#!/bin/bash

home="$(dirname "${0}")"
target="${home}/repo"
repos=('core' 'extra' 'community' 'testing' 'community-testing' 'staging' 'multilib')
arches=('i686' 'x86_64')
lock='/tmp/mirrorsync.lck'
tmp="$(mktemp -d)"

[ -f "${lock}" ] && exit 1
touch "${lock}"
trap "rm -rf '${lock}' '${tmp}'" EXIT INT TERM

renice +10 -p $$ > /dev/null

getpkgname() {
	local tmp

	tmp=${1##*/}
	echo ${tmp%-*.pkg.tar.*}
}


for repo in ${repos[@]}; do
	for arch in ${arches[@]}; do
		repodir=${repo}/os/${arch}
		[ ! -f ${target}/$repodir/$repo.db ] && continue
		echo "$repo/$arch..."
		cached=false

		# extract old file archive
		if [ -f ${target}/${repodir}/${repo}.links.tar.gz ]; then
			mkdir -p ${tmp}/cache/${repodir}
			bsdtar -xf ${target}/${repodir}/${repo}.links.tar.gz -C ${tmp}/cache/${repodir}
			cached=true
		fi

		# create file lists
		for pkg in $(find $target/$repodir -xtype f -name "*-${arch}.pkg.tar.?z"); do
			pkgname=$(getpkgname $pkg)
			tmppkgdir=${tmp}/tmp/${repodir}/${pkgname}
			mkdir -p $tmppkgdir
 			if [ -f "${tmp}/cache/${repodir}/${pkgname}/links" ]; then
				# reuse the cached file
				mv ${tmp}/cache/${repodir}/${pkgname}/links ${tmppkgdir}/links
			else
				echo "$repo/$arch: $pkgname"
				mkdir -p ${tmppkgdir}/pkg
				bsdtar -xof $pkg -C ${tmppkgdir}/pkg --include={opt,{,usr/}{lib{,32},{s,}bin}}'/*' 2>/dev/null
				for f in $(find ${tmppkgdir}/pkg -type f); do
					readelf -d "$f" 2> /dev/null | sed -nr 's/.*Shared library: \[(.*)\].*/\1/p'
				done | sort -u > ${tmppkgdir}/links
				rm -rf ${tmppkgdir}/pkg
				cached=false
 			fi
		done

		# create new file archive
		if ! $cached; then
			# at least one package has changed, so let's rebuild the archive
			pkgdir=${target}/${repodir}
			mkdir -p $pkgdir
			bsdtar --exclude=*.tar.* -czf ${pkgdir}/${repo}.links.tar.gz -C ${tmp}/tmp/${repodir} .
		fi
	done
done