package stats

import (
	"context"
	"math"
	"regexp"
	"testing"
	"time"

	"github.com/DATA-DOG/go-sqlmock"

	"lingniu-vehicle-ingest/go/vehicle-gateway/internal/envelope"
)

func pressureEnvelope(at time.Time) envelope.FrameEnvelope {
	return envelope.FrameEnvelope{
		Protocol: envelope.ProtocolGB32960, VIN: "LA9GG64L0NBAF4175", EventID: "event-1",
		EventTimeMS: at.UnixMilli(), SourceEndpoint: "10.0.0.1:9000",
		Fields: map[string]any{
			"gb32960.fuel_cell.max_hydrogen_pressure_mpa":  6.0,
			"gb32960.fuel_cell.max_hydrogen_temperature_c": 44.0,
			"gb32960.gd_fc_vehicle_info.hydrogen_mass_kg":  99.9,
		},
	}
}

func TestHydrogenStreamSampleUsesPressureTemperatureAndCapacity(t *testing.T) {
	loc := time.FixedZone("Asia/Shanghai", 8*3600)
	eventTime := time.Date(2026, 7, 21, 10, 30, 0, 0, loc)
	sample, reason, ok := HydrogenStreamSampleFromEnvelope(pressureEnvelope(eventTime), loc, eventTime.Add(time.Minute), 2050)
	if !ok || reason != "" {
		t.Fatalf("sample rejected: reason=%q", reason)
	}
	if sample.Date != "2026-07-21" || sample.EventID != "event-1" || sample.TankCapacityLiters != 2050 {
		t.Fatalf("unexpected sample: %#v", sample)
	}
	if math.Abs(sample.MassKG-9.092) > 0.01 {
		t.Fatalf("pressure mass = %.3fkg, want about 9.092kg", sample.MassKG)
	}
	if sample.MassKG == 99.9 {
		t.Fatal("reported Guangdong hydrogen mass must be ignored")
	}

	_, reason, ok = HydrogenStreamSampleFromEnvelope(pressureEnvelope(eventTime), loc, eventTime.AddDate(0, 0, 1), 2050)
	if ok || reason != "not_current_date" {
		t.Fatalf("historical sample accepted: ok=%v reason=%q", ok, reason)
	}
}

func TestHydrogenStreamRejectsMissingCapacity(t *testing.T) {
	loc := time.FixedZone("Asia/Shanghai", 8*3600)
	eventTime := time.Date(2026, 7, 21, 10, 30, 0, 0, loc)
	_, reason, ok := HydrogenStreamSampleFromEnvelope(pressureEnvelope(eventTime), loc, eventTime, 0)
	if ok || reason != "missing_tank_capacity" {
		t.Fatalf("missing capacity accepted: ok=%v reason=%q", ok, reason)
	}
}

func TestNISTHydrogenDensityValidationPoint(t *testing.T) {
	density, ok := HydrogenDensityKGPerM3(10, 26.85)
	if !ok || math.Abs(density-7.625) > 0.01 {
		t.Fatalf("density=%.6f ok=%v", density, ok)
	}
}

func TestAppendHydrogenStreamPersistsPressureEvidenceAtomically(t *testing.T) {
	db, mock, err := sqlmock.New()
	if err != nil {
		t.Fatal(err)
	}
	defer db.Close()
	loc := time.FixedZone("Asia/Shanghai", 8*3600)
	eventTime := time.Date(2026, 7, 21, 10, 30, 0, 0, loc)
	mock.ExpectBegin()
	mock.ExpectExec(regexp.QuoteMeta("INSERT INTO vehicle_open_hydrogen_stream_state")).
		WithArgs("LA9GG64L0NBAF4175", "2026-07-21", "10.0.0.1:9000", sqlmock.AnyArg(), sqlmock.AnyArg(), sqlmock.AnyArg(),
			2050.0, 6.0, 6.0, 44.0, 44.0, eventTime, eventTime, "event-1",
			sqlmock.AnyArg(), 20.0, sqlmock.AnyArg(), 20.0, 20.0, 20.0,
			sqlmock.AnyArg(), sqlmock.AnyArg(), 20.0).
		WillReturnResult(sqlmock.NewResult(1, 1))
	mock.ExpectExec(regexp.QuoteMeta("INSERT INTO vehicle_open_daily_energy")).
		WithArgs("LA9GG64L0NBAF4175", "2026-07-21").
		WillReturnResult(sqlmock.NewResult(1, 1))
	mock.ExpectCommit()

	result, err := AppendHydrogenStream(context.Background(), db, pressureEnvelope(eventTime), loc, eventTime, 2050)
	if err != nil {
		t.Fatal(err)
	}
	if result.Found != 1 || result.Written != 1 {
		t.Fatalf("unexpected result: %#v", result)
	}
	if err := mock.ExpectationsWereMet(); err != nil {
		t.Fatal(err)
	}
}

func TestWriterAppendWithResultUsesInMemoryCapacity(t *testing.T) {
	db, mock, err := sqlmock.New()
	if err != nil {
		t.Fatal(err)
	}
	defer db.Close()
	loc := time.FixedZone("Asia/Shanghai", 8*3600)
	eventTime := time.Now().In(loc).Truncate(time.Millisecond)
	mock.ExpectBegin()
	mock.ExpectExec(regexp.QuoteMeta("INSERT INTO vehicle_open_hydrogen_stream_state")).WillReturnResult(sqlmock.NewResult(1, 1))
	mock.ExpectExec(regexp.QuoteMeta("INSERT INTO vehicle_open_daily_energy")).WillReturnResult(sqlmock.NewResult(1, 1))
	mock.ExpectCommit()

	writer := NewWriter(db, loc)
	writer.hydrogenTankCapacities["LA9GG64L0NBAF4175"] = 2050
	result, err := writer.AppendWithResult(context.Background(), pressureEnvelope(eventTime))
	if err != nil {
		t.Fatalf("AppendWithResult() error = %v", err)
	}
	if result.HydrogenSamplesFound != 1 || result.HydrogenSamplesWritten != 1 {
		t.Fatalf("hydrogen counters lost: %+v", result)
	}
	if err := mock.ExpectationsWereMet(); err != nil {
		t.Fatal(err)
	}
}

func TestHydrogenStreamSQLGuardsDuplicatesAndRecordsPressure(t *testing.T) {
	for _, want := range []string{
		"VALUES(last_event_time)>last_event_time",
		"cycle_min_mass_kg-VALUES(last_mass_kg)>?",
		"tank_capacity_l",
		"last_pressure_mpa",
		"last_temperature_c",
		"PRESSURE_NIST",
	} {
		if !regexp.MustCompile(regexp.QuoteMeta(want)).MatchString(upsertHydrogenStreamStateSQL) {
			t.Fatalf("stream upsert missing %q", want)
		}
	}
}