#!/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
}

uri_encode () {
  ruby -e 'print ARGV[0].gsub(/[^A-Za-z0-9_.-]/) { |x| "%%%02x" % x.ord }' "$1"
}

curl () {
  if [ -n "$GITHUB_TOKEN" ]
  then
    command curl -u "token:$GITHUB_TOKEN" -fSs "$@"
  else
    command curl -nfSs "$@"
  fi
}

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"

  if [ "$arch" = "ppc64le" ]
  then
    echo "Little-endian 64-bit PowerPC"
  elif [ "$arch" = "riscv64" ]
  then
    echo "64-bit RISC-V"
  elif [ "$arch" = "loong64" ]
  then
    echo "64-bit LoongArch"
  else
    echo "$arch" | tr a-z A-Z
  fi
}

# 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 "$file" in
    git-lfs-v*.*.*.tar.gz)
      echo "Source";;
    git-lfs-windows-v*.*.*.exe)
      echo "Windows Installer";;
    sha256sums)
      echo "Unsigned SHA-256 Hashes";;
    sha256sums.asc)
      echo "Signed SHA-256 Hashes";;
    hashes)
      echo "Unsigned Hashes";;
    hashes.asc)
      echo "Signed Hashes";;
    *)
      printf "%s %s\n" "$(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|sha256sums*|hashes*)
      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'
}

# Update the draft release with a new body and print the upload URL for release assets to the
# standard output.  A release with the given version must already exist.
patch_release () {
  local version="$1"
  local bodyfile="$2"

  # Find the URL of this release.
  local url=$(curl https://api.github.com/repos/$REPO/releases | \
    jq -r '.[] | select(.name == "'"$version"'") | .url')

  [ -n "$url" ] || abort "No existing release found for version $version."
  say "Found the existing release for this version."

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

  curl -XPATCH -H'Content-Type: application/json' -d"@$WORKDIR/release-json" \
    $url | \
    jq -r '.upload_url' |
    sed -e 's/{.*}//g'
}

# Find the release files for the given version.
release_files () {
  local version="$1"
  local assets="${2:-bin/releases}"

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

  find "$assets" -name '*.tar.gz' -o \
      -name '*386*.zip' -o \
      -name '*amd64*.zip' -o \
      -name '*arm64*.zip' -o \
      -name '*.exe' -o \
      -name 'sha256sums.asc' -o \
      -name 'hashes.asc' | \
    grep -E "$version|sha256sums.asc|hashes.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"
  local assets="$3"

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

  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/).

$(script/distro-tool --distro-markdown)

## SHA-256 hashes:
EOM

  shasum -a256 $(release_files "$version" "$assets") | \
    ruby -pe '$_.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 src="$3"
  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" "$src" | filter_files "$WORKDIR/existing-assets")
  do
    base=$(basename "$file")
    desc=$(categorize_asset "$base")
    ct=$(content_type "$base")
    encbase=$(uri_encode "$base")
    encdesc=$(uri_encode "$desc")

    say "\tUploading %s as \"%s\" (Content-Type %s)..." "$base" "$desc" "$ct"
    curl --data-binary "@$file" -H'Accept: application/vnd.github.v3+json' \
      -H"Content-Type: $ct" "$upload_url?name=$encbase&label=$encdesc" \
      >"$WORKDIR/response"
    download=$(jq -r '.url' "$WORKDIR/response")
  done

  say "Assets uploaded."
}

# Download assets from GitHub to the specified directory.
download_assets () {
  local version="$1"
  local dir="$2"

  curl https://api.github.com/repos/$REPO/releases | \
    jq -rc '.[] | select(.name == "'"$version"'") | .assets | .[] | [.name,.url]' | \
    ruby -rjson -ne 'puts JSON.parse($_).join(" ")' \
    > "$WORKDIR/assets"

  cat "$WORKDIR/assets" | (while read base url
  do
    say "\tDownloading %s..." "$base"
    (
      cd "$dir" &&
      curl -Lo "$base" -H"Accept: application/octet-stream" "$url"
    )
  done)
}

# Download the assets and verify the signature made on them.
verify_assets () {
  local version="$1"
  local dir="$WORKDIR/verify"
  mkdir "$dir"
  download_assets "$version" "$dir"

  # If the OpenPGP data is not valid, gpg -d will output nothing to stdout, and
  # shasum will then fail.
  say "Checking assets for integrity with SHA-256..."
  (cd "$dir" && gpg -d sha256sums.asc | shasum -a 256 -c)
  say "Checking assets for integrity with SHA-2..."
  (cd "$dir" && gpg -d hashes.asc | grep 'SHA[0-9][^-]' | shasum -c)
  if command -v sha3sum >/dev/null 2>&1
  then
    say "Checking assets for integrity with SHA-3..."
    (cd "$dir" && gpg -d hashes.asc | grep 'SHA3-' | sha3sum -c)
  fi
  if command -v b2sum >/dev/null 2>&1
  then
    say "Checking assets for integrity with BLAKE2b..."
    # b2sum on Linux does not handle BLAKE2s, only BLAKE2b.
    (cd "$dir" && gpg -d hashes.asc | grep 'BLAKE2b' | b2sum -c)
  fi

  say "\nAssets look good!"
}

# Extract the changelog for the given version from the history and save it in a
# file.  Print the filename of the changelog to standard output.
extract_changelog () {
  local version="$1"

  git cat-file blob "$version:CHANGELOG.md" | \
  ruby -ne "version=%Q($version)[1..-1]; state ||= :silent; text ||= [];" \
    -e 'if state == :print && $_.start_with?("## "); puts text.join.strip; exit; end;' \
    -e 'text << $_ if state == :print;' \
    -e 'state = :print if $_.start_with?("## #{version}")' \
    > "$WORKDIR/changelog"
  echo "$WORKDIR/changelog"
}

# Perform the final steps to verify a release
finalize () {
  local version="$1"
  local inspect="$2"
  local downloads="$WORKDIR/finalize"
  local uploads="$WORKDIR/finalize-uploads"

  say "Finalizing the release process..."
  say "Downloading assets..."

  mkdir "$downloads"
  mkdir "$uploads"
  download_assets "$version" "$downloads"

  if [ -n "$inspect" ]
  then
    say "Dropping you to a shell to inspect the assets."
    say "Type 'exit 0' to continue, or 'exit 1' to abort."

    (cd "$downloads" && $SHELL)
  fi

  say "Signing asset manifest..."
  (
    root="$(git rev-parse --show-toplevel)" &&
    cd "$downloads" && \
    shasum -a256 -b * | grep -vE '(assets|sha256sums|hashes)' | \
        gpg --digest-algo SHA256 --clearsign >sha256sums.asc &&
    "$root/script/hash-files" * | grep -vE '(assets|sha256sums|hashes)' | \
        gpg --digest-algo SHA512 --clearsign >hashes.asc
  )

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

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

  say "Uploading final release body..."

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

  say "Uploading final versions of assets..."
  cp "$downloads/sha256sums.asc" "$downloads/hashes.asc" "$uploads"
  upload_assets "$version" "$upload_url" "$uploads"

  # Verification occurs in caller below.
}

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

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 and hashes.asc files.

This script requires ruby, gpg, curl, shasum, and jq.  sha3sum and b2sum will be
used if available, but are optional.

This command must be run from within the repository.
EOM
  exit $status
}

# Check that this script has the prerequisites to continue.
sanity_check () {
  local version="$1"
  local finalize="$2"

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

  if [ -n "$GITHUB_TOKEN" ]
  then
    say "Found a token in the GITHUB_TOKEN environment variable."
  else
    say "Looking for the necessary entries in .netrc..."
    grep -qsF api.github.com "$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."
  fi

  say "Okay, everything looks good."
}

# The main program.
main () {
  local inspect=""

  while [ -n "$1" ]
  do
    case "$1" in
      --help)
        usage 0;;
      --inspect)
        inspect=1
        shift;;
      --skip-verify)
        SKIP_VERIFY=1
        shift;;
      --finalize)
        FINALIZE=1
        shift;;
      --)
        shift
        break;;
      *)
        break;;
    esac
  done

  local version="$1"

  [ -z "$version" ] && usage 1 >&2

  sanity_check "$version" "$FINALIZE"

  if [ -n "$FINALIZE" ]
  then
    finalize "$version" "$inspect"
  else
    say "Formatting the body of the GitHub release now..."

    local changelog=$(extract_changelog "$version")
    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" bin/releases
  fi

  if [ -z "$SKIP_VERIFY" ]
  then
    say "Verifying assets..."
    verify_assets "$version"
  fi

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

main "$@"