sway-launch

#!/usr/bin/env bash

# sway-launch

shopt -s xpg_echo

bold="\033[1m"
green="\033[32m"
red="\033[31m"
reset="\033[0m"

# swaymsg, fallback to i3-msg
swaymsg() {
  if command -v swaymsg >/dev/null 2>&1; then
    command swaymsg "$@"
  else
    command i3-msg "$@"
  fi
}

# get ids and app_ids of all containers
# - this is used to figure out when the program has launched
get_tree_info() {
  swaymsg -t get_tree | jq -r \
    'recurse(.nodes[]) | recurse(.floating_nodes[]) | select(.type == "con") | "\(.id) \(.app_id) \(.window_properties.instance)"'
}

usage() {
  echo "${bold}Usage:${reset} ${green}sway-launch${reset} [OPTIONS] [--]  <command> [arguments...]"
  echo "       ${green}sway-launch${reset} [OPTIONS] [--] '<command> [arguments...]'"
  echo
  echo "- Launch a command. Meant to be called from a wrapper script or alias, which in turn"
  echo "  is called from a terminal running in the Sway/i3 scratchpad."
  echo
  echo "- After running it, the scratchpad is hidden. This is meant to simulate the UX of an"
  echo "  application launcher like rofi, but from a terminal running in the scratchpad."
  echo
  echo "Options:"
  echo "  -w, --workspace=<value>   Launch the command in the given workspace."
  echo "                            - VALUE can be \"current\" (default), \"next\", \"prev\","
  echo "                              \"next-empty\", or a number."
  echo "  -n, --no-hide-scratchpad  Do not hide the scratchpad after launching the command."
  echo "  -e, --window-name <value> Used to check for the new window's existence (by app_id"
  echo "                            or instance). When the window exists, sway-launch exits."
  echo "                            With no value (default), exit as soon as a new window"
  echo "                            is created."
  echo "  -t, --no-wait             Do not wait for a window to open. Exit immediately."
  echo "  -q, --quiet               Do not print any output. (Useful for wrapping scripts"
  echo "                            with their own outputs.)"
  echo "  -d, --debug               Print debug output."
  echo "  -h, --help                Show this help message."
  echo
  echo "Example:"
  echo "  # in .bashrc"
  echo "  alias firefox='sway-launch --workspace=next-empty -- firefox'"
  echo
  echo " <mod>- # open scratchpad"
  echo " firefox<ret> # launch firefox, scratchpad is then hidden."

}

# parse options
hide_scratchpad=1
quiet=0
debug=0
wait_for_window=1
go_to_workspace="current"
window_name=""
while true; do
  case "$1" in
    -n|--no-hide-scratchpad)
      hide_scratchpad=0
      shift
      ;;
    -q|--quiet)
      quiet=1
      shift
      ;;
    -d|--debug)
      debug=1
      shift
      ;;
    -h|--help)
      usage
      exit 0
      ;;
    -w|--workspace)
      go_to_workspace=$2
      shift 2
      ;;
    -e|--window-name)
      window_name=$2
      shift 2
      ;;
    -t|--no-wait)
      wait_for_window=0
      shift
      ;;
    --)
      shift
      break
      ;;
    *)
      break
      ;;
  esac
done

# print usage on invalid arguments
if [[ $# -eq 0 ]]; then
  usage
  exit 1
fi

# handle workspace
if [[ $go_to_workspace != "current" ]]; then
  sway-workspace --quiet $go_to_workspace
  if [[ $? -ne 0 ]]; then
    exit 1
  fi
fi

# check if the scratchpad is focused at the time of calling this script.
is_scratchpad_focused=$(sway-is-scratchpad-focused)

# store current list of container IDs and 'app_id's
old_tree=$(get_tree_info)

# launch the command

[[ $quiet -eq 0 ]] && echo "${bold}sway-launch:${reset} Launching ${green}$@${reset} ..."

# prepare by cleaning latest exit code, if any
exit_code_file="/tmp/sway-launch-exit-code.${USER}"
rm -f ${exit_code_file} > /dev/null 2>&1

# parse arguments into "cmd" and "args"
if [[ "$#" -eq 1 ]]; then
    # if there is only one argument, expand it into parameters with 'eval' to
    # handle quoted arguments
    eval "args=($1)"
    cmd=${args[0]}
    args=("${args[@]:1}")
else
    cmd=$1
    shift
    args=("$@")
fi

# debug info
if [[ $debug -eq 1 ]]; then
  echo sway-launch: cmd: $cmd
  echo sway-launch: args: "${args[@]}"
  for arg in "${args[@]}"; do
    echo "sway-launch:   $arg"
  done
fi

# This is where the magic happens:
# - Launch in the background
# - Launch in a subshell to avoid adding to the shell's job control
# - Redirect all output to /dev/null
# - Make exit code available to this script
(
  ${cmd} "${args[@]}" > /dev/null 2>&1
  echo $?
) > ${exit_code_file} &

# If exit code exists and is not 0, exit with that code
exit_code=$(cat ${exit_code_file})
if [[ $exit_code -ne 0 ]]; then
  [[ $quiet -eq 0 ]] && echo "${bold}sway-launch:${reset} ${red}Error:${reset} Command exited with code ${bold}$exit_code${reset}"
  rm -f ${exit_code_file} > /dev/null 2>&1
  exit $exit_code
fi


# wait for the program to launch
# - this is done by checking if the tree has changed
# - skip if --no-wait was provided
waiting_time=0 
printed_message=0
if [[ $wait_for_window -eq 1 ]]; then
  while true; do
    # print message after 5 seconds
    if [[ $waiting_time -gt 5000 && $printed_message -eq 0 ]]; then
      if [[ $quiet -eq 0 ]]; then
        echo "${bold}sway-launch:${reset} The program is taking a long time to launch."
        printed_message=1
      fi
    fi
    new_tree=$(get_tree_info)
    if [[ "$new_tree" != "$old_tree" ]]; then
      # if "window-name" was provided, check if diff contains the string
      if [[ -n "$window_name" ]]; then
        diff=$(diff <(echo "$old_tree") <(echo "$new_tree"))
        if [[ "$diff" == *"$window_name"* ]]; then
          break
        fi
      else
        break
      fi
    fi
    sleep 0.001
    waiting_time=$((waiting_time+1))
  done
fi

[[ $quiet -eq 0 ]] && echo "${bold}sway-launch:${reset} ${green}Done!${reset}"

# If launching from the scratchpad, hide it aftrewards
# - This simulates the UX of application launchers like rofi, but for a
#   terminal running in the scratchpad.
if [[ $hide_scratchpad -eq 1 && $is_scratchpad_focused == "true" ]]; then
  sway-scratchpad-toggle --quiet
  if [[ $? -ne 0 ]]; then
    exit 1
  fi
fi