#!/bin/sh

# shclip, by yosh
# https://git.unix.dog/yosh/shclip

set -eu
TAB="	"
BN="${0##*/}"

# config file if exists
SHCLIP_CONFIG_DIR="${SHCLIP_CONFIG_DIR:-${XDG_CONFIG_HOME:-$HOME/.config}/shclip}"
. "$SHCLIP_CONFIG_DIR/config"

SHCLIP_MAX_CLIPS="${SHCLIP_MAX_CLIPS:-25}"
SHCLIP_MEMORY_LIMIT="${SHCLIP_MEMORY_LIMIT:-4100}" # memory limit in kb
SHCLIP_ENABLED="${SHCLIP_ENABLED-1}"
SHCLIP_FILTER_ENABLED="${SHCLIP_FILTER_ENABLED-}"
SHCLIP_SYNC_CLIPBOARD="${SHCLIP_SYNC_CLIPBOARD-1}"
SHCLIP_CACHE_PASSWORDS="${SHCLIP_CACHE_PASSWORDS-}"

SHCLIP_TEMP_DIR="${XDG_RUNTIME_DIR:-${TMPDIR:-/tmp}}/shclip-$USER-$DISPLAY"

errecho() { printf '%s\n' "$*" >&2; }
exists() { command -v "$@" >/dev/null 2>&1; }
notify() {
	errecho "$*"
	exists notify-send && notify-send "$*"
	:
}
fail() {
	notify "error: $BN: $*"
	exit 1
}

cleanup() {
	trap 'exit' INT HUP QUIT TERM EXIT
	set +e
	rmdir "$SHCLIP_TEMP_DIR/lock"
	kill "$clipnotify_pid"
	exit
}

toggle() {
	if [ -z "$SHCLIP_ENABLED" ]; then
		SHCLIP_ENABLED=1
		notify "shclip enabled!"
	else
		SHCLIP_ENABLED=""
		notify "shclip disabled!"
	fi
	kill "$clipnotify_pid"
}

filter_toggle() {
	if [ -z "$SHCLIP_FILTER_ENABLED" ]; then
		SHCLIP_FILTER_ENABLED=1
		notify "shclip filter enabled!"
	else
		SHCLIP_FILTER_ENABLED=""
		notify "shclip filter disabled!"
	fi
	kill "$clipnotify_pid"
}

# setup process
setup() {
	mkdir -p -m 700 "$SHCLIP_TEMP_DIR"

	# test the temp/lock directory
	if mkdir -m 700 "$SHCLIP_TEMP_DIR/lock"; then
		errecho "successfully acquired lock"
	else
		fail "cannot acquire lock. is another instance running?
if not, delete the directory at $SHCLIP_TEMP_DIR/lock"
	fi

	trap 'cleanup' INT HUP QUIT TERM EXIT
	trap 'toggle' USR1
	trap 'filter_toggle' USR2

	BUFFER="$SHCLIP_TEMP_DIR/buffer"
	ORDER="$SHCLIP_TEMP_DIR/order"
	PID="$SHCLIP_TEMP_DIR/pid"
	printf '%s' $$ > "$PID"

	# create ORDER file
	if [ ! -f "$ORDER" ]; then
		digits=${#SHCLIP_MAX_CLIPS}
		i=1
		while [ "$i" -le "$SHCLIP_MAX_CLIPS" ]; do
			printf "%0${digits}d.clip\n" "$i"
			i="$((i + 1))"
		done > "$ORDER"
	fi
}

# reclip top of the stack
reclip() {
	n="$(head -n 1 "$ORDER")"
	mime="$(file -bi "$SHCLIP_TEMP_DIR/$n")"
	xclip -sel clipboard -t "${mime%%;*}" "$SHCLIP_TEMP_DIR/$n"
}
updateclip() {
	# some good variables to have
	firstind="$(head -n 1 "$ORDER")" # top of clip stack
	lastind="$(tail -n 1 "$ORDER")" # bottom of stack
	targets="$(xclip -sel clipboard -t TARGETS -o)" || { reclip && return 0; } # targets of clip, will also return if clip doesn't exist
	# this covers if we've copied a file in a GUI file manager
	# probably don't want that in your history
	case "$targets" in
		*gnome-copied-files*) return 0 ;;
		*image/png*) xclip -sel clipboard -t image/png -o > "$BUFFER" ;;
		*x-kde-passwordManagerHint*)
			if [ -n "$SHCLIP_CACHE_PASSWORDS" ]; then
				xclip -sel clipboard -t x-kde-passwordManagerHint -o > "$BUFFER"
			else return 0
			fi
			;;
		*) xclip -sel clipboard -o > "$BUFFER" ;;
	esac

	# check if clip exceeds memory limit
	sz="$(du -k "$BUFFER")"
	if [ "${sz%%${TAB}*}" -gt "$SHCLIP_MEMORY_LIMIT" ]; then
		notify 'clip exceeds memory threshold! not caching...'
		rm -f "$BUFFER"
		return 0
	fi

	# buffer mime matching
	mime="$(file -bi "$BUFFER")"
	case "${mime%%;}" in
		inode/x-empty*) # empty clip
			reclip
			return 0
			;;
		text*)
			# apply text filters
			[ -n "$SHCLIP_FILTER_ENABLED" ] && [ -f "$SHCLIP_CONFIG_DIR/filter.sh" ] && \
				sh "$SHCLIP_CONFIG_DIR/filter.sh" < "$BUFFER" | diff "$BUFFER" - | patch "$BUFFER"
			xclip -sel clipboard "$BUFFER"
			[ -n "$SHCLIP_SYNC_CLIPBOARD" ] && xclip -sel primary "$BUFFER"
			;;
		*) ;;
	esac

	# top of stack & buffer are identical, don't cache
	if cmp "$BUFFER" "$SHCLIP_TEMP_DIR/$firstind" >/dev/null 2>&1; then
		errecho 'duplicate clip! not caching...'
		rm -f "$BUFFER"
		return 0
	fi

	mv -f "$BUFFER" "$SHCLIP_TEMP_DIR/$lastind"

	# edit order file in place
	ed -s "$ORDER" <<-EOF
		${SHCLIP_MAX_CLIPS}m0
		wq
	EOF
}

[ -z "${DISPLAY:-}" ] && fail 'Cannot find $DISPLAY. Is your X server running?'

# parse options
while getopts :hn:f:s:p:c:m OPT; do
	case $OPT in
		h) cat >&2 <<-EOF
				please refer to README for general usage:
				  https://git.unix.dog/yosh/shclip

				options that exist (overrides config file):
				  -h       	    show this help
				  -n <on|off>   enable/disable shclip on startup
				  -f <on|off>   enable/disable filtering
				  -s <on|off>   enable/disable syncing clipboard to primary
				  -p <on|off>   enable/disable caching kde passwords
				  -c <num>      set max clips to <num> clips
				  -m <num>      set memory limit to <num> kibibytes
			EOF
			;;
		n) [ "$OPTARG" = "on" ] && SHCLIP_ENABLED=1 || SHCLIP_ENABLED="" ;;
		f) [ "$OPTARG" = "on" ] && SHCLIP_FILTER_ENABLED=1 || SHCLIP_FILTER_ENABLED="" ;;
		s) [ "$OPTARG" = "on" ] && SHCLIP_SYNC_CLIPBOARD=1 || SHCLIP_SYNC_CLIPBOARD="" ;;
		p) [ "$OPTARG" = "on" ] && SHCLIP_CACHE_PASSWORDS=1 || SHCLIP_CACHE_PASSWORDS="" ;;
		c) SHCLIP_MAX_CLIPS=$OPTARG ;;
		m) SHCLIP_MEMORY_LIMIT=$OPTARG ;;
		*) fail "$BN: unknown option: -$OPTARG" ;;
	esac
done

setup
while
	if [ -z "$SHCLIP_ENABLED" ]; then
		:
	else
		updateclip
	fi
do
	set +e
	clipnotify -s clipboard &
	clipnotify_pid=$!
	wait
	set -e
done