version

#!/bin/bash
#
# FileName: version
# Description: Updates or prints current version number from VERSION file.
# 
# Copyright (C) 2014  K M Masum Habib <masum.habib@gmail.com>
#
# Created: 18 June 2016.

function usage(){
    echo "Usage: version [x.yy.z]"
    echo "  When no option is given, it return version string."
    echo "  options: " 
    echo "    x.yy.z - new version numbers."
    exit 0
}


VERSION_FILE=VERSION
version=`cat $VERSION_FILE`

version_major=`echo $version | awk -F. '{print $1}' | sed 's/^v//g'`
version_minor=`echo $version | awk -F. '{print $2}'`
version_patch=`echo $version | awk -F. '{print $3}'`

new_patch=$version_patch
new_minor=$version_minor
new_major=$version_major

if [[ $# -eq 0 ]]; then
    echo "v$version_major.$version_minor.$version_patch" 
elif [[ $# -eq 1 ]]; then
    IFS='.' read -ra vers <<< "$1"
    nvers=${#vers[@]}
    if [[ $nvers -eq 1 ]];then
        new_patch=${vers[0]}
    elif [[ $nvers -eq 2 ]];then
        new_patch=${vers[1]}
        new_minor=${vers[0]}
    elif [[ $nvers -eq 3 ]];then
        new_patch=${vers[2]}
        new_minor=${vers[1]}
        new_major=${vers[0]}
        new_major=`echo $new_major | sed 's/^v//g'`
    else
        usage
    fi

    new_version=v$new_major.$new_minor.$new_patch

    if [[ $version_major == $new_major && $version_minor == $new_minor 
          && $version_patch == $new_patch ]]; then
        echo "E: New requested version is the same as current version."
        exit 1
    fi

    version_already_exists=`git tag | grep $new_version -c`
    if [[ $version_already_exists -gt 0 ]]; then
        echo "E: Version $new_version already exists in git repo."
        exit 1
    fi

    echo "$new_version" > $VERSION_FILE
    echo "Updated to v$new_major.$new_minor.$new_patch" 
else
    usage
fi