kak-shell

#!/bin/sh

# Environment variables
XDG_DATA_HOME=${XDG_DATA_HOME:-~/.local/share}
KAKOUNE_CONNECT_SCRIPT=$XDG_DATA_HOME/kak/connect/script.sh

main() {
  # Interactively set the Kakoune session.
  # Support to connect to a session by its index.
  if test -z "$KAKOUNE_SESSION"; then
    kak_session_list=$(kak -l | sort)
    echo 'Kakoune sessions:'
    echo_n "$kak_session_list" | number_lines
    echo '+ create new session'
    echo_n 'Kakoune session:'
    read kak_session
    if is_number "$kak_session"; then
      kak_session=$(echo "$kak_session_list" | get_line "$kak_session")
    fi
    KAKOUNE_SESSION=$kak_session
  fi
  # Exit if the Kakoune session is empty.
  if test -z "$KAKOUNE_SESSION"; then
    exit 1
  fi
  # Start an interactive shell.
  start "$@"
}

start() {
  # Start the session in daemon mode.
  setsid kak -s "$KAKOUNE_SESSION" -d < /dev/null > /dev/null 2>&1
  connect "$@"
}

connect() {
  # Alias terminal to connect-detach and enter in the connect environment.
  # connect-detach allows to run CLI apps in the same terminal window.
  kak -c "$KAKOUNE_SESSION" -e "
    connect-set-detach global
    connect-terminal $@
  "
  # Attach the connect terminal command.
  # Act as a “boot loader”.
  if test -e "$KAKOUNE_CONNECT_SCRIPT"; then
    attach
  fi
}

attach() {
  mv "$KAKOUNE_CONNECT_SCRIPT" "$KAKOUNE_CONNECT_SCRIPT~"
  sh "$KAKOUNE_CONNECT_SCRIPT~"
  rm -f "$KAKOUNE_CONNECT_SCRIPT~"
}

# Utilities

echo() {
  printf '%s\n' "$*"
}

echo_n() {
  printf '%s' "$*"
}

is_number() {
  test "$1" -eq "$1" 2> /dev/null
}

number_lines() {
  awk '{ print NR, $0 }'
}

get_line() {
  sed "${1}q;d"
}

main "$@"