222 lines
8.2 KiB
Go
222 lines
8.2 KiB
Go
package db
|
||
|
||
import (
|
||
"context"
|
||
|
||
"github.com/pkg/errors"
|
||
"gorm.io/gorm"
|
||
"gorm.io/gorm/clause"
|
||
|
||
"github.com/tamakyi/TamaBox/internal/dbutil"
|
||
)
|
||
|
||
// MaxFollowUpCount 每条提问允许的最大追问次数（防滥用）。
|
||
// 提问者被回答后，用 token（或登录账号）继续追问，达到上限后不可再追问。
|
||
const MaxFollowUpCount = 3
|
||
|
||
// 追问相关错误（供 handler 区分处理，避免把业务错误当 500）
|
||
var (
|
||
// ErrFollowUpLimitReached 追问次数已达上限
|
||
ErrFollowUpLimitReached = errors.New("follow up limit reached")
|
||
// ErrFollowUpNotFound 追问不存在或不属于该问题
|
||
ErrFollowUpNotFound = errors.New("follow up not found")
|
||
// ErrFollowUpAlreadyAnswered 追问已被回答（禁止覆盖）
|
||
ErrFollowUpAlreadyAnswered = errors.New("follow up already answered")
|
||
)
|
||
|
||
var FollowUps FollowUpsStore
|
||
|
||
type FollowUpsStore interface {
|
||
// CreateIfBelowLimit 原子创建追问：仅当该问题追问次数未达上限时创建。
|
||
// 返回 created=false 且 err==ErrFollowUpLimitReached 表示已达上限。
|
||
// 通过事务内锁定问题行，串行化同一问题的并发追问，消除 count-then-create 竞态。
|
||
CreateIfBelowLimit(ctx context.Context, opts CreateFollowUpOptions) (created bool, err error)
|
||
GetByQuestionID(ctx context.Context, questionID uint) ([]*FollowUp, error)
|
||
// GetLatestByQuestionID 返回某条提问最新的一条追问；无追问时返回 (nil, nil)。
|
||
GetLatestByQuestionID(ctx context.Context, questionID uint) (*FollowUp, error)
|
||
// GetByQuestionIDs 批量获取多个提问的追问，按 question_id 分组返回。
|
||
// 用于账号导出等场景，将 N 次单题查询合并为 1 次 IN 查询，避免 N+1。
|
||
GetByQuestionIDs(ctx context.Context, questionIDs []uint) (map[uint][]*FollowUp, error)
|
||
CountByQuestionID(ctx context.Context, questionID uint) (int64, error)
|
||
// AnswerByID 回答某条追问；questionID 用于防止越权（必须属于该问题）。
|
||
// 仅允许回答尚未回答的追问（answer 为空），已回答的返回 ErrFollowUpAlreadyAnswered，
|
||
// 不存在/不属于该问题返回 ErrFollowUpNotFound。
|
||
AnswerByID(ctx context.Context, questionID uint, id uint, answer string) error
|
||
// UpdateAnswerByID 修改某条追问的回答内容（带 question_id 条件防止越权），
|
||
// 与 AnswerByID 不同，此处允许覆盖已回答的追问（供主人修改回复使用）。
|
||
// 不存在/不属于该问题返回 ErrFollowUpNotFound。
|
||
UpdateAnswerByID(ctx context.Context, questionID uint, id uint, answer string) error
|
||
// DeleteByQuestionID 删除某条提问时级联清理其全部追问（软删除，与提问保持一致）。
|
||
DeleteByQuestionID(ctx context.Context, questionID uint) error
|
||
}
|
||
|
||
func NewFollowUpsStore(db *gorm.DB) FollowUpsStore {
|
||
return &followUps{db}
|
||
}
|
||
|
||
type followUps struct {
|
||
*gorm.DB
|
||
}
|
||
|
||
// FollowUp 表示对某条提问的一轮追问。
|
||
type FollowUp struct {
|
||
dbutil.Model
|
||
QuestionID uint `gorm:"index:idx_follow_up_question" json:"question_id"`
|
||
Content string `gorm:"type:text" json:"content"`
|
||
Answer string `gorm:"type:text" json:"answer"`
|
||
}
|
||
|
||
type CreateFollowUpOptions struct {
|
||
QuestionID uint
|
||
Content string
|
||
}
|
||
|
||
func (db *followUps) CreateIfBelowLimit(ctx context.Context, opts CreateFollowUpOptions) (bool, error) {
|
||
created := false
|
||
err := db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
|
||
// 锁定问题行，串行化同一问题的并发追问（MySQL/Postgres 均支持 FOR UPDATE）。
|
||
var q Question
|
||
if err := tx.Clauses(clause.Locking{Strength: "UPDATE"}).
|
||
Select("id").
|
||
First(&q, opts.QuestionID).Error; err != nil {
|
||
return errors.Wrap(err, "lock question for follow up")
|
||
}
|
||
|
||
var count int64
|
||
if err := tx.Model(&FollowUp{}).
|
||
Where("question_id = ?", opts.QuestionID).
|
||
Count(&count).Error; err != nil {
|
||
return errors.Wrap(err, "count follow ups by question id")
|
||
}
|
||
if count >= MaxFollowUpCount {
|
||
return ErrFollowUpLimitReached
|
||
}
|
||
|
||
f := &FollowUp{
|
||
QuestionID: opts.QuestionID,
|
||
Content: opts.Content,
|
||
}
|
||
if err := tx.Create(f).Error; err != nil {
|
||
return errors.Wrap(err, "create follow up")
|
||
}
|
||
created = true
|
||
return nil
|
||
})
|
||
if err != nil {
|
||
return false, err
|
||
}
|
||
return created, nil
|
||
}
|
||
|
||
// GetByQuestionID 按时间正序返回某条提问的所有追问。
|
||
func (db *followUps) GetByQuestionID(ctx context.Context, questionID uint) ([]*FollowUp, error) {
|
||
var followUps []*FollowUp
|
||
if err := db.WithContext(ctx).
|
||
Where("question_id = ?", questionID).
|
||
Order("created_at ASC").
|
||
Find(&followUps).Error; err != nil {
|
||
return nil, errors.Wrap(err, "get follow ups by question id")
|
||
}
|
||
return followUps, nil
|
||
}
|
||
|
||
// GetLatestByQuestionID 返回某条提问最新的一条追问（created_at 倒序取首条）；
|
||
// 无追问时返回 (nil, nil)。供发布追问前校验"上一条是否已回复"。
|
||
func (db *followUps) GetLatestByQuestionID(ctx context.Context, questionID uint) (*FollowUp, error) {
|
||
var fu FollowUp
|
||
err := db.WithContext(ctx).
|
||
Where("question_id = ?", questionID).
|
||
Order("created_at DESC").
|
||
Limit(1).
|
||
First(&fu).Error
|
||
if err != nil {
|
||
if errors.Is(err, gorm.ErrRecordNotFound) {
|
||
return nil, nil
|
||
}
|
||
return nil, errors.Wrap(err, "get latest follow up by question id")
|
||
}
|
||
return &fu, nil
|
||
}
|
||
|
||
// GetByQuestionIDs 批量获取多个提问的追问，按 question_id 分组返回（解决导出 N+1）。
|
||
func (db *followUps) GetByQuestionIDs(ctx context.Context, questionIDs []uint) (map[uint][]*FollowUp, error) {
|
||
result := make(map[uint][]*FollowUp)
|
||
if len(questionIDs) == 0 {
|
||
return result, nil
|
||
}
|
||
var items []*FollowUp
|
||
if err := db.WithContext(ctx).
|
||
Where("question_id IN ?", questionIDs).
|
||
Order("question_id ASC, created_at ASC").
|
||
Find(&items).Error; err != nil {
|
||
return nil, errors.Wrap(err, "get follow ups by question ids")
|
||
}
|
||
for _, fu := range items {
|
||
result[fu.QuestionID] = append(result[fu.QuestionID], fu)
|
||
}
|
||
return result, nil
|
||
}
|
||
|
||
// CountByQuestionID 统计某条提问的追问次数，用于限制追问上限。
|
||
func (db *followUps) CountByQuestionID(ctx context.Context, questionID uint) (int64, error) {
|
||
var count int64
|
||
if err := db.WithContext(ctx).
|
||
Model(&FollowUp{}).
|
||
Where("question_id = ?", questionID).
|
||
Count(&count).Error; err != nil {
|
||
return 0, errors.Wrap(err, "count follow ups by question id")
|
||
}
|
||
return count, nil
|
||
}
|
||
|
||
// AnswerByID 更新某条追问的回答内容（带 question_id 条件防止越权）。
|
||
// 原子更新条件含 answer=”：已回答的追问不会被覆盖（避免重复提交时邮件/回答被二次写入）。
|
||
// RowsAffected==0 时再查一次以区分"不存在"与"已回答"，返回对应错误。
|
||
func (db *followUps) AnswerByID(ctx context.Context, questionID uint, id uint, answer string) error {
|
||
res := db.WithContext(ctx).
|
||
Model(&FollowUp{}).
|
||
Where("id = ? AND question_id = ? AND answer = ''", id, questionID).
|
||
Update("answer", answer)
|
||
if res.Error != nil {
|
||
return errors.Wrap(res.Error, "answer follow up")
|
||
}
|
||
if res.RowsAffected == 0 {
|
||
var cnt int64
|
||
if err := db.WithContext(ctx).
|
||
Model(&FollowUp{}).
|
||
Where("id = ? AND question_id = ?", id, questionID).
|
||
Count(&cnt).Error; err != nil {
|
||
return errors.Wrap(err, "check follow up existence")
|
||
}
|
||
if cnt == 0 {
|
||
return ErrFollowUpNotFound
|
||
}
|
||
return ErrFollowUpAlreadyAnswered
|
||
}
|
||
return nil
|
||
}
|
||
|
||
// UpdateAnswerByID 修改某条追问的回答内容（带 question_id 条件防止越权），
|
||
// 允许覆盖已回答的追问（用于主人修改回复）。不存在/不属于该问题返回 ErrFollowUpNotFound。
|
||
func (db *followUps) UpdateAnswerByID(ctx context.Context, questionID uint, id uint, answer string) error {
|
||
res := db.WithContext(ctx).
|
||
Model(&FollowUp{}).
|
||
Where("id = ? AND question_id = ?", id, questionID).
|
||
Update("answer", answer)
|
||
if res.Error != nil {
|
||
return errors.Wrap(res.Error, "update follow up answer")
|
||
}
|
||
if res.RowsAffected == 0 {
|
||
return ErrFollowUpNotFound
|
||
}
|
||
return nil
|
||
}
|
||
|
||
// DeleteByQuestionID 删除某条提问时级联清理其全部追问（软删除，与提问保持一致）。
|
||
func (db *followUps) DeleteByQuestionID(ctx context.Context, questionID uint) error {
|
||
if err := db.WithContext(ctx).Where("question_id = ?", questionID).Delete(&FollowUp{}).Error; err != nil {
|
||
return errors.Wrap(err, "delete follow ups by question id")
|
||
}
|
||
return nil
|
||
}
|