module Maglev::Translatable

def add_presence_validator(attributes)
  validate do
    attributes.each do |attribute|
      errors.add(attribute, :blank) if public_send(attribute).blank?
    end
  end
end

def order_by_translated(attr, direction)
  order(translated_arel_attribute(attr, Maglev::I18n.current_locale) => direction)
end

def setup_accessors(attr)
  define_method("#{attr}=") do |value|
    public_send("#{attr}_translations=", translations_for(attr).merge(Maglev::I18n.current_locale.to_s => value))
  end
  define_method(attr) { translations_for(attr)[Maglev::I18n.current_locale.to_s] }
  define_method("default_#{attr}") { translations_for(attr)[Maglev::I18n.default_locale.to_s] }
end

def translate_attr_in(attr, locale, source_locale)
  translations_for(attr)[locale.to_s] ||= translations_for(attr)[source_locale.to_s]
end

def translated_arel_attribute(attr, locale)
  return Arel.sql("#{attr}_translations->>'#{locale}'") unless mysql?
  # MySQL and MariaDB JSON support 🤬🤬🤬
  # Note: doesn't work with Rails 7.0.x
  json_extract = Arel::Nodes::NamedFunction.new(
    'json_extract',
    [Arel::Nodes::SqlLiteral.new("#{attr}_translations"), Arel::Nodes.build_quoted("$.#{locale}")]
  )
  Arel::Nodes::NamedFunction.new('json_unquote', [json_extract])
end

def translates(*attributes, presence: false)
  attributes.each do |attr|
    # MariaDB doesn't support native JSON columns (longtext instead), we need to force it.
    attribute("#{attr}_translations", :json) if respond_to?(:attribute)
    setup_accessors(attr)
  end
  add_presence_validator(attributes) if presence
end

def translations_for(attr)
  # With MySQL, there is no default value for JSON columns, so we need to check for nil
  public_send("#{attr}_translations").presence || {}
end