#!/bin/bash -e

export TMPDIR="`mktemp -d --tmpdir pbs-absrepo-convert.XXXXXXXXXX`"
cleanup() {
	msg "$(gettext "Removing temporary files...")"
	echo rm -rf "$TMPDIR"
}
trap cleanup EXIT

. /usr/bin/libremessages

abort() {
	echo
	error "$(gettext "Aborting...")"
	cleanup
}

_collect-data-gc() {
	local base=$1
	local files=`echo $base.new*`
	cat -- $files 2>>/dev/null | sort -u > $base.tmp
	rm -f -- $files
	mv $base.tmp $base.new
}

collect-data-gc() {(
	cd "$TMPDIR"
	while [[ ! -f collect-data-filter-branch.done ]]; do
		_collect-data-gc packages
		_collect-data-gc repo-arch
		sleep 10
	done
	mv packages.new packages
	mv repo-arch.new repo-arch
)}

##
# Usage: collect-data
# Assumptions:
#   1. Currently in a working copy of the repo
#   2. git branch "master" exists and is untouched
#   3. TMPDIR is set and exists
##
collect-data() {
	msg "$(gettext "Collecting package data...")"
	collect-data-gc &
	git filter-branch --tree-filter pbs-absrepo-convert--list master
	# notify collect-data-gc that filter-branch is done
	touch "${TMPDIR}/collect-data-filter-branch.done"
	# wait for collect-data-gc to finish
	while [[ ! -f "${TMPDIR}/packages" ]]; do
		sleep 10;
	done
	# extract some data from those files
	< "${TMPDIR}/repo-arch" sed -e 's/.*/-/' -e '/^any$/d' | sort -u > "${TMPDIR}/arches"
	{ echo master; cat "${TMPDIR}/arches"; } > "${TMPDIR}/arches.all"
}

##
# Usage: convert-packages SOURCE
# Assumptions:
#   1. Currently in a working copy of the repo
#   2. TMPDIR is set, and collect-data has been run on it
##
convert-packages() {
	msg "$(gettext "Converting packages...")"
	[[ $# != 1 ]] && { usage; return 1; }
	local source=$1

	local ibranch
	local obranch
	local dir

	local count="$(wc -l < "${TMPDIR}/packages")"
	cat -n "${TMPDIR}/packages" | while read n package; do
		msg2 "$(gettext "(%d/%d) %s")" "$n" "$count" "$package"
		if git checkout "packages/${package}" &>/dev/null; then
			# common case (optimization)
			ibranch=orig
			obranch="packages/${package}"
			dir=trunk
		else
			# general (uncommon) case
			ibranch="packages/${package}"
			obranch="packages/${source}/${package}"
			dir="${package}/trunk"
		fi
		git checkout -b "$obranch" "$ibranch"
		if [[ $ibranch != orig ]]; then
			git branch -D "$ibranch"
		fi
		git filter-branch -f --prune-empty --subdirectory-filter "$dir" "$obranch"

		git log --pretty=format:'%T %H' > "${TMPDIR}/packages-${package}.commits"
	done
}

##
# Usage: convert-arches
# Assumptions:
#   1. Currently in a working copy of the repo
#   2. TMPDIR is set, and collect-data has been run on it
#   3. ${TMPDIR}/packages-PACKAGE.commits exists for every package
##
convert-arches() {
	msg "$(gettext "Converting architectures...")"

	local count="$(wc -l < "${TMPDIR}/arches.all")"
	cat -n "${TMPDIR}/arches.all" | while read n arch; do
		msg2 "$(gettext "(%d/%d) %s")" "$n" "$count" "$arch"
		git checkout orig
		git checkout -b "$arch"
		git filter-branch -f --tree-filter \
			"pbs-absrepo-convert--treefilter $arch" "$arch"
	done
}

main() {
	trap abort EXIT
	[[ $# != 1 ]] && { usage; return 1; }
	local source=$1

	local cachedir="$(pbs-plumb-config get core.cachedir)"
	local sourcedir="$(pbs-plumb-config get core.sourcedir)"

	# init #################################################################
	msg "$(gettext "Creating working copy...")"
	git clone "${cachedir}/${source}.git" "${TMPDIR}/repo"
	cd "${TMPDIR}/repo"
	git checkout -b orig
	git checkout master
	collect-data
	git branch -D master

	# main #################################################################

	convert-packages "$source"
	convert-arches "$source"

	# save results #########################################################
	msg "$(gettext "Copying into source directory...")"
	[[ -d "$sourcedir" ]] || mkdir -p "$sourcedir"
	git clone --mirror "${TMPDIR}/repo" "${sourcedir}/${source}.new.git"
	[[ -d "${sourcedir}/${source}.git" ]] && mv "${sourcedir}/${source}"{,.old}.git
	mv "${sourcedir}/${source}"{.new,}.git
	[[ -d "${sourcedir}/${source}.old.git" ]] && rm -rf "${sourcedir}/${source}".old.git
	trap cleanup EXIT
}

main "$@"