package dailyusage

import (
	"context"

	"github.com/gogf/gf/v2/errors/gerror"

	"git.5iot.com/iotlcm-public/iotlcm-worker-svr/internal/dao"
	"git.5iot.com/iotlcm-public/iotlcm-worker-svr/internal/model/entity"
)

// channelScanner augments, rather than replaces, the legacy scanner contract.
// ListChannels is called once before any workers start. ScanChannel must not
// mutate the legacy DatabaseScanner.channelMetadata cache.
type channelScanner interface {
	ListChannels(context.Context) ([]channelMetadata, error)
	ScanChannel(context.Context, string, int64, int) ([]Card, error)
}

// This exact MySQL query shape is a release gate. Do not silently remove hints,
// add an SQL upper bound, or move eligibility filtering after LIMIT.
const channelPageSQL = `SELECT c.id, c.iccid, c.msisdn, c.imsi, c.chan_key, c.current_package_code
FROM t_sim_card_info AS c FORCE INDEX (idx_card_chan_key)
STRAIGHT_JOIN sys_dept AS d
  ON c.dept_id = d.dept_id
 AND c.tenant_id = d.tenant_id
WHERE c.chan_key = ?
  AND c.id > ?
  AND c.iccid <> ''
  AND c.current_package_code <> ''
  AND d.deleted_at IS NULL
ORDER BY c.id ASC
LIMIT ?`

func (s *DatabaseScanner) ListChannels(ctx context.Context) ([]channelMetadata, error) {
	var metadata []channelMetadata
	if err := dao.TSimCardInfo.DB().Model("t_sim_channels").Ctx(ctx).Fields("chan_key,temp_key,sync_enabled,operator").Scan(&metadata); err != nil {
		return nil, gerror.Wrap(err, "list channel metadata")
	}
	return metadata, nil
}

func (s *DatabaseScanner) ScanChannel(ctx context.Context, chanKey string, lastID int64, pageSize int) ([]Card, error) {
	if chanKey == "" || lastID < 0 || pageSize <= 0 {
		return nil, gerror.New("invalid channel pagination parameters")
	}
	var rows []entity.TSimCardInfo
	// Use the card DAO's database group, not a separately configured connection.
	if err := dao.TSimCardInfo.DB().Raw(channelPageSQL, chanKey, lastID, pageSize).Ctx(ctx).Scan(&rows); err != nil {
		return nil, gerror.Wrap(err, "scan channel cards")
	}
	cards := make([]Card, 0, len(rows))
	for _, row := range rows {
		cards = append(cards, Card{ID: row.Id, ICCID: row.Iccid, MSISDN: row.Msisdn, IMSI: row.Imsi, ChanKey: row.ChanKey, PackageCode: row.CurrentPackageCode})
	}
	return cards, nil
}

// Pool counters are shared with other worker traffic. Their deltas are direct
// observations, not an attribution of all connection waits to this producer.
func (*DatabaseScanner) poolWait(ctx context.Context) (int64, int64) {
	var count, nanos int64
	for _, item := range dao.TSimCardInfo.DB().Stats(ctx) {
		stats := item.Stats()
		count += stats.WaitCount
		nanos += int64(stats.WaitDuration)
	}
	return count, nanos
}

// ValidateScanSettings is strict for values read from configuration. The Go
// constructor first fills omitted zero values; explicit YAML zero is rejected.
func ValidateScanSettings(mode string, concurrency int) error {
	if mode != "serial" && mode != "channel" {
		return gerror.Newf("invalid trafficUsageDailySync.producer.scanMode %q (serial or channel required)", mode)
	}
	if concurrency <= 0 {
		return gerror.New("trafficUsageDailySync.producer.scanConcurrency must be positive")
	}
	return nil
}