module ActiveStorage::Streaming

def send_blob_byte_range_data(blob, range_header, disposition: nil)
  ranges = Rack::Utils.get_byte_ranges(range_header, blob.byte_size)
  return head(:range_not_satisfiable) if ranges.blank? || ranges.all?(&:blank?)
  if ranges.length == 1
    range = ranges.first
    content_type = blob.content_type_for_serving
    data = blob.download_chunk(range)
    response.headers["Content-Range"] = "bytes #{range.begin}-#{range.end}/#{blob.byte_size}"
  else
    boundary = SecureRandom.hex
    content_type = "multipart/byteranges; boundary=#{boundary}"
    data = +""
    ranges.compact.each do |range|
      chunk = blob.download_chunk(range)
      data << "\r\n--#{boundary}\r\n"
      data << "Content-Type: #{blob.content_type_for_serving}\r\n"
      data << "Content-Range: bytes #{range.begin}-#{range.end}/#{blob.byte_size}\r\n\r\n"
      data << chunk
    end
    data << "\r\n--#{boundary}--\r\n"
  end
  response.headers["Accept-Ranges"] = "bytes"
  response.headers["Content-Length"] = data.length.to_s
  send_data(
    data,
    disposition: blob.forced_disposition_for_serving || disposition || DEFAULT_BLOB_STREAMING_DISPOSITION,
    filename: blob.filename.sanitized,
    status: :partial_content,
    type: content_type
  )
end

def send_blob_stream(blob, disposition: nil) # :doc:
  send_stream(
      filename: blob.filename.sanitized,
      disposition: blob.forced_disposition_for_serving || disposition || DEFAULT_BLOB_STREAMING_DISPOSITION,
      type: blob.content_type_for_serving) do |stream|
    blob.download do |chunk|
      stream.write chunk
    end
  end
end