class ComplexConfig::Provider

def config(pathname, name = nil)
  datas = []
  path_exist = File.exist?(pathname)
  if path_exist
    datas << IO.binread(pathname)
  end
  decrypted, reason, enc_pathname = decrypt_config_case(pathname)
  case reason
  when :ok
    datas << decrypted
  when :key_missing
    datas.empty? and raise ComplexConfig::EncryptionKeyMissing,
      "encryption key for #{enc_pathname.to_s.inspect} is missing"
  when :file_missing
    datas.empty? and raise ComplexConfig::ConfigurationFileMissing,
      "configuration file #{pathname.to_s.inspect} is missing"
  end
  results = datas.map { |d| evaluate(pathname, d) }
  hashes =
    if ::Psych::VERSION < "4"
      results.map { |r| ::YAML.load(r, pathname) }
    else
      results.map { |r| ::YAML.unsafe_load(r, filename: pathname) }
    end
  settings = ComplexConfig::Settings.build(name, hashes.shift)
  hashes.each { |h| settings.attributes_update(h) }
  if shared = settings.shared?
    shared = shared.to_h
    settings.each do |key, value|
      if value.is_a? ComplexConfig::Settings
        value.attributes_update_if_nil(shared)
      elsif value.nil?
        settings[key] = ComplexConfig::Settings.build(nil, shared.dup)
      end
    end
  end
  deep_freeze? and settings.deep_freeze
  settings
rescue ::Psych::SyntaxError => e
  raise ComplexConfig::ComplexConfigError.wrap(:ConfigurationSyntaxError, e)
end