# Copyright (C) 2010  Red Hat, Inc.
#
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.  The
# ASF licenses this file to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance with the
# License.  You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
# License for the specific language governing permissions and limitations
# under the License.

begin
  require 'eventmachine'
  #--
  # based on the example from http://macournoyer.com/blog/2009/06/04/pusher-and-async-with-thin/
  #--
  class BlobStream
    AsyncResponse = [-1, {}, []].freeze
    def self.call(env, credentials, params)
      body = DeferrableBody.new
      #Get the headers out asap. Don't specify a content-type let
      #the client guess and if they can't they SHOULD default to
      #'application/octet-stream' anyway as per:
      #http://www.w3.org/Protocols/rfc2616/rfc2616-sec7.html#sec7.2.1
      EM.next_tick { env['async.callback'].call [200, {
        'Content-Type' => "#{params['content_type']}",
        'Content-Disposition' => params["content_disposition"],
        'Content-Length' => "#{params['content_length']}"}, body] 
      }
      #call the driver from here. the driver method yields for every chunk of blob it receives. We then
      #use body.call to write that chunk as received.
      driver.blob_data(credentials, params[:bucket], params[:blob], params) {|chunk| body.call ["#{chunk}"]} #close blob_data block
      body.succeed
      AsyncResponse # Tells Thin to not close the connection and continue it's work on other request
    end
  end

  class DeferrableBody
    include EventMachine::Deferrable

    def call(body)
      body.each do |chunk|
        @body_callback.call(chunk)
      end
    end

    def each(&blk)
      @body_callback = blk
    end
  end
rescue LoadError => e
  # EventMachine isn't available, disable blob streaming
  class BlobStream
    def self.call(env, credentials, params)
      raise NotImplementedError.new("Blob streaming is only supported under Thin")
    end
  end
end