#!/bin/sh

set -e

REPO="git-lfs/git-lfs"
WORKDIR="$(mktemp -d)"

trap 'rm -fr "$WORKDIR"' EXIT

say () {
  [ -n "$QUIET" ] && return
  local format="$1"
  shift
  printf "$format\n" "$@" >&2
}

abort () {
  local format="$1"
  shift
  printf "$format\n" "$@" >&2
  exit 2
}

curl () {
  command curl -nfSs "$@"
}

categorize_os () {
  local os="$1"

  if [ "$os" = "freebsd" ]
  then
    echo FreeBSD
  else
    ruby -e 'puts ARGV[0].capitalize' "$os"
  fi
}

categorize_arch () {
  local arch="$1"

  echo "$arch" | tr a-z A-Z
}

# Categorize a release asset and print its human readable name to standard
# output.
categorize_asset () {
  local file="$1"
  local os=$(echo "$file" | sed -e 's/^git-lfs-//' -e 's/[-.].*$//')
  local arch=$(echo "$file" | ruby -pe '$_.gsub!(/\Agit-lfs-[^-]+-([^-]+)[-.].*/, "\\1")')

  case "$file" in
    git-lfs-v*.*.*.tar.gz)
      echo "Source";;
    git-lfs-windows-v*.*.*.exe)
      echo "Windows Installer";;
    sha256sums.asc)
      echo "Signed SHA-256 Hashes";;
    *)
      printf "%s %s\n" "$(categorize_os "$os")" "$(categorize_arch "$arch")";;
  esac
}

# Provide a content type for the asset based on its file name.
content_type () {
  local file="$1"

  case "$file" in
    *.zip)
      echo "application/zip";;
    *.tar.gz)
      echo "application/gzip";;
    *.exe)
      echo "application/octet-stream";;
    *.asc)
      echo "text/plain";;
  esac
}

# Format the JSON for creating the release and print it to standard output.
format_release_json () {
  local version="$1"
  local bodyfile="$2"

  ruby -rjson -e 'puts JSON.generate({
    tag_name: ARGV[0],
    name: ARGV[0],
    draft: true,
    body: File.read(ARGV[1]),
  })' "$version" "$bodyfile"
}

# Create a draft release and print the upload URL for release assets to the
# standard output. If a release with that version already exists, do nothing
# instead.
create_release () {
  local version="$1"
  local bodyfile="$2"

  # Check to see if we already have such a release. If so, don't create it.
  curl https://api.github.com/repos/$REPO/releases | \
    jq -r '.[].name' | grep -qsF "$version" && {
    say "Found an existing release for this version."
    curl https://api.github.com/repos/$REPO/releases | \
      jq -r '.[] | select(.name == "'"$version"'") | .upload_url' | \
      sed -e 's/{.*}//g'
    return
  }

  # This can be large, so pass it in a file.
  format_release_json "$version" "$bodyfile" >> "$WORKDIR/release-json"

  curl -H'Content-Type: application/json' -d"@$WORKDIR/release-json" \
    https://api.github.com/repos/$REPO/releases | \
    jq -r '.upload_url' |
    sed -e 's/{.*}//g'
}

# Find the release files for the given version.
release_files () {
  local version="$1"

  [ -n "$version" ] || return 1

  find bin/releases -name '*.tar.gz' -o -name '*386*.zip' -o \
    -name '*amd64*.zip' -o -name '*.exe' -o -name 'sha256sums.asc' | \
    grep -E "$version|sha256sums.asc" | \
    grep -v "assets" | \
    LC_ALL=C sort
}

# Format the body message and print the file which contains it to the standard
# output.
finalize_body_message () {
  local version="$1"
  local changelog="$2"

  version=$(echo "$version" | sed -e 's/^v//')

  # If you change the list of distributions here, change docker/run_dockers.bsh
  # as well.
  cat "$changelog" > "$WORKDIR/body-template"
  cat <<EOM >> "$WORKDIR/body-template"
## Packages

Up to date packages are available on [PackageCloud](https://packagecloud.io/github/git-lfs) and [Homebrew](http://brew.sh/).

[RPM RHEL 6/CentOS 6](https://packagecloud.io/github/git-lfs/packages/el/6/git-lfs-VERSION-1.el6.x86_64.rpm/download)
[RPM RHEL 7/CentOS 7](https://packagecloud.io/github/git-lfs/packages/el/7/git-lfs-VERSION-1.el7.x86_64.rpm/download)
[Debian 7](https://packagecloud.io/github/git-lfs/packages/debian/wheezy/git-lfs_VERSION_amd64.deb/download)
[Debian 8](https://packagecloud.io/github/git-lfs/packages/debian/jessie/git-lfs_VERSION_amd64.deb/download)
[Debian 9](https://packagecloud.io/github/git-lfs/packages/debian/stretch/git-lfs_VERSION_amd64.deb/download)

## SHA-256 hashes:
EOM

  shasum -a256 $(release_files "$version") | \
    ruby -pe '$_.chomp!' \
    -e '$_.gsub!(/^([0-9a-f]+)\s+.*\/([^\/]+)$/, "**\\2**\n\\1\n\n")' | \
    ruby -0777 -pe '$_.gsub!(/\n+\z/, "\n")' >> "$WORKDIR/body-template"

  sed -e "s/VERSION/$version/g" < "$WORKDIR/body-template" > "$WORKDIR/body"
  echo "$WORKDIR/body"
}

# Filter a list of files from standard input, removing entries found in the file
# provided.
filter_files () {
  local filter="$1"

  # If the filter file is empty (that is, no assets have been uploaded), grep
  # will produce no output, and therefore nothing will be uploaded. That's not
  # what we want, so handle this case specially.
  if [ -s "$filter" ]
  then
    grep -vF -f "$filter"
  else
    cat
  fi
}

# Upload assets from the release directory to GitHub. Only assets that are not
# already existing should be uploaded.
upload_assets () {
  local version="$1"
  local upload_url="$2"
  local file desc base ct encdesc encbase

  curl https://api.github.com/repos/$REPO/releases | \
    jq -r '.[] | select(.name == "'"$version"'") | .assets | .[] | .name' \
    > "$WORKDIR/existing-assets"

  for file in $(release_files "$version" | filter_files "$WORKDIR/existing-assets")
  do
    base=$(basename "$file")
    desc=$(categorize_asset "$base")
    ct=$(content_type "$base")
    encbase=$(ruby -ruri -e 'print URI.escape(ARGV[0])' "$base")
    encdesc=$(ruby -ruri -e 'print URI.escape(ARGV[0])' "$desc")

    say "\tUploading %s as \"%s\" (Content-Type %s)..." "$base" "$desc" "$ct"
    curl -d"@$file" -H'Accept: application/vnd.github.v3+json' \
      -H"Content-Type: $ct" "$upload_url?name=$encbase&label=$encdesc" \
       > /dev/null
  done
}

# Provide a helpful usage message and exit.
usage () {
  local status="$1"
  cat <<EOM
Usage: $0 VERSION CHANGELOG

Create a draft GitHub release for Git LFS using the tag specified by VERSION and
the changelog specified in the file CHANGELOG. Before running this script, the
release assets should be built and ready for upload, including the signed
sha256sums.asc file.

This script requires ruby, curl, shasum, and jq.
EOM
  exit $status
}

# The main program.
main () {
  local version="$1"
  local changelog="$2"

  [ "$version" = "--help" ] && usage 0
  [ -z "$changelog" ] && usage 1 >&2

  say "Checking that you've got some release artifacts..."
  [ -n "$(release_files "$version")" ] || \
    abort "I couldn't find any release files for $version."

  say "Looking for the necessary entries in .netrc..."
  grep -qsF api.github.com "$HOME/.netrc" || \
    abort "I couldn't find api.github.com in your .netrc."
  grep -qsF uploads.github.com "$HOME/.netrc" || \
    abort "I couldn't find uploads.github.com in your .netrc."

  say "Okay, everything looks good."

  say "Formatting the body of the GitHub release now..."

  local bodyfile=$(finalize_body_message "$version" "$changelog")

  say "Creating a GitHub release for %s..." "$version"

  local upload_url=$(create_release "$version" "$bodyfile")

  say "Uploading assets to GitHub..."
  upload_assets "$version" "$upload_url"

  say "Okay, done. Sanity-check the release and publish it."
}

main "$@"