#!/usr/bin/env zsh
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
# specific language governing permissions and limitations
# under the License.

set -e

# setup
0=${0:t}; NAME=$0
svn=${SVN:-svn}
svnadmin=${SVNADMIN:-svnadmin}

usage() {
  echo "usage: $NAME -r N:M"
  echo "  will retrieve all log messages in the range rN:rM, open them in"
  echo "  \$EDITOR, and commit any edits to them."
  echo ""
  echo "  Run this with cwd being a working copy of ^/subversion/trunk."
  # TODO: We only need the cwd in case SVN_CLIENT__REVKIND_NEEDS_WC() is true
  #   for N or M.  When N and M are both numeric or HEAD, teach this script
  #   to disregard its cwd and contact ^/subversion/trunk directly.
}

# parse argv
while getopts r: letter; do
  if [[ $letter == r ]]; then
    revision_range=$OPTARG
  else
    usage >&2
    exit 1
  fi
done
shift $((OPTIND - 1))
[[ -n $revision_range ]] || { usage >&2; exit 1; }

# get log messages
cd "$(mktemp -d)"
echo "${0}: Temporary directory: ${(q-)PWD}"
revisions=( ${(f)"$(
    # We use $OLDPWD rather than a URL in case $revision_range is, say,
    # "BASE:HEAD".
    $svn log -q -r $revision_range -- $OLDPWD |
    grep '^r' | cut -d' ' -f1 | grep '^r[0-9]*$'
)"} )
for rN in $revisions; do
  $svn propget --revprop -r $rN --strict 'svn:log' -- $OLDPWD > ./$rN &
done
wait

# set up to detect which ones have changed
$svnadmin create ./.r
$svn checkout -q file://$PWD/.r ./
$svn add -q ./r*
$svn commit -q -m "Import revisions $revision_range"
rm -rf ./.r # (!)

# edit
case $EDITOR in
  (*vim*) $EDITOR -p ./r*;;
  (*) $EDITOR ./r*;;
esac

# prompt for permission to continue
if $svn status -q | grep -q ''; then
  $svn status -q
  read -q "?Commit the above propedits? " || { echo "${0}: exiting"; exit 0; }
  echo ""
else
  echo "${0}: No changes."
  echo "${0}: You can remove ${(q-)PWD} now."
  exit 0
fi

# make propedits
# TODO: make these changes atomically
#   'svn propedit' is atomic and could drive a non-interactive $EDITOR, but for
#   now, we just trust the committer to read commits@.
targets=( ${(f)"$($svn status -q | grep '^M' | cut -c9-)"} )
for i in $targets; do
  $svn propset --revprop -r $i -F ./$i -- 'svn:log' $OLDPWD
done