remoteConfigCalled = true

				// Verify the URL includes the token parameter
				expectedPath := "/api/projects/@current/feature_flags/test-flag/remote_config"
				if r.URL.Path != expectedPath {
					t.Errorf("Expected path %s, got %s", expectedPath, r.URL.Path)
				}

				// Verify the token parameter is present with the correct value
				token := r.URL.Query().Get("token")
				if token != "test-api-key" {
					t.Errorf("Expected token 'test-api-key', got '%s'", token)
				}

				// Verify Authorization header uses personal API key
				authHeader := r.Header.Get("Authorization")
				expectedAuth := "Bearer test-personal-key"
				if authHeader != expectedAuth {
					t.Errorf("Expected Authorization header '%s', got '%s'", expectedAuth, authHeader)
				}

				w.Header().Set("Content-Type", "application/json")
				w.Write([]byte(`"{\"foo\": \"bar\",\"baz\": 42}"`))
			}
		}))
		defer server.Close()

		client, _ := NewWithConfig("test-api-key", Config{
			PersonalApiKey: "test-personal-key",
			Endpoint:       server.URL,
		})
		defer client.Close()

		payload, err := client.GetRemoteConfigPayload("test-flag")
		if err != nil {
			t.Error("Expected no error, got", err)
		}

		if !remoteConfigCalled {
			t.Error("Expected remote config endpoint to be called")
		}

		expected := `{"foo": "bar","baz": 42}`
		if payload != expected {
			t.Errorf("Expected payload '%s', got '%s'", expected, payload)
		}
	})
}