application_controller.rb

# frozen_string_literal: true

class ApplicationController < ActionController::Base
  after_action :allow_iframe
  before_action :set_locale
  rescue_from ActionController::RoutingError, with: :not_found

  def not_found
    redirect_to '/'
  end

  def fetch_locale
    if @locale
      return @locale
    end

    requested_locale = params[:locale] ||
        session[:locale] ||
        cookies[:locale] ||
        extract_browser_locale(request.env['HTTP_ACCEPT_LANGUAGE']) ||
        I18n.default_locale

    @locale = requested_locale.to_s.split('-').first
  end

  protected
  def allow_iframe
    response.headers.except! 'X-Frame-Options'
  end

  def set_locale
    locale = fetch_locale
    locale = I18n.default_locale unless I18n.available_locales.include?(locale.to_sym)

    session[:locale] = locale
    I18n.locale = locale
  end

  def handle_routing_error
    redirect_to '/'
  end
end