#!/bin/bash
# Comfortable Swipe

# turn on errors per line
set -e

DIR="$(dirname "$0")"
BASENAME="$(basename "$0")"
VERSION="$(cat "$DIR/VERSION" | tr -d '[:space:]')"  # note: this will be hardcoded upon install



# show help
function help {
cat <<EOF
Usage: $BASENAME [--help|--version] <command> [<args>]

    -h, --help        show this help text
    -v, --version     print the program version

Commands:
    start
      starts 3/4-finger gesture service

    stop
      stops 3/4-finger gesture service

    restart
      restarts 3/4-finger gesture service

    autostart [<on|off|toggle|status|path>]
      toggle to automatically run on startup automatically run on startup (toggleable)

    buffer
      parses output of libinput debug-events

    help
      shows the help dialog

    config [<get|set|delete|list|keys|path>...]
      shows the location of the config file

    debug
      logs raw output from input events taken from libinput

    status
      checks status of program and autostart

Report bugs to https://github.com/Hikari9/comfortable-swipe/issues/new
EOF
}


# start comfortable-swipe
# internally pipes debug text to the buffer
function start {
  debug | buffer
}


# stop running comfortable-swipe commands (except self)
function stop {
  function stop_name {
    pgrep -f "${1:?}" | fgrep -v $$ | xargs kill --
  }
  stop_name "$BASENAME"
  stop_name "$(which comfortable-swipe)"
  stop_name "$(which comfortable-swipe-buffer)"
}


# restart comfortable swipe
function restart {
  stop > /dev/null 2>&1
  # restart the server in the background
  nohup "$BASENAME" start 0<&- &>/dev/null &
}


# show debug text
# internally just calls libinput debug-events
function debug {
  if command -v libinput-debug-events > /dev/null 2>&1; then
    local DEBUGEVENTS="libinput-debug-events"
  else
    local DEBUGEVENTS="libinput debug-events"
  fi
  stdbuf -oL -e0 $DEBUGEVENTS 2> >(fgrep -v 'double tracking')
}


# parse input from a buffer
# internally calls comfortable-swipe-main.cpp, which is
# installed as: /usr/local/bin/ comfortable-swipe-buffer
function buffer {
  exec comfortable-swipe-buffer "$@"
}


# get location of configuration file
function config {
  local CONFIG="$HOME/.config/comfortable-swipe.conf"
  local KEYS="left3|left4|right3|right4|up3|up4|down3|down4|threshold|mouse3|mouse4"
  local DEPRECATED="hold3|hold4"
  local USAGE="Usage: $BASENAME config [get|set|delete|list|keys|path]..."
  # show path to config
  function path {
    echo "$CONFIG"
  }
  # get all keys from config, without comments
  # and show only last among duplicates
  function list {
    # dispatch subcommands
    if [[ $# -eq 0 ]]; then
      # no options; just show path
      tac "$CONFIG" |\
        sed -E "s/[#;].*//g" |\
        egrep '\s+' |\
        tr -d ' ' |\
        egrep "^($KEYS|$DEPRECATED)=" |\
        awk '!a[$1]++' |\
        tac |\
        sed 's/=/ = /g'
    else
      # filter list to match arguments as pattern
      local pattern="$1"
      for arg in "${@:2}"; do
        pattern="$pattern|$arg"
      done
      list | egrep "($pattern)[^=]* ="
    fi
  }
  # get a list of all valid keys, one per line
  function keys {
    echo "$KEYS" | sed 's/|/\n/g'
  }
  # Get a specific key in the config
  # Usage: comfortable-swipe config get <key>
  function get {
    # helper function to print usage
    function usage {
      echo "Usage: $BASENAME config get <KEY>"
      echo -n "Keys: "
      echo "$KEYS" | sed 's/|/, /g'
    }
    # no next argument: show list
    if [[ $# -eq 0 ]]; then
      list
      exit $?
    fi
    local KEY="$1"
    # check if key is valid
    if ! [[ "$KEY" =~ ^($KEYS|$DEPRECATED)$ ]]; then
      echo "'$KEY' is an invalid key" >&2
      echo >&2
      usage >&2
      echo >&2
      echo "If you want to filter keys, you can instead try:" >&2
      echo >&2
      echo "    $BASENAME config list $@"
      echo >&2
      exit 1
    fi
    # get key from config file
    list | fgrep -m1 "$KEY =" | sed -E "s/^$KEY = //"
  }
  # Deletes a key in the config
  function delete {
    # helper function to print usage
    function usage {
      echo "Usage: $BASENAME config delete [<KEYS>...]"
    }
    # no next argument: show help
    if [[ $# -eq 0 ]]; then
      echo "Key is required!" >&2
      # no key; show usage
      usage >&2
      exit 1
    fi
    local DELETE="$(list "$@")"
    # check if there is something to delete
    if [[ -z "$DELETE" ]]; then
      echo "No config entry to delete" >&2
      exit 1
    else
      echo "Deleted:"
      echo "$DELETE"
      local RESULT="$(egrep -v "^\\s*($(echo "$DELETE" | awk '{print $1}' | paste -s -d '|'))\\s*=" "$CONFIG")"
      echo "$RESULT" > "$CONFIG"
      # restart comfortable-swipe
      restart
    fi
  }
  # Set a specific key in the config
  # Usage: comfortable-swipe config get <key>
  function set {
    # helper function to print usage
    function usage {
      echo "Usage: $BASENAME config set <KEY> [=] <VALUE>"
      echo -n "Valid keys: "
      echo "$KEYS" | sed 's/|/, /g'
    }
    # no next argument: show help
    if [[ $# -eq 0 ]]; then
      echo "Key is required!" >&2
      echo >&2
      # no key; show usage
      usage >&2
      exit 1
    fi
    # parse key and value option
    local KEYVALUE="${@:1}"
    local KEY=
    local VALUE=
    case "$KEYVALUE" in
      *=*)
        # key has equal sign, we split it
        KEY="${KEYVALUE%%=*}"
        VALUE="${KEYVALUE#*=}"
        ;;
      *)
        # default: just get from next arguments combined
        if [[ $# -eq 1 ]]; then
          echo "Value is required!" >&2
          usage >&2
          echo >&2
          echo "If you want to set value to blank, explicitly pass a blank string:" >&2
          echo >&2
          echo "  $BASENAME config set $@ \"\"" >&2
          echo >&2
          echo "Or delete explicitly:" >&2
          echo >&2
          echo "  $BASENAME config delete $1"
          echo >&2
          exit 1
        fi
        KEY="$1"
        VALUE="${@:2}"
        ;;
    esac
    # trim leading and trailing spaces from key and value
    KEY="$(echo "$KEY" | awk '{$1=$1};1')"
    VALUE="$(echo "$VALUE" | awk '{$1=$1};1')"
    # check if key is valid
    if ! [[ "$KEY" =~ ^($KEYS|$DEPRECATED)$ ]]; then
      echo "'$KEY' is an invalid key" >&2
      echo >&2
      usage
      exit 1
    fi
    # if the key is present in the config, perform a replace
    # replace the last value from the config with the given key
    if list | grep -P "^\Q$KEY =" > /dev/null 2>&1; then
      # apply sed to keep our formatting
      # \\1 - keep any kind of indentation
      # \\2 - keep any comments after the value (with the whitespace instact)
      local RESULT="$(tac "$CONFIG" |\
        sed -E "s/^(\\s*)$KEY\\s*=\\s*(\?!(\\s*[#;]))*(.*)\$/\\1$KEY = $VALUE\\2/1" |\
        tac)"
      # make sure we separate piping from outputing
      echo "$RESULT" > "$CONFIG"
    else
      # otherwise, key is not present so we simply append
      echo "$KEY = $VALUE" >> "$CONFIG"
    fi
    # show newly set value
    echo "$KEY = $(get "$KEY")"
    restart
  }
  # dispatch subcommands
  if [[ $# -eq 0 ]]; then
    # no options; just show path
    path
  elif declare -f "$1" >/dev/null 2>&1; then
    # invoke subcommand function, passing arguments through
    # TODO: unset all nonlocal functions
    "$@" # same as "$1" "$2" "$3" ... for full argument list
  else
    echo "Error: function $1 not recognized" >&2
    echo "$USAGE" >&2
    exit 1
  fi
}


# enable or disable autostart
# you can also set manually by running: gnome-session-properties
function autostart {
  # path to autostart files
  local AUTOSTART="$HOME/.config/autostart/comfortable-swipe.desktop"
  local ENABLED="X-GNOME-Autostart-enabled"
  # show autostart file path
  function path {
    echo "$AUTOSTART"
  }
  # echo autostart status: ON, OFF, MISSING, INVALID
  function status {
    if [[ ! -f "$AUTOSTART" ]]; then
      echo "MISSING"
    elif fgrep "$ENABLED=true" < "$AUTOSTART" > /dev/null; then
      echo "ON"
    elif fgrep "$ENABLED=false" < "$AUTOSTART" > /dev/null; then
      echo "OFF"
    else
      echo "INVALID"
    fi
  }
  # enable autostart
  function on {
    sed -i "s/$ENABLED=false/$ENABLED=true/" "$AUTOSTART"
    echo "Autostart switched on"
  }
  # disable autostart
  function off {
    sed -i "s/$ENABLED=true/$ENABLED=false/" "$AUTOSTART"
    echo "Autostart switched off"
  }
  # toggle to opposite autostart status
  function toggle {
    [[ $(status) = ON ]] && off || on
  }
  # dispatch subcommands
  if [[ $# -eq 0 ]]; then
    # default behavior is to toggle
    toggle
  elif declare -f "$1" >/dev/null 2>&1; then
    # invoke subcommand function, passing arguments through
    # TODO: unset all nonlocal functions
    "$@" # same as "$1" "$2" "$3" ... for full argument list
  else
    echo "Function $1 not recognized" >&2
    echo "Usage: $BASENAME autostart [on|off|toggle|status|path]" >&2
    exit 1
  fi
}


# verbosely show comfortable-swipe status
function status {
  # TODO: show configuration status as well
  echo "Autostart is $("$BASENAME" autostart status)"
  if pgrep -f "$BASENAME" | fgrep -v $$ > /dev/null 2>&1; then
    echo "comfortable-swipe program is RUNNING"
  else
    echo "comfortable-swipe program is STOPPED"
  fi
}


####################
# COMMAND OPTIONS  #
####################
for i in "$@"; do
case $i in
  -h | --help) # eagerly show help
    help
    exit 0
  ;;
  -v | --version) # eagerly print version
    echo "comfortable-swipe $VERSION"
    exit 0
  ;;
  *) # unknown option
    if [[ "$i" == -* ]]; then
      echo "Unknown option: $i" >&2
      exit 1
    fi
  ;;
esac
done

# dispatch subcommands
if [[ $# -eq 0 ]]; then
  # no options; just show help
  help
elif declare -f "$1" >/dev/null 2>&1; then
  # invoke subcommand function, passing arguments through
  # TODO: unset all nonlocal functions
  "$@" # same as "$1" "$2" "$3" ... for full argument list
else
  echo "Error: function $1 not recognized" >&2
  echo "Usage: $BASENAME [--help|--version] [start|stop|restart|config|autostart|buffer|debug|status] [<args>]" >&2
  exit 1
fi