pure-note/internal/store/maint.go

package store

import (
	"fmt"
	"os"
	"time"
)

// GCReport gc 结果报告（dry-run 与 commit 共用）。
type GCReport struct {
	ExpiredNotes   []ExpiredNote `json:"expired_notes"`
	OrphanImages   []Image       `json:"orphan_images"`
	ExpiredSessons int64         `json:"expired_sessions"`
	Committed      bool          `json:"committed"`
}

// ExpiredNote 待物理删除的回收站笔记。
type ExpiredNote struct {
	ID        int64  `json:"id"`
	Slug      string `json:"slug"`
	DeletedAt int64  `json:"deleted_at"`
}

// TrashTTL 回收站保留期（§6.3：30 天）。
const TrashTTL = 30 * 24 * time.Hour

// OrphanGrace 孤儿图片宽限期（§6.3：7 天，防误删编辑中刚上传的图）。
const OrphanGrace = 7 * 24 * time.Hour

// GC 清理：回收站过期笔记物理删除、孤儿图片清除、过期会话清理。
// dryRun=true 时只输出计划不改数据。
func (s *Store) GC(now time.Time, dryRun bool) (*GCReport, error) {
	rep := &GCReport{Committed: !dryRun}

	noteCutoff := now.Add(-TrashTTL).Unix()
	rows, err := s.db.Query(
		`SELECT id, slug, deleted_at FROM notes WHERE deleted_at IS NOT NULL AND deleted_at < ? ORDER BY deleted_at`,
		noteCutoff)
	if err != nil {
		return nil, err
	}
	for rows.Next() {
		var en ExpiredNote
		if err := rows.Scan(&en.ID, &en.Slug, &en.DeletedAt); err != nil {
			rows.Close()
			return nil, err
		}
		rep.ExpiredNotes = append(rep.ExpiredNotes, en)
	}
	if err := rows.Err(); err != nil {
		rows.Close()
		return nil, err
	}
	rows.Close()

	// 孤儿图片：0 引用且超过宽限期
	imageCutoff := now.Add(-OrphanGrace).Unix()
	orphanRows, err := s.db.Query(`
		SELECT i.id, i.sha256, i.mime, i.size, i.created_at FROM images i
		WHERE i.created_at < ? AND NOT EXISTS (SELECT 1 FROM image_refs r WHERE r.image_id = i.id)
		ORDER BY i.created_at`, imageCutoff)
	if err != nil {
		return nil, err
	}
	for orphanRows.Next() {
		var img Image
		if err := orphanRows.Scan(&img.ID, &img.SHA256, &img.MIME, &img.Size, &img.CreatedAt); err != nil {
			orphanRows.Close()
			return nil, err
		}
		rep.OrphanImages = append(rep.OrphanImages, img)
	}
	if err := orphanRows.Err(); err != nil {
		orphanRows.Close()
		return nil, err
	}
	orphanRows.Close()

	if dryRun {
		// 会话计数（不改数据）
		var cnt int64
		if err := s.db.QueryRow(`SELECT COUNT(*) FROM sessions WHERE expires_at < ?`, now.Unix()).Scan(&cnt); err != nil {
			return nil, err
		}
		rep.ExpiredSessons = cnt
		return rep, nil
	}

	for _, en := range rep.ExpiredNotes {
		if err := s.DeleteNoteForever(en.ID); err != nil {
			return nil, fmt.Errorf("物理删除笔记 %d: %w", en.ID, err)
		}
	}
	for _, img := range rep.OrphanImages {
		if err := s.DeleteImage(img.ID); err != nil {
			return nil, fmt.Errorf("删除孤儿图片 %d: %w", img.ID, err)
		}
	}
	n, err := s.DeleteExpiredSessions(now.Unix())
	if err != nil {
		return nil, err
	}
	rep.ExpiredSessons = n
	return rep, nil
}

// Backup 在线备份：VACUUM INTO 一致快照（WAL 下与 serve 并发安全，§10.3）。
func (s *Store) Backup(destPath string) error {
	if _, err := os.Stat(destPath); err == nil {
		return fmt.Errorf("目标文件已存在: %s", destPath)
	}
	// VACUUM INTO 不接受参数绑定，路径经单引号转义（无参数化通道时的最小注入面）。
	if _, err := s.db.Exec("VACUUM INTO " + escapeSQLString(destPath)); err != nil {
		return err
	}
	// 备份含全部私钥内容：强制 0600（§10.3）
	if err := os.Chmod(destPath, 0o600); err != nil {
		return err
	}
	return nil
}

func escapeSQLString(s string) string {
	out := make([]byte, 0, len(s)+2)
	out = append(out, '\'')
	for i := 0; i < len(s); i++ {
		if s[i] == '\'' {
			out = append(out, '\'', '\'')
		} else {
			out = append(out, s[i])
		}
	}
	return string(append(out, '\''))
}