package main

import (
	"bufio"
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"os"
	"os/exec"
	"os/signal"
	"path/filepath"
	"regexp"
	"sort"
	"strconv"
	"strings"
	"time"
)

const (
	version        = "V0.4.0"
	logPath        = "/var/log/proxmox-toolkit.log"
	defaultTimeout = 2 * time.Minute
	actionTimeout  = 10 * time.Minute
)

var (
	tmpDir   string
	nodeName string // the node this program runs on
	sigCh    = make(chan os.Signal, 1)

	// PVE guest IDs are 100..999999999.
	numeric = regexp.MustCompile(`^[1-9][0-9]{2,8}$`)
	// Snapshot names: start with a letter, 2-40 chars, letters/digits/_/-.
	snapName = regexp.MustCompile(`^[A-Za-z][A-Za-z0-9_-]{1,39}$`)
	// Storage IDs must not start with '-' so they can't be parsed as options.
	storageName = regexp.MustCompile(`^[A-Za-z0-9][A-Za-z0-9_.-]*$`)
	nodeRe      = regexp.MustCompile(`^[A-Za-z0-9][A-Za-z0-9-]*$`)
	upidRe      = regexp.MustCompile(`^UPID:[A-Za-z0-9:@!._-]+$`)
)

type guestKind struct {
	typ   string // API type: qemu / lxc
	label string // VM / container
	title string
}

var (
	kindVM = guestKind{"qemu", "VM", "Virtual Machines (QEMU)"}
	kindCT = guestKind{"lxc", "container", "Containers (LXC)"}
)

func kindOf(typ string) guestKind {
	if typ == "lxc" {
		return kindCT
	}
	return kindVM
}

type guest struct {
	ID       int
	Name     string
	Status   string
	Node     string
	Type     string // qemu / lxc
	Pool     string
	Template bool
}

func (g guest) path(suffix string) string {
	return fmt.Sprintf("/nodes/%s/%s/%d%s", g.Node, g.Type, g.ID, suffix)
}

func (g guest) short() string {
	tag := "VM"
	if g.Type == "lxc" {
		tag = "CT"
	}
	return fmt.Sprintf("%d %s [%s] on %s", g.ID, g.Name, tag, g.Node)
}

// ---------------------------------------------------------------- main

func main() {
	if os.Geteuid() != 0 {
		fmt.Fprintf(os.Stderr, "Run this program as root, for example: sudo %s\n", os.Args[0])
		os.Exit(1)
	}
	if _, err := exec.LookPath("whiptail"); err != nil {
		fmt.Fprintln(os.Stderr, "whiptail is required. Install it with: apt install whiptail")
		os.Exit(1)
	}

	var err error
	tmpDir, err = os.MkdirTemp("", "proxmox-toolkit-*")
	if err != nil {
		fmt.Fprintf(os.Stderr, "Could not create temporary directory: %v\n", err)
		os.Exit(1)
	}
	defer os.RemoveAll(tmpDir)

	// Swallow Ctrl-C in the parent so cleanup still runs; followTask uses it
	// to stop following a task.
	signal.Notify(sigCh, os.Interrupt)

	nodeName = detectNode()
	logAction("toolkit %s started on node %s", version, nodeName)

	message(
		"Development software - do not use in production",
		"This toolkit is still in development and has not been validated for production use.\n\n"+
			"Use only in a test environment. Actions may affect VMs, containers, storage, or cluster state "+
			"on ANY node in the cluster.\n\n"+
			"Actions are logged to "+logPath+".",
	)
	mainMenu()
	logAction("toolkit exited")
}

func detectNode() string {
	h, err := os.Hostname()
	if err != nil || h == "" {
		return "localhost"
	}
	if i := strings.IndexByte(h, '.'); i >= 0 {
		h = h[:i]
	}
	return h
}

func logAction(format string, a ...any) {
	f, err := os.OpenFile(logPath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0600)
	if err != nil {
		return
	}
	defer f.Close()
	fmt.Fprintf(f, "%s %s\n", time.Now().Format(time.RFC3339), fmt.Sprintf(format, a...))
}

// ---------------------------------------------------------------- command helpers

func run(timeout time.Duration, name string, args ...string) (string, int, error) {
	ctx, cancel := context.WithTimeout(context.Background(), timeout)
	defer cancel()

	out, err := exec.CommandContext(ctx, name, args...).CombinedOutput()
	status := 0
	if err != nil {
		status = -1
		var exitErr *exec.ExitError
		if errors.As(err, &exitErr) {
			status = exitErr.ExitCode()
		}
		if ctx.Err() == context.DeadlineExceeded {
			err = fmt.Errorf("timed out after %s", timeout)
			status = -1
		}
	}
	return string(out), status, err
}

// runStdout returns only stdout so stderr warnings can't corrupt JSON.
func runStdout(timeout time.Duration, name string, args ...string) ([]byte, error) {
	ctx, cancel := context.WithTimeout(context.Background(), timeout)
	defer cancel()
	return exec.CommandContext(ctx, name, args...).Output()
}

func errText(err error) string {
	var exitErr *exec.ExitError
	if errors.As(err, &exitErr) && len(exitErr.Stderr) > 0 {
		return strings.TrimSpace(string(exitErr.Stderr))
	}
	return err.Error()
}

func requireCommand(name string) bool {
	if _, err := exec.LookPath(name); err != nil {
		message(
			"Command unavailable",
			fmt.Sprintf("The command '%s' is not installed or not available on this node.", name),
		)
		return false
	}
	return true
}

func waitEnter() {
	fmt.Print("Press Enter to return to the menu...")
	_, _ = bufio.NewReader(os.Stdin).ReadString('\n')
}

// ---------------------------------------------------------------- cluster API helpers

// pveshGet runs "pvesh get <path>" and unmarshals the JSON result into v.
func pveshGet(v any, path string, params ...string) error {
	args := append([]string{"get", path}, params...)
	args = append(args, "--output-format", "json")
	out, err := runStdout(60*time.Second, "pvesh", args...)
	if err != nil {
		return errors.New(errText(err))
	}
	return json.Unmarshal(out, v)
}

// apiCall runs a state-changing pvesh call (create/set/delete) and returns
// its raw output; for async operations this is the task UPID.
func apiCall(method, path string, params ...string) (string, error) {
	args := append([]string{method, path}, params...)
	args = append(args, "--output-format", "json")
	logAction("api: pvesh %s", strings.Join(args, " "))
	out, err := runStdout(defaultTimeout, "pvesh", args...)
	if err != nil {
		logAction("api failed: %s", errText(err))
		return "", errors.New(errText(err))
	}
	return strings.Trim(strings.TrimSpace(string(out)), `"`), nil
}

type taskStatus struct {
	Status     string `json:"status"`
	ExitStatus string `json:"exitstatus"`
}

func upidNode(upid string) string {
	parts := strings.Split(upid, ":")
	if len(parts) >= 2 && nodeRe.MatchString(parts[1]) {
		return parts[1]
	}
	return nodeName
}

func taskState(upid string) (taskStatus, error) {
	var st taskStatus
	err := pveshGet(&st, "/nodes/"+upidNode(upid)+"/tasks/"+upid+"/status")
	return st, err
}

func taskLog(upid string, start int) []string {
	var raw []struct {
		T string `json:"t"`
	}
	if err := pveshGet(&raw, "/nodes/"+upidNode(upid)+"/tasks/"+upid+"/log",
		"--start", strconv.Itoa(start), "--limit", "1000"); err != nil {
		return nil
	}
	lines := make([]string, 0, len(raw))
	for _, r := range raw {
		lines = append(lines, r.T)
	}
	return lines
}

// waitTask polls until the task stops (or the timeout passes).
func waitTask(upid string, timeout time.Duration) (taskStatus, string, error) {
	deadline := time.Now().Add(timeout)
	for {
		st, err := taskState(upid)
		if err == nil && st.Status == "stopped" {
			return st, strings.Join(taskLog(upid, 0), "\n"), nil
		}
		if time.Now().After(deadline) {
			return st, strings.Join(taskLog(upid, 0), "\n"),
				fmt.Errorf("task still running after %s (see Cluster > Recent tasks)", timeout)
		}
		time.Sleep(time.Second)
	}
}

// runAPITask performs an API call and shows the resulting task log in a dialog.
func runAPITask(title, method, path string, params ...string) {
	out, err := apiCall(method, path, params...)
	if err != nil {
		displayText(title, "Request failed:\n"+err.Error()+"\n")
		return
	}
	if !upidRe.MatchString(out) {
		text := "Completed (no task returned).\n"
		if out != "" && out != "null" {
			text += out + "\n"
		}
		displayText(title, text)
		return
	}
	st, log, werr := waitTask(out, actionTimeout)
	text := log + "\n"
	switch {
	case werr != nil:
		text += "\n" + werr.Error() + "\n"
	case st.ExitStatus == "OK":
		text += "\nResult: OK\n"
	default:
		text += "\nResult: " + st.ExitStatus + "\n"
	}
	displayText(title, text)
}

// followTask streams a long-running task's log to the terminal.
func followTask(title, upid string) {
	select { // drop any stale Ctrl-C
	case <-sigCh:
	default:
	}
	fmt.Printf("\033[2J\033[H=== %s ===\nTask: %s\nPress Ctrl-C to stop following (the task keeps running on its node).\n\n", title, upid)

	start := 0
	for {
		lines := taskLog(upid, start)
		for _, l := range lines {
			fmt.Println(l)
		}
		start += len(lines)

		if st, err := taskState(upid); err == nil && st.Status == "stopped" {
			for _, l := range taskLog(upid, start) {
				fmt.Println(l)
			}
			fmt.Printf("\nTask finished: %s\n", st.ExitStatus)
			break
		}
		select {
		case <-sigCh:
			fmt.Println("\nStopped following. The task is still running.")
			waitEnter()
			return
		case <-time.After(2 * time.Second):
		}
	}
	waitEnter()
}

// startTask issues a call and follows the task it returns.
func startTask(title, method, path string, params ...string) {
	out, err := apiCall(method, path, params...)
	if err != nil {
		displayText(title, "Request failed:\n"+err.Error()+"\n")
		return
	}
	if !upidRe.MatchString(out) {
		displayText(title, "Unexpected response (no task ID):\n"+out+"\n")
		return
	}
	followTask(title, out)
}

// ---------------------------------------------------------------- resource discovery

type resource struct {
	Type     string      `json:"type"`
	Node     string      `json:"node"`
	Status   string      `json:"status"`
	Name     string      `json:"name"`
	VMID     json.Number `json:"vmid"`
	Pool     string      `json:"pool"`
	Storage  string      `json:"storage"`
	CPU      float64     `json:"cpu"`
	Mem      float64     `json:"mem"`
	MaxMem   float64     `json:"maxmem"`
	Disk     float64     `json:"disk"`
	MaxDisk  float64     `json:"maxdisk"`
	Template json.Number `json:"template"`
}

func fetchResources() ([]resource, error) {
	var res []resource
	if err := pveshGet(&res, "/cluster/resources"); err != nil {
		return nil, err
	}
	return res, nil
}

func guestsFrom(res []resource, typ string) []guest {
	var gs []guest
	for _, r := range res {
		if r.Type != "qemu" && r.Type != "lxc" {
			continue
		}
		if typ != "" && r.Type != typ {
			continue
		}
		id, err := strconv.Atoi(r.VMID.String())
		if err != nil || !nodeRe.MatchString(r.Node) {
			continue
		}
		g := guest{ID: id, Name: r.Name, Status: r.Status, Node: r.Node, Type: r.Type, Pool: r.Pool}
		if r.Template.String() == "1" {
			g.Template = true
			g.Status = "template"
		}
		gs = append(gs, g)
	}
	sort.Slice(gs, func(i, j int) bool { return gs[i].ID < gs[j].ID })
	return gs
}

// listGuests returns guests from the whole cluster; typ "" means VMs and containers.
func listGuests(typ string) ([]guest, error) {
	res, err := fetchResources()
	if err != nil {
		return nil, err
	}
	return guestsFrom(res, typ), nil
}

func findGuest(id string) (guest, bool) {
	gs, err := listGuests("")
	if err != nil {
		return guest{}, false
	}
	for _, g := range gs {
		if strconv.Itoa(g.ID) == id {
			return g, true
		}
	}
	return guest{}, false
}

func guestTable(gs []guest) string {
	var b strings.Builder
	fmt.Fprintf(&b, "%-8s %-6s %-26s %-10s %-16s %s\n", "ID", "TYPE", "NAME", "STATUS", "NODE", "POOL")
	for _, g := range gs {
		fmt.Fprintf(&b, "%-8d %-6s %-26.26s %-10s %-16.16s %s\n", g.ID, g.Type, g.Name, g.Status, g.Node, g.Pool)
	}
	if len(gs) == 0 {
		b.WriteString("(none)\n")
	}
	return b.String()
}

func describeGuests(gs []guest, max int) string {
	var lines []string
	for i, g := range gs {
		if i >= max {
			lines = append(lines, fmt.Sprintf("...and %d more", len(gs)-max))
			break
		}
		lines = append(lines, "  "+g.short())
	}
	return strings.Join(lines, "\n")
}

func pickGuest(typ, prompt string) (guest, bool) {
	if !requireCommand("pvesh") {
		return guest{}, false
	}
	guests, err := listGuests(typ)
	if err != nil {
		message("Error", "Could not list guests:\n"+err.Error())
		return guest{}, false
	}
	if len(guests) == 0 {
		message("Nothing found", "No matching guests were found in the cluster.")
		return guest{}, false
	}
	var items []string
	for _, g := range guests {
		tag := "VM"
		if g.Type == "lxc" {
			tag = "CT"
		}
		label := fmt.Sprintf("[%s] %s (%s) on %s", tag, g.Name, g.Status, g.Node)
		if g.Pool != "" {
			label += " {" + g.Pool + "}"
		}
		items = append(items, strconv.Itoa(g.ID), label)
	}
	choice := menu("Select guest", prompt, items...)
	for _, g := range guests {
		if strconv.Itoa(g.ID) == choice {
			return g, true
		}
	}
	return guest{}, false
}

func listNodes(onlineOnly bool) ([]string, error) {
	var raw []struct {
		Node   string `json:"node"`
		Status string `json:"status"`
	}
	if err := pveshGet(&raw, "/nodes"); err != nil {
		return nil, err
	}
	var nodes []string
	for _, n := range raw {
		if !nodeRe.MatchString(n.Node) || (onlineOnly && n.Status != "online") {
			continue
		}
		nodes = append(nodes, n.Node)
	}
	sort.Strings(nodes)
	return nodes, nil
}

// pickNode lets the user choose a node; a single candidate is selected automatically.
func pickNode(prompt, exclude string, onlineOnly bool) (string, bool) {
	nodes, err := listNodes(onlineOnly)
	if err != nil {
		message("Error", "Could not list nodes:\n"+err.Error())
		return "", false
	}
	var items []string
	for _, n := range nodes {
		if n != exclude {
			items = append(items, n, "node")
		}
	}
	if len(items) == 0 {
		message("No nodes", "No suitable nodes were found.")
		return "", false
	}
	if len(items) == 2 {
		return items[0], true
	}
	choice := menu("Select node", prompt, items...)
	return choice, choice != ""
}

func nextID() string {
	out, err := runStdout(15*time.Second, "pvesh", "get", "/cluster/nextid")
	if err != nil {
		return ""
	}
	return strings.Trim(strings.TrimSpace(string(out)), `"`)
}

func capitalize(s string) string {
	if s == "" {
		return s
	}
	return strings.ToUpper(s[:1]) + s[1:]
}

// ---------------------------------------------------------------- whiptail wrappers

func boxHeight(text string, width int) int {
	lines := 0
	for _, l := range strings.Split(text, "\n") {
		lines += 1 + len(l)/(width-6)
	}
	return lines + 6
}

func termSize() (int, int) {
	cmd := exec.Command("stty", "size")
	cmd.Stdin = os.Stdin
	out, err := cmd.Output()
	if err != nil {
		return 24, 80
	}
	parts := strings.Fields(string(out))
	if len(parts) != 2 {
		return 24, 80
	}
	rows, e1 := strconv.Atoi(parts[0])
	cols, e2 := strconv.Atoi(parts[1])
	if e1 != nil || e2 != nil || rows <= 0 || cols <= 0 {
		return 24, 80
	}
	return rows, cols
}

func whiptailOK(args ...string) (string, bool) {
	readEnd, writeEnd, err := os.Pipe()
	if err != nil {
		return "", false
	}
	defer readEnd.Close()

	args = append([]string{"--output-fd", "3"}, args...)
	cmd := exec.Command("whiptail", args...)
	cmd.Stdin = os.Stdin
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	cmd.ExtraFiles = []*os.File{writeEnd}

	err = cmd.Run()
	_ = writeEnd.Close()

	var result bytes.Buffer
	_, _ = result.ReadFrom(readEnd)
	if err != nil {
		return "", false
	}
	return strings.TrimSpace(result.String()), true
}

func whiptail(args ...string) string {
	out, _ := whiptailOK(args...)
	return out
}

func menu(title, prompt string, items ...string) string {
	n := len(items) / 2
	menuHeight := n
	if menuHeight > 14 {
		menuHeight = 14
	}
	height := menuHeight + strings.Count(prompt, "\n") + 8

	_, cols := termSize()
	width := cols - 4
	if width > 110 {
		width = 110
	}
	if width < 60 {
		width = 60
	}

	args := []string{
		"--title", title,
		"--menu", prompt,
		strconv.Itoa(height),
		strconv.Itoa(width),
		strconv.Itoa(menuHeight),
	}
	args = append(args, items...)
	return whiptail(args...)
}

func message(title, text string) {
	whiptail("--title", title, "--msgbox", text, strconv.Itoa(boxHeight(text, 70)), "70")
}

func confirmAction(text string, destructive bool) bool {
	args := []string{"--title", "Confirm"}
	if destructive {
		args = append(args, "--defaultno")
	}
	args = append(args, "--yesno", text, strconv.Itoa(boxHeight(text, 70)), "70")

	cmd := exec.Command("whiptail", args...)
	cmd.Stdin = os.Stdin
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	return cmd.Run() == nil
}

func inputValue(title, prompt string) (string, bool) {
	return whiptailOK("--title", title, "--inputbox", prompt, strconv.Itoa(boxHeight(prompt, 72)+2), "72")
}

func askID(prompt string) (string, bool) {
	value, ok := inputValue("Enter ID", prompt)
	if !ok {
		return "", false
	}
	if !numeric.MatchString(value) {
		message("Invalid ID", "Enter a numeric VM or container ID between 100 and 999999999.")
		return "", false
	}
	return value, true
}

func askSnapshotName() (string, bool) {
	value, ok := inputValue("Snapshot name",
		"Enter a snapshot name (must start with a letter; letters, digits, _ or - only; max 40 chars):")
	if !ok {
		return "", false
	}
	if !snapName.MatchString(value) {
		message("Invalid snapshot name",
			"Names must start with a letter and contain only letters, digits, underscores and hyphens (2-40 characters).")
		return "", false
	}
	return value, true
}

// ---------------------------------------------------------------- output display

func displayText(title, text string) {
	outputPath := filepath.Join(tmpDir, "output.txt")
	if err := os.WriteFile(outputPath, []byte(text), 0600); err != nil {
		message("Error", "Could not write command output to the temporary file.")
		return
	}

	rows, cols := termSize()
	height := rows - 4
	width := cols - 4
	if height < 12 {
		height = 12
	}
	if width < 50 {
		width = 50
	}

	whiptail("--scrolltext", "--title", title, "--textbox", outputPath,
		strconv.Itoa(height), strconv.Itoa(width))
}

func showOutput(title, name string, args ...string) {
	out, status, err := run(defaultTimeout, name, args...)
	text := out
	if strings.TrimSpace(out) == "" && err == nil {
		text = "Command completed successfully; no output.\n"
	}
	if err != nil {
		if status < 0 {
			text += "\n" + err.Error() + "\n"
		} else {
			text += fmt.Sprintf("\nCommand exited with status %d.\n", status)
		}
	}
	displayText(title, text)
}

func showJSON(title, name string, args ...string) {
	out, err := runStdout(defaultTimeout, name, args...)
	if err != nil {
		displayText(title, errText(err)+"\n")
		return
	}
	var formatted bytes.Buffer
	if err := json.Indent(&formatted, out, "", "  "); err != nil {
		displayText(title, "Could not format JSON:\n"+err.Error()+"\n\n"+string(out))
		return
	}
	displayText(title, formatted.String()+"\n")
}

func showSettings(g guest) {
	var cfg map[string]any
	title := g.short() + " CPU/memory"
	if err := pveshGet(&cfg, g.path("/config")); err != nil {
		displayText(title, err.Error()+"\n")
		return
	}
	keys := []string{"memory", "balloon", "swap", "cores", "sockets", "vcpus", "cpu", "cpulimit", "cpuunits"}
	var lines []string
	for _, k := range keys {
		if v, ok := cfg[k]; ok {
			lines = append(lines, fmt.Sprintf("%-10s %v", k+":", v))
		}
	}
	if len(lines) == 0 {
		lines = []string{"No matching settings found."}
	}
	displayText(title, strings.Join(lines, "\n")+"\n")
}

// ---------------------------------------------------------------- guest menus

func guestMenu(k guestKind) {
	for {
		choice := menu(
			k.title+" - whole cluster", "Choose an action:",
			"list", "List all (every node)",
			"status", "Show status",
			"config", "Show full configuration",
			"resources", "Show CPU / memory settings",
			"start", "Start",
			"shutdown", "Gracefully shut down (60s timeout)",
			"reboot", "Reboot",
			"stop", "Force stop (like pulling the power)",
			"migrate", "Migrate to another node",
			"snapshots", "Snapshots",
			"unlock", "Unlock",
			"back", "Back",
		)

		switch choice {
		case "back", "":
			return
		case "list":
			if !requireCommand("pvesh") {
				continue
			}
			gs, err := listGuests(k.typ)
			if err != nil {
				message("Error", "Could not list guests:\n"+err.Error())
				continue
			}
			displayText(k.title, guestTable(gs))
		default:
			g, ok := pickGuest(k.typ, "Select a "+k.label+":")
			if ok {
				guestAction(g, choice)
			}
		}
	}
}

func guestAction(g guest, action string) {
	k := kindOf(g.Type)
	name := capitalize(k.label) + " " + strconv.Itoa(g.ID)
	switch action {
	case "status":
		showJSON(name+" status", "pvesh", "get", g.path("/status/current"), "--output-format", "json")
	case "config":
		showJSON(name+" configuration", "pvesh", "get", g.path("/config"), "--output-format", "json")
	case "resources":
		showSettings(g)
	case "unlock":
		if confirmAction("Unlock "+g.short()+"?\n\nOnly do this after confirming no task is still running for it.", true) {
			runAPITask("Unlock "+name, "set", g.path("/config"), "--delete", "lock")
		}
	case "start", "shutdown", "reboot", "stop":
		runGuestAction(g, action)
	case "migrate":
		migrateGuest(g)
	case "snapshots":
		snapshotMenu(g)
	}
}

func runGuestAction(g guest, action string) {
	k := kindOf(g.Type)
	prompt := fmt.Sprintf("%s %s?", capitalize(action), g.short())
	destructive := false
	params := []string{}

	switch action {
	case "shutdown":
		prompt += "\n\nThis requests a graceful shutdown and waits up to 60 seconds."
		params = []string{"--timeout", "60"}
	case "stop":
		prompt += "\n\nThis immediately powers off the guest without shutting down the OS. Unsaved data may be lost."
		destructive = true
	case "reboot":
		destructive = true
	}
	if !confirmAction(prompt, destructive) {
		return
	}
	runAPITask(capitalize(action)+" "+k.label+" "+strconv.Itoa(g.ID), "create", g.path("/status/"+action), params...)
}

func migrateGuest(g guest) {
	k := kindOf(g.Type)
	target, ok := pickNode("Migrate "+g.short()+" to:", g.Node, true)
	if !ok {
		return
	}
	params := []string{"--target", target}
	note := ""
	if g.Status == "running" {
		if g.Type == "qemu" {
			params = append(params, "--online", "1")
			note = "\n\nThe VM is running and will be live-migrated."
		} else {
			params = append(params, "--restart", "1")
			note = "\n\nThe container is running and will be restarted on the target (containers cannot live-migrate)."
		}
	}
	if !confirmAction("Migrate "+g.short()+" to node "+target+"?"+note+"\n\nLocal disks or devices may block migration.", true) {
		return
	}
	startTask("Migrate "+k.label+" "+strconv.Itoa(g.ID), "create", g.path("/migrate"), params...)
}

func pickSnapshot(g guest, action string) (string, bool) {
	var raw []struct {
		Name        string `json:"name"`
		Description string `json:"description"`
	}
	if err := pveshGet(&raw, g.path("/snapshot")); err != nil {
		message("Error", "Could not list snapshots:\n"+err.Error())
		return "", false
	}
	var items []string
	for _, s := range raw {
		if s.Name == "current" || !snapName.MatchString(s.Name) {
			continue
		}
		desc := strings.ReplaceAll(s.Description, "\n", " ")
		if desc == "" {
			desc = "(no description)"
		}
		items = append(items, s.Name, desc)
	}
	if len(items) == 0 {
		message("No snapshots", "This guest has no snapshots.")
		return "", false
	}
	name := menu("Select snapshot", "Snapshot to "+action+":", items...)
	return name, name != ""
}

func showSnapshots(g guest) {
	var raw []struct {
		Name        string  `json:"name"`
		SnapTime    float64 `json:"snaptime"`
		Description string  `json:"description"`
	}
	title := g.short() + " snapshots"
	if err := pveshGet(&raw, g.path("/snapshot")); err != nil {
		displayText(title, err.Error()+"\n")
		return
	}
	var b strings.Builder
	fmt.Fprintf(&b, "%-24s %-17s %s\n", "NAME", "CREATED", "DESCRIPTION")
	for _, s := range raw {
		created := "-"
		if s.SnapTime > 0 {
			created = time.Unix(int64(s.SnapTime), 0).Format("2006-01-02 15:04")
		}
		fmt.Fprintf(&b, "%-24.24s %-17s %s\n", s.Name, created, strings.ReplaceAll(s.Description, "\n", " "))
	}
	displayText(title, b.String())
}

func snapshotMenu(g guest) {
	for {
		choice := menu(
			g.short()+" snapshots", "Choose an action:",
			"list", "List snapshots",
			"create", "Create snapshot",
			"rollback", "Roll back to a snapshot",
			"delete", "Delete snapshot",
			"back", "Back",
		)

		switch choice {
		case "list":
			showSnapshots(g)
		case "create":
			name, ok := askSnapshotName()
			if !ok {
				continue
			}
			if confirmAction("Create snapshot '"+name+"' for "+g.short()+"?\n\nSnapshots are not a substitute for backups and may consume storage.", false) {
				runAPITask("Create snapshot "+name, "create", g.path("/snapshot"), "--snapname", name)
			}
		case "rollback":
			name, ok := pickSnapshot(g, "roll back to")
			if !ok {
				continue
			}
			if confirmAction("Roll "+g.short()+" back to snapshot '"+name+"'?\n\nThe current state and any newer snapshots will be lost.", true) {
				runAPITask("Rollback to "+name, "create", g.path("/snapshot/"+name+"/rollback"))
			}
		case "delete":
			name, ok := pickSnapshot(g, "delete")
			if !ok {
				continue
			}
			if confirmAction("Permanently delete snapshot '"+name+"' from "+g.short()+"?\n\nThis cannot be undone.", true) {
				runAPITask("Delete snapshot "+name, "delete", g.path("/snapshot/"+name))
			}
		case "back", "":
			return
		}
	}
}

// ---------------------------------------------------------------- resource pools

type pool struct {
	ID      string `json:"poolid"`
	Comment string `json:"comment"`
}

func listPools() ([]pool, error) {
	var pools []pool
	if err := pveshGet(&pools, "/pools"); err != nil {
		return nil, err
	}
	sort.Slice(pools, func(i, j int) bool { return pools[i].ID < pools[j].ID })
	return pools, nil
}

func poolMembers(gs []guest, id string) []guest {
	var out []guest
	for _, g := range gs {
		if g.Pool == id {
			out = append(out, g)
		}
	}
	return out
}

func pickPool() (string, bool) {
	if !requireCommand("pvesh") {
		return "", false
	}
	pools, err := listPools()
	if err != nil {
		message("Error", "Could not list pools:\n"+err.Error())
		return "", false
	}
	if len(pools) == 0 {
		message("No pools", "No resource pools are defined in this cluster.")
		return "", false
	}
	gs, _ := listGuests("")
	var items []string
	for _, p := range pools {
		label := fmt.Sprintf("%d guests", len(poolMembers(gs, p.ID)))
		if p.Comment != "" {
			label += " - " + strings.ReplaceAll(p.Comment, "\n", " ")
		}
		items = append(items, p.ID, label)
	}
	choice := menu("Select pool", "Resource pool:", items...)
	return choice, choice != ""
}

func showPools() {
	if !requireCommand("pvesh") {
		return
	}
	pools, err := listPools()
	if err != nil {
		message("Error", "Could not list pools:\n"+err.Error())
		return
	}
	gs, _ := listGuests("")
	var b strings.Builder
	for _, p := range pools {
		fmt.Fprintf(&b, "== %s ==", p.ID)
		if p.Comment != "" {
			fmt.Fprintf(&b, "  (%s)", strings.ReplaceAll(p.Comment, "\n", " "))
		}
		b.WriteString("\n")
		b.WriteString(guestTable(poolMembers(gs, p.ID)))
		b.WriteString("\n")
	}
	if len(pools) == 0 {
		b.WriteString("No resource pools are defined.\n")
	}
	displayText("Resource pools", b.String())
}

// bulkRun issues one API call per guest, then waits for all tasks and reports.
func bulkRun(title string, targets []guest, fn func(guest) (string, error)) {
	fmt.Printf("\033[2J\033[H=== %s ===\n\n", title)
	logAction("bulk: %s (%d guests)", title, len(targets))

	type pending struct {
		g    guest
		upid string
	}
	var queue []pending
	failed := 0

	for i, g := range targets {
		fmt.Printf("[%d/%d] %s: requesting...\n", i+1, len(targets), g.short())
		out, err := fn(g)
		switch {
		case err != nil:
			failed++
			fmt.Printf("      FAILED: %s\n", err)
		case upidRe.MatchString(out):
			queue = append(queue, pending{g, out})
		default:
			fmt.Println("      done")
		}
	}

	if len(queue) > 0 {
		fmt.Println("\nWaiting for tasks to finish...")
	}
	for _, p := range queue {
		st, _, err := waitTask(p.upid, actionTimeout)
		switch {
		case err != nil:
			failed++
			fmt.Printf("  %s: %s\n", p.g.short(), err)
		case st.ExitStatus != "OK":
			failed++
			fmt.Printf("  %s: FAILED (%s)\n", p.g.short(), st.ExitStatus)
		default:
			fmt.Printf("  %s: OK\n", p.g.short())
		}
	}
	fmt.Printf("\nFinished: %d succeeded, %d failed.\n", len(targets)-failed, failed)
	waitEnter()
}

func poolAction(action string) {
	id, ok := pickPool()
	if !ok {
		return
	}
	all, err := listGuests("")
	if err != nil {
		message("Error", "Could not list guests:\n"+err.Error())
		return
	}

	var targets []guest
	for _, g := range poolMembers(all, id) {
		switch action {
		case "start":
			if g.Status == "stopped" && !g.Template {
				targets = append(targets, g)
			}
		case "shutdown":
			if g.Status == "running" {
				targets = append(targets, g)
			}
		case "snapshot":
			if !g.Template {
				targets = append(targets, g)
			}
		}
	}
	if len(targets) == 0 {
		message("Nothing to do", "No guests in pool '"+id+"' match this action.")
		return
	}

	var fn func(guest) (string, error)
	verb := ""
	switch action {
	case "start":
		verb = "Start"
		fn = func(g guest) (string, error) { return apiCall("create", g.path("/status/start")) }
	case "shutdown":
		verb = "Gracefully shut down"
		fn = func(g guest) (string, error) {
			return apiCall("create", g.path("/status/shutdown"), "--timeout", "60")
		}
	case "snapshot":
		name, ok := askSnapshotName()
		if !ok {
			return
		}
		verb = "Snapshot '" + name + "' on"
		fn = func(g guest) (string, error) { return apiCall("create", g.path("/snapshot"), "--snapname", name) }
	}

	text := fmt.Sprintf("%s these %d guests in pool '%s'?\n\n%s", verb, len(targets), id, describeGuests(targets, 12))
	if !confirmAction(text, action != "start") {
		return
	}
	bulkRun(verb+" pool "+id, targets, fn)
}

func poolsMenu() {
	for {
		choice := menu(
			"Resource Pools", "Choose an action (applies across all nodes):",
			"list", "List pools and members",
			"start", "Start all stopped guests in a pool",
			"shutdown", "Gracefully shut down all running guests in a pool",
			"snapshot", "Snapshot all guests in a pool",
			"back", "Back",
		)
		switch choice {
		case "list":
			showPools()
		case "start", "shutdown", "snapshot":
			poolAction(choice)
		case "back", "":
			return
		}
	}
}

// ---------------------------------------------------------------- backup / restore

func pickBackupStorage(node string) (string, bool) {
	var raw []struct {
		Storage string  `json:"storage"`
		Type    string  `json:"type"`
		Avail   float64 `json:"avail"`
	}
	if err := pveshGet(&raw, "/nodes/"+node+"/storage", "--content", "backup", "--enabled", "1"); err != nil {
		message("Storage error", "Could not list backup storage on "+node+":\n"+err.Error())
		return "", false
	}
	var items []string
	for _, s := range raw {
		if !storageName.MatchString(s.Storage) {
			continue
		}
		items = append(items, s.Storage, fmt.Sprintf("%s, %.1f GiB free", s.Type, s.Avail/(1<<30)))
	}
	if len(items) == 0 {
		message("No backup storage", "No enabled storage with content type 'backup' on node "+node+".")
		return "", false
	}
	choice := menu("Backup storage ("+node+")", "Select a storage:", items...)
	return choice, choice != ""
}

func backupMenu() {
	g, ok := pickGuest("", "Select the VM or container to back up:")
	if !ok {
		return
	}
	storage, ok := pickBackupStorage(g.Node)
	if !ok {
		return
	}
	mode := menu("Backup mode", "Choose a backup mode:",
		"snapshot", "Snapshot - guest keeps running (recommended)",
		"suspend", "Suspend - brief pause while copying",
		"stop", "Stop - shut down, back up, restart",
	)
	if mode == "" {
		return
	}
	compress := menu("Compression", "Choose compression:",
		"zstd", "zstd (fast, good ratio)",
		"gzip", "gzip",
		"lzo", "lzo (fastest, larger)",
		"0", "None",
	)
	if compress == "" {
		return
	}

	summary := fmt.Sprintf("Back up %s?\n\nStorage: %s\nMode: %s\nCompression: %s", g.short(), storage, mode, compress)
	if !confirmAction(summary, false) {
		return
	}
	startTask("Backup "+g.short(), "create", "/nodes/"+g.Node+"/vzdump",
		"--vmid", strconv.Itoa(g.ID), "--storage", storage, "--mode", mode, "--compress", compress)
}

func manualArchive() (string, bool) {
	archive, ok := inputValue("Backup archive", "Enter the full path to the vzdump archive:")
	if !ok {
		return "", false
	}
	info, err := os.Stat(archive)
	if archive == "" || !filepath.IsAbs(archive) || err != nil || !info.Mode().IsRegular() {
		message("Archive not found", "Enter an absolute path to an existing regular file.")
		return "", false
	}
	return archive, true
}

func pickBackup(node, storage string) (string, bool) {
	var raw []struct {
		VolID string  `json:"volid"`
		Size  float64 `json:"size"`
		CTime float64 `json:"ctime"`
	}
	err := pveshGet(&raw, "/nodes/"+node+"/storage/"+storage+"/content", "--content", "backup")
	local := node == nodeName // manual paths can only be checked on this node
	if err != nil || len(raw) == 0 {
		if local {
			message("No backups listed", "No backups were found on '"+storage+"'. You can enter an archive path manually.")
			return manualArchive()
		}
		message("No backups", "No backups were found on '"+storage+"' ("+node+").")
		return "", false
	}
	sort.Slice(raw, func(i, j int) bool { return raw[i].CTime > raw[j].CTime })

	var items []string
	for i, b := range raw {
		base := b.VolID
		if idx := strings.LastIndexByte(base, '/'); idx >= 0 && !strings.Contains(base, "backup/vm/") && !strings.Contains(base, "backup/ct/") {
			base = base[idx+1:]
		}
		items = append(items, strconv.Itoa(i+1), fmt.Sprintf("%s  %.1f GiB", base, b.Size/(1<<30)))
	}
	if local {
		items = append(items, "manual", "Enter an archive path manually...")
	}

	choice := menu("Select backup", "Newest first:", items...)
	switch choice {
	case "":
		return "", false
	case "manual":
		return manualArchive()
	}
	idx, err := strconv.Atoi(choice)
	if err != nil || idx < 1 || idx > len(raw) {
		return "", false
	}
	return raw[idx-1].VolID, true
}

func detectArchiveType(archive string) string {
	switch {
	case strings.Contains(archive, "vzdump-qemu-"), strings.Contains(archive, "backup/vm/"):
		return "qemu"
	case strings.Contains(archive, "vzdump-lxc-"), strings.Contains(archive, "backup/ct/"):
		return "lxc"
	}
	return ""
}

func restoreMenu() {
	if !requireCommand("pvesh") {
		return
	}
	prompt := "Enter the target VMID / container ID:"
	if n := nextID(); n != "" {
		prompt = "Enter the target VMID / container ID (next free ID: " + n + "):"
	}
	id, ok := askID(prompt)
	if !ok {
		return
	}

	// An existing guest can only be overwritten on the node it lives on.
	existing, exists := findGuest(id)
	var node string
	if exists {
		if !confirmAction("ID "+id+" already exists:\n  "+existing.short()+"\n\nRestoring will DESTROY and overwrite it. Continue?", true) {
			return
		}
		node = existing.Node
	} else if node, ok = pickNode("Restore on which node?", "", true); !ok {
		return
	}

	storage, ok := pickBackupStorage(node)
	if !ok {
		return
	}
	archive, ok := pickBackup(node, storage)
	if !ok {
		return
	}

	typ := detectArchiveType(archive)
	if typ == "" {
		typ = menu("Archive type", "Could not detect the archive type. What is it?",
			"qemu", "QEMU VM",
			"lxc", "Container (LXC)",
		)
		if typ == "" {
			return
		}
	}
	if exists && existing.Type != typ {
		message("Type mismatch", "The existing guest is a "+kindOf(existing.Type).label+
			" but the archive is a "+kindOf(typ).label+". Choose a different ID.")
		return
	}

	target, ok := inputValue("Target storage", "Storage for the restored disks (leave blank for the default):")
	if !ok {
		return
	}
	if target != "" && !storageName.MatchString(target) {
		message("Invalid storage", "Storage names may only contain letters, digits, _, . and -, and must start with a letter or digit.")
		return
	}

	if !confirmAction("Restore '"+archive+"' as ID "+id+" on node "+node+"?", true) {
		return
	}

	params := []string{"--vmid", id}
	if typ == "qemu" {
		params = append(params, "--archive", archive)
	} else {
		params = append(params, "--ostemplate", archive, "--restore", "1")
	}
	if target != "" {
		params = append(params, "--storage", target)
	}
	if exists {
		params = append(params, "--force", "1")
	}
	startTask("Restore ID "+id, "create", "/nodes/"+node+"/"+typ, params...)
}

// ---------------------------------------------------------------- reports

func clusterOverview() {
	if !requireCommand("pvesh") {
		return
	}
	res, err := fetchResources()
	if err != nil {
		message("Error", "Could not read cluster resources:\n"+err.Error())
		return
	}
	gib := func(v float64) float64 { return v / (1 << 30) }

	var b strings.Builder
	b.WriteString("NODES\n")
	fmt.Fprintf(&b, "%-16s %-9s %-7s %-20s %s\n", "NODE", "STATUS", "CPU", "MEMORY (GiB)", "VMs/CTs running")
	gs := guestsFrom(res, "")
	for _, r := range res {
		if r.Type != "node" {
			continue
		}
		running, total := 0, 0
		for _, g := range gs {
			if g.Node == r.Node {
				total++
				if g.Status == "running" {
					running++
				}
			}
		}
		fmt.Fprintf(&b, "%-16.16s %-9s %5.1f%%  %6.1f / %-10.1f %d/%d\n",
			r.Node, r.Status, r.CPU*100, gib(r.Mem), gib(r.MaxMem), running, total)
	}

	b.WriteString("\nSTORAGE\n")
	fmt.Fprintf(&b, "%-20s %-16s %-10s %s\n", "STORAGE", "NODE", "STATUS", "USED")
	for _, r := range res {
		if r.Type != "storage" {
			continue
		}
		pct := 0.0
		if r.MaxDisk > 0 {
			pct = r.Disk / r.MaxDisk * 100
		}
		fmt.Fprintf(&b, "%-20.20s %-16.16s %-10s %5.1f%% of %.0f GiB\n", r.Storage, r.Node, r.Status, pct, gib(r.MaxDisk))
	}

	b.WriteString("\nGUESTS\n")
	b.WriteString(guestTable(gs))
	displayText("Cluster overview (all nodes)", b.String())
}

func storageMenu() {
	for {
		choice := menu(
			"Storage (this node)", "Choose a report:",
			"status", "Proxmox storage status (pvesm status)",
			"pvs", "Physical volumes (pvs)",
			"vgs", "Volume groups (vgs)",
			"lvs", "Logical volumes (lvs)",
			"zfs", "ZFS pool status (zpool status)",
			"df", "Filesystem usage (df -h)",
			"back", "Back",
		)

		switch choice {
		case "status":
			if requireCommand("pvesm") {
				showOutput("Proxmox storage status", "pvesm", "status")
			}
		case "pvs", "vgs", "lvs":
			if requireCommand(choice) {
				showOutput(choice, choice)
			}
		case "zfs":
			if requireCommand("zpool") {
				showOutput("ZFS pool status", "zpool", "status")
			}
		case "df":
			showOutput("Filesystem usage", "df", "-h")
		case "back", "":
			return
		}
	}
}

func resourcesMenu() {
	for {
		choice := menu(
			"Cluster Resources",
			"Choose a resource type to display as formatted JSON:",
			"vm", "Virtual machines and containers",
			"storage", "Storage",
			"node", "Nodes",
			"sdn", "SDN",
			"pool", "Pools",
			"back", "Back",
		)

		switch choice {
		case "vm", "storage", "node", "sdn", "pool":
			if requireCommand("pvesh") {
				showJSON("Cluster "+choice+" resources", "pvesh",
					"get", "/cluster/resources", "--type", choice, "--output-format", "json")
			}
		case "back", "":
			return
		}
	}
}

func clusterMenu() {
	for {
		choice := menu(
			"Cluster and Node", "Choose a report:",
			"overview", "Cluster overview: nodes, storage, all guests",
			"status", "Cluster status (pvecm status)",
			"nodes", "List nodes (JSON)",
			"nodestatus", "Node status: CPU, memory, uptime",
			"tasks", "Recent cluster tasks",
			"back", "Back",
		)

		switch choice {
		case "overview":
			clusterOverview()
		case "status":
			if requireCommand("pvecm") {
				showOutput("Cluster status", "pvecm", "status")
			}
		case "nodes":
			if requireCommand("pvesh") {
				showJSON("Cluster nodes", "pvesh", "get", "/nodes", "--output-format", "json")
			}
		case "nodestatus":
			if !requireCommand("pvesh") {
				continue
			}
			if n, ok := pickNode("Show status for:", "", false); ok {
				showJSON("Node "+n+" status", "pvesh", "get", "/nodes/"+n+"/status", "--output-format", "json")
			}
		case "tasks":
			if requireCommand("pvesh") {
				showJSON("Recent cluster tasks", "pvesh", "get", "/cluster/tasks", "--output-format", "json")
			}
		case "back", "":
			return
		}
	}
}

func systemMenu() {
	for {
		choice := menu(
			"System (this node)", "Choose a report:",
			"services", "Proxmox service status",
			"updates", "Upgradable packages (as of last apt update)",
			"network", "Network addresses (ip -br address)",
			"log", "Toolkit action log",
			"back", "Back",
		)

		switch choice {
		case "services":
			showOutput("Proxmox services", "systemctl", "status",
				"pve-cluster", "pvedaemon", "pveproxy", "pvestatd", "--no-pager", "--lines=0")
		case "updates":
			if requireCommand("apt") {
				showOutput("Upgradable packages", "apt", "list", "--upgradable")
			}
		case "network":
			showOutput("Network addresses", "ip", "-br", "address")
		case "log":
			showOutput("Toolkit log (last 200 lines)", "tail", "-n", "200", logPath)
		case "back", "":
			return
		}
	}
}

// ---------------------------------------------------------------- main menu

func mainMenu() {
	for {
		choice := menu(
			"Proxmox VE Toolkit - DEVELOPMENT ONLY - NOT FOR PRODUCTION "+version,
			"Select a task (running on node: "+nodeName+"):",
			"vms", "Virtual machines (QEMU) - whole cluster",
			"containers", "Containers (LXC) - whole cluster",
			"pools", "Resource pools - bulk actions",
			"backup", "Back up a VM or container (vzdump)",
			"restore", "Restore a VM or container",
			"cluster", "Cluster overview and reports",
			"storage", "Storage / LVM / ZFS reports (this node)",
			"system", "System: services, updates, network, log",
			"resources", "Cluster resources (formatted JSON)",
			"version", "Proxmox version (pveversion -v)",
			"perf", "Host performance test (pveperf)",
			"subscription", "Subscription status",
			"dab", "Debian Appliance Builder help",
			"quit", "Exit",
		)

		switch choice {
		case "vms":
			guestMenu(kindVM)
		case "containers":
			guestMenu(kindCT)
		case "pools":
			poolsMenu()
		case "backup":
			backupMenu()
		case "restore":
			restoreMenu()
		case "cluster":
			clusterMenu()
		case "storage":
			storageMenu()
		case "system":
			systemMenu()
		case "resources":
			resourcesMenu()
		case "version":
			if requireCommand("pveversion") {
				showOutput("Proxmox VE version", "pveversion", "-v")
			}
		case "perf":
			if requireCommand("pveperf") &&
				confirmAction("Run pveperf?\n\nThis can cause temporary disk activity.", false) {
				showOutput("Host performance", "pveperf")
			}
		case "subscription":
			if requireCommand("pvesubscription") {
				showOutput("Subscription status", "pvesubscription", "get")
			}
		case "dab":
			if requireCommand("dab") {
				showOutput("Debian Appliance Builder help", "dab", "help")
			}
		case "quit", "":
			return
		}
	}
}