class Restforce::Middleware::Multipart

def call(env)
  match_content_type(env) do |params|
    env[:request] ||= {}
    env[:request][:boundary] ||= DEFAULT_BOUNDARY
    env[:request_headers][CONTENT_TYPE] += ";boundary=#{env[:request][:boundary]}"
    env[:body] = create_multipart(env, params)
  end
  @app.call env
end

def create_multipart(env, params)
  boundary = env[:request][:boundary]
  parts = []
  # Fields
  parts << Faraday::Parts::Part.new(
    boundary,
    'entity_content',
    params.reject { |k, v| v.respond_to? :content_type }.to_json,
    JSON_CONTENT_TYPE
  )
  # Files
  params.each do |k, v|
    next unless v.respond_to? :content_type
    parts << Faraday::Parts::Part.new(boundary,
                                      k.to_s,
                                      v)
  end
  parts << Faraday::Parts::EpiloguePart.new(boundary)
  body = Faraday::CompositeReadIO.new(parts)
  env[:request_headers]['Content-Length'] = body.length.to_s
  body
end

def has_multipart?(obj)
  # string is an enum in 1.8, returning list of itself
  if obj.respond_to?(:each) && !obj.is_a?(String)
    (obj.respond_to?(:values) ? obj.values : obj).each do |val|
      return true if val.respond_to?(:content_type) || has_multipart?(val)
    end
  end
  false
end

def process_request?(env)
  type = request_type(env)
  env[:body].respond_to?(:each_key) && !env[:body].empty? && (
    (type.empty? && has_multipart?(env[:body])) ||
    type == self.class.mime_type
  )
end