mce/internal/service/post_audit_service.go

package service

import (
	"metazone.cc/metalab/internal/common"
	"metazone.cc/metalab/internal/model"
)

// Update 编辑帖子（权限在 controller 层检查）
func (s *PostService) Update(postID uint, title, body string) error {
	post, err := s.findPost(postID)
	if err != nil {
		return err
	}

	if post.Status == model.PostStatusPending || post.IsLocked {
		return common.ErrPostCannotEdit
	}

	// 已通过帖子：编辑内容保存为待审修订，不影响当前展示
	if post.Status == model.PostStatusApproved {
		post.PendingTitle = title
		post.PendingBody = body
		post.RejectReason = "" // 清空旧退回理由
		err := s.repo.Update(post)
		if err == nil {
			s.invalidateHomeCache()
		}
		return err
	}

	// 草稿/已退回：直接修改原文（现有逻辑）
	post.Title = title
	post.Body = body
	post.Excerpt = generateExcerpt(body)

	if post.Status == model.PostStatusRejected {
		post.Status = model.PostStatusDraft
		post.RejectReason = ""
	}

	err = s.repo.Update(post)
	if err == nil {
		s.invalidateHomeCache()
	}
	return err
}

// Delete 软删除（权限在 controller 层检查）
func (s *PostService) Delete(postID uint) error {
	if err := s.repo.SoftDelete(postID); err != nil {
		return err
	}
	s.invalidateHomeCache()
	return nil
}

// SubmitForAudit 提交审核：draft → pending
func (s *PostService) SubmitForAudit(postID uint) error {
	post, err := s.findPost(postID)
	if err != nil {
		return err
	}
	if post.IsLocked {
		return common.ErrPostCannotEdit
	}
	if post.Status != model.PostStatusDraft && post.Status != model.PostStatusRejected {
		return common.ErrPostCannotSubmit
	}
	post.Status = model.PostStatusPending
	return s.repo.Update(post)
}

// Approve 审核通过：pending → approved；或修订审核通过复制 Pending 到正式字段
func (s *PostService) Approve(postID uint) error {
	post, err := s.findPost(postID)
	if err != nil {
		return err
	}

	wasRevision := post.PendingBody != ""

	// 修订审核：将待审内容覆盖到正式字段
	if wasRevision {
		post.Title = post.PendingTitle
		post.Body = post.PendingBody
		post.Excerpt = generateExcerpt(post.PendingBody)
		post.PendingTitle = ""
		post.PendingBody = ""
		post.Status = model.PostStatusApproved
		post.RejectReason = ""
		if err := s.repo.Update(post); err != nil {
			return err
		}
		s.invalidateHomeCache()
		// 通知作者修订审核通过
		if s.notifier != nil {
			s.notifier.NotifyPostApproved(post.UserID, post.Title, post.ID)
		}
		return nil
	}

	// 首次审核通过
	if post.Status != model.PostStatusPending {
		return common.ErrPostCannotApprove
	}
	post.Status = model.PostStatusApproved
	post.RejectReason = ""
	if err := s.repo.Update(post); err != nil {
		return err
	}
	s.invalidateHomeCache()
	// 通知作者审核通过
	if s.notifier != nil {
		s.notifier.NotifyPostApproved(post.UserID, post.Title, post.ID)
	}
	return nil
}

// Reject 退回：pending/approved → rejected；修订退回则清空 Pending 保持 approved
func (s *PostService) Reject(postID uint, reason string) error {
	post, err := s.findPost(postID)
	if err != nil {
		return err
	}
	if post.Status != model.PostStatusPending && post.Status != model.PostStatusApproved {
		return common.ErrPostCannotReject
	}

	// 修订退回：清空待审修订，保持已发布内容不变
	if post.PendingBody != "" {
		post.PendingTitle = ""
		post.PendingBody = ""
		post.RejectReason = reason
		if err := s.repo.Update(post); err != nil {
			return err
		}
		// 通知作者修订被退回
		if s.notifier != nil {
			s.notifier.NotifyPostRejected(post.UserID, post.Title, reason, post.ID)
		}
		return nil
	}

	// 普通退回（首次审核）
	post.Status = model.PostStatusRejected
	post.RejectReason = reason
	if err := s.repo.Update(post); err != nil {
		return err
	}
	// 通知作者审核被退回
	if s.notifier != nil {
		s.notifier.NotifyPostRejected(post.UserID, post.Title, reason, post.ID)
	}
	return nil
}

// Lock 锁定：设置 IsLocked 标志，禁止编辑，不改变帖子发布状态
// 锁定状态独立于审核状态，任何状态的帖子均可锁定
func (s *PostService) Lock(postID uint, reason string) error {
	post, err := s.findPost(postID)
	if err != nil {
		return err
	}
	post.IsLocked = true
	post.LockReason = reason
	return s.repo.Update(post)
}

// Unlock 解锁：清除 IsLocked 标志，恢复可编辑
func (s *PostService) Unlock(postID uint) error {
	post, err := s.findPost(postID)
	if err != nil {
		return err
	}
	if !post.IsLocked {
		return common.ErrPostCannotUnlock
	}
	post.IsLocked = false
	post.LockReason = ""
	return s.repo.Update(post)
}

// Restore 恢复软删除
func (s *PostService) Restore(postID uint) error {
	err := s.repo.Restore(postID)
	if err != nil {
		return err
	}
	return nil
}

// ListPendingRevisions 查询有待审修订的帖子（approved 且 PendingBody 不为空）
func (s *PostService) ListPendingRevisions(keyword string, page, pageSize int) ([]model.Post, int64, error) {
	return s.listPageable(page, pageSize, func(offset, limit int) ([]model.Post, int64, error) {
		return s.repo.FindPendingRevisions(keyword, offset, limit)
	})
}