#!/bin/sh

##
##        === gosher ===
##
##  gosher is a simple gopher server in a POSIX shell script:
##
##     $ ./gosher [<PORT> [<GOPHERDIR>]
##
##  If PORT is not specified, the default is 70. If GOPHERDIR is not
##  specified, "./" is assumed
##
##  
##  (c) 2018 Vincenzo 'KatolaZ' Nicosia <katolaz@freaknet.org>
##  
##

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

##
## If the script is called with basename "gosher", launch the netcat
## server...
##

NETCAT=netcat
OPREFIX=/tmp/outf_
IPREFIX=/tmp/inf_

##DEBUG=
DEBUG=yes


## function
cleanup(){
	[ -p "${OPREFIX}$$" ] && rm -f ${OPREFIX}$$
	[ -p "${IPREFIX}$$" ] && rm -f ${IPREFIX}$$
	exit 1

}

MYNAME=$(basename $0)

if [ -z "${MYNAME#gosher}" ]; then 
	## we are called as gosher -- launch the server

	PORT=${1:-70}
	GOPHERDIR=${2:-"./"}
	
	trap cleanup 0 HUP INT TRAP TERM QUIT
	
       	OUTF=${OPREFIX}$$
	INF=${IPREFIX}$$
	mkfifo -m 600 $OUTF $INF
	while [ 1 -eq 1 ]; do
		./gosher_serve ${GOPHERDIR} <$INF >$OUTF &
		${NETCAT} -vv -l -p ${PORT} >$INF <$OUTF
		ret=$?
	done
	exit 0
fi


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

##
## ...otherwise, serve a request
##


## function
invalid_selector(){
	sel="$1"
	echo "3Error: Invalid selector: \"$sel\""
	echo "."
	exit 1
}

## function
serve_selector(){
	sel="$1"

	cat "${sel}"
	exit 0
}


### transform a .gph file into a gophermap
## function
serve_index(){
        IDX=$1
        IFS='
'
        while read line; do
                rline=$(echo $line | sed -r -e 's/\r//g')
                case $rline in
                        '['*)
                                echo $rline | sed -r -e 's/\[//g;s/\]//g;s/\|/\t/g;s/\t//;s/$/\r/g'
                        ;;
                       t*)
                               echo $rline | cut -c 2-
                       ;;
                        *)
                                echo $line
                esac
        done < $IDX
	printf ".\r\n"
	exit 0
}



GOPHERDIR=${1:-"./"}

read selector

selector=$(echo $selector | sed -r 's:\$.*::g;s:\r::g' )

[ -n "$DEBUG" ] && {
	echo "iGOPHERDIR: ${GOPHERDIR}"
	echo "iselector: \"${selector}\""
}

case $selector in
	/?*|"")
		RP1=$(realpath "${GOPHERDIR}"/"${selector}" || "")
		[ $? -eq 0 ] || invalid_selector "$selector"
		RP2=$(realpath "${GOPHERDIR}")"${selector}"
		[ $? -eq 0 ] || invalid_selector "$selector"
		[ -n "$DEBUG" ] && {
			echo "iRP1: ${RP1}"
			echo "iRP2: ${RP2}"
		}
		
		if [ "${RP1}" = "${RP2}" ]; then
			if [ -f "${RP1}" ]; then
				serve_selector "${RP1}"
			elif [ -d "${RP1}" ]; then
				[ -f "${RP1}/gophermap" ] && serve_selector "${RP1}/gophermap"
				[ -f "${RP1}/index.gph" ] && serve_index "${RP1}/index.gph"
			fi
		fi
		invalid_selector "$selector"
	;;
	*)
		[ -f "${GOPHERDIR}/gophermap" ] && serve_selector "${GOPHERDIR}/gophermap"
		[ -f "${GOPHERDIR}/index.gph" ] && serve_index "${GOPHERDIR}/index.gph"
		invalid_selector "/"
	;;
esac