// Package businessusergroup 提供业务用户组及其成员规模的只读投影。
// Query 只做筛选、分页与 DTO 投影，不修改任何状态。
package businessusergroup

import (
	"context"
	"strings"
	"time"

	"gorm.io/gorm"

	"github.com/break/junhong_cmp_fiber/internal/model"
	"github.com/break/junhong_cmp_fiber/internal/model/dto"
	"github.com/break/junhong_cmp_fiber/internal/store/postgres"
	"github.com/break/junhong_cmp_fiber/pkg/constants"
	"github.com/break/junhong_cmp_fiber/pkg/errors"
	"github.com/break/junhong_cmp_fiber/pkg/sanitizer"
)

// Query 查询业务用户组及其成员。
type Query struct {
	db    *gorm.DB
	store *postgres.BusinessUserGroupStore
}

// NewQuery 创建业务用户组查询。
func NewQuery(db *gorm.DB, groupStore *postgres.BusinessUserGroupStore) *Query {
	return &Query{db: db, store: groupStore}
}

// List 分页查询业务用户组，供维护与筛选下拉使用。
func (q *Query) List(ctx context.Context, request dto.BusinessUserGroupListRequest) (*dto.BusinessUserGroupPageResult, error) {
	if q == nil || q.db == nil {
		return nil, errors.New(errors.CodeServiceUnavailable, "业务用户组查询尚未配置")
	}
	page, pageSize := normalizePage(request.Page, request.PageSize)
	status := enabledToStatus(request.Enabled)
	query := q.db.WithContext(ctx).Model(&model.BusinessUserGroup{})
	if status != nil {
		query = query.Where("status = ?", *status)
	}
	if request.BusinessLine != nil {
		query = query.Where("business_line = ?", *request.BusinessLine)
	}
	if keyword := strings.TrimSpace(request.Keyword); keyword != "" {
		like := "%" + keyword + "%"
		query = query.Where("name ILIKE ? OR code ILIKE ?", like, like)
	}
	var total int64
	if err := query.Count(&total).Error; err != nil {
		return nil, errors.Wrap(errors.CodeDatabaseError, err, "查询业务用户组总数失败")
	}
	var groups []*model.BusinessUserGroup
	if err := query.Order("sort_order ASC, id ASC").
		Offset((page - 1) * pageSize).Limit(pageSize).Find(&groups).Error; err != nil {
		return nil, errors.Wrap(errors.CodeDatabaseError, err, "查询业务用户组列表失败")
	}
	counts, err := q.memberCounts(ctx, groupIDs(groups))
	if err != nil {
		return nil, err
	}
	items := make([]*dto.BusinessUserGroupResponse, 0, len(groups))
	for _, group := range groups {
		item := toResponse(group)
		item.MemberCount = counts[group.ID]
		items = append(items, item)
	}
	return &dto.BusinessUserGroupPageResult{Items: items, Total: total, Page: page, Size: pageSize}, nil
}

// Detail 查询单个业务用户组详情。
func (q *Query) Detail(ctx context.Context, groupID uint) (*dto.BusinessUserGroupResponse, error) {
	if q == nil || q.store == nil {
		return nil, errors.New(errors.CodeServiceUnavailable, "业务用户组查询尚未配置")
	}
	if groupID == 0 {
		return nil, errors.New(errors.CodeInvalidParam)
	}
	group, err := q.store.GetByID(ctx, groupID)
	if err != nil {
		if err == gorm.ErrRecordNotFound {
			return nil, errors.New(errors.CodeNotFound, "业务用户组不存在")
		}
		return nil, errors.Wrap(errors.CodeDatabaseError, err, "查询业务用户组失败")
	}
	count, err := q.store.CountMembers(ctx, groupID)
	if err != nil {
		return nil, errors.Wrap(errors.CodeDatabaseError, err, "统计业务用户组成员失败")
	}
	response := toResponse(group)
	response.MemberCount = count
	return response, nil
}

// ListMembers 分页查询指定业务用户组保留的全部成员关系。
func (q *Query) ListMembers(ctx context.Context, groupID uint, request dto.BusinessUserGroupMemberListRequest) (*dto.BusinessUserGroupMemberPageResult, error) {
	if q == nil || q.db == nil || q.store == nil {
		return nil, errors.New(errors.CodeServiceUnavailable, "业务用户组成员查询尚未配置")
	}
	if groupID == 0 {
		return nil, errors.New(errors.CodeInvalidParam)
	}
	if _, err := q.store.GetByID(ctx, groupID); err != nil {
		if err == gorm.ErrRecordNotFound {
			return nil, errors.New(errors.CodeNotFound, "业务用户组不存在")
		}
		return nil, errors.Wrap(errors.CodeDatabaseError, err, "查询业务用户组失败")
	}
	page, pageSize := normalizePage(request.Page, request.PageSize)
	base := q.db.WithContext(ctx).Unscoped().Model(&model.BusinessUserGroupMember{}).
		Joins("JOIN tb_account a ON a.id = tb_business_user_group_member.account_id").
		Joins("JOIN tb_business_user_group g ON g.id = tb_business_user_group_member.business_user_group_id").
		Where("tb_business_user_group_member.business_user_group_id = ? AND tb_business_user_group_member.deleted_at IS NULL AND g.deleted_at IS NULL", groupID)
	if keyword := strings.TrimSpace(request.Keyword); keyword != "" {
		like := "%" + keyword + "%"
		base = base.Where("a.username ILIKE ? OR a.phone ILIKE ?", like, like)
	}
	switch request.AccountStatus {
	case "enabled":
		base = base.Where("a.deleted_at IS NULL AND a.status = ?", constants.StatusEnabled)
	case "disabled":
		base = base.Where("a.deleted_at IS NULL AND a.status = ?", constants.StatusDisabled)
	case "deleted":
		base = base.Where("a.deleted_at IS NOT NULL")
	}
	var total int64
	if err := base.Count(&total).Error; err != nil {
		return nil, errors.Wrap(errors.CodeDatabaseError, err, "查询业务用户组成员总数失败")
	}
	var rows []memberRow
	if err := base.Select("tb_business_user_group_member.account_id, a.username, a.phone, a.status, a.deleted_at, tb_business_user_group_member.created_at AS member_created_at, g.id AS group_id, g.code AS group_code, g.name AS group_name, g.status AS group_status").
		Order("tb_business_user_group_member.account_id ASC").
		Offset((page - 1) * pageSize).Limit(pageSize).Scan(&rows).Error; err != nil {
		return nil, errors.Wrap(errors.CodeDatabaseError, err, "查询业务用户组成员失败")
	}
	items := make([]*dto.BusinessUserGroupMemberResponse, 0, len(rows))
	for _, row := range rows {
		items = append(items, &dto.BusinessUserGroupMemberResponse{
			AccountID: row.AccountID, Username: row.Username, Phone: sanitizer.MaskPhone(row.Phone),
			Enabled:    row.Status == constants.StatusEnabled && !row.DeletedAt.Valid,
			StatusName: constants.GetStatusName(row.Status), Deleted: row.DeletedAt.Valid,
			MemberCreatedAt: row.MemberCreatedAt.Format(time.RFC3339), CurrentGroupID: row.GroupID,
			CurrentGroupCode: row.GroupCode, CurrentGroupName: row.GroupName,
			CurrentGroupEnabled: row.GroupStatus == constants.StatusEnabled,
		})
	}
	return &dto.BusinessUserGroupMemberPageResult{Items: items, Total: total, Page: page, Size: pageSize}, nil
}

// ListMemberCandidates 分页查询指定业务用户组的启用平台用户候选。
func (q *Query) ListMemberCandidates(ctx context.Context, groupID uint, request dto.BusinessUserGroupMemberCandidateRequest) (*dto.BusinessUserGroupMemberCandidatePageResult, error) {
	if q == nil || q.db == nil || q.store == nil {
		return nil, errors.New(errors.CodeServiceUnavailable, "业务用户组候选查询尚未配置")
	}
	if groupID == 0 {
		return nil, errors.New(errors.CodeInvalidParam)
	}
	group, err := q.store.GetByID(ctx, groupID)
	if err != nil {
		if err == gorm.ErrRecordNotFound {
			return nil, errors.New(errors.CodeNotFound, "业务用户组不存在")
		}
		return nil, errors.Wrap(errors.CodeDatabaseError, err, "查询业务用户组失败")
	}
	page, pageSize := normalizePage(request.Page, request.PageSize)
	base := q.db.WithContext(ctx).Model(&model.Account{}).
		Where("tb_account.user_type = ? AND tb_account.status = ?", constants.UserTypePlatform, constants.StatusEnabled).
		Joins("LEFT JOIN tb_business_user_group_member m ON m.account_id = tb_account.id AND m.deleted_at IS NULL").
		Joins("LEFT JOIN tb_business_user_group g ON g.id = m.business_user_group_id AND g.deleted_at IS NULL")
	if keyword := strings.TrimSpace(request.Keyword); keyword != "" {
		like := "%" + keyword + "%"
		base = base.Where("tb_account.username ILIKE ? OR tb_account.phone ILIKE ?", like, like)
	}
	switch request.GroupFilter {
	case "ungrouped":
		base = base.Where("m.account_id IS NULL")
	case "current":
		base = base.Where("m.business_user_group_id = ?", groupID)
	case "other":
		base = base.Where("m.business_user_group_id IS NOT NULL AND m.business_user_group_id <> ?", groupID)
	}
	var total int64
	if err := base.Count(&total).Error; err != nil {
		return nil, errors.Wrap(errors.CodeDatabaseError, err, "查询业务用户组候选总数失败")
	}
	var rows []candidateRow
	if err := base.Select("tb_account.id AS account_id, tb_account.username, tb_account.phone, m.business_user_group_id AS group_id, g.code AS group_code, g.name AS group_name, g.status AS group_status").
		Order("tb_account.id ASC").Offset((page - 1) * pageSize).Limit(pageSize).Scan(&rows).Error; err != nil {
		return nil, errors.Wrap(errors.CodeDatabaseError, err, "查询业务用户组候选失败")
	}
	canAdd := group.Status == constants.StatusEnabled
	items := make([]*dto.BusinessUserGroupMemberCandidateResponse, 0, len(rows))
	for _, row := range rows {
		action := "add"
		if row.GroupID != nil {
			action = "move"
			if *row.GroupID == groupID {
				action = "already_member"
			}
		}
		items = append(items, &dto.BusinessUserGroupMemberCandidateResponse{
			AccountID: row.AccountID, Username: row.Username, Phone: sanitizer.MaskPhone(row.Phone),
			CurrentGroupID: row.GroupID, CurrentGroupCode: row.GroupCode, CurrentGroupName: row.GroupName,
			CurrentGroupEnabled: row.GroupStatus != nil && *row.GroupStatus == constants.StatusEnabled,
			Action:              action, CanAdd: canAdd,
		})
	}
	return &dto.BusinessUserGroupMemberCandidatePageResult{Items: items, Total: total, Page: page, Size: pageSize}, nil
}

type memberRow struct {
	AccountID       uint
	Username        string
	Phone           string
	Status          int
	DeletedAt       gorm.DeletedAt
	MemberCreatedAt time.Time
	GroupID         uint `gorm:"column:group_id"`
	GroupCode       string
	GroupName       string
	GroupStatus     int
}

type candidateRow struct {
	AccountID   uint
	Username    string
	Phone       string
	GroupID     *uint
	GroupCode   string
	GroupName   string
	GroupStatus *int
}

func (q *Query) memberCounts(ctx context.Context, ids []uint) (map[uint]int64, error) {
	counts := make(map[uint]int64, len(ids))
	if len(ids) == 0 {
		return counts, nil
	}
	var rows []struct {
		GroupID uint
		Count   int64
	}
	if err := q.db.WithContext(ctx).Model(&model.BusinessUserGroupMember{}).
		Select("business_user_group_id AS group_id, COUNT(*) AS count").
		Where("business_user_group_id IN ?", ids).Group("business_user_group_id").Scan(&rows).Error; err != nil {
		return nil, errors.Wrap(errors.CodeDatabaseError, err, "统计业务用户组成员失败")
	}
	for _, row := range rows {
		counts[row.GroupID] = row.Count
	}
	return counts, nil
}

func groupIDs(groups []*model.BusinessUserGroup) []uint {
	ids := make([]uint, 0, len(groups))
	for _, group := range groups {
		ids = append(ids, group.ID)
	}
	return ids
}

// toResponse 将业务用户组投影为对外响应。
func toResponse(group *model.BusinessUserGroup) *dto.BusinessUserGroupResponse {
	return &dto.BusinessUserGroupResponse{
		ID: group.ID, Code: group.Code, Name: group.Name,
		BusinessLine: group.BusinessLine, BusinessLineName: constants.GetBusinessLineName(group.BusinessLine),
		Sort: group.SortOrder, Enabled: group.Status == constants.StatusEnabled, Remark: group.Remark,
		CreatedAt: group.CreatedAt.Format(time.RFC3339), UpdatedAt: group.UpdatedAt.Format(time.RFC3339),
	}
}

// enabledToStatus 把对外启停布尔映射为既有状态值；未提交时返回 nil 表示不过滤。
func enabledToStatus(enabled *bool) *int {
	if enabled == nil {
		return nil
	}
	status := constants.StatusDisabled
	if *enabled {
		status = constants.StatusEnabled
	}
	return &status
}

// normalizePage 归一化分页参数，执行 DefaultPageSize 与 MaxPageSize 上限。
func normalizePage(page, pageSize int) (int, int) {
	if page <= 0 {
		page = constants.DefaultPage
	}
	if pageSize <= 0 {
		pageSize = constants.DefaultPageSize
	}
	if pageSize > constants.MaxPageSize {
		pageSize = constants.MaxPageSize
	}
	return page, pageSize
}