package exporter

import (
	"context"
	"strconv"

	"gorm.io/gorm"

	"github.com/break/junhong_cmp_fiber/internal/model/dto"
	packageexpiryquery "github.com/break/junhong_cmp_fiber/internal/query/packageexpiry"
	"github.com/break/junhong_cmp_fiber/pkg/constants"
	"github.com/break/junhong_cmp_fiber/pkg/errors"
)

// ExpiringAssetDataSource 临期资产导出数据源。
//
// 粒度为一行对应一项资产，取该资产当前生效主套餐的最终到期时间与剩余天数，加油包不单独成行。
// 候选预筛、最终到期推算与行序全部复用 internal/query/packageexpiry 的列表实现，不另写第二套到期口径。
// 店铺、业务员与用户组按导出执行时的当前归属补充，结果仍受任务创建时冻结的可见店铺范围约束。
type ExpiringAssetDataSource struct {
	db      *gorm.DB
	expiryQ *packageexpiryquery.Query
}

// NewExpiringAssetDataSource 创建临期资产导出数据源。
func NewExpiringAssetDataSource(db *gorm.DB) *ExpiringAssetDataSource {
	return &ExpiringAssetDataSource{db: db, expiryQ: packageexpiryquery.NewQuery(db)}
}

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

// Count 统计临期资产导出行数，与列表同一筛选下的行集合一致。
func (s *ExpiringAssetDataSource) Count(ctx context.Context, params ExportParams) (int, error) {
	items, err := s.items(ctx, params)
	if err != nil {
		return 0, err
	}
	return len(items), nil
}

// Headers 返回临期资产导出表头，列序与 111.md §18.1 逐列一致。
func (s *ExpiringAssetDataSource) Headers(context.Context, ExportParams) ([]string, error) {
	return []string{
		"店铺", "业务员", "用户组", "资产类型", "设备类型", "设备型号", "资产标识", "当前套餐", "到期时间", "剩余天数",
	}, nil
}

// Fetch 按 offset/limit 查询临期资产导出数据。
func (s *ExpiringAssetDataSource) Fetch(ctx context.Context, params ExportParams, offset, limit int) ([][]string, error) {
	if limit <= 0 {
		return [][]string{}, nil
	}
	items, err := s.items(ctx, params)
	if err != nil {
		return nil, err
	}
	if offset >= len(items) {
		return [][]string{}, nil
	}
	end := offset + limit
	if end > len(items) {
		end = len(items)
	}
	page := items[offset:end]

	shopIDs := make([]uint, 0, len(page))
	deviceIDs := make([]uint, 0, len(page))
	for _, item := range page {
		if item.ShopID != nil {
			shopIDs = append(shopIDs, *item.ShopID)
		}
		if item.AssetType == constants.AssetTypeDevice {
			deviceIDs = append(deviceIDs, item.AssetID)
		}
	}
	shops, err := s.loadShopOwners(ctx, normalizeUintSlice(shopIDs))
	if err != nil {
		return nil, err
	}
	ownerIDs := make([]uint, 0, len(shops))
	for _, shop := range shops {
		if shop.BusinessOwnerAccountID != nil {
			ownerIDs = append(ownerIDs, *shop.BusinessOwnerAccountID)
		}
	}
	ownerIDs = normalizeUintSlice(ownerIDs)
	ownerNames, err := loadAccountNames(ctx, s.db, ownerIDs)
	if err != nil {
		return nil, err
	}
	groupNames, err := businessUserGroupNames(ctx, s.db, ownerIDs)
	if err != nil {
		return nil, err
	}
	devices, err := s.loadDeviceAttributes(ctx, normalizeUintSlice(deviceIDs))
	if err != nil {
		return nil, err
	}

	rows := make([][]string, 0, len(page))
	for _, item := range page {
		var shopName, ownerName, groupName string
		if item.ShopID != nil {
			shop := shops[*item.ShopID]
			shopName = shop.ShopName
			if shop.BusinessOwnerAccountID != nil {
				ownerName = ownerNames[*shop.BusinessOwnerAccountID]
				groupName = currentOwnerGroupName(groupNames, shop.BusinessOwnerAccountID)
			}
		}
		var deviceType, deviceModel string
		if item.AssetType == constants.AssetTypeDevice {
			device := devices[item.AssetID]
			deviceType, deviceModel = device.DeviceType, device.DeviceModel
		}
		rows = append(rows, []string{
			shopName,
			ownerName,
			groupName,
			assetTypeName(item.AssetType),
			deviceType,
			deviceModel,
			item.Identifier,
			item.PackageName,
			formatOptionalTime(item.EstimatedFinalExpiresAt),
			formatRemainingDaysValue(item.DaysUntilFinalExpiry),
		})
	}
	return rows, nil
}

// items 复用列表同一候选预筛与最终到期推算，数据范围来自任务创建时冻结的可见店铺范围。
func (s *ExpiringAssetDataSource) items(ctx context.Context, params ExportParams) ([]dto.ExpiringAssetItem, error) {
	filter, err := s.listFilter(params)
	if err != nil {
		return nil, err
	}
	scope := func(query *gorm.DB) *gorm.DB {
		return applyExportShopScope(query, params, "shop_id")
	}
	return s.expiryQ.ListAllWithScope(ctx, scope, filter)
}

// listFilter 把任务冻结的筛选快照转换为列表同一口径的筛选条件。
func (s *ExpiringAssetDataSource) listFilter(params ExportParams) (packageexpiryquery.ListFilter, error) {
	filter := packageexpiryquery.ListFilter{
		AssetType: filterValue(params.Filters, "asset_type"),
		Keyword:   filterValue(params.Filters, "keyword"),
	}
	if shopID, ok := filterUint(params.Filters, "shop_id"); ok {
		filter.ShopID = &shopID
	}
	if packageID, ok := filterUint(params.Filters, "package_id"); ok {
		filter.PackageID = &packageID
	}
	if daysMin, ok := filterInt(params.Filters, "days_min"); ok {
		filter.DaysMin = &daysMin
	}
	if daysMax, ok := filterInt(params.Filters, "days_max"); ok {
		filter.DaysMax = &daysMax
	}
	start, end, err := strictTimeRange(params.Filters)
	if err != nil {
		return packageexpiryquery.ListFilter{}, err
	}
	filter.StartTime, filter.EndTime = start, end
	return filter, nil
}

func (s *ExpiringAssetDataSource) loadShopOwners(ctx context.Context, shopIDs []uint) (map[uint]expiringAssetShop, error) {
	result := make(map[uint]expiringAssetShop, len(shopIDs))
	if len(shopIDs) == 0 {
		return result, nil
	}
	var rows []expiringAssetShop
	if err := s.db.WithContext(ctx).Table("tb_shop").
		Select("id, shop_name, business_owner_account_id").
		Where("id IN ? AND deleted_at IS NULL", shopIDs).
		Scan(&rows).Error; err != nil {
		return nil, errors.Wrap(errors.CodeDatabaseError, err, "查询临期导出店铺当前归属失败")
	}
	for _, row := range rows {
		result[row.ID] = row
	}
	return result, nil
}

func (s *ExpiringAssetDataSource) loadDeviceAttributes(ctx context.Context, deviceIDs []uint) (map[uint]expiringAssetDevice, error) {
	result := make(map[uint]expiringAssetDevice, len(deviceIDs))
	if len(deviceIDs) == 0 {
		return result, nil
	}
	var rows []expiringAssetDevice
	if err := s.db.WithContext(ctx).Table("tb_device").
		Select("id, device_type, device_model").
		Where("id IN ?", deviceIDs).
		Scan(&rows).Error; err != nil {
		return nil, errors.Wrap(errors.CodeDatabaseError, err, "查询临期导出设备类型与型号失败")
	}
	for _, row := range rows {
		result[row.ID] = row
	}
	return result, nil
}

// expiringAssetShop 是执行时当前店铺归属投影。
type expiringAssetShop struct {
	ID                     uint   `gorm:"column:id"`
	ShopName               string `gorm:"column:shop_name"`
	BusinessOwnerAccountID *uint  `gorm:"column:business_owner_account_id"`
}

// expiringAssetDevice 是执行时当前设备类型与型号投影。
type expiringAssetDevice struct {
	ID          uint   `gorm:"column:id"`
	DeviceType  string `gorm:"column:device_type"`
	DeviceModel string `gorm:"column:device_model"`
}

// formatRemainingDaysValue 输出列表同一最终到期推算给出的剩余上海自然日天数；无法精确推算时为空。
func formatRemainingDaysValue(days *int) string {
	if days == nil {
		return ""
	}
	return strconv.Itoa(*days)
}