module I18n::Backend::Chain::Implementation

def _deep_merge(hash, other_hash)
  copy = hash.dup
  other_hash.each_pair do |k,v|
    value_from_other = hash[k]
    copy[k] = value_from_other.is_a?(Hash) && v.is_a?(Hash) ? _deep_merge(value_from_other, v) : v
  end
  copy
end

def available_locales
  backends.map { |backend| backend.available_locales }.flatten.uniq
end

def eager_load!
  backends.each { |backend| backend.eager_load! }
end

def exists?(locale, key, options = EMPTY_HASH)
  backends.any? do |backend|
    backend.exists?(locale, key, options)
  end
end

def init_translations
  backends.each do |backend|
    backend.send(:init_translations)
  end
end

def initialize(*backends)
  self.backends = backends
end

def initialized?
  backends.all? do |backend|
    backend.instance_eval do
      return false unless initialized?
    end
  end
  true
end

def localize(locale, object, format = :default, options = EMPTY_HASH)
  backends.each do |backend|
    catch(:exception) do
      result = backend.localize(locale, object, format, options) and return result
    end
  end
  throw(:exception, I18n::MissingTranslation.new(locale, format, options))
end

def namespace_lookup?(result, options)
  result.is_a?(Hash) && !options.has_key?(:count)
end

def reload!
  backends.each { |backend| backend.reload! }
end

def store_translations(locale, data, options = EMPTY_HASH)
  backends.first.store_translations(locale, data, options)
end

def translate(locale, key, default_options = EMPTY_HASH)
  namespace = nil
  options = Utils.except(default_options, :default)
  backends.each do |backend|
    catch(:exception) do
      options = default_options if backend == backends.last
      translation = backend.translate(locale, key, options)
      if namespace_lookup?(translation, options)
        namespace = _deep_merge(translation, namespace || {})
      elsif !translation.nil? || (options.key?(:default) && options[:default].nil?)
        return translation
      end
    end
  end
  return namespace if namespace
  throw(:exception, I18n::MissingTranslation.new(locale, key, options))
end

def translations
  backends.reverse.each_with_object({}) do |backend, memo|
    partial_translations = backend.instance_eval do
      init_translations unless initialized?
      translations
    end
    Utils.deep_merge!(memo, partial_translations) { |_, a, b| b || a }
  end
end