PrintToVeraeTimeStamp/cmd/verae-print/keysetup_linux.go

//go:build linux

package main

import (
	"errors"
	"fmt"
	"os"
	"os/exec"
	"strings"

	"github.com/VeraeLLC/PrintToVeraeTimeStamp/internal/vlog"
)

// Linux desktop sign-in dialogs (zenity, GNOME/Cinnamon/XFCE/KDE all ship or
// package it). Launched by the CUPS backend in the job user's session when a
// print needs a key, or by hand: verae-print key-dialog.

const (
	dlgTitle     = "Verae Print Stamp"
	machineWord  = "computer"
	keyStoreDesc = "~/.verae, readable only by you"
)

func zenityPath() string {
	p, err := exec.LookPath("zenity")
	if err != nil {
		return ""
	}
	return p
}

func guiAvailable() bool {
	if os.Getenv("DISPLAY") == "" && os.Getenv("WAYLAND_DISPLAY") == "" {
		return false
	}
	return zenityPath() != ""
}

func openURL(u string) {
	cmd := exec.Command("xdg-open", u)
	cmd.Stdout, cmd.Stderr = nil, nil
	_ = cmd.Start()
	go func() { _ = cmd.Wait() }()
}

// zenity renders --text as Pango markup.
func markupEscape(s string) string {
	return strings.NewReplacer("&", "&amp;", "<", "&lt;", ">", "&gt;").Replace(s)
}

// zen runs zenity; returns stdout (trimmed) and exit code. Exit 1 = cancel or
// an extra button (whose label is printed), 5 = timeout, -1 = could not run.
func zen(args ...string) (string, int) {
	base := []string{"--title=" + dlgTitle, "--width=520", "--timeout=900"}
	cmd := exec.Command(zenityPath(), append(base, args...)...)
	cmd.Stderr = nil
	out, err := cmd.Output()
	s := strings.TrimRight(string(out), "\n")
	if err != nil {
		var ee *exec.ExitError
		if errors.As(err, &ee) {
			return s, ee.ExitCode()
		}
		return "", -1
	}
	return s, 0
}

// ask shows a dialog; returns (button, answer). The default button is OK, the
// first other button is Cancel, the rest are extra buttons.
func ask(msg, def string, hidden, withAnswer bool, buttons []string, defBtn string) (string, string, error) {
	if !guiAvailable() {
		return "", "", fmt.Errorf("no desktop session for dialogs")
	}
	var others []string
	for _, b := range buttons {
		if b != defBtn {
			others = append(others, b)
		}
	}
	var args []string
	switch {
	case withAnswer:
		args = []string{"--entry", "--text=" + markupEscape(msg), "--entry-text=" + def}
		if hidden {
			args = append(args, "--hide-text")
		}
	case len(others) == 0:
		args = []string{"--info", "--text=" + markupEscape(msg)}
	default:
		args = []string{"--question", "--text=" + markupEscape(msg)}
	}
	args = append(args, "--ok-label="+defBtn)
	if len(others) > 0 {
		args = append(args, "--cancel-label="+others[0])
		for _, b := range others[1:] {
			args = append(args, "--extra-button="+b)
		}
	}
	out, code := zen(args...)
	switch code {
	case 0:
		return defBtn, out, nil
	case 1:
		for _, b := range others[min(1, len(others)):] {
			if out == b {
				return b, "", nil
			}
		}
		if len(others) > 0 {
			return others[0], "", nil
		}
		return defBtn, "", nil // info dialog closed
	case -1:
		return "", "", fmt.Errorf("zenity could not start")
	default:
		return "", "", errCancel // timeout / window killed
	}
}

func say(msg string) { _, _, _ = ask(msg, "", false, false, []string{"OK"}, "OK") }

func choose(msg string, opts []string) (string, error) {
	if !guiAvailable() {
		return "", fmt.Errorf("no desktop session for dialogs")
	}
	args := []string{"--list", "--radiolist", "--hide-header", "--height=470",
		"--text=" + markupEscape(msg), "--column=", "--column=Option",
		"--ok-label=Continue", "--cancel-label=Skip"}
	for i, o := range opts {
		sel := "FALSE"
		if i == 0 {
			sel = "TRUE"
		}
		args = append(args, sel, o)
	}
	out, code := zen(args...)
	if code != 0 || out == "" {
		return "", errCancel
	}
	return out, nil
}

// runKeyDialog: verae-print key-dialog — the desktop "get a signing key" flow.
func runKeyDialog() int {
	vlog.Init("installer", false)
	if !guiAvailable() {
		fmt.Println("key-dialog needs a desktop session with zenity installed (sudo apt install zenity); or run: verae-print setup")
		return 1
	}
	vlog.Printf("key-dialog start user=%s display=%s", os.Getenv("USER"), os.Getenv("DISPLAY"))
	release, ok := promptLock()
	if !ok {
		vlog.Printf("key-dialog: another Verae sign-in window is already open")
		return 1
	}
	reason := os.Getenv("VERAE_KEY_REASON")
	result, saved := keyFlow(reason)
	release()
	vlog.Printf("key-dialog result: %s", result)
	fmt.Println("key:", result)
	if saved || strings.HasPrefix(result, "kept") {
		if n := len(listPending()); n > 0 {
			done, remaining, _ := retryPending(stampFile)
			vlog.Printf("key-dialog: retried held print jobs: %d stamped, %d remaining", done, remaining)
		}
		return 0
	}
	return 1
}