#!/bin/sh
set -e

# Version from which to generate the changelog.
from=""

while [ $# -gt 0 ]; do
  case "$1" in
    --from-version)
      if [ -z "$2" ]; then
        echo "error: '--from-version' requires a version number" >&2
        exit 1
      fi
      shift
      from=$(echo "$1" | sed 's/^releases\///')
      break
      ;;
    *)
      echo "error: unknown argument '$1'" >&2
      exit 1
      ;;
  esac
done

# Get version from Cargo.toml
version=$(grep '^version = ' "$(dirname "$0")/../Cargo.toml" | head -1 | sed 's/version = "\(.*\)"/\1/')

if [ -z "$version" ]; then
  echo "error: could not determine version from Cargo.toml" >&2
  exit 1
fi

# Current/latest tag or HEAD
current="releases/${version}"

# Check if the tag exists, otherwise use HEAD
if git rev-parse --verify "$current^{tag}" >/dev/null 2>&1; then
  use_head=false
else
  echo "warning: tag '$current' not found, using HEAD instead" >&2
  current="HEAD"
  use_head=true
fi

if [ -z "$from" ]; then
  # Try to find the previous tag
  if previous=$(git describe --tags --abbrev=0 --match='releases/*' "$current^" 2>/dev/null); then
    :  # previous tag found
  else
    # No previous tag found, use the first commit
    previous=$(git rev-list --max-parents=0 HEAD)
    echo "warning: no previous release tag found, using first commit" >&2
  fi
else
  previous="releases/$from"
fi

if [ -n "$from" ] && ! git rev-parse --verify "$previous^{tag}" >/dev/null 2>&1; then
  echo "error: '$from' is not a valid version, tag '$previous' not found" >&2
  exit 1
fi

echo "# radicle-httpd $version"
echo
echo "radicle-httpd $version ($(git rev-parse --short HEAD)) is released."
echo
echo "## Changelog"

range="${previous}..${current}"
ncommits=$(git rev-list --count "$range")
ncontribs=$(git log "$range" --format='%ae' | sort -u | wc -l)

echo
echo "This release contains $ncommits commit(s) by $ncontribs contributor(s)."
echo

# shellcheck disable=SC2016
git log --pretty=format:'* `%h` **%s** *<%ae>*' "$range"

echo
echo "## Checksums"
echo

echo '```'
"$(dirname "$0")/checksums"
echo '```'