// Command localsim 模拟桌面端本地执行 runner（联调工具，无需起真 Wails 桌面端）：
// 连 gateway 的 /api/v1/local/runner WS，注册为当前用户的本地执行器，
// 在指定工作目录内响应 local_list_dir / local_read_file（只读，与桌面端同协议）。
//
// 用法：LOCALSIM_TOKEN=<jwt> go run ./cmd/localsim [-gw ws://localhost:8080] [-dir /path/to/workdir]
package main

import (
	"context"
	"encoding/json"
	"flag"
	"fmt"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"time"

	"github.com/gorilla/websocket"
)

type req struct {
	ID   string         `json:"id"`
	Tool string         `json:"tool"`
	Args map[string]any `json:"args,omitempty"`
}

type resp struct {
	ID      string `json:"id"`
	OK      bool   `json:"ok"`
	Content string `json:"content,omitempty"`
	Error   string `json:"error,omitempty"`
	Workdir string `json:"workdir,omitempty"`
}

func main() {
	gw := flag.String("gw", "ws://localhost:8080", "gateway WS 基址")
	dir := flag.String("dir", ".", "沙箱工作目录")
	flag.Parse()
	token := os.Getenv("LOCALSIM_TOKEN")
	if token == "" {
		log.Fatal("缺 LOCALSIM_TOKEN（用户 JWT）")
	}
	root, err := filepath.Abs(*dir)
	if err != nil {
		log.Fatal(err)
	}

	url := strings.TrimRight(*gw, "/") + "/api/v1/local/runner?token=" + token
	// 断线自动重连（对齐真桌面端 runner 的 5s 退避）：网关重启时联调不用手动重拉。
	for {
		if err := serveOnce(url, root); err != nil {
			log.Printf("连接断开（5s 后重连）: %v", err)
		}
		time.Sleep(5 * time.Second)
	}
}

func serveOnce(url, root string) error {
	conn, _, err := websocket.DefaultDialer.Dial(url, nil)
	if err != nil {
		return err
	}
	defer conn.Close()
	log.Printf("已注册为本地执行器 workdir=%s", root)

	hello, _ := json.Marshal(resp{ID: "hello", OK: true, Workdir: root})
	_ = conn.WriteMessage(websocket.TextMessage, hello)

	for {
		_, data, err := conn.ReadMessage()
		if err != nil {
			return err
		}
		var r req
		if json.Unmarshal(data, &r) != nil {
			continue
		}
		log.Printf("收到调用 tool=%s args=%v", r.Tool, r.Args)
		out, _ := json.Marshal(handle(root, &r))
		if err := conn.WriteMessage(websocket.TextMessage, out); err != nil {
			return err
		}
	}
}

func handle(root string, r *req) *resp {
	rel, _ := r.Args["path"].(string)
	p := filepath.Join(root, filepath.Clean("/"+rel)) // 简版沙箱（联调工具；正式沙箱在桌面端）
	switch r.Tool {
	case "local_list_dir":
		ents, err := os.ReadDir(p)
		if err != nil {
			return &resp{ID: r.ID, OK: false, Error: err.Error()}
		}
		var names []string
		for _, e := range ents {
			n := e.Name()
			if e.IsDir() {
				n += "/"
			}
			names = append(names, n)
		}
		data, _ := json.Marshal(map[string]any{"dir": rel, "entries": names})
		return &resp{ID: r.ID, OK: true, Content: string(data)}
	case "local_read_file":
		b, err := os.ReadFile(p)
		if err != nil {
			return &resp{ID: r.ID, OK: false, Error: err.Error()}
		}
		if len(b) > 64*1024 {
			b = b[:64*1024]
		}
		return &resp{ID: r.ID, OK: true, Content: string(b)}
	case "local_write_file":
		// 联调工具无 GUI：自动批准（真桌面端会弹原生确认框，见 desktop/localexec.go）。
		content, _ := r.Args["content"].(string)
		if err := os.WriteFile(p, []byte(content), 0o644); err != nil {
			return &resp{ID: r.ID, OK: false, Error: err.Error()}
		}
		log.Printf("  [sim] 已写入 %s（%d 字节，真桌面端此处会先弹确认框）", p, len(content))
		return &resp{ID: r.ID, OK: true, Content: fmt.Sprintf("已写入 %s（%d 字节）", rel, len(content))}
	case "local_exec":
		cmdStr, _ := r.Args["command"].(string)
		log.Printf("  [sim] 执行命令: %s（真桌面端此处会先弹确认框 + 走黑名单）", cmdStr)
		ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
		defer cancel()
		c := exec.CommandContext(ctx, "/bin/sh", "-c", cmdStr)
		c.Dir = root
		out, err := c.CombinedOutput()
		text := string(out)
		if len(text) > 16*1024 {
			text = text[:16*1024] + "\n…（截断）"
		}
		if err != nil {
			return &resp{ID: r.ID, OK: true, Content: fmt.Sprintf("退出码非零（%v）。输出：\n%s", err, text)}
		}
		if strings.TrimSpace(text) == "" {
			text = "（成功，无输出）"
		}
		return &resp{ID: r.ID, OK: true, Content: text}
	default:
		return &resp{ID: r.ID, OK: false, Error: fmt.Sprintf("不支持: %s", r.Tool)}
	}
}