class ActiveStorage::Service::GCSService

def bucket
  @bucket ||= client.bucket(config.fetch(:bucket))
end

def client
  @client ||= Google::Cloud::Storage.new(config.except(:bucket))
end

def delete(key)
  instrument :delete, key do
    begin
      file_for(key).delete
    rescue Google::Cloud::NotFoundError
      # Ignore files already deleted
    end
  end
end

def download(key)
  instrument :download, key do
    io = file_for(key).download
    io.rewind
    if block_given?
      yield io.read
    else
      io.read
    end
  end
end

def exist?(key)
  instrument :exist, key do |payload|
    answer = file_for(key).exists?
    payload[:exist] = answer
    answer
  end
end

def file_for(key)
  bucket.file(key, skip_lookup: true)
end

def headers_for_direct_upload(key, content_type:, checksum:, **)
  { "Content-Type" => content_type, "Content-MD5" => checksum }
end

def initialize(**config)
  @config = config
end

def upload(key, io, checksum: nil)
  instrument :upload, key, checksum: checksum do
    begin
      bucket.create_file(io, key, md5: checksum)
    rescue Google::Cloud::InvalidArgumentError
      raise ActiveStorage::IntegrityError
    end
  end
end

def url(key, expires_in:, filename:, content_type:, disposition:)
  instrument :url, key do |payload|
    generated_url = file_for(key).signed_url expires: expires_in, query: {
      "response-content-disposition" => content_disposition_with(type: disposition, filename: filename),
      "response-content-type" => content_type
    }
    payload[:url] = generated_url
    generated_url
  end
end

def url_for_direct_upload(key, expires_in:, content_type:, content_length:, checksum:)
  instrument :url, key do |payload|
    generated_url = bucket.signed_url key, method: "PUT", expires: expires_in,
      content_type: content_type, content_md5: checksum
    payload[:url] = generated_url
    generated_url
  end
end