#!/bin/bash
#-------------------------------------------------------------------------------
# (C) British Crown Copyright 2006-17 Met Office.
#
# This file is part of FCM, tools for managing and building source code.
#
# FCM is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# FCM is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with FCM. If not, see <http://www.gnu.org/licenses/>.
#-------------------------------------------------------------------------------
# NAME
#   pre-revprop-change
#
# SYNOPSIS
#   pre-revprop-change REPOS REV PROP_AUTHOR PROP_NAME ACTION
#
# ARGUMENTS
#   REPOS - the path to the Subversion repository
#   REV - the revision relevant for the property
#   PROP_AUTHOR - the author of this property change
#   PROP_NAME - the name of the property, should only be "svn:log"
#   ACTION - the action of the property change, should only be "M"
#
# DESCRIPTION
#   This script enables users to change revision properties.
#
#   By default, only "M svn:log" is allowed. If
#   "$REPOS/hooks/pre-revprop-change-ok.conf" exists, the contents should be a
#   list of allowed changes to revision properties. E.g.:
#
#   M svn:author
#   M svn:log
#
#   An empty file disables all changes.
#
#   It e-mails the host user account whenever an action is blocked.
#-------------------------------------------------------------------------------
set -eu

REPOS=$1
REV=$2
USER=$3
PROPNAME=$4
ACTION=$5

export PATH=${PATH:-'/usr/local/bin:/bin:/usr/bin'}:$(dirname $0)
THIS=$(basename "$0")
USER=${USER:-(whoami)}
NAME=$(basename "$REPOS")

OK_CHANGES=$(echo 'M svn:log')
OK_CHANGES_FILE="$REPOS/hooks/$THIS-ok.conf"
if [[ -f $OK_CHANGES_FILE ]]; then
    OK_CHANGES=$(<$OK_CHANGES_FILE)
fi

NOW=$(date -u +%FT%H:%M:%SZ)
if ! grep -q "$ACTION  *$PROPNAME" <<<"$OK_CHANGES"; then
    if [[ -n "$OK_CHANGES" ]]; then
        echo -n "[$ACTION $PROPNAME] permission denied. Can only do:" >&2
        while read; do
            echo -n " [$REPLY]" >&2
        done <<<"$OK_CHANGES"
        echo >&2
    else
        echo "[$ACTION $PROPNAME] permission denied." >&2
    fi
    if [[ -n ${FCM_SVN_HOOK_ADMIN_EMAIL:-} ]]; then
        mail -s "$NAME:$THIS" "$FCM_SVN_HOOK_ADMIN_EMAIL" <<<"[! $NOW] $@" \
            || true
    fi
    echo "[! $NOW] $@"
    exit 1
fi
exit