#!/bin/zsh
use config --group remote

DEPENDENCIES+=(timeout ssh)
#####################################################################

USAGE__options='
	-n, --name                session name to test
	-s, --connection-string   explicit session host / ssh connection string to test
	-t, --maximum-timeout     maximum connection timeout before failure (in seconds)
	-c, --command             testing command; performs echo by default
'

USAGE__description='
	Tests whether you can connect to a particular session or
	host string.
'

#####################################################################

MAIN() {
	local CONNECTION_STRING REMOTE_NAME
	local TIMEOUT_SECONDS=3
	local COMMAND='echo OK &>/dev/null'
	while [[ $# -gt 0 ]]
	do
		case $1 in
			-n | --name )
				REMOTE_NAME=$2
				CONNECTION_STRING=$(REMOTE__GET_CONNECTION_STRING $REMOTE_NAME)
				shift 1
				;;
			-s | --connection_string ) 
				CONNECTION_STRING="$2"
				shift 1
				;;
			-t | --maximum-timout )
				TIMEOUT_SECONDS=$2
				[[ $TIMEOUT_SECONDS -gt 0 ]] \
					|| ERROR "invalid timeout seconds '$TIMEOUT_SECONDS'"
				shift 1
				;;
			-c | --command )
				COMMAND=$2
				shift 1
				;;
			* ) ERROR "unrecognized argument '$1'" ;;
		esac
		shift 1
	done

	[ $CONNECTION_STRING ] \
		|| ERROR "unable to determine connection string"

	CHECK_ERRORS

	##########################################
	
	case $CONNECTION_STRING in
		localhost | $USER@localhost )
			CONNECTION_TEST() { return 0; } # current user on local machine can always connect
			;;
		* ) 
			CONNECTION_TEST() {
				[ $REMOTE_NAME ] && {
					[[ $(REMOTE__QUERY_CONNECTION .sessions.$REMOTE_NAME) =~ false ]] && {
						return 1
					}
				}
				local REMOTE_ARGS=()
				REMOTE_ARGS+=($(REMOTE__GET_SSH_ARGS --type ssh --no-tty $REMOTE_NAME))
				REMOTE_ARGS+=(-o BatchMode=yes)
				DEBUG "attempting\nssh ${REMOTE_ARGS[@]} \"$CONNECTION_STRING\" \"$COMMAND\""
				timeout $TIMEOUT_SECONDS ssh ${REMOTE_ARGS[@]} "$CONNECTION_STRING" "$COMMAND" >&2
			}
			;;
	esac

	[ $REMOTE_NAME ] || REMOTE_NAME=explicit
	STATUS "testing connection $CONNECTION_STRING ($REMOTE_NAME)" \
		&& CONNECTION_TEST \
		&& SUCCESS "successfully connected to '$CONNECTION_STRING' ($REMOTE_NAME)" \
		|| ERROR "connection to '$CONNECTION_STRING ($REMOTE_NAME)' failed" \
}