#!/bin/bash -e

current_tag="$1"
if [ -z "${current_tag}" ]; then
  echo "Displays changes since previous tag"
  echo "Usage: changelog <current tag>"
  echo "Examples:"
  echo "  changelog HEAD"
  echo "  changelog 2.15.0"
  exit 1
fi

previous_tag=$(git describe --tags --abbrev=0 "${current_tag}^")

format="- %s ([%h](https://github.com/thumbsup/thumbsup/commit/%h))"
git log --pretty=format:"${format}" "${previous_tag}".."${current_tag}"