package main

import (
	"bufio"
	"bytes"
	"context"
	"fmt"
	"io"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"regexp"
	"runtime"
	"runtime/debug"
	"strconv"
	"strings"
	"sync"
	"time"

	wailsruntime "github.com/wailsapp/wails/v2/pkg/runtime"
)

// App is the Wails application backend.
type App struct {
	ctx context.Context

	mu          sync.Mutex
	dshCmd      *exec.Cmd
	dshURL      string
	startedAt   time.Time
	running     bool
}

// NewApp creates a new App application struct.
func NewApp() *App {
	initCrashLog()
	// 在进程启动时预先初始化 npm prefix 缓存,后续 buildChildEnv 直接读缓存。
	// 这步可能 exec npm 子命令(限 2s 超时),但不会和 buildChildEnv 互相递归。
	initNpmPrefix()
	return &App{}
}

// initNpmPrefix triggers the cached npm prefix lookup exactly once.
// 必须在启动早期(且不依赖 buildChildEnv)调用,避免 buildChildEnv → cachedNpmPrefix
// 第一次执行时栈还未充分展开导致后续路径无法解析。
func initNpmPrefix() {
	_, _ = cachedNpmPrefix()
}

// initCrashLog wires a panic logger that writes to ~/Library/Logs/dsh-launcher.log.
// macOS GUI 进程 stderr 没终端,panic 信息看不到,落盘最稳。
var crashLogOnce sync.Once

func initCrashLog() {
	crashLogOnce.Do(func() {
		home, _ := os.UserHomeDir()
		logPath := filepath.Join(home, "Library", "Logs", "dsh-launcher.log")
		_ = os.MkdirAll(filepath.Dir(logPath), 0o755)
		f, err := os.OpenFile(logPath, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0o644)
		if err != nil {
			return
		}
		log.SetOutput(f)
		log.SetFlags(log.LstdFlags | log.Lmicroseconds | log.Lshortfile)
	})
}

// safeGo wraps a goroutine with recover so a panic in any background
// task can't take down the whole Wails app.
func safeGo(name string, fn func()) {
	go func() {
		defer func() {
			if r := recover(); r != nil {
				log.Printf("[panic:%s] %v\n%s", name, r, debugStack())
			}
		}()
		fn()
	}()
}

func debugStack() string {
	return string(debug.Stack())
}

// startup is called when the app starts.
func (a *App) startup(ctx context.Context) {
	a.ctx = ctx
}

// shutdown is called when the app is closing. Ensure dsh is killed
// so we never leak a child process.
func (a *App) shutdown(ctx context.Context) {
	a.stopDSH()
}

// ---- Types exposed to the frontend ----

// CheckResult is returned by CheckEnv.
type CheckResult struct {
	NodePath     string   `json:"nodePath"`
	NodeVersion  string   `json:"nodeVersion"`
	NodeOK       bool     `json:"nodeOK"`
	DshPath      string   `json:"dshPath"`
	DshVersion   string   `json:"dshVersion"`
	CredFile     string   `json:"credFile"`
	CredExists   bool     `json:"credExists"`
	HomeDshDir   string   `json:"homeDshDir"`
	PortBusy     bool     `json:"portBusy"`
	PortBusyBy   string   `json:"portBusyBy"`
	Issues       []string `json:"issues"` // 始终非 nil,前端可放心访问
}

// StartResult is returned by Start.
type StartResult struct {
	OK     bool   `json:"ok"`
	URL    string `json:"url"`
	Error  string `json:"error"`
	Output string `json:"output"`
	Hidden bool   `json:"hidden"` // 是否已自动隐藏窗口
}

// StatusResult is returned by GetStatus.
type StatusResult struct {
	Running   bool   `json:"running"`
	URL       string `json:"url"`
	StartedAt string `json:"startedAt"`
	Pid       int    `json:"pid"`
}

// ---- 3 core methods ----

// CheckEnv inspects Node, dsh, ~/.dsh credentials and port 3080.
// 所有外部命令都套超时 + panic recover,任何一个失败不能让整个 app 闪退。
func (a *App) CheckEnv() (res CheckResult) {
	defer func() {
		if r := recover(); r != nil {
			log.Printf("[panic:CheckEnv] %v\n%s", r, debugStack())
			res.Issues = append(res.Issues, fmt.Sprintf("CheckEnv 内部错误: %v", r))
		}
	}()

	home := os.Getenv("HOME")
	if home == "" {
		home = "/tmp"
	}
	res = CheckResult{
		HomeDshDir: filepath.Join(home, ".dsh"),
		CredFile:   filepath.Join(home, ".dsh", ".credentials.yaml"),
		PortBusy:   false,
		Issues:     []string{}, // 确保 JSON 序列化为 [] 而非 null
	}

	// node
	res.NodePath = lookPath("node")
	if res.NodePath != "" {
		if v, err := runQuiet(res.NodePath, "-v"); err == nil {
			res.NodeVersion = strings.TrimSpace(v)
			if nodeMajor(res.NodeVersion) >= 18 {
				res.NodeOK = true
			}
		} else {
			log.Printf("CheckEnv node -v err: %v", err)
		}
	}
	if !res.NodeOK {
		res.Issues = append(res.Issues, "Node >= 18 未安装或不可用")
	}

	// dsh
	res.DshPath = lookPath("dsh")
	if res.DshPath == "" {
		// fallback to npm prefix bin
		if npm, err := runQuiet("npm", "prefix", "-g"); err == nil {
			prefix := strings.TrimSpace(npm)
			candidate := filepath.Join(prefix, "bin", "dsh")
			if _, statErr := os.Stat(candidate); statErr == nil {
				res.DshPath = candidate
			}
		} else {
			log.Printf("CheckEnv npm prefix err: %v", err)
		}
	}
	if res.DshPath != "" {
		if v, err := runQuiet(res.DshPath, "--version"); err == nil {
			res.DshVersion = strings.TrimSpace(v)
		} else {
			log.Printf("CheckEnv dsh --version err: %v", err)
		}
	} else {
		res.Issues = append(res.Issues, "dsh 命令未找到(请 npm i -g @deepseek-ai/dsh)")
	}

	// credentials
	if _, err := os.Stat(res.CredFile); err == nil {
		res.CredExists = true
	} else {
		res.Issues = append(res.Issues, "缺少 ~/.dsh/.credentials.yaml,请先 dsh login")
	}

	// port 3080 — lsof 在受限进程下可能挂死,超时保护
	if pids, err := lsofPort(3080); err == nil && len(pids) > 0 {
		res.PortBusy = true
		res.PortBusyBy = strings.Join(pids, ", ")
	}

	return res
}

// Start launches dsh web, captures the token URL and opens the browser.
func (a *App) Start() StartResult {
	a.mu.Lock()
	if a.running {
		a.mu.Unlock()
		return StartResult{OK: false, URL: a.dshURL, Error: "已在运行中"}
	}
	a.mu.Unlock()

	dshBin := lookPath("dsh")
	if dshBin == "" {
		if npm, err := runQuiet("npm", "prefix", "-g"); err == nil {
			candidate := filepath.Join(strings.TrimSpace(npm), "bin", "dsh")
			if _, statErr := os.Stat(candidate); statErr == nil {
				dshBin = candidate
			}
		}
	}
	if dshBin == "" {
		return StartResult{OK: false, Error: "找不到 dsh 可执行文件"}
	}

	// --no-open 让 dsh 只打印 URL,我们自己用系统 open 打开
	cmd := exec.Command(dshBin, "--profile", "web", "--no-open")
	cmd.Env = buildChildEnv()

	stdout, err := cmd.StdoutPipe()
	if err != nil {
		return StartResult{OK: false, Error: "无法创建 stdout 管道: " + err.Error()}
	}
	stderr, err := cmd.StderrPipe()
	if err != nil {
		return StartResult{OK: false, Error: "无法创建 stderr 管道: " + err.Error()}
	}

	if err := cmd.Start(); err != nil {
		return StartResult{OK: false, Error: "启动 dsh 失败: " + err.Error()}
	}

	a.mu.Lock()
	a.dshCmd = cmd
	a.running = true
	a.startedAt = time.Now()
	a.dshURL = ""
	a.mu.Unlock()

	// 异步读 stdout/stderr,抓 URL
	urlCh := make(chan string, 1)
	errCh := make(chan string, 1)
	safeGo("scanForURL", func() { scanForURL(stdout, urlCh) })
	safeGo("drainStderr", func() { drainStderr(stderr, errCh) })

	// 监听子进程退出
	safeGo("dshWait", func() {
		_ = cmd.Wait()
		a.mu.Lock()
		a.running = false
		a.mu.Unlock()
	})

	// 等 URL(最多 30 秒)
	select {
	case url := <-urlCh:
		a.mu.Lock()
		a.dshURL = url
		a.mu.Unlock()
		// 用系统 open 唤起浏览器
		if openErr := openBrowser(url); openErr != nil {
			return StartResult{OK: true, URL: url, Error: "已启动,但自动开浏览器失败: " + openErr.Error()}
		}
		// 启动成功 + 已打开浏览器 → 最小化到 Dock(用 WindowMinimise 不用 WindowHide,
		// 这样点 Dock 图标系统会自动 unminimise 恢复窗口,而不是再也打不开)。
		if a.ctx != nil {
			wailsruntime.WindowMinimise(a.ctx)
		}
		return StartResult{OK: true, URL: url, Hidden: true}
	case errMsg := <-errCh:
		return StartResult{OK: false, Error: "dsh 输出错误: " + errMsg}
	case <-time.After(30 * time.Second):
		return StartResult{OK: false, Error: "等待 dsh URL 超时(30s)"}
	}
}

// Stop kills the dsh process and verifies the port is released.
func (a *App) Stop() StartResult {
	a.mu.Lock()
	cmd := a.dshCmd
	a.mu.Unlock()

	if cmd != nil && cmd.Process != nil {
		_ = cmd.Process.Kill()
		_, _ = cmd.Process.Wait()
	}

	// 兜底:把 dsh 整个进程树都杀(dsh 自己 + dsh-pet Electron helper + GPU/renderer/utility 等)
	// 不杀全,dsh-pet 会在 EPIPE 时弹 JavaScript 错误弹窗。
	killDSHTree()

	time.Sleep(500 * time.Millisecond)

	a.mu.Lock()
	a.dshCmd = nil
	a.dshURL = ""
	a.running = false
	a.mu.Unlock()

	if pids, err := lsofPort(3080); err == nil && len(pids) > 0 {
		return StartResult{OK: false, Error: "端口 3080 仍被占用: " + strings.Join(pids, ", ")}
	}
	return StartResult{OK: true}
}

// ShowWindow brings the application window to the front.
func (a *App) ShowWindow() {
	if a.ctx != nil {
		wailsruntime.WindowShow(a.ctx)
	}
}

// HideWindow minimises the application window to Dock.
// 用 WindowMinimise 而不是 WindowHide,这样 macOS 上点 Dock 图标系统会
// 自动 unminimise 恢复窗口(WindowHide 之后点 Dock 不会自动恢复)。
func (a *App) HideWindow() {
	if a.ctx != nil {
		wailsruntime.WindowMinimise(a.ctx)
	}
}

// GetStatus returns the current dsh state.
func (a *App) GetStatus() StatusResult {
	a.mu.Lock()
	defer a.mu.Unlock()
	res := StatusResult{Running: a.running, URL: a.dshURL}
	if a.dshCmd != nil && a.dshCmd.Process != nil {
		res.Pid = a.dshCmd.Process.Pid
	}
	if !a.startedAt.IsZero() {
		res.StartedAt = a.startedAt.Format(time.RFC3339)
	}
	return res
}

// ---- internal helpers ----

func (a *App) stopDSH() {
	a.mu.Lock()
	cmd := a.dshCmd
	a.running = false
	a.mu.Unlock()
	if cmd != nil && cmd.Process != nil {
		_ = cmd.Process.Kill()
	}
	killDSHTree()
}

// buildChildEnv 手动把 homebrew 路径塞进子进程 PATH。
// macOS GUI 启动的进程不读 ~/.zshrc,直接拿环境变量 PATH 经常缺 /opt/homebrew/bin。
// 注意:本函数不能调任何 exec 子命令(包括 npm),否则会触发栈溢出。
// npm 全局 bin 路径由 cachedNpmPrefix() 在 initNpmPrefix() 中预先算好。
func buildChildEnv() []string {
	env := os.Environ()
	home := os.Getenv("HOME")
	extra := []string{
		"/opt/homebrew/bin",
		"/usr/local/bin",
		"/usr/bin",
		"/bin",
		"/usr/sbin",
		"/sbin",
	}
	// 加上缓存好的 npm 全局 bin(如果有)
	if prefix, ok := cachedNpmPrefix(); ok {
		extra = append(extra, filepath.Join(prefix, "bin"))
	}

	hasPath := false
	for i, e := range env {
		if strings.HasPrefix(e, "PATH=") {
			hasPath = true
			cur := strings.TrimPrefix(e, "PATH=")
			merged := mergePath(cur, extra)
			env[i] = "PATH=" + merged
		}
	}
	if !hasPath {
		env = append(env, "PATH="+strings.Join(extra, ":"))
	}
	if home == "" {
		env = append(env, "HOME=/tmp")
	}
	return env
}

// mergePath 拼接 PATH。绝对不能调 runQuiet / 任何 exec 子命令,
// 否则会触发 buildChildEnv → mergePath 的无限递归 → 栈溢出。
// npm 全局 bin 用 sync.Once 懒加载 + 超时兜底,在 initEnvOnce 里完成。
func mergePath(cur string, extra []string) string {
	seen := map[string]bool{}
	out := []string{}
	add := func(p string) {
		if p == "" || seen[p] {
			return
		}
		seen[p] = true
		out = append(out, p)
	}
	for _, p := range strings.Split(cur, ":") {
		add(p)
	}
	for _, p := range extra {
		add(p)
	}
	return strings.Join(out, ":")
}

// npmPrefixCache 用 sync.Once 缓存 `npm prefix -g` 的输出,
// 避免每次 buildChildEnv 都 exec npm。
var (
	npmPrefixOnce  sync.Once
	npmPrefixValue string
	npmPrefixReady bool
)

func cachedNpmPrefix() (string, bool) {
	npmPrefixOnce.Do(func() {
		// 只在确实有 npm 时才跑
		bin := lookPath("npm")
		if bin == "" {
			return
		}
		// 硬超时 2s,失败就算了,不致命。
		// 注意:这里直接 exec 用 os.Environ(),不走 buildChildEnv,
		// 否则初始化期间可能再次触发 buildChildEnv 形成循环。
		cmd := exec.Command(bin, "prefix", "-g")
		cmd.Env = os.Environ()
		var buf bytes.Buffer
		cmd.Stdout = &buf
		cmd.Stderr = &buf
		if err := cmd.Start(); err != nil {
			return
		}
		done := make(chan error, 1)
		go func() { done <- cmd.Wait() }()
		select {
		case <-done:
			npmPrefixValue = strings.TrimSpace(buf.String())
			npmPrefixReady = npmPrefixValue != ""
		case <-time.After(2 * time.Second):
			_ = cmd.Process.Kill()
			<-done
		}
	})
	return npmPrefixValue, npmPrefixReady
}

func scanForURL(r io.Reader, urlCh chan<- string) {
	scanner := bufio.NewScanner(r)
	scanner.Buffer(make([]byte, 64*1024), 1024*1024)
	// dsh web: http://127.0.0.1:3080/?token=xxx
	// 兼容多种格式
	re := regexp.MustCompile(`https?://[^\s)]+token=[A-Za-z0-9._\-]+`)
	for scanner.Scan() {
		line := scanner.Text()
		if m := re.FindString(line); m != "" {
			urlCh <- m
			return
		}
		// 兜底:任何 http URL 也接受
		if strings.Contains(line, "http://") || strings.Contains(line, "https://") {
			if m := regexp.MustCompile(`https?://[^\s]+`).FindString(line); m != "" {
				urlCh <- strings.TrimRight(m, ".,;)")
				return
			}
		}
	}
}

func drainStderr(r io.Reader, errCh chan<- string) {
	scanner := bufio.NewScanner(r)
	scanner.Buffer(make([]byte, 64*1024), 1024*1024)
	for scanner.Scan() {
		// 把 stderr 行发给 errCh,Start 收到后会返回
		select {
		case errCh <- scanner.Text():
		default:
		}
	}
}

func openBrowser(url string) error {
	switch runtime.GOOS {
	case "darwin":
		bin := lookPath("open")
		if bin == "" {
			bin = "/usr/bin/open"
		}
		return exec.Command(bin, url).Start()
	case "windows":
		return exec.Command("rundll32", "url.dll,FileProtocolHandler", url).Start()
	default:
		bin := lookPath("xdg-open")
		if bin == "" {
			return fmt.Errorf("xdg-open not found")
		}
		return exec.Command(bin, url).Start()
	}
}

func lookPath(name string) string {
	// 先用 PATH
	if p, err := exec.LookPath(name); err == nil {
		return p
	}
	// macOS GUI 进程常缺 PATH,兜底几个常见位置
	for _, dir := range []string{"/opt/homebrew/bin", "/usr/local/bin", "/usr/bin"} {
		candidate := filepath.Join(dir, name)
		if _, err := os.Stat(candidate); err == nil {
			return candidate
		}
	}
	return ""
}

func runQuiet(name string, args ...string) (string, error) {
	return runQuietTimeout(name, 3*time.Second, args...)
}

// runQuietTimeout runs a command with a hard timeout. If it doesn't finish in time,
// the child is killed and an error is yielded. macOS 上某些 fork-exec 失败场景,
// 没有超时保护会一直 hang,进而拖垮调用方。
func runQuietTimeout(name string, timeout time.Duration, args ...string) (string, error) {
	if name == "" {
		return "", fmt.Errorf("empty command")
	}
	// 用我们自己的 lookPath(GUI 进程 PATH 缺失时也能找到 /opt/homebrew/bin 等),
	// 不能用 exec.LookPath —— 它只读系统 PATH,看不到我们手动塞的路径。
	bin := lookPath(name)
	if bin == "" {
		return "", fmt.Errorf("not found: %s (也没在 /opt/homebrew/bin 找到)", name)
	}
	cmd := exec.Command(bin, args...)
	cmd.Env = buildChildEnv()
	// 输出大小限制,防止 npm 输出爆 buffer 卡死
	var buf bytes.Buffer
	cmd.Stdout = &buf
	cmd.Stderr = &buf

	if err := cmd.Start(); err != nil {
		return "", fmt.Errorf("start %s: %w", bin, err)
	}

	done := make(chan error, 1)
	go func() { done <- cmd.Wait() }()

	select {
	case err := <-done:
		return buf.String(), err
	case <-time.After(timeout):
		_ = cmd.Process.Kill()
		<-done
		return "", fmt.Errorf("timeout after %s: %s %s", timeout, bin, strings.Join(args, " "))
	}
}

func nodeMajor(v string) int {
	v = strings.TrimPrefix(v, "v")
	parts := strings.SplitN(v, ".", 2)
	if len(parts) == 0 {
		return 0
	}
	n := 0
	for _, ch := range parts[0] {
		if ch < '0' || ch > '9' {
			break
		}
		n = n*10 + int(ch-'0')
	}
	return n
}

// lsofPort 返回占用该端口的 PID 列表(macOS)。带超时 + panic recover。
func lsofPort(port int) (res []string, err error) {
	defer func() {
		if r := recover(); r != nil {
			log.Printf("[panic:lsofPort] %v\n%s", r, debugStack())
			err = fmt.Errorf("lsof panic: %v", r)
		}
	}()

	lsofBin := lookPath("lsof")
	if lsofBin == "" {
		return nil, nil // 没 lsof,跳过
	}
	cmd := exec.Command(lsofBin, "-nP", fmt.Sprintf("-iTCP:%d", port), "-sTCP:LISTEN", "-t")
	cmd.Env = buildChildEnv()
	var buf bytes.Buffer
	cmd.Stdout = &buf
	cmd.Stderr = &buf

	if err := cmd.Start(); err != nil {
		return nil, fmt.Errorf("lsof start: %w", err)
	}

	done := make(chan error, 1)
	go func() { done <- cmd.Wait() }()

	select {
	case err := <-done:
		out := buf.Bytes()
		if err != nil && len(out) == 0 {
			// lsof 无命中时退出码非 0 + 空输出 = 端口空闲
			return nil, nil
		}
		for _, l := range strings.Split(strings.TrimSpace(string(out)), "\n") {
			l = strings.TrimSpace(l)
			if l != "" {
				res = append(res, l)
			}
		}
		return res, err
	case <-time.After(3 * time.Second):
		_ = cmd.Process.Kill()
		<-done
		return nil, fmt.Errorf("lsof timeout")
	}
}

// ---- Install / Update ----

const dshPkg = "@deepseek-ai/dsh"

// UpdateInfo describes the available update for dsh.
type UpdateInfo struct {
	Installed   string `json:"installed"`
	Latest      string `json:"latest"`
	HasUpdate   bool   `json:"hasUpdate"`
	Raw         string `json:"raw"`
}

// InstallResult is returned by InstallDsh / UpdateDsh.
type InstallResult struct {
	OK     bool   `json:"ok"`
	Error  string `json:"error"`
	Output string `json:"output"`
}

// killDSHTree kills all processes related to the dsh service:
//   - the dsh CLI itself (npm/node dsh/lib/bin.js)
//   - dsh-pet Electron helper (main / renderer / gpu / utility / network)
//   - any Electron app launched from ~/.dsh/electron
//
// 不只 kill 主进程: dsh-pet 还在跑时,EPIPE 会在 pipe 关闭后让它抛
// "Uncaught Exception" 弹窗,污染退出 UX。
func killDSHTree() {
	pids := listDSHPids()
	if len(pids) == 0 {
		return
	}
	log.Printf("killDSHTree: %d pids to kill", len(pids))
	for _, pid := range pids {
		// kill -9 强杀,避免 dsh-pet 还在做 graceful shutdown 又触发 EPIPE
		if err := exec.Command("kill", "-9", pid).Run(); err != nil {
			log.Printf("killDSHTree: kill %s: %v", pid, err)
		}
	}
}

// listDSHPids 列出所有跟 dsh 相关的进程 PID(去重 + 排除自身)。
// 用 ps + grep 而不是 pgrep,以兼容 macOS 默认 PATH 不带 /usr/bin 的情况。
func listDSHPids() []string {
	out, err := runQuiet("ps", "-axo", "pid=,command=")
	if err != nil {
		log.Printf("listDSHPids: ps err: %v", err)
		return nil
	}
	seen := map[string]bool{}
	var pids []string
	self := os.Getpid()
	for _, line := range strings.Split(out, "\n") {
		line = strings.TrimSpace(line)
		if line == "" {
			continue
		}
		// 格式: "PID COMMAND..."
		sp := strings.IndexByte(line, ' ')
		if sp <= 0 {
			continue
		}
		pidStr := line[:sp]
		cmd := line[sp+1:]
		// 跳过自身进程,免得自杀
		if pid, _ := strconv.Atoi(pidStr); pid == self {
			continue
		}
		// 匹配规则: dsh 启动的所有相关进程
		if isDSHProcess(cmd) {
			if !seen[pidStr] {
				seen[pidStr] = true
				pids = append(pids, pidStr)
			}
		}
	}
	return pids
}

// isDSHProcess 判断一条 ps command 是不是 dsh 相关的进程。
// 规则:
func isDSHProcess(cmd string) bool {
	matches := []string{
		"dsh/lib/bin.js",      // dsh CLI 主进程
		"dsh-pet",             // dsh-pet Electron helper
		".dsh/electron",       // dsh 内置的 Electron runtime
		"dsh-pet-electron-helper", // dsh-pet user-data-dir
	}
	for _, m := range matches {
		if strings.Contains(cmd, m) {
			return true
		}
	}
	return false
}
func (a *App) CheckUpdate() UpdateInfo {
	installed := ""
	if p := lookPath("dsh"); p != "" {
		if v, err := runQuietTimeout(p, 5*time.Second, "--version"); err == nil {
			installed = strings.TrimSpace(v)
		} else {
			log.Printf("CheckUpdate dsh --version err: %v", err)
		}
	}

	latest, raw := latestVersionFromNPM(dshPkg)

	info := UpdateInfo{
		Installed: installed,
		Latest:    latest,
		Raw:       raw,
	}
	if installed != "" && latest != "" && installed != latest {
		info.HasUpdate = true
	}
	return info
}

// latestVersionFromNPM 用 `npm view <pkg> version` 取最新版。
// 带 10 秒超时,带 stderr 捕获以便诊断。
func latestVersionFromNPM(pkg string) (string, string) {
	npmBin := lookPath("npm")
	if npmBin == "" {
		return "", "npm not found in PATH"
	}
	cmd := exec.Command(npmBin, "view", pkg, "version", "--registry=https://registry.npmjs.org/")
	cmd.Env = buildChildEnv()
	var stdout, stderr bytes.Buffer
	cmd.Stdout = &stdout
	cmd.Stderr = &stderr

	if err := cmd.Start(); err != nil {
		return "", "start npm: " + err.Error()
	}

	done := make(chan error, 1)
	go func() { done <- cmd.Wait() }()

	select {
	case err := <-done:
		out := strings.TrimSpace(stdout.String())
		errMsg := strings.TrimSpace(stderr.String())
		if err != nil {
			raw := errMsg
			if raw == "" {
				raw = err.Error()
			}
			return "", raw
		}
		// npm 输出可能带换行 / 警告,只取第一行 token
		first := out
		if i := strings.IndexAny(out, "\n\r"); i >= 0 {
			first = strings.TrimSpace(out[:i])
		}
		// 清理 npm 有时会附加的 @ 标签
		first = strings.TrimPrefix(first, "@")
		return first, out
	case <-time.After(15 * time.Second):
		_ = cmd.Process.Kill()
		<-done
		return "", "npm view 超时(15s),请检查网络"
	}
}

// InstallDsh runs `npm install -g @deepseek-ai/dsh` and streams output via Wails events.
// Returns InstallResult once the command exits.
func (a *App) InstallDsh() InstallResult {
	return a.runNpmEvent("install", []string{"install", "-g", dshPkg}, "dsh:install:done")
}

// UpdateDsh runs `npm install -g @deepseek-ai/dsh@latest` and streams output.
func (a *App) UpdateDsh() InstallResult {
	return a.runNpmEvent("update", []string{"install", "-g", dshPkg + "@latest"}, "dsh:update:done")
}

func (a *App) runNpmEvent(phase string, args []string, doneEvent string) InstallResult {
	npmBin := lookPath("npm")
	if npmBin == "" {
		errMsg := "找不到 npm(系统 PATH 和 /opt/homebrew/bin 都没找到)"
		if a.ctx != nil {
			wailsruntime.EventsEmit(a.ctx, "dsh:"+phase+":log", "✗ "+errMsg+"\n")
			wailsruntime.EventsEmit(a.ctx, doneEvent, InstallResult{Error: errMsg})
		}
		return InstallResult{Error: errMsg}
	}
	if a.ctx != nil {
		wailsruntime.EventsEmit(a.ctx, "dsh:"+phase+":log", "▶ "+npmBin+" "+strings.Join(args, " ")+"\n")
	}

	cmd := exec.Command(npmBin, args...)
	cmd.Env = buildChildEnv()
	stdout, err := cmd.StdoutPipe()
	if err != nil {
		return InstallResult{Error: err.Error()}
	}
	stderr, err := cmd.StderrPipe()
	if err != nil {
		return InstallResult{Error: err.Error()}
	}
	if err := cmd.Start(); err != nil {
		return InstallResult{Error: "启动 npm 失败: " + err.Error()}
	}

	var buf strings.Builder
	var mu sync.Mutex
	collect := func(line string) {
		mu.Lock()
		buf.WriteString(line)
		buf.WriteString("\n")
		mu.Unlock()
		if a.ctx != nil {
			wailsruntime.EventsEmit(a.ctx, "dsh:"+phase+":log", line+"\n")
		}
	}
	safeGo("scanStdout", func() { scanLines(stdout, collect) })
	safeGo("scanStderr", func() { scanLines(stderr, collect) })

	waitErr := cmd.Wait()
	mu.Lock()
	out := buf.String()
	mu.Unlock()

	res := InstallResult{Output: out}
	if waitErr != nil {
		res.Error = waitErr.Error()
	} else {
		res.OK = true
	}
	if a.ctx != nil {
		wailsruntime.EventsEmit(a.ctx, doneEvent, res)
	}
	return res
}

func scanLines(r io.Reader, fn func(string)) {
	scanner := bufio.NewScanner(r)
	scanner.Buffer(make([]byte, 64*1024), 1024*1024)
	for scanner.Scan() {
		fn(scanner.Text())
	}
}