#!/bin/sh

cd "$(dirname "$0")" || exit 1
root=$(pwd -P) || exit 1
uid=$(id -u) || exit 1

if test "$#" -eq 0; then
	set --
	for font in \
		/usr/share/fonts/TTF/DejaVuSans.ttf \
		/usr/share/fonts/TTF/Jigmo.ttf \
		/usr/share/fonts/TTF/Jigmo2.ttf \
		/usr/share/fonts/noto/NotoSansCJK-Regular.ttc
	do
		if test -f "$font"; then
			set -- "$@" "$font"
		fi
	done
	if test "$#" -eq 0; then
		echo "run.sh: no default font found; pass a font file" >&2
		exit 1
	fi
fi

if ! test -x ./strans; then
	echo "run.sh: ./strans is not executable; run make first" >&2
	exit 1
fi
if test -n "${DISPLAY-}" && ! test -x xim/strans-xim; then
	echo "run.sh: xim/strans-xim is not executable; run make first" >&2
	exit 1
fi

case ${XDG_RUNTIME_DIR-} in
/)	ipc=/strans.sock ;;
/*/)	ipc=${XDG_RUNTIME_DIR}strans.sock ;;
/*)	ipc=${XDG_RUNTIME_DIR}/strans.sock ;;
*)	ipc=/tmp/strans.$(id -u) ;;
esac
if test -n "${XDG_CONFIG_HOME-}"; then
	busdir=$XDG_CONFIG_HOME/ibus/bus
elif test "${HOME+x}" = x; then
	busdir=$HOME/.config/ibus/bus
else
	echo "run.sh: HOME or XDG_CONFIG_HOME is required for IBus discovery" >&2
	exit 1
fi

strans_pid=
xim_pid=
old_daemon_pid=
old_daemon_start=
old_launcher_pid=
old_launcher_start=

cleanup()
{
	status=$?
	trap - 0 1 2 15
	if test -n "$xim_pid"; then
		kill "$xim_pid" 2>/dev/null || :
		wait "$xim_pid" 2>/dev/null || :
		xim_pid=
	fi
	if test -n "$strans_pid"; then
		kill "$strans_pid" 2>/dev/null || :
		wait "$strans_pid" 2>/dev/null || :
		strans_pid=
	fi
	exit "$status"
}

ibusready()
{
	for address in "$busdir"/*; do
		test -f "$address" || continue
		foundpid=
		foundaddress=
		while IFS= read -r line; do
			case $line in
			IBUS_DAEMON_PID="$strans_pid")	foundpid=1 ;;
			IBUS_ADDRESS=unix:abstract=strans-"$strans_pid",*)	foundaddress=1 ;;
			esac
		done <"$address"
		if test -n "$foundpid" && test -n "$foundaddress"; then
			return 0
		fi
	done
	return 1
}

procuid()
{
	{
		while IFS=' 	' read -r key real effective saved filesystem rest; do
			case $key in
			Uid:)
				test "$real" = "$effective" &&
				    test "$real" = "$saved" &&
				    test "$real" = "$filesystem" || return 1
				printf '%s\n' "$real"
				return 0
				;;
			esac
		done <"/proc/$1/status"
	} 2>/dev/null
	return 1
}

procparent()
{
	{
		while IFS=' 	' read -r key value rest; do
			case $key in
			PPid:)	printf '%s\n' "$value"; return 0 ;;
			esac
		done <"/proc/$1/status"
	} 2>/dev/null
	return 1
}

procstart()
{
	proc_stat=
	{ IFS= read -r proc_stat <"/proc/$1/stat"; } 2>/dev/null || return 1
	proc_stat=${proc_stat##*) }
	set -- $proc_stat
	test "$#" -ge 20 || return 1
	test "$1" != Z || return 1
	printf '%s\n' "${20}"
}

sameproc()
{
	test -n "$2" || return 1
	proc_now=$(procstart "$1") || return 1
	test "$proc_now" = "$2"
}

listeninginode()
{
	listener_inode=
	listener_count=0
	{
		while IFS=' 	' read -r num ref proto flags type state inode path; do
			if test "$flags" = 00010000 && test "$type" = 0001 &&
			   test "$state" = 01 && test "$path" = "$1"; then
				listener_inode=$inode
				listener_count=$((listener_count + 1))
			fi
		done </proc/net/unix
	} 2>/dev/null
	test "$listener_count" -eq 1 || return 1
	printf '%s\n' "$listener_inode"
}

socketowned()
{
	socket_inode=$(listeninginode "$2") || return 1
	for socket_fd in "/proc/$1/fd"/*; do
		test "$(readlink "$socket_fd" 2>/dev/null)" = \
		    "socket:[$socket_inode]" && return 0
	done
	return 1
}

validdaemon()
{
	test "$(procuid "$1")" = "$uid" || return 1
	test "$(readlink "/proc/$1/cwd" 2>/dev/null)" = "$root" || return 1
	daemon_exe=$(readlink "/proc/$1/exe" 2>/dev/null) || return 1
	case $daemon_exe in
	"$root/strans"|"$root/strans (deleted)")	;;
	*)	return 1 ;;
	esac
	test -S "$ipc" || return 1
	socketowned "$1" "$ipc" || return 1
	socketowned "$1" "@strans-$1"
}

finddaemon()
{
	old_daemon_pid=
	old_daemon_start=
	for address in "$busdir"/*; do
		test -f "$address" || continue
		address_pid=
		address_ok=
		while IFS= read -r line; do
			case $line in
			IBUS_DAEMON_PID=*)	address_pid=${line#IBUS_DAEMON_PID=} ;;
			esac
		done <"$address"
		case $address_pid in
		''|*[!0-9]*)	continue ;;
		esac
		while IFS= read -r line; do
			case $line in
			IBUS_ADDRESS=unix:abstract=strans-"$address_pid",*)
				address_ok=1 ;;
			esac
		done <"$address"
		test -n "$address_ok" || continue
		validdaemon "$address_pid" || continue
		address_start=$(procstart "$address_pid") || continue
		validdaemon "$address_pid" || continue
		old_daemon_pid=$address_pid
		old_daemon_start=$address_start
		return 0
	done
	return 1
}

findlauncher()
{
	launcher_env=$({ tr '\000' '\n' <"/proc/$old_daemon_pid/environ"; } \
	    2>/dev/null) || return 1
	old_launcher_pid=$(printf '%s\n' "$launcher_env" |
	    sed -n 's/^STRANS_RUN_OWNER_PID=//p')
	old_launcher_start=$(printf '%s\n' "$launcher_env" |
	    sed -n 's/^STRANS_RUN_OWNER_START=//p')
	case $old_launcher_pid in
	''|*[!0-9]*|0|1|"$$")	return 1 ;;
	esac
	case $old_launcher_start in
	''|*[!0-9]*)	return 1 ;;
	esac
	test "$(procuid "$old_launcher_pid")" = "$uid" || return 1
	test "$(readlink "/proc/$old_launcher_pid/cwd" 2>/dev/null)" = "$root" ||
		return 1
	sameproc "$old_launcher_pid" "$old_launcher_start" || return 1
	sameproc "$old_daemon_pid" "$old_daemon_start" || return 1
	test "$(procparent "$old_daemon_pid")" = "$old_launcher_pid" || return 1
	return 0
}

stoplauncher()
{
	sameproc "$old_daemon_pid" "$old_daemon_start" || return 1
	test "$(procparent "$old_daemon_pid")" = "$old_launcher_pid" || return 1
	sameproc "$old_launcher_pid" "$old_launcher_start" || return 1
	kill "$old_launcher_pid" 2>/dev/null || return 1
	echo "run.sh: stopping previous launcher $old_launcher_pid (daemon $old_daemon_pid)"

	stop_attempt=0
	while test "$stop_attempt" -lt 10; do
		if ! sameproc "$old_launcher_pid" "$old_launcher_start" &&
		   ! sameproc "$old_daemon_pid" "$old_daemon_start"; then
			return 0
		fi
		stop_attempt=$((stop_attempt + 1))
		if test "$stop_attempt" -lt 10; then
			sleep 1
		fi
	done
	echo "run.sh: previous launcher did not stop within 10 seconds" >&2
	return 1
}

trap cleanup 0
trap 'exit 129' 1
trap 'exit 130' 2
trap 'exit 143' 15

launcher_start=$(procstart "$$") || {
	echo "run.sh: cannot read launcher process identity from /proc" >&2
	exit 1
}

if finddaemon; then
	if ! findlauncher; then
		echo "run.sh: daemon $old_daemon_pid owns the current endpoints but has no" >&2
		echo "run.sh: live run.sh owner; leaving it untouched (stop it once, then retry)" >&2
		exit 1
	fi
	if ! stoplauncher; then
		echo "run.sh: previous launcher did not stop cleanly; refusing to start another daemon" >&2
		exit 1
	fi
fi

STRANS_RUN_OWNER_PID=$$ STRANS_RUN_OWNER_START=$launcher_start \
	./strans map "$@" &
strans_pid=$!

attempt=0
while test "$attempt" -lt 10; do
	if test -S "$ipc" && ibusready; then
		break
	fi
	if ! kill -0 "$strans_pid" 2>/dev/null; then
		wait "$strans_pid"
		status=$?
		strans_pid=
		if test "$status" -eq 0; then
			status=1
		fi
		echo "run.sh: daemon exited before publishing IPC and IBus endpoints" >&2
		exit "$status"
	fi
	attempt=$((attempt + 1))
	if test "$attempt" -lt 10; then
		sleep 1
	fi
done
if test "$attempt" -eq 10; then
	echo "run.sh: daemon did not publish IPC and IBus endpoints within 10 seconds" >&2
	exit 1
fi

echo "run.sh: daemon $strans_pid is ready"
if test -z "${DISPLAY-}"; then
	echo "run.sh: DISPLAY is unset; XIM will not be started"
	wait "$strans_pid"
	status=$?
	strans_pid=
	exit "$status"
fi

xim/strans-xim &
xim_pid=$!
echo "run.sh: started XIM $xim_pid; press Ctrl-C to stop both processes"
wait "$xim_pid"
status=$?
xim_pid=
exit "$status"