#!/bin/sh

# Get the last tag
TAG=$(git describe --abbrev=0 --tags --match="v[0-9]*\.[0-9]*\.[0-9]*" 2>/dev/null)
(test $? != 0 || test -z "$TAG") && (echo "unknown"; exit 1)

# Get the current branch
BRANCH=$(git symbolic-ref -q HEAD --short 2>/dev/null)
(test $? != 0 || test -z "$BRANCH") && BRANCH="master"

# Split out into major, minor and patch numbers
MAJOR=$(echo $TAG | cut -c 2- | cut -d "." -f 1)
MINOR=$(echo $TAG | cut -c 2- | cut -d "." -f 2)
PATCH=$(echo $TAG | cut -c 2- | cut -d "." -f 3)

# Output in the desired format
if [ $((PATCH)) -eq 0 ]; then
  printf '%s%d.%d' "$PREPEND" "$((MAJOR))" "$((MINOR))"
else
  printf '%s%d.%d.%d' "$PREPEND" "$((MAJOR))" "$((MINOR))" "$((PATCH))"
fi

# Add the build tag on non-master branches
if [ "$BRANCH" != "master" ]; then
  BUILD=$(git rev-list $TAG..HEAD --count)
  if [ $? = 0 ] && [ -n "$BUILD" ]; then
    if [ $((BUILD)) -gt 0 ]; then
        printf -- "-%04d" "$((BUILD))"
    fi
  fi
fi