class Ey::Hmac::Adapter::Faraday < Ey::Hmac::Adapter
  def method
    request[:method].to_s.upcase
  end

  def content_type
    @content_type ||= find_header(
      *%w[CONTENT-TYPE CONTENT_TYPE Content-Type Content_Type]
    )
  end

  def content_digest
    @content_digest ||= find_header(
      *%w[CONTENT-DIGEST CONTENT_DIGEST Content-Digest Content_Digest]
    )
  end

  def set_content_digest
    return if content_digest

    digestable = if body.respond_to?(:rewind)
                   body.rewind
                   body.read.tap { |_| body.rewind }
                 else
                   body.to_s
                 end

    if digestable && digestable != ""
      @content_digest = request[:request_headers]['Content-Digest'] = Digest::MD5.hexdigest(digestable)
    end
  end

  def body
    if request[:body] && request[:body].to_s != ""
      request[:body]
    end
  end

  def date
    find_header(*%w[DATE Date])
  end

  def set_date
    unless date
      request[:request_headers]['Date'] = Time.now.httpdate
    end
  end

  def path
    request[:url].path
  end

  def sign!(key_id, key_secret)
    set_content_digest
    set_date

    if options[:version]
      request[:request_headers]['X-Signature-Version'] = options[:version]
    end

    request[:request_headers][authorization_header] = authorization(key_id, key_secret)
  end

  def authorization_signature
    find_header(*%w[Authorization AUTHORIZATION])
  end

  private

  def find_header(*keys)
    value = nil
    keys.find { |k| value = request[:request_headers][k] }
    value
  end
end