main.go

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//                          daky's X11 hotkey daemon
package main

import (
	"bytes"
	"errors"
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"os/exec"
	"os/signal"
	"path/filepath"
	"runtime"
	"strconv"
	"syscall"
	"time"

	"github.com/BurntSushi/xgbutil"
	"github.com/BurntSushi/xgbutil/keybind"
	"github.com/BurntSushi/xgbutil/mousebind"
	"github.com/BurntSushi/xgbutil/xevent"
	"github.com/dakyskye/dxhd/config"
	"github.com/dakyskye/dxhd/listener"
	"github.com/dakyskye/dxhd/logger"
	"github.com/dakyskye/dxhd/options"
	"github.com/dakyskye/dxhd/parser"
	"github.com/sirupsen/logrus"
)

var usage = `NAME
  dxhd - daky's X11 Hotkey Daemon
VERSION
  %s
SYNOPSIS
  dxhd [OPTIONS]
DESCRIPTION
  dxhd is an easy-to-use X11 hotkey daemon, written in Go programming language, and inspired by sxhkd.
  More can be read here - https://github.com/dakyskye/dxhd#readme
OPTIONS%s
EXAMPLE CONFIG
  #!/usr/bin/bash
  ## restart i3
  # super + shift + r
  i3-msg -t command restart
  ## switch to workspace 1-10
  # super + @{1-9,0}
  i3-msg -t command workspace {1-9,10}
  ## switch to workspace 11-20
  # super + ctrl + {1-9,0}
  i3-msg -t command workspace {11-19,20}
  ## switch to next/prev workspace
  # super + @mouse{4,5}
  i3-msg -t command workspace {next,prev}
BUGS
  report a bug here if you find one - https://github.com/dakyskye/dxhd/issues
AUTHOR
  Lasha Kanteladze <kanteladzelasha339@gmail.com>`

var version = `master`

func main() {
	if runtime.GOOS != "linux" {
		logger.L().Fatalln("dxhd is only supported on linux")
	}

	stdin := new([]byte)

	stat, err := os.Stdin.Stat()
	if err != nil {
		logger.L().WithError(err).Fatal("can not stat stdin")
	}
	if stat.Mode()&os.ModeCharDevice == 0 {
		*stdin, err = ioutil.ReadAll(os.Stdin)
		if err != nil {
			logger.L().WithError(err).Fatal("can not read the stdin")
		}
	} else {
		stdin = nil
	}

	opts, err := options.Parse()
	if err != nil {
		logger.L().Fatalln(err)
	}

	usage = fmt.Sprintf(usage, version, options.OptionsToPrint)

	exit := false

	if opts.Help {
		fmt.Println(usage)
		fmt.Println()
		exit = true
	} else if opts.Version {
		fmt.Println("you are using dxhd, version " + version)
		fmt.Println()
		exit = true
	}

	runInBackground := func(data *[]byte) (err error) {
		exc, err := os.Executable()
		if err != nil {
			logger.L().WithError(err).Fatal("can not get the executable")
		}
		cmd := exec.Command(exc, os.Args...)
		if data != nil {
			cmd.Stdin = bytes.NewReader(*data)
		}
		cmd.Stdout = os.Stdout
		cmd.Stderr = os.Stderr
		cmd.SysProcAttr = &syscall.SysProcAttr{
			Foreground: false,
			Setsid:     true,
		}
		err = cmd.Start()
		if err != nil {
			logger.L().WithError(err).Fatal("can not run dxhd in the background")
		}
		time.Sleep(time.Microsecond * 10)
		return
	}

	if opts.Background && !opts.Interactive {
		err = runInBackground(stdin)
		if err != nil {
			logger.L().WithError(err).Fatal("can not run dxhd in the background")
		}
		os.Exit(0)
	}

	findEditor := func() (ed string, e error) {
		editor := os.Getenv("EDITOR")
		editors := [5]string{editor, "nano", "nvim", "vim", "vi"}
		for _, ed = range editors {
			ed, e = exec.LookPath(ed)
			if e == nil {
				break
			}
		}
		if e != nil {
			e = errors.New("no text editor was found installed")
		}
		return
	}

	if opts.Edit != nil {
		editor, err := findEditor()
		if err != nil {
			logger.L().WithError(err).Fatal("can not find a suitable editor to use")
		}
		_, configDir, _ := config.GetDefaultConfigPath()
		if *opts.Edit == "" {
			*opts.Edit = "dxhd.sh"
		}
		path := filepath.Join(configDir, *opts.Edit)
		cmd := exec.Command(editor, path)
		cmd.Stdout = os.Stdout
		cmd.Stderr = os.Stderr
		cmd.Stdin = os.Stdin
		err = cmd.Run()
		if err != nil {
			logger.L().WithError(err).WithFields(logrus.Fields{"editor": editor, "path": path}).Fatal("cannot invoke editor")
		}
		exit = true
	}

	var (
		configFilePath string
		validPath      bool
	)

	if stdin == nil {
		if opts.Interactive && opts.Config == nil {
			editor, err := findEditor()
			if err != nil {
				logger.L().WithError(err).Fatal("can not find a suitable editor to use")
			}
			tmp, err := ioutil.TempFile("/tmp", "dxhd")
			if err != nil {
				logger.L().WithError(err).Fatal("can not create a temp file for interactive l")
			}

			_, err = tmp.WriteString("#!/bin/sh")
			if err != nil {
				logger.L().WithError(err).WithField("file", tmp.Name()).Warn("can not write default shebang to temp file")
			}

			cmd := exec.Command(editor, tmp.Name())
			cmd.Stdout = os.Stdout
			cmd.Stderr = os.Stderr
			cmd.Stdin = os.Stdin
			err = cmd.Run()
			if err != nil {
				logger.L().WithError(err).WithFields(logrus.Fields{"editor": editor, "path": tmp.Name()}).Fatal("cannot invoke editor")
			}

			stdin = new([]byte)
			*stdin, err = ioutil.ReadFile(tmp.Name()) // ioutil.ReadAll(tmp) omits the shebang
			if err != nil {
				logger.L().WithError(err).WithField("file", tmp).Fatal("can not read file")
			}

			err = os.Remove(tmp.Name())
			if err != nil {
				logger.L().WithError(err).Warn("can not delete temp file dxhd created")
			}

			if opts.Background {
				err = runInBackground(stdin)
				if err != nil {
					logger.L().WithError(err).Fatal("can not run dxhd in the background")
				}
				os.Exit(0)
			}
		} else if opts.Config != nil {
			if validPath, err = config.IsPathToConfigValid(*opts.Config); !(err == nil && validPath) {
				logger.L().WithFields(logrus.Fields{
					"path":  *opts.Config,
					"valid": validPath,
				}).WithError(err).Fatal("path to the config is not valid")
			}
			configFilePath = *opts.Config
		} else {
			configFilePath, _, err = config.GetDefaultConfigPath()
			if err != nil {
				logger.L().WithError(err).Fatal("can not get config path")
			}

			if validPath, err = config.IsPathToConfigValid(configFilePath); !(err == nil && validPath) {
				if os.IsNotExist(err) {
					err = config.CreateDefaultConfig()
					if err != nil {
						logger.L().WithField("path", configFilePath).Fatal("can not create default config")
					}
					logger.L().WithField("path", configFilePath).Info("created the default config")
					os.Exit(0)
				} else {
					logger.L().WithFields(logrus.Fields{"path": configFilePath, "valid": validPath}).WithError(err).Fatal("path to the config is not valid")
				}
			}
		}
	}

	var (
		data      []parser.FileData
		shell     string
		globals   string
		startTime time.Time
	)

	if opts.ParseTime {
		startTime = time.Now()
	}

	if stdin != nil {
		shell, globals, err = parser.Parse(*stdin, &data)
		*stdin = []byte("")
	} else {
		shell, globals, err = parser.Parse(configFilePath, &data)
	}
	if err != nil {
		logger.L().WithField("file", configFilePath).WithError(err).Fatal("failed to parse config")
	}

	if opts.ParseTime {
		since := time.Since(startTime)
		timeTaken := fmt.Sprintf("%.0fs%dms%dµs",
			since.Seconds(),
			since.Milliseconds(),
			since.Microseconds(),
		)
		fmt.Printf("it took %s to parse the config\n", timeTaken)
		fmt.Printf("%d parsed keybindins (including replicated variants and ranges)\n", len(data))
		exit = true
	}

	if opts.DryRun {
		fmt.Println("dxhd dry run")
		for _, d := range data {
			fmt.Println("binding: " + d.OriginalBinding)
			fmt.Println("command:")
			fmt.Println(d.Command.String())
		}
		fmt.Println()
		exit = true
	}

	if opts.Kill || opts.Reload {
		execName, err := os.Executable()
		if err != nil {
			logger.L().WithError(err).Fatal("can not get executable")
		}

		if opts.Kill {
			err = exec.Command("pkill", "-INT", "-x", filepath.Base(execName)).Start()
		} else {
			err = exec.Command("pkill", "-USR1", "-x", filepath.Base(execName)).Start()
		}

		if err != nil {
			if opts.Kill {
				log.Println("can not kill dxhd instances:")
				log.Fatalln(err)
			} else {
				log.Println("can not reload dxhd instances:")
				log.Fatalln(err)
			}
		}

		if opts.Kill {
			fmt.Println("killing every running instances of dxhd")
		} else {
			fmt.Println("reloading every running instances of dxhd")
		}

		exit = true
	}

	if exit {
		os.Exit(0)
	}

	logger.L().WithFields(logrus.Fields{"version": version, "path": configFilePath}).Debug("starting dxhd")

	// catch these signals
	signals := make(chan os.Signal, 1)
	signal.Notify(signals, os.Interrupt, syscall.SIGINT, syscall.SIGTERM, syscall.SIGUSR1, syscall.SIGUSR2)

	// errors channel
	errs := make(chan error)

	// infinite loop - if user sends USR signal, reload configration (so, continue loop), otherwise, exit
toplevel:
	for {
		if len(data) == 0 && stdin == nil {
			shell, globals, err = parser.Parse(configFilePath, &data)
			if err != nil {
				logger.L().WithField("file", configFilePath).WithError(err).Fatal("failed to parse config")
			}
		}

		X, err := xgbutil.NewConn()
		if err != nil {
			logger.L().WithError(err).Fatal("can not open connection to Xorg")
		}

		keybind.Initialize(X)
		mousebind.Initialize(X)

		for _, d := range data {
			err = listener.ListenKeybinding(X, errs, d.EvtType, shell, globals, d.Binding.String(), d.Command.String())
			if err != nil {
				logger.L().WithField("keybinding", d.Binding.String()).WithError(err).Warn("can not register a keybinding")
			}
		}

		data = nil

		go xevent.Main(X)

		for {
			select {
			case err = <-errs:
				if err != nil {
					logger.L().WithError(err).Warn("a command resulted into an error")
				}
				continue
			case sig := <-signals:
				if (sig == syscall.SIGUSR1 || sig == syscall.SIGUSR2) && stdin != nil {
					logger.L().Debug("user defined signal received, but not reloading, as dxhd's using memory config")
					continue
				}
				keybind.Detach(X, X.RootWin())
				mousebind.Detach(X, X.RootWin())
				xevent.Quit(X)
				if (sig == syscall.SIGUSR1 || sig == syscall.SIGUSR2) && stdin == nil {
					logger.L().Debug("user defined signal received, reloading")
					continue toplevel
				}
				logger.L().WithField("signal", sig.String()).Info("signal received, shutting down")
				if env, err := strconv.ParseBool(os.Getenv("STACKTRACE")); env && err == nil {
					buf := make([]byte, 1<<20)
					stackLen := runtime.Stack(buf, true)
					log.Printf("\nPriting goroutine stack trace, because `STACKTRACE` was set.\n%s\n", buf[:stackLen])
				}
				os.Exit(0)
			}
		}
	}
}