package exporter

import (
	"context"
	"strconv"
	"strings"
	"time"

	"gorm.io/gorm"

	"github.com/break/junhong_cmp_fiber/internal/domain/packagetrafficalert"
	"github.com/break/junhong_cmp_fiber/pkg/constants"
	"github.com/break/junhong_cmp_fiber/pkg/errors"
)

// PackageTrafficAlertDataSource 套餐真流量达量预警导出数据源。
//
// 粒度为一条预警记录。套餐、用量、总量、阈值、到期时间与资产标识类列一律读预警行冻结的触发快照；
// 店铺、业务员与用户组按导出执行时当前归属补充，用户组按既有实时推导，不写入店铺表。
// 本场景只对超级管理员与平台账号开放：受控入口已做角色门禁，这里再校验一次，
// 阻止通过通用导出入口以代理身份创建本场景任务后读到预警数据。
type PackageTrafficAlertDataSource struct {
	db *gorm.DB
}

// NewPackageTrafficAlertDataSource 创建套餐真流量达量预警导出数据源。
func NewPackageTrafficAlertDataSource(db *gorm.DB) *PackageTrafficAlertDataSource {
	return &PackageTrafficAlertDataSource{db: db}
}

// Scene 返回导出场景编码。
func (s *PackageTrafficAlertDataSource) Scene() string {
	return constants.ExportTaskScenePackageTrafficAlert
}

// Count 统计导出预警行数。
func (s *PackageTrafficAlertDataSource) Count(ctx context.Context, params ExportParams) (int, error) {
	if err := ensurePackageTrafficAlertExportAllowed(params); err != nil {
		return 0, err
	}
	var total int64
	if err := s.applyFilters(s.baseQuery(ctx, params), params).Count(&total).Error; err != nil {
		return 0, err
	}
	return int(total), nil
}

// Headers 返回套餐真流量达量预警导出表头。
// 表头在 dispatch 阶段冻结，历史任务重导出沿用同一列序；不含任何运营商通道列。
func (s *PackageTrafficAlertDataSource) Headers(context.Context, ExportParams) ([]string, error) {
	return []string{
		"资产类型", "资产标识", "对应标识符", "卡标识", "设备类型", "设备型号",
		"套餐名称", "真流量已用量(MB)", "真流量额度(MB)", "比例(%)", "阈值快照(%)",
		"到期时间", "剩余天数", "触发时间", "店铺", "业务员", "用户组", "通知投递结果",
	}, nil
}

// Fetch 按 offset/limit 查询预警导出数据。
func (s *PackageTrafficAlertDataSource) Fetch(ctx context.Context, params ExportParams, offset, limit int) ([][]string, error) {
	if limit <= 0 {
		return [][]string{}, nil
	}
	if err := ensurePackageTrafficAlertExportAllowed(params); err != nil {
		return nil, err
	}
	var items []packageTrafficAlertExportRow
	query := s.applyFilters(s.baseQuery(ctx, params), params).
		Select(`
			a.asset_type,
			a.asset_identifier_snapshot,
			a.counterpart_identifier_snapshot,
			a.card_identifier_snapshot,
			a.device_type_snapshot,
			a.device_model_snapshot,
			a.package_name_snapshot,
			a.used_mb_snapshot,
			a.limit_mb_snapshot,
			a.usage_percent_snapshot,
			a.threshold_percent_snapshot,
			a.expires_at_snapshot,
			a.triggered_at,
			a.shop_id_snapshot,
			a.shop_name_snapshot,
			a.business_owner_account_id_snapshot,
			a.business_owner_name_snapshot,
			a.notification_event_id,
			sh.id AS current_shop_id,
			COALESCE(sh.shop_name, '') AS current_shop_name,
			owner.id AS current_owner_id,
			COALESCE(owner.username, '') AS current_owner_name,
			oe.status AS outbox_status,
			n.id AS notification_id
		`).
		Order("a.triggered_at DESC").Order("a.id DESC").
		Limit(limit).Offset(offset)
	if err := query.Scan(&items).Error; err != nil {
		return nil, errors.Wrap(errors.CodeDatabaseError, err, "查询套餐真流量达量预警导出数据失败")
	}
	groupNames, err := s.loadBusinessUserGroupNames(ctx, items)
	if err != nil {
		return nil, err
	}
	now := time.Now().UTC()
	rows := make([][]string, 0, len(items))
	for _, item := range items {
		rows = append(rows, []string{
			assetTypeName(item.AssetType),
			item.AssetIdentifier,
			item.CounterpartIdentifier,
			item.CardIdentifier,
			item.DeviceType,
			item.DeviceModel,
			item.PackageName,
			strconv.FormatInt(item.UsedMB, 10),
			strconv.FormatInt(item.LimitMB, 10),
			formatPercentValue(item.UsagePercent),
			formatPercentValue(item.ThresholdPercent),
			formatOptionalTime(item.ExpiresAt),
			formatRemainingDays(item.ExpiresAt, now),
			item.TriggeredAt.Format(exportTimeLayout),
			item.CurrentShopName,
			item.CurrentOwnerName,
			currentOwnerGroupName(groupNames, item.CurrentOwnerID),
			constants.GetPackageTrafficAlertNotifyStatusName(resolveAlertNotifyStatus(item)),
		})
	}
	return rows, nil
}

// baseQuery 构造预警导出基础查询。
// 归属展示列按执行时当前归属补充：资产 → 当前店铺 → 店铺当前业务员；用户组随后按业务员账号实时推导。
func (s *PackageTrafficAlertDataSource) baseQuery(ctx context.Context, params ExportParams) *gorm.DB {
	query := s.db.WithContext(ctx).Table("tb_package_traffic_alert AS a").
		Joins("LEFT JOIN tb_iot_card AS c ON a.asset_type = ? AND c.id = a.asset_id AND c.deleted_at IS NULL",
			constants.AssetTypeIotCard).
		Joins("LEFT JOIN tb_device AS d ON a.asset_type = ? AND d.id = a.asset_id AND d.deleted_at IS NULL",
			constants.AssetTypeDevice).
		Joins("LEFT JOIN tb_shop AS sh ON sh.id = COALESCE(c.shop_id, d.shop_id) AND sh.deleted_at IS NULL").
		Joins("LEFT JOIN tb_account AS owner ON owner.id = sh.business_owner_account_id AND owner.deleted_at IS NULL").
		Joins("LEFT JOIN tb_outbox_event AS oe ON oe.event_id = a.notification_event_id").
		Joins("LEFT JOIN tb_notification AS n ON n.event_id = a.notification_event_id")
	// 数据范围使用导出侧范围过滤（空范围拒绝），不得使用请求上下文版过滤（空范围语义相反）。
	return applyExportShopScope(query, params, "a.shop_id_snapshot")
}

// applyFilters 应用导出筛选快照。
// 筛选口径与列表一致，都作用在触发快照列上；时间范围按触发时间的闭区间解析。
func (s *PackageTrafficAlertDataSource) applyFilters(query *gorm.DB, params ExportParams) *gorm.DB {
	if packageID, ok := filterUint(params.Filters, "package_id"); ok {
		query = query.Where("a.package_id = ?", packageID)
	}
	if shopID, ok := filterUint(params.Filters, "shop_id"); ok {
		query = query.Where("a.shop_id_snapshot = ?", shopID)
	}
	if ownerID, ok := filterUint(params.Filters, "business_owner_account_id"); ok {
		query = query.Where("a.business_owner_account_id_snapshot = ?", ownerID)
	}
	if assetType, ok := filterString(params.Filters, "asset_type"); ok {
		query = query.Where("a.asset_type = ?", assetType)
	}
	if identifier, ok := filterString(params.Filters, "asset_identifier"); ok {
		pattern := "%" + identifier + "%"
		query = query.Where("(a.asset_identifier_snapshot ILIKE ? OR a.card_identifier_snapshot ILIKE ? "+
			"OR a.counterpart_identifier_snapshot ILIKE ?)", pattern, pattern, pattern)
	}
	if threshold, ok := alertFilterFloat(params.Filters, "threshold_percent"); ok {
		query = query.Where("a.threshold_percent_snapshot = ?",
			packagetrafficalert.NormalizeThresholdPercent(threshold))
	}
	if startTime, ok := filterTime(params.Filters, "start_time"); ok {
		query = query.Where("a.triggered_at >= ?", startTime.UTC())
	}
	if endTime, ok := filterTime(params.Filters, "end_time"); ok {
		query = query.Where("a.triggered_at <= ?", endTime.UTC())
	}
	if status, ok := filterInt(params.Filters, "notification_status"); ok {
		query = applyAlertNotificationStatusFilter(query, status)
	}
	return query
}

// applyAlertNotificationStatusFilter 按通知投递结果筛选，口径与读侧列表一致。
func applyAlertNotificationStatusFilter(query *gorm.DB, status int) *gorm.DB {
	const hasEvent = "a.notification_event_id <> ''"
	const hasNotification = "n.id IS NOT NULL"
	switch status {
	case constants.PackageTrafficAlertNotifyNoBusinessOwner:
		return query.Where("a.notification_event_id = ''")
	case constants.PackageTrafficAlertNotifyNotified:
		return query.Where(hasEvent).Where(hasNotification)
	case constants.PackageTrafficAlertNotifyPending:
		return query.Where(hasEvent).Where("NOT ("+hasNotification+")").
			Where("oe.status IN ?", []int{constants.OutboxStatusPending, constants.OutboxStatusDelivering})
	case constants.PackageTrafficAlertNotifyFailed:
		return query.Where(hasEvent).Where("NOT ("+hasNotification+")").
			Where("oe.status = ?", constants.OutboxStatusFailed)
	case constants.PackageTrafficAlertNotifyRecipientGone:
		return query.Where(hasEvent).Where("NOT ("+hasNotification+")").
			Where("oe.status = ?", constants.OutboxStatusDelivered)
	default:
		return query
	}
}

// loadBusinessUserGroupNames 按执行时当前业务员账号批量推导业务用户组名称。
// 用户组不落在店铺库表上，按既有实时推导读取，多个组按排序拼接。
func (s *PackageTrafficAlertDataSource) loadBusinessUserGroupNames(ctx context.Context,
	items []packageTrafficAlertExportRow) (map[uint]string, error) {
	result := make(map[uint]string)
	ownerIDs := make([]uint, 0, len(items))
	seen := make(map[uint]struct{}, len(items))
	for _, item := range items {
		if item.CurrentOwnerID == nil || *item.CurrentOwnerID == 0 {
			continue
		}
		if _, exists := seen[*item.CurrentOwnerID]; exists {
			continue
		}
		seen[*item.CurrentOwnerID] = struct{}{}
		ownerIDs = append(ownerIDs, *item.CurrentOwnerID)
	}
	if len(ownerIDs) == 0 {
		return result, nil
	}
	var rows []struct {
		AccountID uint   `gorm:"column:account_id"`
		GroupName string `gorm:"column:group_name"`
	}
	if err := s.db.WithContext(ctx).Table("tb_business_user_group_member AS m").
		Select("m.account_id, g.name AS group_name").
		Joins("JOIN tb_business_user_group AS g ON g.id = m.business_user_group_id AND g.deleted_at IS NULL").
		Where("m.account_id IN ? AND m.deleted_at IS NULL", ownerIDs).
		Order("m.account_id ASC, g.sort_order ASC, g.id ASC").
		Scan(&rows).Error; err != nil {
		return nil, errors.Wrap(errors.CodeDatabaseError, err, "查询业务员业务用户组失败")
	}
	for _, row := range rows {
		if existing := result[row.AccountID]; existing != "" {
			result[row.AccountID] = existing + "、" + row.GroupName
			continue
		}
		result[row.AccountID] = row.GroupName
	}
	return result, nil
}

// packageTrafficAlertExportRow 是预警导出的一行原始投影。
type packageTrafficAlertExportRow struct {
	AssetType             string     `gorm:"column:asset_type"`
	AssetIdentifier       string     `gorm:"column:asset_identifier_snapshot"`
	CounterpartIdentifier string     `gorm:"column:counterpart_identifier_snapshot"`
	CardIdentifier        string     `gorm:"column:card_identifier_snapshot"`
	DeviceType            string     `gorm:"column:device_type_snapshot"`
	DeviceModel           string     `gorm:"column:device_model_snapshot"`
	PackageName           string     `gorm:"column:package_name_snapshot"`
	UsedMB                int64      `gorm:"column:used_mb_snapshot"`
	LimitMB               int64      `gorm:"column:limit_mb_snapshot"`
	UsagePercent          float64    `gorm:"column:usage_percent_snapshot"`
	ThresholdPercent      float64    `gorm:"column:threshold_percent_snapshot"`
	ExpiresAt             *time.Time `gorm:"column:expires_at_snapshot"`
	TriggeredAt           time.Time  `gorm:"column:triggered_at"`
	ShopIDSnapshot        uint       `gorm:"column:shop_id_snapshot"`
	ShopNameSnapshot      string     `gorm:"column:shop_name_snapshot"`
	BusinessOwnerID       *uint      `gorm:"column:business_owner_account_id_snapshot"`
	BusinessOwnerName     string     `gorm:"column:business_owner_name_snapshot"`
	NotificationEventID   string     `gorm:"column:notification_event_id"`
	CurrentShopID         *uint      `gorm:"column:current_shop_id"`
	CurrentShopName       string     `gorm:"column:current_shop_name"`
	CurrentOwnerID        *uint      `gorm:"column:current_owner_id"`
	CurrentOwnerName      string     `gorm:"column:current_owner_name"`
	OutboxStatus          *int       `gorm:"column:outbox_status"`
	NotificationID        *uint      `gorm:"column:notification_id"`
}

// resolveAlertNotifyStatus 推导导出行的通知投递结果，与列表、详情同口径。
func resolveAlertNotifyStatus(item packageTrafficAlertExportRow) int {
	return constants.ResolvePackageTrafficAlertNotifyStatus(
		item.NotificationEventID != "", item.OutboxStatus, item.NotificationID != nil)
}

// ensurePackageTrafficAlertExportAllowed 只允许超级管理员与平台账号使用本场景。
// 通用导出入口不做场景级角色校验，因此这一层门禁是防止代理越权读取预警数据的必要防线。
func ensurePackageTrafficAlertExportAllowed(params ExportParams) error {
	if params.UserType == constants.UserTypeSuperAdmin || params.UserType == constants.UserTypePlatform {
		return nil
	}
	return errors.New(errors.CodeForbidden, constants.PlatformManagementForbiddenMessage)
}

// alertFilterFloat 解析导出筛选中的小数百分比。
// 阈值筛选只在预警导出使用，为避免改动既有共享筛选助手文件，这里就地解析。
func alertFilterFloat(filters map[string]any, key string) (float64, bool) {
	value, ok := filters[key]
	if !ok || value == nil {
		return 0, false
	}
	switch typed := value.(type) {
	case float64:
		return typed, true
	case float32:
		return float64(typed), true
	case int:
		return float64(typed), true
	case int64:
		return float64(typed), true
	case string:
		parsed, err := strconv.ParseFloat(strings.TrimSpace(typed), 64)
		if err != nil {
			return 0, false
		}
		return parsed, true
	default:
		return 0, false
	}
}

// currentOwnerGroupName 返回执行时当前业务员的用户组名称，无有效业务员时为空。
func currentOwnerGroupName(groupNames map[uint]string, ownerID *uint) string {
	if ownerID == nil {
		return ""
	}
	return groupNames[*ownerID]
}

// assetTypeName 返回资产类型的中文名称。
func assetTypeName(assetType string) string {
	if assetType == constants.AssetTypeDevice {
		return "设备"
	}
	return "物联网卡"
}

// formatPercentValue 输出保留两位小数的百分比。
func formatPercentValue(value float64) string {
	return strconv.FormatFloat(value, 'f', 2, 64)
}

// formatRemainingDays 按上海自然日推算剩余天数；无到期时间时输出空字符串。
func formatRemainingDays(expiresAt *time.Time, now time.Time) string {
	if expiresAt == nil {
		return ""
	}
	location := time.FixedZone("Asia/Shanghai", 8*60*60)
	localExpires := expiresAt.In(location)
	localNow := now.In(location)
	expiresDate := time.Date(localExpires.Year(), localExpires.Month(), localExpires.Day(), 0, 0, 0, 0, location)
	nowDate := time.Date(localNow.Year(), localNow.Month(), localNow.Day(), 0, 0, 0, 0, location)
	days := int(expiresDate.Sub(nowDate).Hours() / 24)
	return strconv.Itoa(days)
}