require 'fog'
require 'digest/md5'
require 'filemagic'
connection = Fog::Storage.new({ :provider => "AWS", :aws_access_key_id => access_key, :aws_secret_access_key => secret_key })

file = File.absolute_path(file)
file_name = "myfiles/#{File.basename(file)}"
file_md5sum = Digest::MD5.file(file).to_s

multipart_uploads = connection.list_multipart_uploads("myS3bucket")

multipart_uploads.data[:body]["Upload"].each do |part|
  if part["Key"] == file_name
    abort_result = connection.abort_multipart_upload(myS3bucket, file_name, part["UploadId"])
  end
end

content_type = FileMagic.new(FileMagic::MAGIC_MIME).file(file).split(';').first

file_temporary_directory = Dir.mktmpdir
file_split_result = system("/usr/bin/split -C 10M -a 4 -d #{file} #{file_temporary_directory}/")

file_md5_parts = {}

file_parts = Dir.glob("#{file_temporary_directory}/*").sort

file_parts.each do |file_part|
  file_md5_parts[file_part] = Digest::MD5.file(file_part).base64digest
end

s3_multipart = connection.initiate_multipart_upload(myS3bucket, file_name, { 'x-amz-acl' => access, 'Content-MD5' => file_md5sum, 'Content-Type' => content_type } )

s3_upload_id = s3_multipart.body["UploadId"]

md5_indices = []
threads = []

file_md5_parts.each_with_index do |file_md5_part, index|
  file_part_number = index + 1

  connection.reload

  threads < < Thread.new(file_md5_part) do |f|
    File.open(file_md5_part[0]) do |part|
      response = connection.upload_part(myS3bucket, file_name, s3_upload_id, file_part_number, part, { 'Content-MD5' => file_md5_part[1] } )
      md5_indices[index] = response.headers['ETag']
    end
  end
end

threads.each do |t|
  begin
    t.join
  rescue Exception => e
    puts "failed upload: #{e.message}"
    exit 1
  end
end

connection.reload

begin
  completed_upload_result = connection.complete_multipart_upload(myS3bucket, file_name, s3_upload_id, md5_indices)
rescue => error
  exit 1 if error.message =~ /400 Bad Request/
end

if completed_upload_result.status == 200
  copy_result = connection.copy_object(myS3bucket, file_name, myS3bucket, file_name, { 'x-amz-metadata-directive' => 'REPLACE' })

  if copy_result.status == 200
    exit 1 if copy_result.data[:body]["ETag"] != file_md5sum
  end
end