#!/bin/bash
# diff sources unpacked by two ebuilds (works only for simple ebuilds)

set -e -x

mode=
while [[ ${#} -gt 0 ]]; do
	case ${1} in
		--build-system|-b)
			mode=build-system
			;;
		*)
			break
			;;
	esac
	shift
done

get_category() {
	local dir=.
	[[ ${1} != */* ]] || dir=${1%/*}
	dir=$( cd "${dir}" && pwd )
	dir="${dir%/*}"
	echo "${dir##*/}"
}

cat1=$(get_category "${1}")
cat2=$(get_category "${2}")
fn1=${1##*/}
fn2=${2##*/}

export PORTAGE_TMPDIR=/tmp/pkgdiff
mkdir -p "${PORTAGE_TMPDIR}"
ebuild "${1}" unpack
ebuild "${2}" unpack
s1=$(sed -nr 's/^declare -x S="(.*)"/\1/p' "${PORTAGE_TMPDIR}"/portage/${cat1}/${fn1%.ebuild}/temp/environment)
s2=$(sed -nr 's/^declare -x S="(.*)"/\1/p' "${PORTAGE_TMPDIR}"/portage/${cat2}/${fn2%.ebuild}/temp/environment)

{
	case "${mode}" in
		build-system)
			find "${s1}" "${s2}" -type f \
				! \( \
						-name 'configure.ac' -o \
						-name 'meson.build' -o \
						-name 'meson_options.txt' -o \
						-name '*.cmake' -o \
						-name 'CMakeLists.txt' -o \
						-name 'setup.py' -o \
						-name 'setup.cfg' -o \
						-name 'pyproject.toml' \
				\) -printf "%f\n"
			;;
	esac
} | diff --color=always --strip-trailing-cr -X - -dupNr "${s1}" "${s2}" | ${PAGER:-less}
