#!/usr/bin/env bash
# Distributed under the terms of the GNU General Public License v2
# Copyright (c) 2006 Fernando J. Pereda <ferdy@gentoo.org>
#
# Adapted version of the one found under howto/update-hook-example.txt
#

# Leave this or gremlings will attack your system
umask 002
GLOBIGNORE=*

# Need to debug?
debug=false

# Do you really want it to be quiet?
reallyquiet=false

refname=$1
oldsha1=$2
newsha1=$3

user=$(id -u -n)

info() {
	${reallyquiet} || echo >&2 "(II) $1"
}

debug() {
	${debug} && echo >&2 "(--) $1"
}

grant() {
	${reallyquiet} || echo >&2 "(**) $1"
	exit 0
}

deny() {
	${reallyquiet} || echo >&2 "(EE) $1"
	exit 1
}

[[ ${oldsha1} =~ '^0*$' ]] && isnew=true || isnew=false

case "${refname}" in
	refs/tags/*)
		if [[ -f ${GIT_DIR}/${refname} ]] ; then
			deny "Trying to overwrite a tag (${refname##*/}), thats bad."
		fi
	;;
	refs/heads/tmp/*)
		if ${isnew} ; then
			info "New temporal branch '${refname##refs/heads/tmp/}' created."
		else
			info "Forde-updating temporal branch '${refname##refs/heads/tmp/}'."
		fi
	;;
	refs/heads/*)
		if ${isnew} ; then
			info "New branch '${refname##refs/heads/}' created."
		else
			base=$(git merge-base "${oldsha1}" "${newsha1}")
			case "${base},${oldsha1}" in
				"${oldsha1},${base}") debug "Update is a fast-forward." ;;
				*) deny "This is not a fast-forward update." ;;
			esac
		fi
	;;
	*)
		deny "Branch not under refs/heads/ or refs/tags/? Give up the crack."
	;;
esac

while read refpat userpatts ; do
	if [[ ${refname} =~ ${refpat} ]] ; then
		debug "Pattern '${refpat}' matches '${refname}'"

		for p in ${userpatts} ; do
			debug "Checking '${user}' against '${p}'"
			if [[ ${user} =~ ${p} ]] ; then
				grant "Access granted. Please come back soon."
			fi
		done
	fi
done < ${GIT_DIR}/info/users-allowed
	
deny "You are not allowed to update this ref. Please come back soon."