#!/bin/bash

# version: Semver helper
#
# Author: Steven Enten <steven@enten.fr>
# License : MIT
# Requirements: awk basename dirname cat echo eval grep readlink shift
# Site: https//github.com/enten/losh

set -eu

#
# consts
#
CMDNAME=$(basename $0)
CMDVERS="0.0.1"
CMDUSAGE="[release] <M|m|p> [inc] ..."
CMDDESC="Semver helper"
TAB="    "

#
# vars
#
major=
minor=
patch=
increment=
i=
j=
k=
tmp=

#
# initialize vars
#
init() {
  tmp=$(dirname $(readlink -f $(echo $0)))

  while [ ! -f "$tmp/VERSION" ]; do
    tmp=$(dirname $tmp)
    [ "$tmp" = "/" ] && break
  done

  [ ! -f "$tmp/VERSION" ] && echo "VERSION was not found" && exit 1

  VERSPATH="$tmp/VERSION"
  VERSION=$(cat $VERSPATH)
  [ -z "$VERSION" ] && VERSION="0.0.0"

  return 0
}

#
# usage
#
usage() {
  echo "NAME:"
  echo "${TAB}${CMDNAME} - ${CMDDESC}"
  echo
  echo "VERSION:"
  echo "${TAB}${CMDVERS}"
  echo
  echo "USAGE:"
  echo "${TAB}${CMDNAME} ${CMDUSAGE}"
  echo
  echo "COMMANDS:"
  echo "${TAB}${CMDNAME}                              Current version"
  echo "${TAB}${CMDNAME} <M|m|p> [inc] ...            Bump version"
  echo "${TAB}${CMDNAME} release <M|m|p> [inc] ...    Update version"
  echo "${TAB}${CMDNAME} ?|h|help                     Print this help message"
  echo
  [ $# -gt 0 ] && exit $1 || return 0
}

write_version() {
  echo $VERSION > $VERSPATH
  echo "$VERSPATH initialized with $VERSION"

  return 0
}

#
# what we do when there are a new release
#
handle_release() {
  write_version
  #try_commit

  return 0
}

#
# try to make commit
#
try_commit() {
  tmp=$(dirname $VERSPATH)

  if [ -d "$tmp/.git" ]; then
    git add $VERSPATH
    git commit -m "Release version $VERSION"
    git tag -a "v$0.0.1" -m "version $VERSION" $(git log --pretty=oneline -n 1 | awk '{print $1}')
  fi

  return 0
}

#
# command: version
#
cmdVoid() {
  echo $VERSION && exit 0
}

#
# command: version ?|h|help
#
cmdHelp() {
  usage 0
}

#
# command: version init|set [version]
#
cmdInit() {
  VERSION="0.0.0"
  [ $# -gt 0 ] && VERSION=$1

  write_version

  exit 0
}

#
# command: version release <M|m|p> [increment] ...
#
cmdRelease() {
  tmp=$0

  [ $# -lt 1 ] && usage 1

  VERSION=$($tmp $@)
  k=$?

  [ $k -ne 0 ] && usage 1

  i=$($tmp)

  echo "Old: $i"
  echo "New: $VERSION"

  handle_release

  exit 0
}

#
# command: version <M|m|p> [increment] ...
#
cmdDefault() {
  j=0
  for i in $(echo $VERSION | tr "\." "\n"); do
    [ $j -eq 0 ] && major=$i
    [ $j -eq 1 ] && minor=$i
    [ $j -eq 2 ] && patch=$i
    j=$(expr $j + 1)
  done

  i=1
  j=
  tmp=""
  while [ $i -le $# ]; do
    increment=1

    tmp="$tmp $(eval echo \${$i})"

    i=$(expr $i + 1)

    if [ $i -le $# ]; then
      j=$(eval echo \${$i})
      if echo "$j" | grep -qE ^\-?[0-9\]+$; then
        increment=$j
        i=$(expr $i + 1)
      fi
    fi
    tmp="$tmp:$increment "
  done

  for i in $(echo $tmp); do
    j=$(echo $i | awk -F ':' '{print $1}')
    k=$(echo $i | awk -F ':' '{print $2}')

    set -- $j $k

    case $1 in
      M|major)
        major=$(expr $major + $2)
        minor=0
        patch=0
        ;;
      m|minor)
        minor=$(expr $minor + $2)
        patch=0
        ;;
      p|patch)
        patch=$(expr $patch + $2)
        ;;
      *)
        usage 1
      ;;
    esac
  done

  [ $major -lt 0 ] && major=0
  [ $minor -lt 0 ] && minor=0
  [ $patch -lt 0 ] && patch=0

  VERSION="${major}.${minor}.${patch}"

  echo $VERSION
}

main() {
  init

  # command: version
  [ $# -eq 0 ] && cmdVoid

  # command: version ?|h|help
  if [ "$1" = "?" ] || [ "$1" = "h" ] || [ "$1" = "help" ]; then
    cmdHelp
  fi

  # command: version init|set [version]
  if [ "$1" = "init" ] || [ "$1" = "set" ]; then
    shift
    cmdInit $@
  fi

  # command: version release <M|m|p> [increment] ...
  if [ "$1" = "release" ]; then
    shift
    cmdRelease $@
  fi

  # command: version <M|m|p> [increment] ...
  cmdDefault $@
}

main $@