#!/bin/sh
set -eu

error() {
  printf 'trackstore: %s\n' "$*" >&2
  exit 1
}

download() {
  if command -v curl >/dev/null 2>&1; then
    curl -fsSL "$1" -o "$2" || error "download failed: $1"
  elif command -v wget >/dev/null 2>&1; then
    wget -qO- "$1" >"$2" || error "download failed: $1"
  else
    error "curl or wget is required"
  fi
}

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

main() {
  base=${TRACKSTORE_BASE_URL:-https://monorail.sh/trackstore}
  system=$(uname -s) || error "could not determine operating system"
  machine=$(uname -m) || error "could not determine machine architecture"

  case "$system" in
    Darwin) os=darwin ;;
    Linux) os=linux ;;
    *) error "unsupported platform $system/$machine; binaries exist for darwin-arm64, darwin-x64, linux-arm64, linux-x64" ;;
  esac

  case "$machine" in
    arm64|aarch64) arch=arm64 ;;
    x86_64|amd64) arch=x64 ;;
    *) error "unsupported platform $system/$machine; binaries exist for darwin-arm64, darwin-x64, linux-arm64, linux-x64" ;;
  esac

  tmp_dir=
  staging=
  trap cleanup 0
  trap 'exit 1' 1 2 15
  tmp_dir=$(mktemp -d) || error "could not create temporary directory"

  version=${TRACKSTORE_VERSION:-}
  if [ -n "$version" ]; then
    version=${version#v}
  else
    download "$base/latest.json" "$tmp_dir/latest.json"
    version=$(sed -n 's/.*"version"[[:space:]]*:[[:space:]]*"\([^"]*\)".*/\1/p' "$tmp_dir/latest.json" | sed -n '1p')
  fi

  case "$version" in
    ''|*[!0-9A-Za-z.+_-]*) error "could not determine a valid release version" ;;
  esac

  filename=trackstore-$os-$arch
  download "$base/v$version/$filename" "$tmp_dir/$filename"
  download "$base/v$version/SHA256SUMS" "$tmp_dir/SHA256SUMS"

  expected_hash=
  while IFS=' ' read -r hash listed_file; do
    case "$listed_file" in
      "$filename"|\*"$filename")
        expected_hash=$hash
        break
        ;;
    esac
  done <"$tmp_dir/SHA256SUMS"
  [ -n "$expected_hash" ] || error "checksum for $filename not found"

  if command -v sha256sum >/dev/null 2>&1; then
    hash_output=$(sha256sum "$tmp_dir/$filename") || error "could not compute checksum"
  elif command -v shasum >/dev/null 2>&1; then
    hash_output=$(shasum -a 256 "$tmp_dir/$filename") || error "could not compute checksum"
  else
    error "sha256sum or shasum is required"
  fi
  actual_hash=${hash_output%% *}
  [ "$actual_hash" = "$expected_hash" ] || error "checksum mismatch for $filename"

  if [ -n "${TRACKSTORE_INSTALL_DIR:-}" ]; then
    dir=$TRACKSTORE_INSTALL_DIR
  else
    home=${HOME:-}
    [ -n "$home" ] || error "HOME is not set"
    dir=$home/.local/bin
  fi

  mkdir -p "$dir" || error "could not create install directory $dir"
  staging=$dir/.trackstore.$$
  cp "$tmp_dir/$filename" "$staging" || error "could not copy binary to $staging"
  chmod 755 "$staging" || error "could not set executable permissions on $staging"
  mv -f "$staging" "$dir/trackstore" || error "could not install $dir/trackstore"
  staging=

  case ":${PATH:-}:" in
    *":$dir:"*) ;;
    *)
      printf "trackstore: warning: %s is not on PATH; add:\n  export PATH=\"%s:\$PATH\"\n" "$dir" "$dir" >&2
      ;;
  esac

  "$dir/trackstore" version
}

main "$@"