package store_test

import (
	"context"
	"testing"
	"time"

	"github.com/wangjia/pangolin/server/internal/usage"
)

// The timezone-fix proof: usage stored at UTC 18:00 yesterday must land on a
// DIFFERENT local calendar day under UTC (offset 0) vs UTC+8 (offset 480) —
// exactly the "今天却显示昨天数据" bug. UsageCurve re-buckets UTC hourly rows by
// the client's local day so "today" matches the user's calendar.
func TestSQLite_UsageCurve_LocalDayBucketing(t *testing.T) {
	ctx := context.Background()
	db := openSQLite(t)

	// Yesterday 18:00 UTC = today 02:00 in UTC+8 → straddles the day boundary.
	now := time.Now().UTC()
	y := now.AddDate(0, 0, -1)
	utc18 := time.Date(y.Year(), y.Month(), y.Day(), 18, 0, 0, 0, time.UTC)
	hourEpoch := utc18.Unix() / 3600
	if _, err := db.Exec(
		`INSERT INTO usage_hourly (user_id, hour, bytes_up, bytes_down, minutes_used) VALUES (1,?,?,?,?)`,
		hourEpoch, 1000, 2000, 5); err != nil {
		t.Fatalf("seed: %v", err)
	}

	cn := time.FixedZone("UTC+8", 8*3600)
	utcDate := utc18.Format("2006-01-02")    // yesterday (UTC)
	cnDate := utc18.In(cn).Format("2006-01-02") // today (UTC+8)
	if utcDate == cnDate {
		t.Fatalf("test setup expected different dates, got %s == %s", utcDate, cnDate)
	}

	svc := usage.NewService(usage.NewStore(db), nil, nil, time.Hour)

	find := func(days, offset int, date string) (usage.UsagePoint, bool) {
		pts, e := svc.UsageCurve(ctx, 1, days, offset, "")
		if e != nil {
			t.Fatalf("UsageCurve(off=%d): %v", offset, e)
		}
		for _, p := range pts {
			if p.Date == date {
				return p, true
			}
		}
		return usage.UsagePoint{}, false
	}

	// Offset 0 (UTC): the data is on yesterday's UTC date.
	if p, ok := find(3, 0, utcDate); !ok || p.BytesDown != 2000 || p.BytesUp != 1000 || p.MinutesUsed != 5 {
		t.Fatalf("UTC bucket: want data on %s, got ok=%v %+v", utcDate, ok, p)
	}
	// Offset +480 (UTC+8): the SAME data is on today's local date instead.
	if p, ok := find(3, 480, cnDate); !ok || p.BytesDown != 2000 {
		t.Fatalf("UTC+8 bucket: want data on %s, got ok=%v %+v", cnDate, ok, p)
	}
	// And under +480 it must NOT appear on the UTC date.
	if p, ok := find(3, 480, utcDate); ok && p.BytesDown != 0 {
		t.Fatalf("UTC+8: data leaked onto UTC date %s: %+v", utcDate, p)
	}
}