install

#!/usr/bin/env bash
set -euo pipefail

repo="${OPENKNOWLEDGE_REPO:-openknowledge-sh/openknowledge}"
version="${OPENKNOWLEDGE_VERSION:-latest}"
base_url="${OPENKNOWLEDGE_BASE_URL:-}"
install_dir="${OPENKNOWLEDGE_INSTALL_DIR:-$HOME/.local/bin}"
binary="openknowledge"
tmp=""
staging=""

cleanup() {
  if [ -n "$staging" ]; then
    rm -f -- "$staging"
  fi
  if [ -n "$tmp" ]; then
    rm -rf -- "$tmp"
  fi
}

trap cleanup EXIT

need() {
  if ! command -v "$1" >/dev/null 2>&1; then
    echo "openknowledge install: missing required command: $1" >&2
    exit 1
  fi
}

detect_os() {
  case "$(uname -s)" in
    Darwin) echo "darwin" ;;
    Linux) echo "linux" ;;
    *)
      echo "openknowledge install: unsupported OS: $(uname -s)" >&2
      exit 1
      ;;
  esac
}

detect_arch() {
  case "$(uname -m)" in
    x86_64 | amd64) echo "amd64" ;;
    arm64 | aarch64) echo "arm64" ;;
    *)
      echo "openknowledge install: unsupported architecture: $(uname -m)" >&2
      exit 1
      ;;
  esac
}

release_base() {
  if [ -n "$base_url" ]; then
    echo "${base_url%/}"
    return
  fi

  if [ "$version" = "latest" ]; then
    echo "https://github.com/$repo/releases/latest/download"
    return
  fi

  tag="${version#v}"
  echo "https://github.com/$repo/releases/download/v$tag"
}

checksum_line() {
  checksums="$1"
  asset="$2"

  while read -r sum file extra; do
    if [ "$file" = "$asset" ] && [ -z "${extra:-}" ]; then
      if ! [[ "$sum" =~ ^[0-9a-fA-F]{64}$ ]]; then
        echo "openknowledge install: invalid checksum for $asset" >&2
        return 1
      fi
      printf '%s  %s\n' "$sum" "$file"
      return 0
    fi
  done < "$checksums"

  return 1
}

verify_checksum() {
  checksums="$1"
  archive="$2"
  asset="$3"

  line="$(checksum_line "$checksums" "$asset" || true)"
  if [ -z "$line" ]; then
    echo "openknowledge install: checksum missing for $asset" >&2
    exit 1
  fi

  if command -v sha256sum >/dev/null 2>&1; then
    (cd "$(dirname "$archive")" && printf '%s\n' "$line" | sha256sum -c -)
    return
  fi

  if command -v shasum >/dev/null 2>&1; then
    (cd "$(dirname "$archive")" && printf '%s\n' "$line" | shasum -a 256 -c -)
    return
  fi

  echo "openknowledge install: missing sha256sum or shasum for checksum verification" >&2
  exit 1
}

need curl
need tar
need install

if [ "$version" != "latest" ] && ! [[ "${version#v}" =~ ^[0-9]+\.[0-9]+\.[0-9]+(-[0-9A-Za-z.-]+)?$ ]]; then
  echo "openknowledge install: version must be latest or a semantic version" >&2
  exit 1
fi
if [ -z "$base_url" ] && ! [[ "$repo" =~ ^[A-Za-z0-9_.-]+/[A-Za-z0-9_.-]+$ ]]; then
  echo "openknowledge install: repository must use owner/name" >&2
  exit 1
fi

os="$(detect_os)"
arch="$(detect_arch)"
base="$(release_base)"
asset="openknowledge_${os}_${arch}.tar.gz"
tmp="$(mktemp -d)"

archive="$tmp/$asset"
checksums="$tmp/checksums.txt"

echo "Installing openknowledge from $base"
curl_options=(--fail --silent --show-error --location --connect-timeout 15 --max-time 600 --retry 3)
if [ -z "$base_url" ]; then
  curl_options+=(--proto '=https' --tlsv1.2)
fi
curl "${curl_options[@]}" "$base/$asset" -o "$archive"
curl "${curl_options[@]}" "$base/checksums.txt" -o "$checksums"
verify_checksum "$checksums" "$archive" "$asset"

candidate="$tmp/$binary.candidate"
if ! tar -xOzf "$archive" "$binary" > "$candidate"; then
  echo "openknowledge install: archive did not contain $binary" >&2
  exit 1
fi
if [ ! -s "$candidate" ]; then
  echo "openknowledge install: extracted $binary is empty" >&2
  exit 1
fi

mkdir -p "$install_dir"
destination="$install_dir/$binary"
if { [ -e "$destination" ] || [ -L "$destination" ]; } && [ ! -f "$destination" ] && [ ! -L "$destination" ]; then
  echo "openknowledge install: destination is not a regular file: $destination" >&2
  exit 1
fi
staging="$(mktemp "$install_dir/.openknowledge.install.XXXXXX")"
install -m 0755 "$candidate" "$staging"

if ! candidate_version="$("$staging" version)"; then
  echo "openknowledge install: downloaded binary failed its version preflight" >&2
  exit 1
fi
if ! [[ "$candidate_version" =~ ^[0-9]+\.[0-9]+\.[0-9]+(-[0-9A-Za-z.-]+)?$ ]]; then
  echo "openknowledge install: downloaded binary reported an invalid version: $candidate_version" >&2
  exit 1
fi
if [ "$version" != "latest" ] && [ "$candidate_version" != "${version#v}" ]; then
  echo "openknowledge install: downloaded binary is $candidate_version, expected ${version#v}" >&2
  exit 1
fi

mv -f -- "$staging" "$destination"
staging=""

echo "Installed $candidate_version to $destination"

case ":$PATH:" in
  *":$install_dir:"*) ;;
  *)
    echo "Add $install_dir to PATH to run openknowledge from any shell."
    ;;
esac