#!/bin/bash


# (1) Init.
#--------------------------------------------------------#
# (1) Get current absolute dir
ROOT=$(dirname `realpath $0`);

# (2) Check argc
test $# -lt 2 && echo -e "error: too fewarguments\n\n\e[1mUSAGE\e[0m\n\tpool <key> <port>\n\n\e[1mARGUMENTS\e[0m\n\t<key>\tThe key of the pool (client must match it)\n\t<port>\tTo port to listen to\n" && exit 1;

# (3) Check @PORT range #
MIN_PORT=1024;
MAX_PORT=49151;
test "$2" -gt "$MAX_PORT" -o "$2" -lt "$MIN_PORT" && echo "error: <port> must be between $MIN_PORT and $MAX_PORT" && exit 1;

# (4) Set argument explicit names #
POOL_KEY="$1";
POOL_PORT="$2";

# (5) init logger variables #
declare -A INPUT_PID; # will contain each bind-input pid




# (2) Set exit management
#--------------------------------------------------------#
# (1) On-Exit routine #
on_exit(){

	echo "killing 'bind-input' sub processes";

	for logger_name in "${!INPUT_PID[@]}"; do

		# kill each logger input
		kill -9 ${INPUT_PID[$logger_name]} 2>/dev/null;
		$INPUT_PID[$logger_name]="";

	done;

	echo "killing 'pool' input listener";
	kill -9 $POOL_PID 2>/dev/null;

	echo "killing 'pool' loop";
	kill -9 $LOOP_PID 2>/dev/null;

}

trap "on_exit;" INT KILL;





# (3) Launch pool listener
#--------------------------------------------------------#
# (1) Bind-input #
echo "(.) listen $POOL_PORT";
$ROOT/bind-input pool $POOL_PORT&
POOL_PID=$?;



# (4) Launch pool manager
#--------------------------------------------------------#
# infinite listener
while sleep 1; do

	# Listen on port @POOL_PORT
	MSG=`$ROOT/read pool`;

	# Do nothing if empty msg or invalid format
	test -z "$MSG" && continue;
	echo -n "$MSG" | grep -vP '^([^:]+):([^:]+):([^:]+):([^:]+)$' >/dev/null && echo '     /!\\ invalid format' && continue;

	# Extract ID - PORT
	KEY="`echo -ne \"$MSG\" | sed 's/^\(.\+\):\(.\+\):\(.\+\):\(.\+\)$/\1/'`";
	LOGGER_NAME="`echo -ne \"$MSG\" | sed 's/^\(.\+\):\(.\+\):\(.\+\):\(.\+\)$/\2/'`";
	LOGGER_HOST="`echo -ne \"$MSG\" | sed 's/^\(.\+\):\(.\+\):\(.\+\):\(.\+\)$/\3/'`";
	LOGGER_PORT="`echo -ne \"$MSG\" | sed 's/^\(.\+\):\(.\+\):\(.\+\):\(.\+\)$/\4/'`";

	# if ID does not match
	test "$KEY" != "$POOL_KEY" && echo '    /!\\ wrong id' && continue;

	# create new listening socket
	echo "    (.) binding input for logger@$LOGGER_NAME ($LOGGER_HOST:$LOGGER_PORT)";

	# Find an available port
	PORT="$MIN_PORT";

	while true; do

		# ignore pool port
		test "$PORT" = "$POOL_PORT" && PORT="`expr $PORT + 1`" && continue;

		# if port not in use -> use it
		ss -tl4 "( sport = :$PORT )" | grep "$PORT" >/dev/null 2>&1 || break;

		# else try next port (+1)
		PORT="`expr $PORT + 1`";

	done;

	# Bind-input for the logger at the free port found
	$ROOT/bind-input $LOGGER_NAME $PORT&

	# if already an input for this logger -> kill it
	test ! -z "${INPUT_PID[$LOGGER_NAME]}" && kill -9 ${INPUT_PID[$LOGGER_NAME]};

	# Store bind-input PID
	INPUT_PID[LOGGER_NAME]=$!;

	# Notify that input is active to MASTER
	bash -c "exec 4<>/dev/tcp/$LOGGER_HOST/$LOGGER_PORT; echo -n \"$PORT\" >&4;";

done&

LOOP_PID=$!;

wait $LOOP_PID;