version

#!/bin/bash

function usage() {
  echo "usage: $0 ( major | minor | patch )" 1>&2
  exit 42
}

function fileMissingError() {
  echo "missing or unreadable $1 file, please make sure $1 exists and is in root directory of the project" 1>&2
  exit 42
}

function incorrectVersionFormat() {
  echo "Current version: $1 in file $2 is in incorrect format, please fix the version number"
  exit 42
}

VERSION_FILE="version.txt"
INDEX=0

if [[ $1 == "major" ]]; then
  echo "Major version change"
elif [[ $1 == "minor" ]]; then
  echo "Minor version change"
  INDEX=1
elif [[ $1 == "patch" ]]; then
  echo "Patch version change"
  INDEX=2
else
  echo "Invalid option to change version specified"
  usage $0
fi

if [ ! -r $VERSION_FILE ]; then
  fileMissingError $VERSION_FILE
fi

VERSION=`head -n 1 $VERSION_FILE`

if ! egrep -q "^(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)$" <<< "$VERSION"; then
  incorrectVersionFormat $VERSION $VERSION_FILE
fi

echo "Current version: $VERSION"

arrVersion=(${VERSION//./ })

(( arrVersion[$INDEX]++ ))
(( INDEX++ ))


END=3
for ((i=INDEX;i<END;i++)); do
  arrVersion[$i]=0
done

echo "New Version: ${arrVersion[0]}.${arrVersion[1]}.${arrVersion[2]}"

echo ${arrVersion[0]}.${arrVersion[1]}.${arrVersion[2]} > $VERSION_FILE

git add $VERSION_FILE
git commit -m "`cat $VERSION_FILE`"
git tag -a v${arrVersion[0]}.${arrVersion[1]}.${arrVersion[2]}