#!/usr/bin/env bash
# Copyright (c) 2005, Intel Corporation, James Ketrenos

function die()
{
	ret=$1
	shift
	echo $@ >&2
	exit $ret
}

function pull-delta-repo()
{
	parent=$1

	if echo "$parent" | egrep -q "#"; then
		branch=$(echo $parent | sed -ne "s,.*#\(.*\),\1,p")
		parent=$(echo $parent | sed -ne "s,\([^#]*\).*,\1,")
	else
		branch=master
	fi
	echo "$parent" | grep -q "/\$" || parent="$parent/"

	mkdir -p ${dst}{refs/{heads,branches},objects}

	echo "Grabbing repo:"
	echo -en "\tparent..."
	rsync ${RSYNC_FLAGS} -ap ${parent}refs/heads/${branch} \
		${2}refs/heads/parent || 
		die 5 "Could not pull $parent $branch"
	echo "done."

	echo -en "\tancestors..."
	rsync ${RSYNC_FLAGS} -ap ${parent}refs/ancestors \
		${2}refs/ancestors || 
		die 5 "Could not pull $parent $branch"
	echo "done."

	cat ${2}refs/ancestors |
	while read url sha; do
		echo $url | grep "^#.*" && continue
		url=$(echo $url | sed -e "s,\([^#]*\).*,\1,")
		echo $url | grep -q "/\$" || url="$url/"
		dir=$(echo $sha | sed -ne "s#^\(..\).*#\1#p")
		obj=$(echo $sha | sed -ne "s#^..\(.*\)#\1#p")
		echo -e "Checking for updates on:\n\t$url\nfor\n\t$sha..."
		if [ ! -e ${2}objects/$dir/$obj ]; then
			echo "Updating objects from $url..."
			rsync ${RSYNC_FLAGS} -avpr \
				${url}objects/ \
				${2}objects/ ||
				die 6 "Could not pull objects from $url."
			echo "Updated."
		else
			echo "$url up to date."
		fi
	done || exit 1

	url=$parent
	sha=$(cat ${2}/refs/heads/parent)
	dir=$(echo $sha | sed -ne "s#^\(..\).*#\1#p")
	obj=$(echo $sha | sed -ne "s#^..\(.*\)#\1#p")
	if [ ! -e ${2}objects/$dir/$obj ]; then
		echo "Updating objects from $url..."
		rsync ${RSYNC_FLAGS} -avpr \
			${url}objects/ \
			${2}objects/ ||
		die 6 "Coult not pull objects from $url."
	else
		echo "$url up to date."
	fi

	echo -e "$parent\t$sha" >> ${2}refs/ancestors
	cp ${2}refs/heads/parent ${2}refs/heads/master
	ln -sf refs/heads/master ${2}HEAD
#	rsync ${RSYNC_FLAGS} -ap ${1}refs/branches ${2}refs/branches/
}

([ ! "$1" ] || [ ! "$2" ]) && echo \
"usage: git-grab-overlay src_delta_repo target_full_repo" && exit 1

src="${1}"
echo ${src} | grep -q "/\$" || src="${src}/"
echo ${src} | grep -q "\.git/\$" || src="${src}.git/"

dst="${2}"
echo ${dst} | grep -q "/\$" || dst="${dst}/"
echo ${dst} | grep -q "\.git/\$" || dst="${dst}.git/"
[ ! -d ${dst} ] && (mkdir -p ${dst} || die 5 "Error creating '${dst}'")
dst=`readlink -f ${dst}`/

pull-delta-repo $src $dst || exit 1

echo ""
echo "${2} now contains the full tree from ${1}."
echo -e "\nTo sync the files to the cache state, run:"
echo -e "\t% cd ${2}"
echo -e "\t% git-read-tree -m HEAD && git-checkout-cache -q -f -u -a"
while true; do
	read -p "Do you want to do this now? [Y/n] :" reply
	case $reply in
	"n")	exit 0
		;;
	"Y"|"y"|"")
		dir=$PWD
		cd ${2}
		git-read-tree -m HEAD
		git-checkout-cache -q -f -u -a
		cd $PWD
		exit 0
	esac
done