[sxhkd] Add script to show current sxhkd mode

Script can be used in a statusbar or otherwise and will return the
currently active sxhkd mode. Look into the README for further
explanation.

sxhkd/.local/bin/sxhkd-chain-labels

@@ -0,0 +1,156 @@
+#!/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 "$@"