#!/usr/bin/env bash
set -e

usage() {
  echo "usage: ruby-package fetch [--check] PACKAGE" >&2
  exit 1
}

check() {
  local url="$1"

  set +e
  curl -ILfs "$url" >/dev/null
  local result="$?"
  set -e

  if [ "$result" -ne 0 ]; then
    return 1
  fi
}

download() {
  local url="$1"
  local filename="$2"

  set +e
  curl -Lfs "$url" > "$filename"
  local result="$?"
  set -e

  if [ "$result" -ne 0 ]; then
    return 1
  elif [ ! -f "$filename" ]; then
    return 1
  else
    echo "$filename"
  fi
}

check=""
if [ "$1" = "--check" ]; then
  check=1
  shift
fi

package="$1"
if [ -z "$package" ]; then
  usage
fi

package_name="${package}.$(ruby-package platform).rubypackage"

package_repo="${RUBY_PACKAGE_REPO%/}"
if [ -z "$ruby_package_repo" ]; then
  package_repo="https://github.com/downloads/sstephenson/ruby-packages"
fi

package_url="${package_repo}/${package_name}"

if [ -n "$check" ]; then
  check "$package_url" || {
    echo "error: package \`$package' not found ($package_url)"
    exit 1
  } >&2
else
  package_filename="${TMPDIR}/${package_name}.$$"
  echo "Downloading $package_url..." >&2
  download "$package_url" "$package_filename" || {
    echo "error: couldn't download package \`$package' ($package_url)"
    exit 1
  } >&2
fi