module I18n::Backend::Base

def available_locales
  raise NotImplementedError
end

def default(locale, object, subject, options = {})
  options = options.dup.reject { |key, value| key == :default }
  case subject
  when Array
    subject.each do |item|
      result = resolve(locale, object, item, options) and return result
    end and nil
  else
    resolve(locale, object, subject, options)
  end
end

def interpolate(locale, string, values = {})
  return string unless string.is_a?(::String) && !values.empty?
  values.each do |key, value|
    value = value.call(values) if interpolate_lambda?(value, string, key)
    value = value.to_s unless value.is_a?(::String)
    values[key] = value
  end
  string % values
rescue KeyError => e
  if string =~ RESERVED_KEYS_PATTERN
    raise ReservedInterpolationKey.new($1.to_sym, string)
  else
    raise MissingInterpolationArgument.new(values, string)
  end
end

def interpolate_lambda?(object, string, key)
  object.respond_to?(:call) && string =~ /%\{#{key}\}|%\<#{key}>.*?\d*\.?\d*[bBdiouxXeEfgGcps]\}/
end

def load_file(filename)
  type = File.extname(filename).tr('.', '').downcase
  raise UnknownFileType.new(type, filename) unless respond_to?(:"load_#{type}", true)
  data = send(:"load_#{type}", filename)
  raise InvalidLocaleData.new(filename) unless data.is_a?(Hash)
  data.each { |locale, d| store_translations(locale, d || {}) }
end

def load_rb(filename)
  eval(IO.read(filename), binding, filename)
end

def load_translations(*filenames)
  filenames = I18n.load_path.flatten if filenames.empty?
  filenames.each { |filename| load_file(filename) }
end

def load_yml(filename)
  YAML.load_file(filename)
end

def localize(locale, object, format = :default, options = {})
  raise ArgumentError, "Object must be a Date, DateTime or Time object. #{object.inspect} given." unless object.respond_to?(:strftime)
  if Symbol === format
    key  = format
    type = object.respond_to?(:sec) ? 'time' : 'date'
    options = options.merge(:raise => true, :object => object, :locale => locale)
    format  = I18n.t(:"#{type}.formats.#{key}", options)
  end
  # format = resolve(locale, object, format, options)
  format = format.to_s.gsub(/%[aAbBp]/) do |match|
    case match
    when '%a' then I18n.t(:"date.abbr_day_names",                  :locale => locale, :format => format)[object.wday]
    when '%A' then I18n.t(:"date.day_names",                       :locale => locale, :format => format)[object.wday]
    when '%b' then I18n.t(:"date.abbr_month_names",                :locale => locale, :format => format)[object.mon]
    when '%B' then I18n.t(:"date.month_names",                     :locale => locale, :format => format)[object.mon]
    when '%p' then I18n.t(:"time.#{object.hour < 12 ? :am : :pm}", :locale => locale, :format => format) if object.respond_to? :hour
    end
  end
  object.strftime(format)
end

def lookup(locale, key, scope = [], options = {})
  raise NotImplementedError
end

def pluralize(locale, entry, count)
  return entry unless entry.is_a?(Hash) && count
  key = :zero if count == 0 && entry.has_key?(:zero)
  key ||= count == 1 ? :one : :other
  raise InvalidPluralizationData.new(entry, count) unless entry.has_key?(key)
  entry[key]
end

def reload!
  @skip_syntax_deprecation = false
end

def resolve(locale, object, subject, options = {})
  return subject if options[:resolve] == false
  case subject
  when Symbol
    I18n.translate(subject, options.merge(:locale => locale, :raise => true))
  when Proc
    date_or_time = options.delete(:object) || object
    resolve(locale, object, subject.call(date_or_time, options))
  else
    subject
  end
rescue MissingTranslationData
  nil
end

def store_translations(locale, data, options = {})
  raise NotImplementedError
end

def translate(locale, key, options = {})
  raise InvalidLocale.new(locale) unless locale
  entry = key && lookup(locale, key, options[:scope], options)
  if options.empty?
    entry = resolve(locale, key, entry, options)
  else
    count, default = options.values_at(:count, :default)
    values = options.except(*RESERVED_KEYS)
    entry = entry.nil? && default ?
      default(locale, key, default, options) : resolve(locale, key, entry, options)
  end
  raise(I18n::MissingTranslationData.new(locale, key, options)) if entry.nil?
  entry = entry.dup if entry.is_a?(String)
  entry = pluralize(locale, entry, count) if count
  entry = interpolate(locale, entry, values) if values
  entry
end

def warn_syntax_deprecation!(locale, string) #:nodoc:
  return if @skip_syntax_deprecation
  warn "The {{key}} interpolation syntax in I18n messages is deprecated. Please use %{key} instead.\n#{locale} - #{string}\n"
  @skip_syntax_deprecation = true
end