#!/usr/bin/env bash
# License: Unspecified

. "$(librelib messages)"

set -e
shopt -s extglob

IGNORE_INTERNAL=0

if [[ $1 = "--ignore-internal" ]]; then
	IGNORE_INTERNAL=1
	shift
fi

script_mode=${0##*/find-lib}

case $script_mode in
	deps|provides) true;;
	*) die "Unknown mode %s" "$script_mode" ;;
esac

usage() {
	print "Usage: %s [OPTIONS] {PACKAGE_FILE|EXTRACTED_PACKAGE_DIR}" "${0##*/}"
	print "Find library dependencies or provides of a package."
	echo
	prose 'Prints a list of library dependencies in the format:'
	echo
	print '    <soname>=<soversion>-<soarch>'
	echo
	prose "Where <soversion> is the shared library version, or
	      <soname> repeated if there is no version attached; and
	      <soarch> is the architecture of the library (either \`32\`
	      or \`64\`, based on the ELF Class)."
	echo
	print "Options:"
	flag \
		"--ignore-internal" "Ignore internal libraries; libraries
		                     without a version attached" \
		"-h, --help"        "Show this message"
}

mode=run
if ! args="$(getopt -n "${0##*/}" -o 'h' -l 'help' -- "$@")"; then
	mode=errusage
else
	eval "set -- $args"
	while true; do
		flag=$1
		shift
		case "$flag" in
			-h | --help) mode=usage ;;
			--) break ;;
			*) panic 'unhandled flag: %q' "$flag" ;;
		esac
	done
	if [[ $mode == run && $# -ne 1 ]]; then
		gnuerror 'expected 1 non-flag argument, got %d' "$#"
		mode=errusage
	fi
fi
case "$mode" in
	errusage)
		print "Try '%s --help' for more information." "${0##*/}" >&2
		exit $EXIT_INVALIDARGUMENT
		;;
	usage)
		usage
		exit $EXIT_SUCCESS
		;;
	run) : ;;
	*) panic 'invalid mode: %q' "$mode" ;;
esac

if [[ -d $1 ]]; then
	pushd "$1" >/dev/null
else
	setup_workdir

	case ${script_mode} in
		deps) bsdtar -C "$WORKDIR" -xf "$1";;
		provides) bsdtar -C "$WORKDIR" -xf "$1" --include="*.so*";;
	esac

	pushd "$WORKDIR" >/dev/null
fi

process_sofile() {
	# extract the library name: libfoo.so
	soname="${sofile%.so?(+(.+([0-9])))}".so
	# extract the major version: 1
	soversion="${sofile##*\.so\.}"
	if [[ "$soversion" = "$sofile" ]] && ((IGNORE_INTERNAL)); then
		continue
	fi
	if ! in_array "${soname}=${soversion}-${soarch}" "${soobjects[@]}"; then
		# libfoo.so=1-64
		echo "${soname}=${soversion}-${soarch}"
		soobjects+=("${soname}=${soversion}-${soarch}")
	fi
}

case $script_mode in
	deps) find_args=(-perm -u+x);;
  provides) find_args=(-name '*.so*');;
esac

find . -type f "${find_args[@]}" | while read -r filename; do
	if [[ $script_mode = "provides" ]]; then
		# ignore if we don't have a shared object
		if ! LC_ALL=C readelf -h "$filename" 2>/dev/null | grep -q '.*Type:.*DYN (Shared object file).*'; then
			continue
		fi
	fi

	# get architecture of the file; if soarch is empty it's not an ELF binary
	soarch=$(LC_ALL=C readelf -h "$filename" 2>/dev/null | sed -n 's/.*Class.*ELF\(32\|64\)/\1/p')
	[[ -n $soarch ]] || continue

	if [[ $script_mode = "provides" ]]; then
		# get the string binaries link to: libfoo.so.1.2 -> libfoo.so.1
		sofile=$(LC_ALL=C readelf -d "$filename" 2>/dev/null | sed -n 's/.*Library soname: \[\(.*\)\].*/\1/p')
		[[ -z $sofile ]] && sofile="${filename##*/}"
		process_sofile
	elif [[ $script_mode = "deps" ]]; then
		# process all libraries needed by the binary
		for sofile in $(LC_ALL=C readelf -d "$filename" 2>/dev/null | sed -nr 's/.*Shared library: \[(.*)\].*/\1/p'); do
			process_sofile
		done
	fi
done

popd >/dev/null
