package trafficusage

import (
	"context"
	"database/sql"
	"fmt"
	"git.5iot.com/iotlcm-public/iotlcm-admin-svr/internal/cmd/inithttp"
	"git.5iot.com/iotlcm-public/iotlcm-admin-svr/internal/library/tdengine"
	"git.5iot.com/iotlcm-public/iotlcm-admin-svr/internal/model"
	"git.5iot.com/iotlcm-public/iotlcm-admin-svr/internal/service"
	"hash/fnv"
	"math"
	"regexp"
	"strconv"
	"strings"
	"time"
	"unicode"

	"github.com/gogf/gf/v2/errors/gerror"
	"github.com/gogf/gf/v2/frame/g"
)

// identifierPattern 限制 database/stable 只能是普通标识符，防止拼 SQL 时传入非法名称。
var identifierPattern = regexp.MustCompile(`^[A-Za-z_][A-Za-z0-9_]*$`)

type sTrafficUsage struct {
}

func NewTrafficUsage() *sTrafficUsage {
	return &sTrafficUsage{}
}

func init() {
	service.RegisterTrafficUsage(NewTrafficUsage())
	// 只注册连接释放逻辑，不在应用启动时自动创建 TDengine 库表。
	inithttp.RegisterHttpCleanupFunc("trafficUsage", func(ctx context.Context) error {
		return tdengine.Close()
	})
}

// WriteDaily 批量写入日流量数据。
// 每个 ICCID 会落到独立子表，子表通过 t_sim_card_usage_daily 超级表自动创建。
func (s *sTrafficUsage) WriteDaily(ctx context.Context, items []model.TrafficUsageDailyItem) error {
	if len(items) == 0 {
		return nil
	}
	if !tdengine.Enabled(ctx) {
		g.Log().Debug(ctx, "sTrafficUsage.WriteDaily skipped, tdengine disabled")
		return gerror.New("TDengine disabled; daily usage was not persisted")
	}

	cfg := tdengine.GetConfig(ctx)
	dbName := cfg.DbNameFor(cfg.DailyStable)
	if err := validateTableConfig(dbName, cfg.DailyStable); err != nil {
		return err
	}

	batchSize := normalizeBatchSize(cfg.BatchSize)
	for start := 0; start < len(items); start += batchSize {
		end := start + batchSize
		if end > len(items) {
			end = len(items)
		}
		batch := items[start:end]

		var builder strings.Builder
		builder.WriteString("INSERT INTO ")
		for i, item := range batch {
			if item.Iccid == "" {
				return gerror.New("traffic usage daily item iccid is empty")
			}
			if err := validateUsageMb("traffic usage daily item usage mb", item.UsageMb); err != nil {
				return err
			}
			if i > 0 {
				builder.WriteByte(' ')
			}
			builder.WriteString(qualify(dbName, childTrafficTableName(cfg.DailyStable, item.Iccid)))
			builder.WriteString(" USING ")
			builder.WriteString(qualify(dbName, cfg.DailyStable))
			builder.WriteString(" TAGS (")
			builder.WriteString(sqlString(item.Iccid))
			builder.WriteString(") VALUES (")
			builder.WriteString(strings.Join([]string{
				sqlTime(dayStart(item.Date)),
				sqlFloat(item.UsageMb),
				sqlString(item.PackageCode),
			}, ", "))
			builder.WriteByte(')')
		}

		if _, err := tdengine.Exec(ctx, builder.String()); err != nil {
			return gerror.Wrap(err, "tdengine write daily traffic usage failed")
		}
	}
	return nil
}

// WriteMonthly 批量写入月流量数据。
// 月流量和日流量共用同一个 TDengine database，但使用不同超级表。
func (s *sTrafficUsage) WriteMonthly(ctx context.Context, items []model.TrafficUsageMonthlyItem) error {
	if len(items) == 0 {
		return nil
	}
	if !tdengine.Enabled(ctx) {
		g.Log().Debug(ctx, "sTrafficUsage.WriteMonthly skipped, tdengine disabled")
		return gerror.New("TDengine disabled; monthly usage was not persisted")
	}

	cfg := tdengine.GetConfig(ctx)
	dbName := cfg.DbNameFor(cfg.MonthlyStable)
	if err := validateTableConfig(dbName, cfg.MonthlyStable); err != nil {
		return err
	}

	batchSize := normalizeBatchSize(cfg.BatchSize)
	for start := 0; start < len(items); start += batchSize {
		end := start + batchSize
		if end > len(items) {
			end = len(items)
		}
		batch := items[start:end]

		var builder strings.Builder
		builder.WriteString("INSERT INTO ")
		for i, item := range batch {
			if item.Iccid == "" {
				return gerror.New("traffic usage monthly item iccid is empty")
			}
			if err := validateUsageMb("traffic usage monthly item usage mb", item.UsageMb); err != nil {
				return err
			}
			if i > 0 {
				builder.WriteByte(' ')
			}
			builder.WriteString(qualify(dbName, childTrafficTableName(cfg.MonthlyStable, item.Iccid)))
			builder.WriteString(" USING ")
			builder.WriteString(qualify(dbName, cfg.MonthlyStable))
			builder.WriteString(" TAGS (")
			builder.WriteString(sqlString(item.Iccid))
			builder.WriteString(") VALUES (")
			builder.WriteString(strings.Join([]string{
				sqlTime(monthStart(item.Month)),
				sqlFloat(item.UsageMb),
				sqlString(item.PackageCode),
			}, ", "))
			builder.WriteByte(')')
		}

		if _, err := tdengine.Exec(ctx, builder.String()); err != nil {
			return gerror.Wrap(err, "tdengine write monthly traffic usage failed")
		}
	}
	return nil
}

// WritePoolUsageDaily 批量写入流量池的流量使用记录。
// 每个 FlowPoolCode 会落到独立子表，子表通过 t_flow_pool_usage_daily 超级表自动创建。
func (s *sTrafficUsage) WritePoolUsageDaily(ctx context.Context, items []model.TrafficPoolUsageItem) error {
	return s.writePoolUsage(ctx, items, tdengine.GetConfig(ctx).PoolDailyStable, "flow_pool_usage_d_", dayStart, "daily")
}

// WritePoolUsageMonthly 批量写入流量池的流量使用记录。
// 每个 FlowPoolCode 会落到独立子表，子表通过 t_flow_pool_usage_monthly 超级表自动创建。
func (s *sTrafficUsage) WritePoolUsageMonthly(ctx context.Context, items []model.TrafficPoolUsageItem) error {
	return s.writePoolUsage(ctx, items, tdengine.GetConfig(ctx).PoolMonthlyStable, "flow_pool_usage_m_", monthStart, "monthly")
}

// WritePoolCardCountDaily 批量写入流量池的卡数量记录。
// 每个 FlowPoolCode 会落到独立子表，子表通过 t_flow_pool_card_count_daily 超级表自动创建。
func (s *sTrafficUsage) WritePoolCardCountDaily(ctx context.Context, items []model.TrafficPoolCardCountItem) error {
	return s.writePoolCardCount(ctx, items, tdengine.GetConfig(ctx).PoolCardCountDailyStable, "flow_pool_card_count_d_", dayStart, "daily")
}

// WritePoolCardCountMonthly 批量写入流量池的卡数量记录。
// 每个 FlowPoolCode 会落到独立子表，子表通过 t_flow_pool_card_count_monthly 超级表自动创建。
func (s *sTrafficUsage) WritePoolCardCountMonthly(ctx context.Context, items []model.TrafficPoolCardCountItem) error {
	return s.writePoolCardCount(ctx, items, tdengine.GetConfig(ctx).PoolCardCountMonthlyStable, "flow_pool_card_count_m_", monthStart, "monthly")
}

// UpdateDaily 更新日流量数据。
func (s *sTrafficUsage) UpdateDaily(ctx context.Context, items []model.TrafficUsageDailyItem) error {
	return s.WriteDaily(ctx, items)
}

// UpdateMonthly 更新月流量数据。
func (s *sTrafficUsage) UpdateMonthly(ctx context.Context, items []model.TrafficUsageMonthlyItem) error {
	return s.WriteMonthly(ctx, items)
}

// DeleteDaily 删除日流量数据。
func (s *sTrafficUsage) DeleteDaily(ctx context.Context, input model.TrafficUsageDeleteInput) error {
	if !tdengine.Enabled(ctx) {
		g.Log().Debug(ctx, "sTrafficUsage.DeleteDaily skipped, tdengine disabled")
		return nil
	}
	if input.Iccid == "" {
		return gerror.New("traffic usage daily delete iccid is empty")
	}
	cfg := tdengine.GetConfig(ctx)
	dbName := cfg.DbNameFor(cfg.DailyStable)
	if err := validateTableConfig(dbName, cfg.DailyStable); err != nil {
		return err
	}
	return deleteRange(ctx, qualify(dbName, childTrafficTableName(cfg.DailyStable, input.Iccid)), input.StartTime, input.EndTime)
}

// DeleteMonthly 删除月流量数据。
func (s *sTrafficUsage) DeleteMonthly(ctx context.Context, input model.TrafficUsageDeleteInput) error {
	if !tdengine.Enabled(ctx) {
		g.Log().Debug(ctx, "sTrafficUsage.DeleteMonthly skipped, tdengine disabled")
		return nil
	}
	if input.Iccid == "" {
		return gerror.New("traffic usage monthly delete iccid is empty")
	}
	cfg := tdengine.GetConfig(ctx)
	dbName := cfg.DbNameFor(cfg.MonthlyStable)
	if err := validateTableConfig(dbName, cfg.MonthlyStable); err != nil {
		return err
	}
	return deleteRange(ctx, qualify(dbName, childTrafficTableName(cfg.MonthlyStable, input.Iccid)), input.StartTime, input.EndTime)
}

// QueryDaily 查询日流量数据。
func (s *sTrafficUsage) QueryDaily(ctx context.Context, input model.TrafficUsageQueryInput) ([]model.TrafficUsageDailyRecord, int, error) {
	if !tdengine.Enabled(ctx) {
		return nil, 0, nil
	}
	if input.Iccid == "" {
		return nil, 0, gerror.New("traffic usage daily query iccid is empty")
	}
	cfg := tdengine.GetConfig(ctx)
	dbName := cfg.DbNameFor(cfg.DailyStable)
	if err := validateTableConfig(dbName, cfg.DailyStable); err != nil {
		return nil, 0, err
	}

	table := qualify(dbName, childTrafficTableName(cfg.DailyStable, input.Iccid))
	total, err := countRows(ctx, table, input.StartTime, input.EndTime)
	if err != nil {
		if isTableNotExist(err) {
			return []model.TrafficUsageDailyRecord{}, 0, nil
		}
		return nil, 0, err
	}
	rows, err := queryRows(ctx, table, input)
	if err != nil {
		if isTableNotExist(err) {
			return []model.TrafficUsageDailyRecord{}, 0, nil
		}
		return nil, 0, err
	}
	defer rows.Close()

	list := make([]model.TrafficUsageDailyRecord, 0)
	for rows.Next() {
		var item model.TrafficUsageDailyRecord
		if err = rows.Scan(&item.Ts, &item.UsageMb, &item.PackageCode, &item.Iccid); err != nil {
			return nil, 0, err
		}
		list = append(list, item)
	}
	if err = rows.Err(); err != nil {
		return nil, 0, err
	}
	return list, total, nil
}

// QueryMonthly 查询月流量数据。
func (s *sTrafficUsage) QueryMonthly(ctx context.Context, input model.TrafficUsageQueryInput) ([]model.TrafficUsageMonthlyRecord, int, error) {
	if !tdengine.Enabled(ctx) {
		return nil, 0, nil
	}
	if input.Iccid == "" {
		return nil, 0, gerror.New("traffic usage monthly query iccid is empty")
	}
	cfg := tdengine.GetConfig(ctx)
	dbName := cfg.DbNameFor(cfg.MonthlyStable)
	if err := validateTableConfig(dbName, cfg.MonthlyStable); err != nil {
		return nil, 0, err
	}

	table := qualify(dbName, childTrafficTableName(cfg.MonthlyStable, input.Iccid))
	total, err := countRows(ctx, table, input.StartTime, input.EndTime)
	if err != nil {
		if isTableNotExist(err) {
			return []model.TrafficUsageMonthlyRecord{}, 0, nil
		}
		return nil, 0, err
	}
	rows, err := queryRows(ctx, table, input)
	if err != nil {
		if isTableNotExist(err) {
			return []model.TrafficUsageMonthlyRecord{}, 0, nil
		}
		return nil, 0, err
	}
	defer rows.Close()

	list := make([]model.TrafficUsageMonthlyRecord, 0)
	for rows.Next() {
		var item model.TrafficUsageMonthlyRecord
		if err = rows.Scan(&item.Ts, &item.UsageMb, &item.PackageCode, &item.Iccid); err != nil {
			return nil, 0, err
		}
		list = append(list, item)
	}
	if err = rows.Err(); err != nil {
		return nil, 0, err
	}
	return list, total, nil
}

// AggregatePoolUsageDaily 汇总日流量数据。
func (s *sTrafficUsage) AggregatePoolUsageDaily(ctx context.Context, date time.Time, cards []model.TrafficPoolCard) ([]model.TrafficPoolUsageAggregate, error) {
	return s.aggregatePoolUsage(ctx, dayStart(date), cards, tdengine.GetConfig(ctx).DailyStable, "daily")
}

// AggregatePoolUsageMonthly 汇总月流量数据。
func (s *sTrafficUsage) AggregatePoolUsageMonthly(ctx context.Context, month time.Time, cards []model.TrafficPoolCard) ([]model.TrafficPoolUsageAggregate, error) {
	return s.aggregatePoolUsage(ctx, monthStart(month), cards, tdengine.GetConfig(ctx).MonthlyStable, "monthly")
}

// aggregatePoolUsage 汇总流量数据。
func (s *sTrafficUsage) aggregatePoolUsage(ctx context.Context, ts time.Time, cards []model.TrafficPoolCard, stable string, name string) ([]model.TrafficPoolUsageAggregate, error) {
	if len(cards) == 0 {
		return []model.TrafficPoolUsageAggregate{}, nil
	}
	if !tdengine.Enabled(ctx) {
		g.Log().Debugf(ctx, "sTrafficUsage.aggregatePoolUsage %s skipped, tdengine disabled", name)
		return []model.TrafficPoolUsageAggregate{}, nil
	}

	cfg := tdengine.GetConfig(ctx)
	dbName := cfg.DbNameFor(stable)
	if err := validateTableConfig(dbName, stable); err != nil {
		return nil, err
	}

	grouped := make(map[string][]string)
	for _, card := range cards {
		if card.FlowPoolCode == "" || card.Iccid == "" {
			continue
		}
		grouped[card.FlowPoolCode] = append(grouped[card.FlowPoolCode], card.Iccid)
	}

	result := make([]model.TrafficPoolUsageAggregate, 0, len(grouped))
	for flowPoolCode, iccids := range grouped {
		usageMb, recordCount, err := aggregatePoolUsageByIccids(ctx, dbName, stable, ts, iccids)
		if err != nil {
			return nil, gerror.Wrapf(err, "tdengine aggregate %s traffic pool usage failed, flowPoolCode:%s", name, flowPoolCode)
		}
		if recordCount != int64(len(iccids)) {
			return nil, gerror.Newf(
				"tdengine aggregate %s traffic pool usage incomplete, flowPoolCode:%s, expected:%d, actual:%d",
				name,
				flowPoolCode,
				len(iccids),
				recordCount,
			)
		}
		result = append(result, model.TrafficPoolUsageAggregate{
			FlowPoolCode: flowPoolCode,
			UsageMb:      usageMb,
			RecordCount:  recordCount,
		})
	}
	return result, nil
}

// writePoolUsage 批量写入流量池使用量数据。
// 每个 FlowPoolCode 会落到独立子表，子表通过对应的超级表自动创建。
func (s *sTrafficUsage) writePoolUsage(ctx context.Context, items []model.TrafficPoolUsageItem, stable string, prefix string, normalizeTime func(time.Time) time.Time, name string) error {
	if len(items) == 0 {
		return nil
	}
	if !tdengine.Enabled(ctx) {
		g.Log().Debugf(ctx, "sTrafficUsage.writePoolUsage %s skipped, tdengine disabled", name)
		return nil
	}

	cfg := tdengine.GetConfig(ctx)
	dbName := cfg.DbNameFor(stable)
	if err := validateTableConfig(dbName, stable); err != nil {
		return err
	}

	batchSize := normalizeBatchSize(cfg.BatchSize)
	for start := 0; start < len(items); start += batchSize {
		end := start + batchSize
		if end > len(items) {
			end = len(items)
		}
		batch := items[start:end]

		var builder strings.Builder
		builder.WriteString("INSERT INTO ")
		for i, item := range batch {
			if item.FlowPoolCode == "" {
				return gerror.New("traffic pool usage item flow pool code is empty")
			}
			if err := validateUsageMb("traffic pool usage item usage mb", item.UsageMb); err != nil {
				return err
			}
			if i > 0 {
				builder.WriteByte(' ')
			}
			builder.WriteString(qualify(dbName, childTableNameWithPrefix(prefix, item.FlowPoolCode)))
			builder.WriteString(" USING ")
			builder.WriteString(qualify(dbName, stable))
			builder.WriteString(" TAGS (")
			builder.WriteString(sqlString(item.FlowPoolCode))
			builder.WriteString(") VALUES (")
			builder.WriteString(strings.Join([]string{
				sqlTime(normalizeTime(item.Date)),
				sqlFloat(item.UsageMb),
			}, ", "))
			builder.WriteByte(')')
		}

		if _, err := tdengine.Exec(ctx, builder.String()); err != nil {
			return gerror.Wrapf(err, "tdengine write %s traffic pool usage failed", name)
		}
	}
	return nil
}

// writePoolCardCount 批量写入流量池卡数量数据。
// 每个 FlowPoolCode 会落到独立子表，子表通过对应的超级表自动创建。
func (s *sTrafficUsage) writePoolCardCount(ctx context.Context, items []model.TrafficPoolCardCountItem, stable string, prefix string, normalizeTime func(time.Time) time.Time, name string) error {
	if len(items) == 0 {
		return nil
	}
	if !tdengine.Enabled(ctx) {
		g.Log().Debugf(ctx, "sTrafficUsage.writePoolCardCount %s skipped, tdengine disabled", name)
		return nil
	}

	cfg := tdengine.GetConfig(ctx)
	dbName := cfg.DbNameFor(stable)
	if err := validateTableConfig(dbName, stable); err != nil {
		return err
	}

	batchSize := normalizeBatchSize(cfg.BatchSize)
	for start := 0; start < len(items); start += batchSize {
		end := start + batchSize
		if end > len(items) {
			end = len(items)
		}
		batch := items[start:end]

		var builder strings.Builder
		builder.WriteString("INSERT INTO ")
		for i, item := range batch {
			if item.FlowPoolCode == "" {
				return gerror.New("traffic pool card count item flow pool code is empty")
			}
			if item.CardCount < 0 {
				return gerror.Newf("traffic pool card count item card count cannot be negative: %d", item.CardCount)
			}
			if i > 0 {
				builder.WriteByte(' ')
			}
			builder.WriteString(qualify(dbName, childTableNameWithPrefix(prefix, item.FlowPoolCode)))
			builder.WriteString(" USING ")
			builder.WriteString(qualify(dbName, stable))
			builder.WriteString(" TAGS (")
			builder.WriteString(sqlString(item.FlowPoolCode))
			builder.WriteString(") VALUES (")
			builder.WriteString(strings.Join([]string{
				sqlTime(normalizeTime(item.Date)),
				strconv.FormatInt(item.CardCount, 10),
			}, ", "))
			builder.WriteByte(')')
		}

		if _, err := tdengine.Exec(ctx, builder.String()); err != nil {
			return gerror.Wrapf(err, "tdengine write %s traffic pool card count failed", name)
		}
	}
	return nil
}

// aggregatePoolUsageByIccids 汇总流量数据。
// 每个 ICCID 会落到独立子表，子表通过 t_sim_card_usage_daily 或 t_sim_card_usage_monthly 超级表自动创建。
func aggregatePoolUsageByIccids(ctx context.Context, database string, stable string, ts time.Time, iccids []string) (float64, int64, error) {
	var usageMb float64
	var recordCount int64
	for _, iccid := range iccids {
		table := qualify(database, childTrafficTableName(stable, iccid))
		row, err := tdengine.QueryRow(ctx, fmt.Sprintf("SELECT usage_mb FROM %s WHERE ts = %s", table, sqlTime(ts)))
		if err != nil {
			return 0, 0, gerror.Wrap(err, "tdengine query traffic usage row failed")
		}
		var value float64
		if err = row.Scan(&value); err != nil {
			if err == sql.ErrNoRows || isTableNotExist(err) {
				continue
			}
			return 0, 0, gerror.Wrap(err, "tdengine scan traffic usage row failed")
		}
		usageMb += value
		recordCount++
	}
	return usageMb, recordCount, nil
}

// countRows 统计流量数据记录数。
func countRows(ctx context.Context, table string, startTime, endTime time.Time) (int, error) {
	where := whereRangeSQL(startTime, endTime)
	row, err := tdengine.QueryRow(ctx, fmt.Sprintf("SELECT COUNT(*) FROM %s%s", table, where))
	if err != nil {
		return 0, gerror.Wrap(err, "tdengine count traffic usage failed")
	}
	total := 0
	if err = row.Scan(&total); err != nil {
		return 0, gerror.Wrap(err, "tdengine count traffic usage failed")
	}
	return total, nil
}

// queryRows 查询流量数据记录。
func queryRows(ctx context.Context, table string, input model.TrafficUsageQueryInput) (*sql.Rows, error) {
	fields := "ts, usage_mb, package_code, iccid"
	where := whereRangeSQL(input.StartTime, input.EndTime)
	order := "DESC"
	if input.Asc {
		order = "ASC"
	}
	limit := ""
	page, pageSize := normalizePage(input.Page, input.PageSize)
	if pageSize > 0 {
		limit = fmt.Sprintf(" LIMIT %d OFFSET %d", pageSize, (page-1)*pageSize)
	}
	rows, err := tdengine.Query(ctx, fmt.Sprintf("SELECT %s FROM %s%s ORDER BY ts %s%s", fields, table, where, order, limit))
	if err != nil {
		return nil, gerror.Wrap(err, "tdengine query traffic usage failed")
	}
	return rows, nil
}

// deleteRange 删除流量数据记录。
func deleteRange(ctx context.Context, table string, startTime, endTime time.Time) error {
	where := whereRangeSQL(startTime, endTime)
	if where == "" {
		return gerror.New("traffic usage delete time range is empty")
	}
	if _, err := tdengine.Exec(ctx, fmt.Sprintf("DELETE FROM %s%s", table, where)); err != nil {
		if isTableNotExist(err) {
			return nil
		}
		return gerror.Wrap(err, "tdengine delete traffic usage failed")
	}
	return nil
}

// whereRangeSQL 构建时间范围查询条件。
func whereRangeSQL(startTime, endTime time.Time) string {
	clauses := make([]string, 0, 2)
	if !startTime.IsZero() {
		clauses = append(clauses, "ts >= "+sqlTime(startTime))
	}
	if !endTime.IsZero() {
		clauses = append(clauses, "ts <= "+sqlTime(endTime))
	}
	if len(clauses) == 0 {
		return ""
	}
	return " WHERE " + strings.Join(clauses, " AND ")
}

// validateTableConfig 验证表配置是否有效。
func validateTableConfig(database, stable string) error {
	if !identifierPattern.MatchString(database) {
		return gerror.Newf("invalid tdengine database name: %s", database)
	}
	if !identifierPattern.MatchString(stable) {
		return gerror.Newf("invalid tdengine stable name: %s", stable)
	}
	return nil
}

// qualify 格式化表名。
func qualify(database, table string) string {
	return fmt.Sprintf("%s.%s", database, table)
}

// childTrafficTableName 构建子表名。
// 每个 ICCID 会落到独立子表，子表通过 t_sim_card_usage_daily 或 t_sim_card_usage_monthly 超级表自动创建。
func childTrafficTableName(stable string, iccid string) string {
	prefix := "sim_card_usage_m_"
	if stable == "t_sim_card_usage_daily" {
		prefix = "sim_card_usage_d_"
	}
	return childTableNameWithPrefix(prefix, iccid)
}

// childTableNameWithPrefix 构建子表名。
func childTableNameWithPrefix(prefix string, value string) string {
	var builder strings.Builder
	builder.WriteString(prefix)
	for _, r := range strings.ToLower(value) {
		if unicode.IsLetter(r) || unicode.IsDigit(r) || r == '_' {
			builder.WriteRune(r)
		}
	}
	name := builder.String()
	if name == prefix || len(name) > 190 {
		return fmt.Sprintf("%s%x", prefix, hashString(value))
	}
	return name
}

// hashString 对字符串进行哈希处理。
// 用于生成子表名。
func hashString(value string) uint32 {
	hash := fnv.New32a()
	_, _ = hash.Write([]byte(value))
	return hash.Sum32()
}

// normalizeBatchSize 归一化批量大小。
func normalizeBatchSize(size int) int {
	if size <= 0 {
		return 200
	}
	return size
}

// normalizePage 归一化分页参数。
func normalizePage(page, pageSize int) (int, int) {
	if page <= 0 {
		page = 1
	}
	if pageSize < 0 {
		pageSize = 0
	}
	return page, pageSize
}

// dayStart 获取指定日期的快照时间。
// 用于查询指定日期的流量数据记录。
func dayStart(t time.Time) time.Time {
	if t.IsZero() {
		t = time.Now()
	}
	return time.Date(t.Year(), t.Month(), t.Day(), 23, 59, 59, 0, t.Location())
}

// monthStart 获取指定月份的快照时间。
// 用于查询指定月份的流量数据记录。
func monthStart(t time.Time) time.Time {
	if t.IsZero() {
		t = time.Now()
	}
	lastDay := time.Date(t.Year(), t.Month()+1, 0, 23, 59, 59, 0, t.Location())
	return lastDay
}

// sqlString 格式化字符串为SQL字符串。
func sqlString(value string) string {
	return "'" + strings.ReplaceAll(value, "'", "''") + "'"
}

// sqlTime 格式化时间时间为SQL时间。
func sqlTime(value time.Time) string {
	return sqlString(value.Format("2006-01-02 15:04:05.000"))
}

// sqlFloat 格式化浮点数为SQL浮点数。
func sqlFloat(value float64) string {
	return strconv.FormatFloat(value, 'f', -1, 64)
}

// validateUsageMb 验证流量使用记录是否有效。
// 用于检查流量使用记录是否为有限的浮点数，且是否为负数。
func validateUsageMb(name string, value float64) error {
	if math.IsNaN(value) || math.IsInf(value, 0) {
		return gerror.Newf("%s must be finite: %v", name, value)
	}
	if value < 0 {
		return gerror.Newf("%s cannot be negative: %v", name, value)
	}
	return nil
}

// isTableNotExist 检查表是否存在。
// 用于在删除流量数据记录时，检查表是否存在。
func isTableNotExist(err error) bool {
	if err == nil {
		return false
	}
	text := strings.ToLower(err.Error())
	return strings.Contains(text, "table does not exist") ||
		strings.Contains(text, "table not exist") ||
		strings.Contains(text, "does not exist")
}

// GetTopUsageCardsYesterday 查询前一天流量使用前五名的卡片
func (s *sTrafficUsage) GetTopUsageCardsYesterday(ctx context.Context) ([]model.TopUsageCard, error) {
	if !tdengine.Enabled(ctx) {
		return nil, nil
	}
	cfg := tdengine.GetConfig(ctx)
	dbName := cfg.DbNameFor(cfg.DailyStable)
	if err := validateTableConfig(dbName, cfg.DailyStable); err != nil {
		return nil, err
	}

	// 获取前一天日期
	yesterday := time.Now().AddDate(0, 0, -1)
	startStr := yesterday.Format("2006-01-02")
	endStr := dayStart(yesterday).Format("2006-01-02 15:04:05")

	table := qualify(dbName, cfg.DailyStable)
	sql := fmt.Sprintf(
		"SELECT iccid, FIRST(usage_mb), LAST(usage_mb) FROM %s WHERE ts >= '%s' AND ts <= '%s' GROUP BY iccid ORDER BY LAST(usage_mb) DESC LIMIT 5",
		table, startStr, endStr)
	rows, err := tdengine.Query(ctx, sql)
	if err != nil {
		if isTableNotExist(err) {
			return []model.TopUsageCard{}, nil
		}
		return nil, err
	}
	defer rows.Close()

	result := make([]model.TopUsageCard, 0)
	for rows.Next() {
		var iccid string
		var firstUsage, lastUsage float64
		if err = rows.Scan(&iccid, &firstUsage, &lastUsage); err != nil {
			return nil, err
		}
		result = append(result, model.TopUsageCard{
			Iccid:    iccid,
			UsageMb:  lastUsage,
			StatDate: yesterday.Format("2006-01-02"),
		})
	}
	if err = rows.Err(); err != nil {
		return nil, err
	}
	return result, nil
}