package trafficusage

import (
	"context"
	"fmt"
	"git.5iot.com/iotlcm-public/iotlcm-admin-svr/internal/consts"
	"git.5iot.com/iotlcm-public/iotlcm-admin-svr/internal/dao"
	"git.5iot.com/iotlcm-public/iotlcm-admin-svr/internal/library/rabbitmq"
	"git.5iot.com/iotlcm-public/iotlcm-admin-svr/internal/model"
	"git.5iot.com/iotlcm-public/iotlcm-admin-svr/internal/model/entity"
	"git.5iot.com/iotlcm-public/iotlcm-admin-svr/internal/service"
	"time"

	"git.5iot.com/iotlcm-public/iotlcm-admin-svr/utility/uuid32"
	"github.com/gogf/gf/v2/frame/g"
)

const (
	trafficUsageMonthlyPageSize = 100
)

type sTrafficUsageMonthlySync struct {
}

const monthlyUsageFullSyncOperation = "current_month_usage_full_sync"

// These indirections keep the trigger deterministic in unit tests without changing
// the production publisher, clock, or run-id generator.
var (
	monthlyUsageNow           = time.Now
	monthlyUsageRunID         = uuid32.S
	monthlyUsageRabbitEnabled = rabbitmq.Enabled
	monthlyUsagePublish       = rabbitmq.Publish

	monthlyHistoryNow           = time.Now
	monthlyHistoryRunID         = uuid32.S
	monthlyHistoryRabbitEnabled = rabbitmq.Enabled
	monthlyHistoryPublish       = rabbitmq.Publish
)

func NewTrafficUsageMonthlySync() *sTrafficUsageMonthlySync {
	return &sTrafficUsageMonthlySync{}
}

func init() {
	service.RegisterTrafficUsageMonthlySync(NewTrafficUsageMonthlySync())
}

// StartMonthly publishes one command for Worker to execute the full monthly
// usage sync. Admin deliberately does not scan cards or call an upstream service.
func (s *sTrafficUsageMonthlySync) StartMonthly(ctx context.Context) error {
	_, err := s.StartMonthlyRun(ctx)
	return err
}

func (s *sTrafficUsageMonthlySync) StartMonthlyRun(ctx context.Context) (string, error) {
	return s.StartMonthlyRunScoped(ctx, nil)
}

// StartMonthlyRunScoped starts a run restricted to scope.Channels. A nil scope,
// or one whose channels normalize to empty, starts a full sync.
func (s *sTrafficUsageMonthlySync) StartMonthlyRunScoped(ctx context.Context, scope *model.SyncScope) (string, error) {
	if ctx == nil {
		ctx = context.Background()
	}
	startedAt := time.Now()
	normalized, err := model.NormalizeScope(scope)
	if err != nil {
		g.Log().Errorf(ctx, "event=monthly_usage_trigger status=failed stage=validate durationMs=%d error=%q", elapsedMilliseconds(startedAt), err.Error())
		return "", err
	}
	if !monthlyUsageRabbitEnabled(ctx) {
		err := fmt.Errorf("monthly usage start skipped: rabbitmq is disabled")
		g.Log().Errorf(ctx, "event=monthly_usage_trigger status=failed stage=precheck durationMs=%d reason=%q", elapsedMilliseconds(startedAt), err.Error())
		return "", err
	}

	location, err := time.LoadLocation("Asia/Shanghai")
	if err != nil {
		g.Log().Errorf(ctx, "event=monthly_usage_trigger status=failed stage=timezone durationMs=%d error=%q", elapsedMilliseconds(startedAt), err.Error())
		return "", fmt.Errorf("load monthly usage timezone: %w", err)
	}
	now := monthlyUsageNow().In(location)
	message := model.TrafficUsageMonthlyStartMessage{
		RunID:       fmt.Sprintf("current-month-usage-%s-%s", now.Format("20060102"), monthlyUsageRunID()),
		Operation:   monthlyUsageFullSyncOperation,
		QueryMonth:  now.Format("200601"),
		TriggeredAt: now.Format(time.RFC3339),
		Scope:       normalized,
	}
	if err = monthlyUsagePublish(ctx, consts.QueueTrafficUsageMonthlyStart, message); err != nil {
		g.Log().Errorf(ctx, "event=monthly_usage_trigger status=failed stage=publish runId=%s queryMonth=%s durationMs=%d error=%q", message.RunID, message.QueryMonth, elapsedMilliseconds(startedAt), err.Error())
		return "", fmt.Errorf("publish monthly usage start: %w", err)
	}
	g.Log().Infof(ctx, "event=monthly_usage_trigger status=published runId=%s queryMonth=%s triggeredAt=%s durationMs=%d", message.RunID, message.QueryMonth, message.TriggeredAt, elapsedMilliseconds(startedAt))
	return message.RunID, nil
}

func elapsedMilliseconds(startedAt time.Time) int64 {
	return time.Since(startedAt).Milliseconds()
}

// StartMonthlyHistory publishes one command for Worker to execute the
// previous-month usage history sync (the TDengine monthly table).
func (s *sTrafficUsageMonthlySync) StartMonthlyHistory(ctx context.Context) error {
	_, err := s.StartMonthlyHistoryRun(ctx)
	return err
}

func (s *sTrafficUsageMonthlySync) StartMonthlyHistoryRun(ctx context.Context) (string, error) {
	return s.StartMonthlyHistoryRunScoped(ctx, nil)
}

// StartMonthlyHistoryRunScoped starts a monthly history run restricted to
// scope.Channels. A nil scope, or one whose channels normalize to empty, starts
// a full sync.
//
// The period is the previous month, matching what the legacy SyncMonthly scan
// wrote. Do not confuse this with StartMonthlyRunScoped, which fills the
// current-month snapshot in MySQL.
func (s *sTrafficUsageMonthlySync) StartMonthlyHistoryRunScoped(ctx context.Context, scope *model.SyncScope) (string, error) {
	return s.StartMonthlyHistoryRunScopedAt(ctx, scope, "")
}

// StartMonthlyHistoryRunScopedAt starts a monthly history run for the given
// month (yyyyMM). An empty queryMonth keeps the historical behaviour and covers
// the previous calendar month; a non-empty value lets an operator backfill one
// specific past month.
func (s *sTrafficUsageMonthlySync) StartMonthlyHistoryRunScopedAt(ctx context.Context, scope *model.SyncScope, queryMonth string) (string, error) {
	if ctx == nil {
		ctx = context.Background()
	}
	startedAt := time.Now()
	normalized, err := model.NormalizeScope(scope)
	if err != nil {
		g.Log().Errorf(ctx, "event=monthly_history_trigger status=failed stage=validate durationMs=%d error=%q", elapsedMilliseconds(startedAt), err.Error())
		return "", err
	}
	if !monthlyHistoryRabbitEnabled(ctx) {
		err := fmt.Errorf("monthly history start skipped: rabbitmq is disabled")
		g.Log().Errorf(ctx, "event=monthly_history_trigger status=failed stage=precheck durationMs=%d reason=%q", elapsedMilliseconds(startedAt), err.Error())
		return "", err
	}

	location, err := time.LoadLocation("Asia/Shanghai")
	if err != nil {
		g.Log().Errorf(ctx, "event=monthly_history_trigger status=failed stage=timezone durationMs=%d error=%q", elapsedMilliseconds(startedAt), err.Error())
		return "", fmt.Errorf("load monthly history timezone: %w", err)
	}
	now := monthlyHistoryNow().In(location)
	resolvedMonth, err := resolveMonthlyHistoryQueryMonth(now, location, queryMonth)
	if err != nil {
		g.Log().Errorf(ctx, "event=monthly_history_trigger status=failed stage=validate reason=invalid_query_month queryMonth=%q durationMs=%d error=%q", queryMonth, elapsedMilliseconds(startedAt), err.Error())
		return "", err
	}
	message := model.TrafficUsageMonthlyHistoryStartMessage{
		RunID:       fmt.Sprintf("monthly-history-%s-%s", resolvedMonth, monthlyHistoryRunID()),
		Operation:   model.OperationPreviousMonthUsageFullSync,
		QueryMonth:  resolvedMonth,
		TriggeredAt: now.Format(time.RFC3339),
		Scope:       normalized,
	}
	if err = monthlyHistoryPublish(ctx, consts.QueueTrafficUsageMonthlyHistoryStart, message); err != nil {
		g.Log().Errorf(ctx, "event=monthly_history_trigger status=failed stage=publish runId=%s queryMonth=%s durationMs=%d error=%q", message.RunID, message.QueryMonth, elapsedMilliseconds(startedAt), err.Error())
		return "", fmt.Errorf("publish monthly history start: %w", err)
	}
	g.Log().Infof(ctx, "event=monthly_history_trigger status=published runId=%s queryMonth=%s triggeredAt=%s durationMs=%d", message.RunID, message.QueryMonth, message.TriggeredAt, elapsedMilliseconds(startedAt))
	return message.RunID, nil
}

// minBackfillMonth is the earliest month a manual backfill may target. It only
// catches obvious typos; it is not a business boundary.
const minBackfillMonth = "202001"

// resolveMonthlyHistoryQueryMonth returns the month a history run must cover. An
// empty requested value keeps the legacy default (the previous calendar month);
// otherwise the value is validated and returned in canonical yyyyMM form.
func resolveMonthlyHistoryQueryMonth(now time.Time, location *time.Location, requested string) (string, error) {
	currentMonth := time.Date(now.Year(), now.Month(), 1, 0, 0, 0, 0, location)
	if requested == "" {
		// The previous month is what the legacy scan backfilled, and the
		// month-first day is what the worker's snapshotMonth derives the
		// end-of-month ts from.
		return currentMonth.AddDate(0, -1, 0).Format("200601"), nil
	}
	parsed, err := time.ParseInLocation("200601", requested, location)
	if err != nil {
		return "", fmt.Errorf("invalid queryMonth %q: want yyyyMM", requested)
	}
	// The current month is served by the MySQL snapshot chain
	// (StartMonthlyRunScoped), not by the TDengine history chain.
	if !parsed.Before(currentMonth) {
		return "", fmt.Errorf("invalid queryMonth %q: must be earlier than the current month %s", requested, currentMonth.Format("200601"))
	}
	if parsed.Format("200601") < minBackfillMonth {
		return "", fmt.Errorf("invalid queryMonth %q: must not be earlier than %s", requested, minBackfillMonth)
	}
	return parsed.Format("200601"), nil
}

// SyncMonthly is the legacy in-process scan. It is retained as the rollback path
// until the worker monthly history chain is verified in production.
func (s *sTrafficUsageMonthlySync) SyncMonthly(ctx context.Context) {
	month := previousUsageMonth(time.Now())
	queryDate := month.Format("200601")

	cardColumns := dao.TSimCardInfo.Columns()
	cardTable := dao.TSimCardInfo.Table()
	snapshotMaxID, err := trafficUsageEligibleCardModel(ctx).Max(cardTable + "." + cardColumns.Id)
	if err != nil {
		g.Log().Errorf(ctx, "SyncTrafficUsageMonthly snapshot sim cards failed: %+v", err)
		return
	}
	maxID := int64(snapshotMaxID)
	if maxID <= 0 {
		return
	}

	var lastID int64
	for lastID < maxID {
		list := []entity.TSimCardInfo{}
		if err = trafficUsageEligibleCardModel(ctx).
			Fields(trafficUsageCardFields()).
			WhereGT(cardTable+"."+cardColumns.Id, lastID).
			WhereLTE(cardTable+"."+cardColumns.Id, maxID).
			OrderAsc(cardTable + "." + cardColumns.Id).
			Limit(trafficUsageMonthlyPageSize).
			Scan(&list); err != nil {
			g.Log().Errorf(ctx, "SyncTrafficUsageMonthly list sim cards failed, lastId:%d, err:%+v", lastID, err)
			return
		}
		if len(list) == 0 {
			return
		}
		lastID = list[len(list)-1].Id

		cardMap := trafficUsageMonthlyCardMap(list)
		simKeys := trafficUsageMonthlySimKeys(list)
		output, err := service.UpstreamChan().QuerySimDatausageMonthly(ctx, &model.SimDataUsageMonthlyInput{
			SimKeys: simKeys,
			ReqData: model.SimDataUsageMonthlyInputItem{
				QueryDate: queryDate,
			},
		})
		if err != nil {
			g.Log().Errorf(ctx, "SyncTrafficUsageMonthly query monthly failed, lastId:%d, count:%d, err:%+v", lastID, len(simKeys), err)
			for _, simKey := range simKeys {
				s.publishRetry(ctx, simKey, cardMap[simKey.ICCID], queryDate)
			}
			continue
		}

		success, failed := reconcileUsageWithPeriod(simKeys, output, func(item model.SimDataUsageMonthlyOutputItem) float64 { return item.DataAmount }, func(item model.SimDataUsageMonthlyOutputItem) string { return item.DeadLine }, normalizeUsageMonth, queryDate)
		for _, key := range failed {
			s.publishRetry(ctx, key, cardMap[key.ICCID], queryDate)
		}

		if items := s.buildMonthlyItems(success, cardMap, month); len(items) > 0 {
			if err = service.TrafficUsage().UpdateMonthly(ctx, items); err != nil {
				g.Log().Errorf(ctx, "SyncTrafficUsageMonthly write tdengine failed, lastId:%d, err:%+v", lastID, err)
				for _, item := range success {
					s.publishRetry(ctx, item.SimKey, cardMap[item.SimKey.ICCID], queryDate, item.ResData.DataAmount)
				}
			}
		}
	}
}

func (s *sTrafficUsageMonthlySync) buildMonthlyItems(output []model.SimBaseRes[model.SimDataUsageMonthlyOutputItem], cardMap map[string]model.TrafficUsageSimCard, month time.Time) []model.TrafficUsageMonthlyItem {
	items := make([]model.TrafficUsageMonthlyItem, 0, len(output))
	for _, item := range output {
		if item.SimKey == nil {
			continue
		}
		card := cardMap[item.SimKey.ICCID]
		items = append(items, model.TrafficUsageMonthlyItem{
			TrafficUsageBase: model.TrafficUsageBase{
				Iccid:       item.SimKey.ICCID,
				UsageMb:     item.ResData.DataAmount,
				PackageCode: card.PackageCode,
			},
			Month: month,
		})
	}
	return items
}

func (s *sTrafficUsageMonthlySync) publishRetry(ctx context.Context, simKey *model.SimKey, card model.TrafficUsageSimCard, queryDate string, usage ...float64) {
	var snapshot *float64
	if len(usage) > 0 {
		snapshot = &usage[0]
	}
	if !rabbitmq.Enabled(ctx) {
		g.Log().Errorf(ctx, "traffic usage monthly retry skipped, rabbitmq disabled, simKey:%+v, queryDate:%s", simKey, queryDate)
		return
	}
	if err := rabbitmq.PublishConfirmed(ctx, consts.QueueTrafficUsageMonthlyRetry, model.TrafficUsageMonthlyRetryMessage{
		UsageMb:   snapshot,
		SimKey:    simKey,
		Card:      card,
		QueryDate: queryDate,
	}); err != nil {
		g.Log().Errorf(ctx, "publish traffic usage monthly retry failed, simKey:%+v, queryDate:%s, err:%+v", simKey, queryDate, err)
	}
}

func trafficUsageMonthlySimKeys(list []entity.TSimCardInfo) []*model.SimKey {
	simKeys := make([]*model.SimKey, 0, len(list))
	for _, item := range list {
		simKeys = append(simKeys, &model.SimKey{
			ChanKey: item.ChanKey,
			ICCID:   item.Iccid,
			IMSI:    item.Imsi,
			MSISDN:  item.Msisdn,
		})
	}
	return simKeys
}

func trafficUsageMonthlyCardMap(list []entity.TSimCardInfo) map[string]model.TrafficUsageSimCard {
	cardMap := make(map[string]model.TrafficUsageSimCard, len(list))
	for _, item := range list {
		cardMap[item.Iccid] = model.TrafficUsageSimCard{
			Iccid:       item.Iccid,
			PackageCode: item.CurrentPackageCode,
		}
	}
	return cardMap
}