module ViewComponent::Translatable

def build_i18n_backend
  return if compiled?
  # We need to load the translations files from the ancestors so a component
  # can inherit translations from its parent and is able to overwrite them.
  translation_files = ancestors.reverse_each.with_object([]) do |ancestor, files|
    if ancestor.is_a?(Class) && ancestor < ViewComponent::Base
      files.concat(ancestor.sidecar_files(TRANSLATION_EXTENSIONS))
    end
  end
  # In development it will become nil if the translations file is removed
  self.i18n_backend = if translation_files.any?
    I18nBackend.new(
      i18n_scope: i18n_scope,
      load_paths: translation_files
    )
  end
end

def html_escape_translation_options!(options)
  options.except(*::I18n::RESERVED_KEYS).each do |name, value|
    next if name == :count && value.is_a?(Numeric)
    options[name] = ERB::Util.html_escape(value.to_s)
  end
end

def html_safe_translation(translation)
  if translation.respond_to?(:map)
    translation.map { |element| html_safe_translation(element) }
  else
    # It's assumed here that objects loaded by the i18n backend will respond to `#html_safe?`.
    # It's reasonable that if we're in Rails, `active_support/core_ext/string/output_safety.rb`
    # will provide this to `Object`.
    translation.html_safe
  end
end

def i18n_key(key, scope = nil)
  scope = scope.join(".") if scope.is_a? Array
  key = key&.to_s unless key.is_a?(String)
  key = "#{scope}.#{key}" if scope
  key = "#{i18n_scope}#{key}" if key.start_with?(".")
  key
end

def i18n_scope
  @i18n_scope ||= virtual_path.sub(%r{^/}, "").gsub(%r{/_?}, ".")
end

def i18n_scope
  self.class.i18n_scope
end

def translate(key = nil, **options)
  return key.map { |k| translate(k, **options) } if key.is_a?(Array)
  ensure_compiled
  locale = options.delete(:locale) || ::I18n.locale
  key = i18n_key(key, options.delete(:scope))
  i18n_backend.translate(locale, key, options)
end

def translate(key = nil, **options)
  raise ViewComponent::TranslateCalledBeforeRenderError if view_context.nil?
  return super unless i18n_backend
  return key.map { |k| translate(k, **options) } if key.is_a?(Array)
  locale = options.delete(:locale) || ::I18n.locale
  key = self.class.i18n_key(key, options.delete(:scope))
  as_html = HTML_SAFE_TRANSLATION_KEY.match?(key)
  html_escape_translation_options!(options) if as_html
  if key.start_with?(i18n_scope + ".")
    translated =
      catch(:exception) do
        i18n_backend.translate(locale, key, options)
      end
    # Fallback to the global translations
    if translated.is_a? ::I18n::MissingTranslation
      return super(key, locale: locale, **options)
    end
    translated = html_safe_translation(translated) if as_html
    translated
  else
    super(key, locale: locale, **options)
  end
end