package main

import (
	"encoding/json"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"sync"
)

const dshPackage = "@deepseek-ai/dsh"

var (
	npmRootOnce sync.Once
	npmRootPath string
)

// npmGlobalRoot 执行 npm root -g（隐藏窗口），结果缓存（仅首次调用起子进程）。
func npmGlobalRoot() string {
	npmRootOnce.Do(func() {
		exe, args := npmCommandFor("root", "-g")
		cmd := exec.Command(exe, args...)
		hideWindow(cmd)
		out, err := cmd.Output()
		if err != nil {
			return
		}
		npmRootPath = strings.TrimSpace(string(out))
	})
	return npmRootPath
}

// npmCommandFor 组装 npm 调用：优先 node + npm-cli.js（无 shell），回退 cmd /c npm。
func npmCommandFor(args ...string) (string, []string) {
	if node, err := exec.LookPath("node"); err == nil {
		if cli := detectNpmCLI(node); cli != "" {
			return node, append([]string{cli}, args...)
		}
	}
	return "cmd.exe", append([]string{"/c", "npm"}, args...)
}

func detectNpmCLI(node string) string {
	base := filepath.Dir(node)
	candidates := []string{
		filepath.Join(base, "node_modules", "npm", "bin", "npm-cli.js"),
		filepath.Join(base, "..", "lib", "node_modules", "npm", "bin", "npm-cli.js"),
	}
	for _, c := range candidates {
		if fileExists(c) {
			return c
		}
	}
	return ""
}

// readPackageVersion 读取 package.json 的 version 字段。
func readPackageVersion(path string) string {
	data, err := os.ReadFile(path)
	if err != nil {
		return ""
	}
	var v struct {
		Version string `json:"version"`
	}
	if err := json.Unmarshal(data, &v); err != nil {
		return ""
	}
	return v.Version
}