package stats

import (
	"context"
	"database/sql"
	"strings"
	"testing"
	"time"

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

func TestSamplesFromEnvelopeDerivesDailyMileageAndTotal(t *testing.T) {
	loc := time.FixedZone("Asia/Shanghai", 8*3600)
	env := envelope.FrameEnvelope{
		Protocol:    envelope.ProtocolJT808,
		VIN:         "LNBVIN00000000001",
		EventTimeMS: time.Date(2026, 7, 1, 8, 30, 0, 0, loc).UnixMilli(),
		Fields: map[string]any{
			envelope.FieldTotalMileageKM: 10241.2,
		},
	}

	samples, err := SamplesFromEnvelope(env, loc)
	if err != nil {
		t.Fatalf("SamplesFromEnvelope() error = %v", err)
	}
	if len(samples) != 2 {
		t.Fatalf("sample count = %d", len(samples))
	}
	if samples[0].MetricKey != MetricDailyMileageKM || samples[0].MetricValue != 0 {
		t.Fatalf("unexpected daily mileage sample: %#v", samples[0])
	}
	if samples[1].MetricKey != MetricDailyTotalMileageKM || samples[1].MetricValue != 10241.2 {
		t.Fatalf("unexpected daily total sample: %#v", samples[1])
	}
	if samples[0].StatDate != "2026-07-01" {
		t.Fatalf("stat date = %q", samples[0].StatDate)
	}
}

func TestSamplesFromEnvelopeSkipsMissingVINOrMileage(t *testing.T) {
	samples, err := SamplesFromEnvelope(envelope.FrameEnvelope{
		Protocol: envelope.ProtocolJT808,
		Fields:   map[string]any{envelope.FieldTotalMileageKM: 1.2},
	}, nil)
	if err != nil {
		t.Fatalf("SamplesFromEnvelope() error = %v", err)
	}
	if len(samples) != 0 {
		t.Fatalf("expected no samples without vin, got %#v", samples)
	}

	samples, err = SamplesFromEnvelope(envelope.FrameEnvelope{
		Protocol: envelope.ProtocolGB32960,
		VIN:      "LNBVIN00000000002",
		Fields:   map[string]any{},
	}, nil)
	if err != nil {
		t.Fatalf("SamplesFromEnvelope() error = %v", err)
	}
	if len(samples) != 0 {
		t.Fatalf("expected no samples without mileage, got %#v", samples)
	}
}

func TestWriterEnsuresSchemaAndUpsertsTwoMetrics(t *testing.T) {
	exec := &recordingExec{}
	writer := NewWriter(exec, time.FixedZone("Asia/Shanghai", 8*3600))
	if err := writer.EnsureSchema(context.Background()); err != nil {
		t.Fatalf("EnsureSchema() error = %v", err)
	}
	if err := writer.Append(context.Background(), envelope.FrameEnvelope{
		Protocol:    envelope.ProtocolGB32960,
		VIN:         "LNBVIN00000000002",
		EventTimeMS: time.Date(2026, 7, 1, 9, 0, 0, 0, time.FixedZone("Asia/Shanghai", 8*3600)).UnixMilli(),
		Fields: map[string]any{
			envelope.FieldTotalMileageKM: "10000.0",
		},
	}); err != nil {
		t.Fatalf("Append() error = %v", err)
	}

	if !strings.Contains(exec.calls[0].query, "CREATE TABLE IF NOT EXISTS vehicle_daily_metric") {
		t.Fatalf("unexpected schema sql: %s", exec.calls[0].query)
	}
	if len(exec.calls) != 3 {
		t.Fatalf("exec calls = %d", len(exec.calls))
	}
	if !strings.Contains(exec.calls[1].query, "ON DUPLICATE KEY UPDATE") {
		t.Fatalf("unexpected upsert sql: %s", exec.calls[1].query)
	}
}

type execCall struct {
	query string
	args  []any
}

type recordingExec struct {
	calls []execCall
}

func (e *recordingExec) ExecContext(_ context.Context, query string, args ...any) (sql.Result, error) {
	e.calls = append(e.calls, execCall{query: query, args: args})
	return nil, nil
}