#!/usr/bin/env sh

# output is to stdout unless explicitly set through -o
OUTPUTF=""

# set fifo input file, according (somewhat) to xdg
[ -n "$SXHKD_FIFO" ] && FIFO="$SXHKD_FIFO"
[ ! -e "$FIFO" ] && FIFO="${XDG_RUNTIME_DIR}"/sxhkd_fifo
[ ! -e "$FIFO" ] && FIFO="${XDG_CACHE_HOME:-$HOME/.cache}"/sxhkd_fifo
[ ! -e "$FIFO" ] && FIFO="$HOME/.sxhkd_fifo"

# set label config file, according (somewhat) to xdg
[ -n "$SXHKD_LABELCONFIG" ] && LABELCONFIG="$SXHKD_LABELCONFIG"
[ ! -f "$LABELCONFIG" ] && LABELCONFIG="${XDG_CONFIG_HOME:-$HOME/.config}"/sxhkd/chain-labels.conf
[ ! -f "$LABELCONFIG" ] && LABELCONFIG="$HOME/.chain-labels.conf"

main() {
  while read -r event; do
    detect_event "$event"
  done <"$FIFO"
}

detect_event() {
  ev="$(echo "$1" | sed -e 's/^H.*$/hotkey/;s/^C.*$/command/;s/^BBegin chain.*$/chainstart/;s/^EEnd chain.*$/chainend/;')"

  case $ev in
  hotkey) ev_hotkey "$(echo "$1" | sed -e 's/^H//')" ;;
  # command) ev_command "$(echo "$1" | sed -e 's/^C//')" ;;
  chainstart) ev_chainstart "$(echo "$1" | sed -e 's/^B//')" ;;
  chainend) ev_chainend "$(echo "$1" | sed -e 's/^E//')" ;;
  *) ;;
  esac
}

send_msg() {
  if [ -n "$OUTPUTF" ]; then
    echo "$1" >"$OUTPUTF"
  else
    echo "$1"
  fi
}

ev_hotkey() {
  LAST_HOTKEY="$1"
}

# compare labels to last hotkey, return mode name
ev_chainstart() {
  [ -z "$LAST_HOTKEY" ] && return 1
  found=$(echo "$LABELS" | sed -e "/$LAST_HOTKEY/!d;s/^\(.\+\):.*$/\1/")
  send_msg "$found"
}

ev_chainend() {
  send_msg ""
}

# TODO add option to also display last command done in chain
# ev_command() {
#   send_msg "command: $1"
# }

# read config from file, remove comments (lines starting with #) and empty lines
read_config() {
  [ -f "$1" ] && LABELS="$(sed -e '/^#/d;/^[[:blank:]]*$/d' <"$1")" || LABELS=""
}

get_help() {
  printf \
    "Usage: sxhkd-chain-labels [-c config file][-o output file][-s input pipe]
    
 By default will take the input from the input pipe (at XDG_RUNTIME_DIR/sxhkd_fifo) and 
 print the current sxhkd chain mode to stdout. That means, sxhkd needs to be started
 with a fifo pipe running, ideally to the XDG_RUNTIME_DIR:

  mkfifo \$XDG_RUNTIME_DIR/sxhkd_fifo && sxhkd -s \$XDG_RUNTIME_DIR/sxhkd_fifo

 When given a key combination which maps to a specific mode, it will print out the name
 of the mode instead. These maps can be passed with -c flag, specifying an options file.
 By default it will look in \$XDG_CONFIG_HOME/sxhkd/sxhkd-chain-labels.conf

 When passed the -o flag it will replace the contents of the file passed in with the 
 current sxhkd chain mode, emptying the file when no mode is active.

 Default lookup places for files, in descending order:
   :input fifo
     \$SXHKD_FIFO (env variable)
     \$XDG_RUNTIME_DIR/sxhkd_fifo
     \$XDG_CACHE_HOME/sxhkd_fifo
     ~/.cache/sxhkd_fifo
     ~/.sxhkd_fifo

   :label configuration
     \$SXHKD_LABELCONFIG (env variable)
     \$XDG_CONFIG_HOME/sxhkd/chain-labels.conf
     ~/.config/sxhkd/chain-labels.conf
     ~/.chain-labels.conf 

 The label configuration file uses the following format:
   mode-name:chain activation combination

 Lines beginning with a # will be ignored. Whitespace is 
 important, sxhkd will, by default, put a single space 
 between any component of the key combination.

 An example file:

   media:super + alt + m
   system:super + backspace

  \n"
}

get_version() {
  printf \
    "%s: 0.1

  fifo input pipe:
    %s
  label configuration file:
    %s
  output:
    %s \n" \
    "$0" \
    "$FIFO" \
    "$LABELCONFIG" \
    "${OUTPUTF:-stdout}"
}

while getopts "vho:s:c:" opt; do
  case "$opt" in
  \?)
    printf "Usage: sxhkd-chain-labels [-c config file][-o output file][-s input pipe]\n"
    exit 0
    ;;
  h)
    get_help
    exit 0
    ;;
  v)
    get_version
    exit 0
    ;;
  o) OUTPUTF="$OPTARG" ;;
  s) FIFO="$OPTARG" ;;
  c) LABELCONFIG="$OPTARG" ;;
  esac
done
shift $((OPTIND - 1))

[ "${1:-}" = "--" ] && shift

# look for default label config
[ -z "$LABELS" ] && read_config "$LABELCONFIG"

main "$@"