#!/usr/bin/env sh

# If the first argument to this script is "latest" or unset, it fetches the
# latest proxy binary from the linkerd2-proxy github releases. If it's set to
# a linkerd2-proxy version number (such as v2.76.0), it will fetch the binary
# matching that version number instead.

set -eu

bindir=$( cd "${0%/*}" && pwd )
rootdir=$( cd "$bindir"/.. && pwd )
builddir="$rootdir/target/proxy"

proxy_repo="${LINKERD2_PROXY_REPO:-}"
if [ -z "$proxy_repo" ]; then
  proxy_repo=linkerd/linkerd2-proxy
fi

releases_url=https://api.github.com/repos/"$proxy_repo"/releases
release_prefix="${LINKERD2_PROXY_RELEASE_PREFIX:-release/}"

github_token="${GITHUB_TOKEN:-}"
if [ -z "$github_token" ] && [ -n "${GITHUB_TOKEN_FILE:-}" ] && [ -f "$GITHUB_TOKEN_FILE" ]; then
  github_token=$(cat "$GITHUB_TOKEN_FILE")
fi

ghcurl() {
  if [ -n "${github_token:-}" ]; then
    "$bindir"/scurl -H "Authorization: Bearer ${github_token:-}" "$@"
  else
    "$bindir"/scurl "$@"
  fi
}

mkdir -p "$builddir"
cd "$builddir"

version=${1:-latest}
arch=${2:-amd64}
if [ "$version" = latest ]; then
  ghcurl "$releases_url"/latest > release.json
  version=$(jq -r .tag_name release.json | sed 's,^'"${release_prefix}"',,')
else
  tag="${release_prefix}${version}"
  ghcurl "$releases_url"/tags/"$(printf "$tag" | jq -sRr @uri)" > release.json
fi

pkgname="linkerd2-proxy-${version}-${arch}"

pkgfile="${pkgname}.tar.gz"
pkgurl=$(jq -r '.assets[] | select(.name == "'"$pkgfile"'") | .url' release.json)
ghcurl -H 'Accept: application/octet-stream' -o "$pkgfile" "$pkgurl"

shafile="${pkgname}.txt"
shaurl=$(jq -r '.assets[] | select(.name == "'"$shafile"'") | .url' release.json)
ghcurl -H 'Accept: application/octet-stream' -o "$shafile" "$shaurl"

tar -zxvf "$pkgfile" >&2
expected=$(awk '{print $1}' "$shafile")
if [ "$(uname)" = "Darwin" ]; then
  computed=$(openssl dgst -sha256 "$pkgfile" | awk '{print $2}')
else
  computed=$(sha256sum "$pkgfile" | awk '{print $1}')
fi
if [ "$computed" != "$expected" ]; then
  echo 'sha mismatch' >&2
  exit 1
fi

mv "$pkgname/LICENSE" .
mv "$pkgname/linkerd2-proxy" .
rm -r "$pkgfile" "$pkgname"
mv linkerd2-proxy "$pkgname"
echo "$builddir/$pkgname"