#!/usr/bin/env bash
# if you don't have bash on your system, you could try ksh, pdksh, or
# sh.

case "$(uname)" in
	SunOS|Linux|AIX|OSF1|IRIX*|DragonFly|Darwin)
		;;
	*)
		echo 'Warning: running find-sym on an untested platform.' 1>&2
		echo 'There may be anomalies!  :)' 1>&2
		echo 1>&2
		;;
esac

function usage
{
	retval="$1"
	case "$retval" in
		0)
			;;
		*)
			exec 1>&2
			;;
	esac

	echo Usage: "$0 [-l] [-i] [-v] [-h] [-s symbol] [-p] [-h]"
	echo '-q says to only list -L, -I and -l options - be quiet'
	echo '-l	says to only check for libraries including the symbol'
	echo '-h	says to only check for header files including the symbol'
	echo '-v	says to run (very) verbosely'
	echo '-s	symbol says to check for only one symbol'
	echo '-p	says to parse stdin for unresolved external messages from'
	echo '	gcc, and search for each of them'
	echo
	echo '-l and -h are mutually exclusive'
	echo '-s and -p are mutually exclusive'
	echo
	echo 'Run with no arguments to get help'

	exit "$retval"
}

# shellcheck disable=SC2046
set -- $(getopt vhps:ilq "$@")

if test $? != 0
then
	usage 1
fi

for arg
do
	case "$arg" in
		-q)
			QUIET=true
			shift
			;;
		-l)
			LIBSONLY=true
			shift
			;;
		-i)
			INCLUDESONLY=true
			shift
			;;
		-v)
			VERBOSE=true
			shift
			;;
		-h)
			shift
			usage 0
			;;
		-s)
			if [ "$syms" = "" ]
			then
				syms="$2"
				shift
				shift
			else
				echo 'Sorry, -s can only be specified once' 1>&2
				shift
				shift
				usage 1
			fi
			;;
		-p)
			PARSE=true
			shift
			;;
		--)
			shift
			remainder="$*"
			break
			;;
	esac
done

if [ "$remainder" != "" ]
then
	echo Trailing garbage at the end of the command: "$@" 1>&2
	usage 1
fi

if [ "$syms" = "" ] && [ "$PARSE" = "" ]
then
	echo Must specify either -s or -p
	usage 1
fi

if [ "$INCLUDESONLY" = "true" ] && [ "$LIBSONLY" = "true" ]
then
	echo You can only specify one of -i or -l 1>&2
	usage 1
fi

PATH=/bin:/usr/bin:/sbin:/usr/sbin:/usr/ccs/bin
export PATH

DEBUG=false

case "$DEBUG" in
	false)
		LIBSEARCHDIRS="/lib
		/usr/lib
		/usr/sfw
		/usr/lib64
		/usr/local
		/usr/X11R6/lib
		/usr/X11/lib
		/usr/lib/X11
		/usr/openwin/lib
		/opt/freeware/lib
		/usr/lpp"

	INCSEARCHDIRS="/usr/include
		/usr/local
		/usr/X11R6/include
		/usr/include/X11
		/usr/X11/include
		/usr/openwin/include
		/opt
		/usr/lpp"
		;;
	true)
		LIBSEARCHDIRS="/lib"
		INCSEARCHDIRS=""
#set -x
		;;
esac

if [ "$syms" = "" ]
then
	if [ "$VERBOSE" = true ]
	then
		echo Deriving symbols to look for from stdin 1>&2
	fi
	syms="$(grep -Ei 'undefined reference to `[a-zA-Z0-9_]*'"'" | \
		sed 's/^.*`\([a-zA-Z0-9_]*\)'"'"'.*$/\1/' |
		sort | \
		uniq)"
	if [ "$VERBOSE" = true ]
	then
		echo "Symbols found: $syms" 1>&2
	fi
fi

if [ "$INCLUDESONLY" != true ]
then
	for symbol in $syms
	do
		if [ "$VERBOSE" = true ]
		then
			echo "Searching for libraries containing $symbol" 1>&2
		fi
		for dir in $LIBSEARCHDIRS
		do
			if [ "$VERBOSE" = true ]
			then
				echo " Searching in $dir" 1>&2
			fi
			(
				# skip symlinks!
				find $dir -name 'lib*.a' -print
				find $dir -name 'lib*.so\.*' -print
				find $dir -name 'lib*.dylib' -print
			) 2> /dev/null | \
				while read -r libpath
				do
					if [ "$VERBOSE" = true ]
					then
						echo "  Searching in $libpath" 1>&2
					fi
					#echo libpath is $libpath, uname is `uname` 1>&2
					#set -x
					case "$(uname)" in
						IRIX*)
							nm -B "$libpath" | sed "s#^#$libpath:#"
							;;
						SunOS|OSF1)
							# here we're munging Sun format around into linux
							# format
							nm -P "$libpath" | awk ' { print $3,$2,$1 } ' | \
								sed "s#^#$libpath:#"
							;;
						Linux|DragonFly|Darwin)
							nm -o "$libpath"
							;;
						AIX)
							#AIX: .popen               T     0430424        14
							# -X bits specifies the bitwidth for the library
							# -p says don't sort - Much faster
							nm -X 32 -p -o "$libpath" | awk ' { print $3,$2,$1 } ' | \
								sed "s#^#$libpath:#"
							nm -X 64 -p -o "$libpath" | awk ' { print $3,$2,$1 } ' | \
								sed "s#^#$libpath:#"
							;;
					esac 2> /dev/null | \
						grep "$symbol" | \
						case "$(uname)" in
							AIX)
								awk ' { if (($2 == "t" || $2 == "T") && ($3 == "'"$symbol"'" || $3 == "'".$symbol"'")) print }'
								;;
							OSF1)
								awk ' { if (($2 == "t" || $2 == "T") && ($3 == "'"$symbol"'" || $3 == "'"__$symbol"'")) print }'
								;;
							DragonFly)
								awk ' { if ($2 == "T" && $3 == "'"$symbol"'") print }'
								;;
							Darwin)
								awk ' { if (($3 == "t" || $3 == "T") && $4 == "'"_$symbol"'") print }'
								;;
							Linux*|SunOS|IRIX*|*)
								awk ' { if (($2 == "t" || $2 == "T" || $2 == "D") && ($3 == "'"$symbol"'" || $3 == "'"_$symbol"'")) print }'
								;;
						esac | \
						awk -F':' ' { print $1 }' | \
						while read -r lib
						do
							case "$lib" in
								*lib*.a)
									add="-L$(dirname "$libpath") -l$(basename "$lib" | sed -e 's/^lib//' -e 's/\.a$//')"
									;;
								*lib*.so\.*)
									add="-L$(dirname "$libpath") -l$(basename "$lib" | sed -e 's/^lib//' -e 's/\.so\..*$//')"
									;;
								*lib*.dylib)
									add="-L$(dirname "$libpath") -l$(basename "$lib" | sed -e 's/^lib//' -e 's/\.dylib$//')"
									;;
								*)
									echo "Internal error: unrecognized library filename form: $lib" 1>&2
									exit 1
									;;
							esac
							if [ "$QUIET" = true ]
							then
								echo "$add"
							else
								# shellcheck disable=SC2016
								echo 'Library candidate for addition to your $CC'
								echo 'link line: '"$add"'   You may also want'
								echo "-R$(dirname "$libpath")"' (on Sun) or -Wl,-rpath'
								echo -Wl,"$(dirname "$libpath")"' (most other unixes'
								echo 'and linuxes) to build the'
								echo 'relevant directory into the resulting'
								echo 'executable'"'"'s search path - this is'
								echo 'generally preferred to using'
								# shellcheck disable=SC2016
								echo '$LD_LIBRARY_PATH or similar, though using'
								# shellcheck disable=SC2016
								echo '$LD_LIBRARY_PATH from a wrapper script is not'
								echo 'that bad.'
								case "$(uname)" in
									AIX)
										echo 'You may need to add -X32 or -X64 to your'
										echo 'compile and link options, since this is AIX'
										;;
								esac
								echo '_____'
							fi
						done
				done
		done
	done
fi

if [ "$LIBSONLY" != 'true' ]
then
	for symbol in $syms
	do
		if [ "$VERBOSE" = true ]
		then
			echo "Searching for includes containing $symbol" 1>&2
		fi
		for dir in $INCSEARCHDIRS
		do
			if [ "$VERBOSE" = true ]
			then
				echo " Searching in $dir" 1>&2
			fi
			if [ -d "$dir" ]
			then
				cd "$dir" || exit 1
				find "." -name '*.h' -print 2> /dev/null | \
					while read -r headerfile
					do
						if [ "$VERBOSE" = true ]
						then
							echo '  '"Searching in $headerfile" 1>&2
						fi
						if grep -E "#[ 	]*define[ 	][ 	]*$symbol\>" "$headerfile" > /dev/null 2>&1
						then
							if [ "$QUIET" = true ]
							then
								# shellcheck disable=SC2001
								echo "$headerfile" and "#include <$(echo "$headerfile" | sed 's#^\./##')>"
							else
								# shellcheck disable=SC2001
								echo Header candidate: "#include <$(echo "$headerfile" | sed 's#^\./##')>"
								echo Must concommittantly add -I"$dir" to your
								# shellcheck disable=SC2016
								echo '$CC' compile line for the .c file.  Please
								echo note that it is possible that this headerfile
								echo only -conditionally- defines this symbol.  If
								echo this symbol is conditionally defined,
								echo 'then you may have to include some other header'
								echo first, '#define' another symbol, or add a
								echo suitable -D for some other symbol to your
								# shellcheck disable=SC2016
								echo '$CC' compile line
								echo _____
							fi
						fi
					done
			fi
		done
	done
fi

echo The cleanest way of adding some flags to your link line is to add
# shellcheck disable=SC2016
echo them to '$LDFLAGS', remove ./config.cache if there is one, and
echo rerun ./configure.
echo
echo The same is true for compilation flags: the cleanest way is to add
# shellcheck disable=SC2016
echo them to your '$CFLAGS'.
echo
echo 'However, I have found a surprising number of applications that do'
echo not use these variables.
echo
echo In that case, I have found that a larger number of applications
# shellcheck disable=SC2016
echo will accept your additional flags by adding them to your '$CC'
echo variable.
echo _____
echo
echo This is a -very- simplistic heuristic, but if you find yourself
echo with lots of library choices to choose between, you will often be
echo best off using the directory and library with the shortest name.  ':)'
echo _____
echo