package main

import (
	"context"
	"errors"
	"io"
	"log/slog"
	"os"
	"strings"
	"testing"
	"time"

	"lingniu-vehicle-ingest/go/vehicle-gateway/internal/authentication"
	"lingniu-vehicle-ingest/go/vehicle-gateway/internal/envelope"
	"lingniu-vehicle-ingest/go/vehicle-gateway/internal/identity"
	"lingniu-vehicle-ingest/go/vehicle-gateway/internal/metrics"
)

func TestNATSSinkConfigFromEnvUsesExplicitSubjects(t *testing.T) {
	t.Setenv("NATS_URL", "nats://172.17.111.56:4222")
	t.Setenv("NATS_SUBJECT_GB32960_RAW", "custom.raw.gb32960")
	t.Setenv("NATS_SUBJECT_JT808_RAW", "custom.raw.jt808")
	t.Setenv("NATS_SUBJECT_YUTONG_MQTT_RAW", "custom.raw.yutong")
	t.Setenv("NATS_SUBJECT_GB32960_FIELDS", "custom.fields.gb32960")
	t.Setenv("NATS_SUBJECT_JT808_FIELDS", "custom.fields.jt808")
	t.Setenv("NATS_SUBJECT_YUTONG_MQTT_FIELDS", "custom.fields.yutong")
	t.Setenv("NATS_SUBJECT_UNIFIED", "custom.unified")
	t.Setenv("NATS_OUTBOX_MAX_INFLIGHT", "12000")
	t.Setenv("NATS_OUTBOX_ACK_TIMEOUT_MS", "4500")

	cfg := natsSinkConfigFromEnv()

	if got, want := cfg.URL, "nats://172.17.111.56:4222"; got != want {
		t.Fatalf("URL = %q, want %q", got, want)
	}
	if got, want := cfg.RawSubjects[envelope.ProtocolGB32960], "custom.raw.gb32960"; got != want {
		t.Fatalf("gb32960 subject = %q, want %q", got, want)
	}
	if got, want := cfg.RawSubjects[envelope.ProtocolJT808], "custom.raw.jt808"; got != want {
		t.Fatalf("jt808 subject = %q, want %q", got, want)
	}
	if got, want := cfg.RawSubjects[envelope.ProtocolYutongMQTT], "custom.raw.yutong"; got != want {
		t.Fatalf("yutong subject = %q, want %q", got, want)
	}
	if got, want := cfg.FieldsSubjects[envelope.ProtocolGB32960], "custom.fields.gb32960"; got != want {
		t.Fatalf("gb32960 fields subject = %q, want %q", got, want)
	}
	if got, want := cfg.FieldsSubjects[envelope.ProtocolJT808], "custom.fields.jt808"; got != want {
		t.Fatalf("jt808 fields subject = %q, want %q", got, want)
	}
	if got, want := cfg.FieldsSubjects[envelope.ProtocolYutongMQTT], "custom.fields.yutong"; got != want {
		t.Fatalf("yutong fields subject = %q, want %q", got, want)
	}
	if got, want := cfg.UnifiedSubject, "custom.unified"; got != want {
		t.Fatalf("unified subject = %q, want %q", got, want)
	}
	if got, want := cfg.AsyncMaxPending, 12000; got != want {
		t.Fatalf("async max pending = %d, want %d", got, want)
	}
	if got, want := cfg.AsyncAckTimeout, 4500*time.Millisecond; got != want {
		t.Fatalf("async ack timeout = %s, want %s", got, want)
	}
}

func TestNATSOutboxConfigFromEnvIsExplicitAndDefaultsToSafeFsync(t *testing.T) {
	t.Setenv("NATS_DURABLE_OUTBOX_ENABLED", "true")
	t.Setenv("NATS_OUTBOX_DIR", "/var/lib/lingniu-go/nats-outbox")
	t.Setenv("NATS_OUTBOX_REPLAY_BATCH_SIZE", "750")
	t.Setenv("NATS_OUTBOX_REPLAY_INTERVAL_MS", "250")
	t.Setenv("NATS_OUTBOX_CLOSE_TIMEOUT_MS", "7000")
	t.Setenv("NATS_OUTBOX_WAL_SEGMENT_BYTES", "8388608")
	t.Setenv("NATS_OUTBOX_WAL_SEGMENT_AGE_MS", "4000")
	t.Setenv("NATS_OUTBOX_WAL_APPEND_QUEUE_SIZE", "50000")
	t.Setenv("NATS_OUTBOX_WAL_COMMIT_BATCH_SIZE", "128")
	t.Setenv("NATS_OUTBOX_WAL_COMMIT_INTERVAL_MS", "2")
	t.Setenv("NATS_OUTBOX_FSYNC", "")
	registry := metrics.NewRegistry()
	onError := func(error) {}

	runtime := natsOutboxConfigFromEnv(registry, onError)

	if !runtime.Enabled {
		t.Fatal("outbox should be enabled")
	}
	if got, want := runtime.Config.Directory, "/var/lib/lingniu-go/nats-outbox"; got != want {
		t.Fatalf("directory = %q, want %q", got, want)
	}
	if got, want := runtime.Config.ReplayBatchSize, 750; got != want {
		t.Fatalf("replay batch = %d, want %d", got, want)
	}
	if !runtime.Config.SyncWrites {
		t.Fatal("outbox fsync should default to true")
	}
	if got, want := runtime.Config.CloseTimeout, 7*time.Second; got != want {
		t.Fatalf("close timeout = %s, want %s", got, want)
	}
	if got, want := runtime.Config.WALSegmentBytes, int64(8<<20); got != want {
		t.Fatalf("WAL segment bytes = %d, want %d", got, want)
	}
	if got, want := runtime.Config.WALSegmentAge, 4*time.Second; got != want {
		t.Fatalf("WAL segment age = %s, want %s", got, want)
	}
	if got, want := runtime.Config.WALAppendQueue, 50_000; got != want {
		t.Fatalf("WAL append queue = %d, want %d", got, want)
	}
	if got, want := runtime.Config.WALCommitBatch, 128; got != want {
		t.Fatalf("WAL commit batch = %d, want %d", got, want)
	}
	if got, want := runtime.Config.WALCommitWait, 2*time.Millisecond; got != want {
		t.Fatalf("WAL commit wait = %s, want %s", got, want)
	}
	if got, want := runtime.ReplayInterval, 250*time.Millisecond; got != want {
		t.Fatalf("replay interval = %s, want %s", got, want)
	}
	if runtime.Config.Metrics != registry || runtime.Config.OnError == nil {
		t.Fatal("metrics and error callback should be wired")
	}
}

func TestNATSOutboxConfigDoesNotReuseLegacySpoolDirectory(t *testing.T) {
	t.Setenv("NATS_DURABLE_OUTBOX_ENABLED", "")
	t.Setenv("NATS_OUTBOX_DIR", "")
	t.Setenv("NATS_SPOOL_DIR", "/var/lib/lingniu-go/nats-spool")
	t.Setenv("NATS_OUTBOX_FSYNC", "false")

	runtime := natsOutboxConfigFromEnv(nil, nil)

	if runtime.Enabled {
		t.Fatal("outbox must remain opt-in")
	}
	if runtime.Config.Directory != "" {
		t.Fatalf("WAL directory must be explicit, got %q", runtime.Config.Directory)
	}
	if runtime.Config.SyncWrites {
		t.Fatal("explicit false should disable fsync")
	}
}

func TestBuildGB32960AuthenticatorUsesConfiguredCredentials(t *testing.T) {
	t.Setenv("GB32960_AUTH_MODE", "enforce")
	t.Setenv("GB32960_PLATFORM_CREDENTIALS_FILE", "")
	t.Setenv("GB32960_PLATFORM_CREDENTIALS_JSON", `{"platform-a":"secret-a","platform-b":["secret-b-old","secret-b"]}`)

	authenticator, mode, count, err := buildGB32960Authenticator()
	if err != nil {
		t.Fatalf("buildGB32960Authenticator() error = %v", err)
	}
	if mode != authentication.ModeEnforce || count != 2 {
		t.Fatalf("mode=%q count=%d", mode, count)
	}
	result := authenticator.Authenticate(envelope.FrameEnvelope{
		Protocol:  envelope.ProtocolGB32960,
		MessageID: "0x05",
		Parsed: map[string]any{
			"platform_login": map[string]any{"username": "platform-b", "password": "secret-b"},
		},
	})
	if !result.Allowed || result.Status != authentication.StatusAccepted {
		t.Fatalf("authentication result = %#v", result)
	}
}

func TestBuildGB32960AuthenticatorRejectsEnforceWithoutCredentials(t *testing.T) {
	t.Setenv("GB32960_AUTH_MODE", "enforce")
	t.Setenv("GB32960_PLATFORM_CREDENTIALS_FILE", "")
	t.Setenv("GB32960_PLATFORM_CREDENTIALS_JSON", "")
	if _, _, _, err := buildGB32960Authenticator(); err == nil {
		t.Fatal("expected enforce mode configuration error")
	}
}

func TestGatewayConfiguresIdentityLookupCacheTTL(t *testing.T) {
	source, err := os.ReadFile("main.go")
	if err != nil {
		t.Fatalf("read main.go: %v", err)
	}
	for _, want := range []string{"LookupCacheTTL", "StaleLookupTTL", "IDENTITY_LOOKUP_CACHE_TTL_SECONDS", "IDENTITY_STALE_LOOKUP_TTL_SECONDS", "IDENTITY_LOOKUP_CACHE_MAX_ENTRIES", "IDENTITY_LOOKUP_CACHE_CLEANUP_INTERVAL_SECONDS", "vehicle_gateway_identity_cache_entries", "vehicle_gateway_jt808_registration_write_total", "OnRegistrationWriteResult", "IDENTITY_SOURCE_CODE_LOOKUP_ENABLED", "IDENTITY_RESOLVE_TIMEOUT_MS", "IDENTITY_SNAPSHOT_ONLY_ENABLED", "IDENTITY_SNAPSHOT_REFRESH_INTERVAL_SECONDS", "startIdentitySnapshotRefresh", "JT808_REGISTRATION_LOCATION_TOUCH_RETRY_INTERVAL_SECONDS", "JT808_REGISTRATION_WRITE_RETRY_ATTEMPTS", "JT808_REGISTRATION_WRITE_RETRY_DELAY_MS", "JT808_REGISTRATION_ASYNC_WRITE_ENABLED", "JT808_REGISTRATION_WRITE_QUEUE_SIZE", "JT808_REGISTRATION_WRITE_WORKERS", "JT808_REGISTRATION_WRITE_ENQUEUE_TIMEOUT_MS", "TimeoutResolver"} {
		if !strings.Contains(string(source), want) {
			t.Fatalf("gateway should expose identity lookup cache ttl, missing %s", want)
		}
	}
}

func TestRecordIdentityCacheStatsIncludesLocationTouchFailures(t *testing.T) {
	registry := metrics.NewRegistry()
	recordIdentityCacheStats(registry, identity.CacheStats{
		LookupEntries:               1,
		RegistrationEntries:         2,
		SourceCodeEntries:           3,
		LocationTouchEntries:        4,
		LocationTouchFailureEntries: 5,
		SnapshotBindingEntries:      6,
		SnapshotIdentifierEntries:   7,
		SnapshotRegistrationEntries: 8,
		SnapshotSourceEntries:       9,
		SnapshotReady:               true,
		SnapshotRefreshedAt:         time.Unix(1234, 0),
		MaxEntries:                  9,
	})

	rendered := registry.Render()
	for _, want := range []string{
		`vehicle_gateway_identity_cache_entries{cache="location_touch_failure"} 5`,
		`vehicle_gateway_identity_cache_entries{cache="registration_write_queue"} 0`,
		`vehicle_gateway_identity_cache_entries{cache="snapshot_binding"} 6`,
		`vehicle_gateway_identity_cache_entries{cache="snapshot_identifier"} 7`,
		`vehicle_gateway_identity_cache_entries{cache="snapshot_registration"} 8`,
		`vehicle_gateway_identity_cache_entries{cache="snapshot_source"} 9`,
		`vehicle_gateway_identity_cache_max_entries{cache="location_touch_failure"} 9`,
		`vehicle_gateway_identity_snapshot_ready 1`,
		`vehicle_gateway_identity_snapshot_last_success_unix_seconds 1234`,
	} {
		if !strings.Contains(rendered, want) {
			t.Fatalf("identity cache metrics missing %s in:\n%s", want, rendered)
		}
	}
}

func TestRecordIdentitySnapshotRefresh(t *testing.T) {
	registry := metrics.NewRegistry()
	recordIdentitySnapshotRefresh(registry, identity.SnapshotRefreshResult{
		BindingEntries:      10,
		IdentifierEntries:   20,
		RegistrationEntries: 30,
		SourceEntries:       40,
		RefreshedAt:         time.Unix(5678, 0),
	}, "ok")

	rendered := registry.Render()
	for _, want := range []string{
		`vehicle_gateway_identity_snapshot_refresh_total{status="ok"} 1`,
		`vehicle_gateway_identity_snapshot_entries{kind="binding"} 10`,
		`vehicle_gateway_identity_snapshot_entries{kind="identifier"} 20`,
		`vehicle_gateway_identity_snapshot_entries{kind="registration"} 30`,
		`vehicle_gateway_identity_snapshot_entries{kind="source"} 40`,
		`vehicle_gateway_identity_snapshot_last_success_unix_seconds 5678`,
	} {
		if !strings.Contains(rendered, want) {
			t.Fatalf("identity snapshot metrics missing %s in:\n%s", want, rendered)
		}
	}
}

func TestIdentityDatabaseMaintenanceDoesNotBlockIngressStartup(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	db := &blockingIdentityDatabase{
		started: make(chan struct{}),
		release: make(chan struct{}),
	}
	logger := slog.New(slog.NewTextHandler(io.Discard, nil))

	startedAt := time.Now()
	startIdentityDatabaseMaintenance(ctx, logger, db, nil, false, time.Second, time.Second)
	if elapsed := time.Since(startedAt); elapsed > 100*time.Millisecond {
		t.Fatalf("database maintenance blocked gateway startup for %s", elapsed)
	}

	select {
	case <-db.started:
	case <-time.After(time.Second):
		t.Fatal("database maintenance did not start in background")
	}
	close(db.release)
}

func TestIdentitySnapshotRefreshDoesNotBlockIngressStartup(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	refresher := &blockingIdentitySnapshotRefresher{started: make(chan struct{})}
	logger := slog.New(slog.NewTextHandler(io.Discard, nil))

	startedAt := time.Now()
	startIdentitySnapshotRefresh(ctx, logger, metrics.NewRegistry(), refresher, time.Hour, time.Second)
	if elapsed := time.Since(startedAt); elapsed > 100*time.Millisecond {
		t.Fatalf("snapshot refresh blocked gateway startup for %s", elapsed)
	}

	select {
	case <-refresher.started:
	case <-time.After(time.Second):
		t.Fatal("snapshot refresh did not start in background")
	}
}

func TestRecordJT808RegistrationWriteResult(t *testing.T) {
	registry := metrics.NewRegistry()
	recordJT808RegistrationWriteResult(registry, identity.RegistrationWriteResult{
		Mode:   "async_background",
		Status: "error",
	})

	rendered := registry.Render()
	for _, want := range []string{
		`vehicle_gateway_jt808_registration_write_total{mode="async_background",status="error"} 1`,
		`vehicle_gateway_last_jt808_registration_write_unix_seconds{mode="async_background",status="error"}`,
	} {
		if !strings.Contains(rendered, want) {
			t.Fatalf("registration write metric missing %s in:\n%s", want, rendered)
		}
	}
}

type blockingIdentityDatabase struct {
	started chan struct{}
	release chan struct{}
}

func (d *blockingIdentityDatabase) PingContext(ctx context.Context) error {
	close(d.started)
	select {
	case <-ctx.Done():
		return ctx.Err()
	case <-d.release:
		return nil
	}
}

type blockingIdentitySnapshotRefresher struct {
	started chan struct{}
}

func (r *blockingIdentitySnapshotRefresher) RefreshSnapshot(ctx context.Context) (identity.SnapshotRefreshResult, error) {
	close(r.started)
	<-ctx.Done()
	return identity.SnapshotRefreshResult{}, errors.New("test refresh stopped")
}

func TestGatewayDefaultsTo100KConnectionCeiling(t *testing.T) {
	source, err := os.ReadFile("main.go")
	if err != nil {
		t.Fatalf("read main.go: %v", err)
	}
	if !strings.Contains(string(source), `envInt("TCP_MAX_CONNECTIONS", 120_000)`) {
		t.Fatal("gateway should default TCP_MAX_CONNECTIONS to a 100K-ready ceiling")
	}
}

func TestGatewayPassesMetricsRegistryToAsyncSink(t *testing.T) {
	source, err := os.ReadFile("main.go")
	if err != nil {
		t.Fatalf("read main.go: %v", err)
	}
	for _, want := range []string{
		"buildSink(ctx, logger, registry)",
		"Metrics:          registry",
		"EnqueueTimeout:   enqueueTimeout",
		"NewPartitionedAsyncSink",
		"NATS_PARTITIONED_ASYNC_ENABLED",
		"KAFKA_PARTITIONED_ASYNC_ENABLED",
		"_ASYNC_RAW_QUEUE_SIZE",
		"_ASYNC_DERIVED_QUEUE_SIZE",
		"_ASYNC_RAW_ENQUEUE_TIMEOUT_MS",
		"_ASYNC_DERIVED_ENQUEUE_TIMEOUT_MS",
		"RawEnqueueTimeout",
		"DerivedEnqueueTimeout",
		"NATS_ASYNC_ENQUEUE_TIMEOUT_MS",
		"KAFKA_ASYNC_ENQUEUE_TIMEOUT_MS",
		`Name:             "nats"`,
		`Name:             "kafka"`,
	} {
		if !strings.Contains(string(source), want) {
			t.Fatalf("gateway async sink metrics wiring missing %s", want)
		}
	}
}

func TestGatewayExposesNATSDurableSpoolConfig(t *testing.T) {
	source, err := os.ReadFile("main.go")
	if err != nil {
		t.Fatalf("read main.go: %v", err)
	}
	for _, want := range []string{
		"NATS_DURABLE_OUTBOX_ENABLED",
		"NATS_OUTBOX_DIR",
		"NATS_OUTBOX_MAX_INFLIGHT",
		"NATS_OUTBOX_ACK_TIMEOUT_MS",
		"NATS_OUTBOX_FSYNC",
		"NATS_OUTBOX_CLOSE_TIMEOUT_MS",
		"NATS_OUTBOX_REPLAY_BATCH_SIZE",
		"NATS_OUTBOX_REPLAY_INTERVAL_MS",
		"NATS_OUTBOX_WAL_SEGMENT_BYTES",
		"NATS_OUTBOX_WAL_SEGMENT_AGE_MS",
		"NATS_OUTBOX_WAL_APPEND_QUEUE_SIZE",
		"NATS_OUTBOX_WAL_COMMIT_BATCH_SIZE",
		"NATS_OUTBOX_WAL_COMMIT_INTERVAL_MS",
		"eventbus.NewDurableOutboxSink",
		"nats durable outbox enabled",
		"NATS_SPOOL_DIR",
		"NATS_SPOOL_REPLAY_BATCH_SIZE",
		"NATS_SPOOL_REPLAY_INTERVAL_MS",
		"nats durable spool enabled",
		"nats spool replay failed",
		"eventbus.NewDurableSink",
		"Metrics:         registry",
		`Name:            "nats"`,
		`Name:            "kafka"`,
	} {
		if !strings.Contains(string(source), want) {
			t.Fatalf("gateway nats spool wiring missing %s", want)
		}
	}
}

func TestNATSSinkConfigFromEnvDefaultsToGoSubjects(t *testing.T) {
	t.Setenv("NATS_URL", "nats://172.17.111.56:4222")

	cfg := natsSinkConfigFromEnv()

	if got, want := cfg.RawSubjects[envelope.ProtocolGB32960], "vehicle.raw.go.gb32960.v1"; got != want {
		t.Fatalf("gb32960 subject = %q, want %q", got, want)
	}
	if got, want := cfg.RawSubjects[envelope.ProtocolJT808], "vehicle.raw.go.jt808.v1"; got != want {
		t.Fatalf("jt808 subject = %q, want %q", got, want)
	}
	if got, want := cfg.RawSubjects[envelope.ProtocolYutongMQTT], "vehicle.raw.go.yutong-mqtt.v1"; got != want {
		t.Fatalf("yutong subject = %q, want %q", got, want)
	}
	if got, want := cfg.FieldsSubjects[envelope.ProtocolGB32960], "vehicle.fields.go.gb32960.v1"; got != want {
		t.Fatalf("gb32960 fields subject = %q, want %q", got, want)
	}
	if got, want := cfg.FieldsSubjects[envelope.ProtocolJT808], "vehicle.fields.go.jt808.v1"; got != want {
		t.Fatalf("jt808 fields subject = %q, want %q", got, want)
	}
	if got, want := cfg.FieldsSubjects[envelope.ProtocolYutongMQTT], "vehicle.fields.go.yutong-mqtt.v1"; got != want {
		t.Fatalf("yutong fields subject = %q, want %q", got, want)
	}
	if got, want := cfg.UnifiedSubject, "vehicle.event.go.unified.v1"; got != want {
		t.Fatalf("unified subject = %q, want %q", got, want)
	}
}