#!/bin/bash

# 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.

# Var
tmpMessageFile="${PWD}/.git-tmp-message.txt"

# Check if branch was specified
branch=$1
if [ -z ${branch} ]; then
  echo "Usage: git fwd-merge branch-name"
  echo
  exit 1
fi

# save old commit
oldhead=$(git show | grep commit |  cut -d ' ' -f 2)

# Construct merge message
currentBranch=$(git branch | grep "^*" | sed -e "s/^[*] //")
echo "Merge release branch ${branch} to ${currentBranch}" > ${tmpMessageFile}

# Are you sure?
echo "Merging release branch ***${branch}*** into ***${currentBranch}*** branch in 5 seconds. CTRL+c to abort.."
sec=5
while [ $sec -ge 0 ]; do
  echo -n "${sec} "
  sec=$((sec-1))
  sleep 1
done
echo "There we go!"

# Do the actual merge
git merge --no-ff --log -m "$(cat .git-tmp-message.txt)" ${branch}
if [ $? -gt 0 ]; then
  echo "ERROR: Merge failed, aborting."
  git merge --abort
fi

# Clean up
rm -fr ${tmpMessageFile}

apache_remote=$(git remote -v | grep -E "git-wip-us\.apache\.org" | head -n 1 | cut -f1)
echo "INFO: Actual diff in commits is: (running git log --pretty=oneline --abbrev-commit ${oldhead}..${currentBranch})"
echo
git log --pretty=oneline --abbrev-commit ${oldhead}..${currentBranch}

# What's next
echo "We're done! Please double check using 'git log -p' and 'git push' when you're sure."