#!/bin/sh

libsl=""

doautolib=true
verbose=false

if [ "x$1" = "x-l" ]
then
	shift
	doautolib=false
elif [ "x$1" = "x-v" ]
then
	shift
	verbose=true
fi

target=a.out
if [ "x$1" = "x-o" ]
then
	target=$2
fi

if $doautolib
then
	ofiles=""
	for i
	do
		case "$i" in
		*.[ao])
			ofiles="$ofiles $i"
			;;
		esac
	done
	
	# echo "ofiles $ofiles"
	autolibs=""
	if [ "x$ofiles" != "x" ]
	then
		a=`
			nm $ofiles |
			grep '__p9l_autolib_[a-zA-Z0-9+-]*$' |
			sed 's/.*__p9l_autolib_//' |
			sort -u
		`
		for i in $a
		do
			autolibs="$autolibs $i"
			eval "need$i=true"
		done
	fi

	# fetch dependencies out of libraries
	workq="$autolibs"
	while [ "x$workq" != "x" ]
	do
		w="$workq"
		workq=""
		for i in $w
		do
			# can't trust the libraries about using
			# libthread - we might not be linking with
			# those object files.
			a=`
				nm $PLAN9/lib/lib$i.a |
				grep '__p9l_autolib_[a-zA-Z0-9+-]*$' |
				sed 's/.*__p9l_autolib_//' |
				sort -u |
				grep -v thread
			`
			okayfn="true"
			for j in $a
			do
				if eval "[ x\$need$j = x ]"
				then
					autolibs="$autolibs $j"
					workq="$workq $j"
					eval "need$j=true"
				fi
				if [ $j != $i ]
				then
					okayfn="$okayfn && have$j"
				fi
			done
			# echo "can$i: $okayfn"
			eval "can$i() { $okayfn; }"
		done
	done
	if $verbose
	then
		echo "autolibs $autolibs"
	fi

	for i in $autolibs
	do
		eval "have$i() { false; }"
	done
	havethread() { false; }

	# now find correct order
	libsl=""
	while [ "x$autolibs" != x ]
	do
		stillneed=""
		didnothing=true
		for i in $autolibs
		do
			if eval "can$i"
			then
				libsl="-l$i $libsl"
				eval "have$i() { true; }"
				didnothing=false
			else
				stillneed="$stillneed $i"
			fi
		done
		# break cycle by setting the last library on the list
		# to have no dependencies
		if $didnothing
		then
			j="xxx"
			for i in $autolibs
			do
				j=$i
			done
			echo "dependency cycle: $autolibs; breaking with $j"
			eval "can$j() { true; }"
		fi
		autolibs="$stillneed"
	done
	if $verbose
	then
		echo "liborder $libsl"
	fi
	libsl="$libsl -l9"

	# cycle: lib9 expects p9main, which is defined in libthread.  oops.
	if havethread
	then
		libsl="$libsl -lthread -l9"
	fi

	if [ "x$needdraw" = xtrue ]
	then
		if [ "x$X11" = "x" ]
		then
			X11=/usr/X11R6
		fi
		libsl="$libsl -L$X11/lib -lX11"
	fi
fi

extralibs="-lm"
tag="${SYSNAME:-`uname`}-${OBJTYPE:-`uname -m`}"
case "$tag" in
*OpenBSD*)
	ld=gcc
	extralibs="$extralibs -lutil -lpthread"
	;;
*FreeBSD*)
	ld=gcc
	extralibs="$extralibs -lutil"
	case "`uname -r`" in
	[5-9].*)
		extralibs="$extralibs -lpthread"
		;;
	esac
	;;
*BSD*)
	ld=gcc
	extralibs="$extralibs -lutil"
	;;
*Linux*)
	ld=gcc
	extralibs="$extralibs -lutil"
	case "`uname -r`" in
	2.6.*)
		extralibs="$extralibs -lpthread"
		;;
	esac
	;;
*Darwin*)
	ld=gcc
	;;
*SunOS*)
	ld="${CC9:-cc} -g"
	extralibs="$extralibs -lrt -lpthread -lsocket -lnsl"
	# Record paths to shared libraries to avoid needing LD_LIBRARY_PATH 
	for i in "$@"
	do
		case "$i" in
		-L*)
			s=`echo $i | sed 's/-L/-R/'`
			extralibs="$extralibs $s"
			;;
		esac
	done
	;;
*)
	echo do not know how to link on "$tag" 1>&2
	exit 1
esac

if $verbose
then
	echo $ld -L$PLAN9/lib "$@" $libsl $extralibs
fi
if $ld -L$PLAN9/lib "$@" $libsl $extralibs
then
	exit 0
else
	rm -f $target
	exit 1
fi