jiang13-bbs/backend/service/overview.go

package service

import (
	"time"

	"github.com/freefire/jiang13-bbs/model"
	"gorm.io/gorm"
)

// OverviewService 首页聚合服务：一次请求返回统计、热门榜、活跃用户、板块计数
type OverviewService struct {
	db *gorm.DB
}

func NewOverviewService(db *gorm.DB) *OverviewService {
	return &OverviewService{db: db}
}

// OverviewStats 社区整体统计
type OverviewStats struct {
	Posts      int64 `json:"posts"`
	Users      int64 `json:"users"`
	Comments   int64 `json:"comments"`
	TodayPosts int64 `json:"today_posts"`
}

// ActiveUser 近 14 天活跃用户
type ActiveUser struct {
	ID            uint   `json:"id"`
	Username      string `json:"username"`
	Nickname      string `json:"nickname"`
	Avatar        string `json:"avatar"`
	ActivityCount int64  `json:"activity_count"`
}

// BoardCount 板块及其已发布帖子计数（Board 字段被 encoding/json 展平）
type BoardCount struct {
	model.Board
	PostCount int64 `json:"post_count"`
}

// OverviewData 首页聚合数据
type OverviewData struct {
	Stats       OverviewStats  `json:"stats"`
	Hot         []PostListItem `json:"hot"`
	ActiveUsers []ActiveUser   `json:"active_users"`
	Boards      []BoardCount   `json:"boards"`
}

const activeUserWindow = 14 * 24 * time.Hour

// Get 聚合首页数据。hot 的 liked 态由 handler 层按当前用户填充。
func (s *OverviewService) Get() (*OverviewData, error) {
	data := &OverviewData{
		Hot:         []PostListItem{},
		ActiveUsers: []ActiveUser{},
		Boards:      []BoardCount{},
	}

	now := time.Now()
	dayStart := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
	since := now.Add(-activeUserWindow)

	// 统计
	postQ := s.db.Model(&model.Post{}).Where("status = ?", model.ContentStatusPublished)
	if err := postQ.Count(&data.Stats.Posts).Error; err != nil {
		return nil, err
	}
	if err := s.db.Model(&model.User{}).Count(&data.Stats.Users).Error; err != nil {
		return nil, err
	}
	if err := s.db.Model(&model.Comment{}).Where("status = ?", model.ContentStatusPublished).Count(&data.Stats.Comments).Error; err != nil {
		return nil, err
	}
	if err := s.db.Model(&model.Post{}).
		Where("status = ? AND created_at >= ?", model.ContentStatusPublished, dayStart).
		Count(&data.Stats.TodayPosts).Error; err != nil {
		return nil, err
	}

	// 热门榜：非置顶，按 赞 + 评论×2
	var hotPosts []model.Post
	if err := s.db.Where("status = ? AND pinned = 0", model.ContentStatusPublished).
		Order("(like_count + comment_count * 2) DESC, created_at DESC").
		Limit(5).Preload("Board").Preload("User").Find(&hotPosts).Error; err != nil {
		return nil, err
	}
	data.Hot = toPostListItems(hotPosts)

	// 活跃用户：近 14 天发帖+评论合并计数，JOIN 用户过滤封禁/软删
	type activityRow struct {
		UserID        uint
		ActivityCount int64
	}
	var rows []activityRow
	activitySQL := `
SELECT a.user_id AS user_id, COUNT(*) AS activity_count
FROM (
	SELECT user_id FROM posts WHERE status = ? AND created_at >= ? AND deleted_at IS NULL
	UNION ALL
	SELECT user_id FROM comments WHERE status = ? AND created_at >= ? AND deleted_at IS NULL
) AS a
JOIN users AS u ON u.id = a.user_id
WHERE u.banned = ? AND u.deleted_at IS NULL
GROUP BY a.user_id
ORDER BY activity_count DESC, a.user_id ASC
LIMIT 5`
	if err := s.db.Raw(activitySQL,
		model.ContentStatusPublished, since,
		model.ContentStatusPublished, since,
		false).Scan(&rows).Error; err != nil {
		return nil, err
	}
	if len(rows) > 0 {
		ids := make([]uint, 0, len(rows))
		for _, r := range rows {
			ids = append(ids, r.UserID)
		}
		var users []model.User
		if err := s.db.Where("id IN ?", ids).Find(&users).Error; err != nil {
			return nil, err
		}
		userMap := make(map[uint]model.User, len(users))
		for _, u := range users {
			userMap[u.ID] = u
		}
		for _, r := range rows {
			u, ok := userMap[r.UserID]
			if !ok {
				continue
			}
			data.ActiveUsers = append(data.ActiveUsers, ActiveUser{
				ID:            u.ID,
				Username:      u.Username,
				Nickname:      u.Nickname,
				Avatar:        u.Avatar,
				ActivityCount: r.ActivityCount,
			})
		}
	}

	// 板块 + 各自帖子计数（一条 GROUP BY）
	var boards []model.Board
	if err := s.db.Order("sort_order ASC, id ASC").Find(&boards).Error; err != nil {
		return nil, err
	}
	type countRow struct {
		BoardID uint
		Cnt     int64
	}
	var counts []countRow
	if err := s.db.Model(&model.Post{}).
		Select("board_id, COUNT(*) AS cnt").
		Where("status = ?", model.ContentStatusPublished).
		Group("board_id").Scan(&counts).Error; err != nil {
		return nil, err
	}
	countMap := make(map[uint]int64, len(counts))
	for _, c := range counts {
		countMap[c.BoardID] = c.Cnt
	}
	for _, b := range boards {
		data.Boards = append(data.Boards, BoardCount{Board: b, PostCount: countMap[b.ID]})
	}

	return data, nil
}