.git_subtree_funcs

gitrc_git_is_clean()
{
    if ! git rev-parse --git-dir > /dev/null 2>&1; then
    	echo "Not in git repository directory"
        return 0
    fi
	if git diff --quiet 2>/dev/null >&2; then
		return 0
	else
		return 1
	fi
}

gitrc_git_subtree_add_help()
{
	read -d '' help <<- EOF
usage "git st-add <-bbranch> <-aalias> <-pprefix> <-r> REMOTE"
EOF
	echo "$help"
}

gitrc_git_subtree_add()
{
    if ! git rev-parse --git-dir > /dev/null 2>&1; then
    	echo "Not in git repository directory"
        return 1
    fi

	OPTIND=1
	remote=""
	remote_alias=""
	prefix=""
	branch="master"
	dry_run=0
	reg_only=0

	while getopts "a:b:p:nr" opt; do
		case "$opt" in
		a)
			remote_alias=$OPTARG
			;;
		b)
			branch=$OPTARG
			;;
		p)
			prefix=$OPTARG
			;;
		n)
			dry_run=1
			;;
		r)
			reg_only=1
			;;
		esac
	done

	shift $((OPTIND - 1))

	[ "$1" = "--" ] && shift

	remote=$1 && shift

	if [ -z "$remote" ]; then
		echo "Remote name is empty";
		gitrc_git_subtree_add_help;
		return 1;
	fi

	if [ -z "$remote_alias" ]; then
		if [[ "$remote" =~ ^.*/([a-zA-Z0-9_-]+)\.git$ ]]; then
			remote_alias=${BASH_REMATCH[1]};
		else
			echo "Failed to parse remote";
			return 1;
		fi
	fi

	subtree_prefix=$(git config --local --get subtrees.prefix)

	if [ -z "$subtree_prefix" ]; then
		echo "WARNING. Subtree prefix is empty. Use gitrc_git_set_default_subtree_prefix to set it";
	fi

	if [ -z "$prefix" ]; then
		prefix=$remote_alias;
	fi

	if [ $dry_run -ne 0 ]; then
		echo "Will store setting for remote $remote alias $remote_alias branch $branch prefix $prefix"
		echo "Will run commands:"
		echo "  git remote add -f $remote_alias $remote"
		echo "  git subtree add --prefix $subtree_prefix/$prefix $remote_alias $branch --squash"
	else
		git config --local subtrees.$remote_alias.remote "$remote"
		git config --local subtrees.$remote_alias.prefix "$subtree_prefix/$prefix"
		git config --local subtrees.$remote_alias.branch "$branch"
		if [ $reg_only -ne 0 ]; then
			echo "Registered data for subtree alias $remote_alias"
		else
		    repo_dirty=1
		    if gitrc_git_is_clean; then
		    	repo_dirty=0
		    fi

			pushd `git rev-parse --show-toplevel` > /dev/null 2>&1
			if [ $repo_dirty -eq 1 ]; then
				echo "Stash uncommitted changes"
				git stash
			fi
			echo "Add remote $remote with alias $remote_alias"
			git remote add -f $remote_alias $remote
			echo "Add subtree $subtree_prefix/$prefix"
			if ! [ -z "$subtree_prefix" ]; then
				mkdir -p $subtree_prefix
			fi
			git subtree add --prefix "$subtree_prefix/$prefix" $remote_alias $branch --squash
			if [ $repo_dirty -eq 1 ]; then
				echo "Unstash uncommitted changes"
				git stash pop
			fi
			popd > /dev/null 2>&1
		fi
	fi
}

gitrc_subtree_command()
{
	cmd=$1
	remote_alias=$2

	if [ -z "$remote_alias" ]; then
		echo "usage 'git st-$2 remote_alias'";
		gitrc_list_subtrees;
		return 1;
	fi

	prefix=$(git config --local --get subtrees.$remote_alias.prefix)
	if [ -z "$prefix" ]; then
		echo "$prefix was not registered. Pleas use git st-add to add or register a subtree";
		return 1;
	fi
	branch=$(git config --local --get subtrees.$remote_alias.branch)
	if [ -z "$branch" ]; then
		branch="master"
	fi

    repo_dirty=1
    if gitrc_git_is_clean; then
    	repo_dirty=0
    fi
	pushd `git rev-parse --show-toplevel` > /dev/null 2>&1
	if [ $repo_dirty -eq 1 ]; then
		echo "Stash uncommitted changes"
		git stash
	fi

	_gitrc_git_subtree_${cmd}_impl $remote_alias $prefix $branch

	if [ $repo_dirty -eq 1 ]; then
		echo "Unstash uncommitted changes"
		git stash pop
	fi
	popd > /dev/null 2>&1
}

_gitrc_git_subtree_pull_impl()
{
	# alias prefix branch
	git fetch $1
	git subtree pull --prefix $2 $1 $3 --squash
}

_gitrc_git_subtree_push_impl()
{
	# alias prefix branch
	git subtree push --prefix $2 $1 $3
}

gitrc_list_subtrees()
{
	echo "Registered subtree aliases"
	git config -l | grep "^subtrees.*branch=" | awk -F[.=] -e '{print $2 " (" $4 ")"}'
}

gitrc_git_set_default_subtree_prefix()
{
	git config --local subtrees.prefix $1
}

gitrc_git_get_default_subtree_prefix()
{
	subtree_prefix=$(git config --local --get subtrees.prefix)
	echo "$subtree_prefix"
}

gitrc_git_subtree_prefix()
{
	if [[ -z "$1" || "$1" = "--get" ]]; then
		gitrc_git_get_default_subtree_prefix
	else
		gitrc_git_set_default_subtree_prefix $1
	fi
}

gitrc_register_aliases()
{
	script_name=$1
	if [ -z "$script_name" ]; then
		echo "Usage";
		echo "gitrc_register_aliases <path to .git_subtree_funcs script>";
		return 1;
	fi
	git config --global alias.st-prefix "!bash -c '. $script_name && gitrc_git_subtree_prefix \$@' -"
	git config --global alias.st-add "!bash -c '. $script_name && gitrc_git_subtree_add \$@' -"
	git config --global alias.st-pull "!bash -c '. $script_name && gitrc_subtree_command pull \$@' -"
	git config --global alias.st-push "!bash -c '. $script_name && gitrc_subtree_command push \$@' -"
	git config --global alias.st-ls "!bash -c '. $script_name && gitrc_list_subtrees \$@' -"
}

if [ "$1" = "--install" ]; then
	gitrc_register_aliases $0
fi