class AWS::Glacier::ArchiveCollection

def [] archive_id
  Archive.new(vault, archive_id, :config => config, :account_id => account_id)
end

def compute_checksums data
  digest = OpenSSL::Digest::Digest.new('sha256')
  tree_digest = OpenSSL::Digest::Digest.new('sha256')
  tree_parts = []
  until data.eof?
    chunk = data.read(1024 * 1024) # read 1MB
    tree_parts << tree_digest.update(chunk).digest
    tree_digest.reset
    digest.update(chunk)
  end
  data.rewind
  [digest.to_s, compute_tree_hash(tree_parts)]
end

def compute_tree_hash hashes
  digest = OpenSSL::Digest::Digest.new('sha256')
  until hashes.count == 1
    hashes = hashes.each_slice(2).map do |h1,h2|
      digest.reset
      if h2
        digest.update(h1)
        digest.update(h2)
        digest.digest
      else
        h1
      end
    end
  end
  hashes.first.bytes.map{|x| x.to_i.to_s(16).rjust(2,'0')}.join('')
end

def convert_to_io data
  return Core::ManagedFile.open(data) if
    data.is_a?(Pathname) or data.is_a?(String)
  return data if io_like?(data)
  msg = "expected data to be IO-like or a file path (String/Pathanme)."
  raise ArgumentError, msg
end

def create data, options = {}
  data = convert_to_io(data)
  hash, tree_hash = compute_checksums(data)
  upload_options = {}
  upload_options[:vault_name] = vault.name
  upload_options[:account_id] = account_id
  upload_options[:body] = data
  upload_options[:checksum] = tree_hash
  upload_options[:content_sha256] = hash
  upload_options[:archive_description] = options[:description] if
    options[:description]
  resp = client.upload_archive(upload_options)
  self[resp[:archive_id]]
end

def initialize vault, options = {}
  @vault = vault
  @account_id = options[:account_id] || '-'
  super
end

def io_like? data
  data.respond_to?(:read) and
  data.respond_to?(:eof?) and
  data.respond_to?(:rewind) and
  data.respond_to?(:size)
end