Agent-System-Backend/internal/runmgr/rewind.go

package runmgr

import (
	"fmt"
	"log"
	"path/filepath"
	"strings"

	"agent-native/runtime/checkpoint"
	core "agent-system-core"
)

func (m *Manager) checkpointFile(owner, convID string) (string, error) {
	if m == nil || m.workspaceRoot == "" || owner == "" || convID == "" {
		return "", fmt.Errorf("未配置工作区，不能记录文件检查点")
	}
	return filepath.Join(m.workspaceRoot, owner, convID, ".agentx", "checkpoints.jsonl"), nil
}

// OpenCheckpoints 打开这个会话的文件检查点日志。
func (m *Manager) OpenCheckpoints(owner, convID string) (*checkpoint.Log, error) {
	path, err := m.checkpointFile(owner, convID)
	if err != nil {
		return nil, err
	}
	return checkpoint.Open(path)
}

func (c *runCtx) OpenCheckpoints() (*checkpoint.Log, error) {
	if c == nil || c.mgr == nil {
		return nil, fmt.Errorf("未配置工作区，不能记录文件检查点")
	}
	return c.mgr.OpenCheckpoints(c.run.Owner, c.run.ConversationID)
}

func (c *runCtx) CheckpointAnchor() string {
	if c == nil {
		return ""
	}
	return c.userMessage.ID
}

// NoteFileCheckpoint 记录一次工作区写入的改前内容。
func (c *runCtx) NoteFileCheckpoint(rel string, before []byte, existed bool, after []byte) error {
	log, err := c.OpenCheckpoints()
	if err != nil {
		return err
	}
	root := c.ConversationSandbox()
	return log.Record(c.CheckpointAnchor(), root, rel, before, existed, after)
}

func (t *toolCtx) NoteFileCheckpoint(rel string, before []byte, existed bool, after []byte) error {
	if t == nil || t.rc == nil {
		return nil
	}
	return t.rc.NoteFileCheckpoint(rel, before, existed, after)
}

// PlanRewind 列出从这条用户消息起会被回滚的文件，不改磁盘。
func (m *Manager) PlanRewind(owner, convID, messageID string) (checkpoint.Result, error) {
	ordered, err := m.userMessageIDs(convID, messageID)
	if err != nil {
		return checkpoint.Result{}, err
	}
	log, err := m.OpenCheckpoints(owner, convID)
	if err != nil {
		return checkpoint.Result{}, err
	}
	return log.Plan(messageID, ordered)
}

// RewindFiles 把文件退回到这条用户消息之前，并追加一条系统说明。
func (m *Manager) RewindFiles(owner, convID, messageID string) (checkpoint.Result, error) {
	ordered, err := m.userMessageIDs(convID, messageID)
	if err != nil {
		return checkpoint.Result{}, err
	}
	cpLog, err := m.OpenCheckpoints(owner, convID)
	if err != nil {
		return checkpoint.Result{}, err
	}
	res, err := cpLog.Rewind(messageID, ordered)
	if err != nil {
		return checkpoint.Result{}, err
	}
	// 保留策略（N3 WP3）：成功的回滚后按 anchor 数裁到 200，日志有界。
	if cerr := cpLog.Compact(200); cerr != nil {
		log.Printf("[runmgr] checkpoint compact %s: %v", convID, cerr)
	}
	note := rewindNote(res)
	msg := core.Message{
		ConversationID: convID, Role: core.RoleSystem,
		Parts: []core.Part{{Type: core.PartText, Text: note}},
	}
	if err := m.st.AppendMessage(&msg); err != nil {
		return res, err
	}
	return res, nil
}

func (m *Manager) userMessageIDs(convID, messageID string) ([]string, error) {
	msgs, err := m.st.ListMessages(convID)
	if err != nil {
		return nil, err
	}
	var ordered []string
	found := false
	for _, msg := range msgs {
		if msg.Role != core.RoleUser {
			continue
		}
		ordered = append(ordered, msg.ID)
		if msg.ID == messageID {
			found = true
		}
	}
	if !found {
		return nil, fmt.Errorf("找不到用户消息 %s", messageID)
	}
	return ordered, nil
}

func rewindNote(res checkpoint.Result) string {
	var b strings.Builder
	b.WriteString("已把文件回滚到这条消息之前。")
	if len(res.Restored) == 0 && len(res.Skipped) == 0 {
		b.WriteString("没有需要回滚的文件。")
		return b.String()
	}
	if len(res.Restored) > 0 {
		b.WriteString("已恢复：")
		b.WriteString(strings.Join(res.Restored, "、"))
		b.WriteString("。")
	}
	if len(res.Skipped) > 0 {
		b.WriteString("已跳过：")
		b.WriteString(strings.Join(res.Skipped, "、"))
		b.WriteString("（文件在追踪之外被改过）。")
	}
	return b.String()
}