class ActionView::Helpers::Tags::Base

def add_default_name_and_id(options)
  index = name_and_id_index(options)
  options["name"] = options.fetch("name"){ tag_name(options["multiple"], index) }
  options["id"] = options.fetch("id"){ tag_id(index) }
  if namespace = options.delete("namespace")
    options['id'] = options['id'] ? "#{namespace}_#{options['id']}" : namespace
  end
end

def add_default_name_and_id_for_value(tag_value, options)
  if tag_value.nil?
    add_default_name_and_id(options)
  else
    specified_id = options["id"]
    add_default_name_and_id(options)
    if specified_id.blank? && options["id"].present?
      options["id"] += "_#{sanitized_value(tag_value)}"
    end
  end
end

def add_options(option_tags, options, value = nil)
  if options[:include_blank]
    option_tags = content_tag_string('option', options[:include_blank].kind_of?(String) ? options[:include_blank] : nil, :value => '') + "\n" + option_tags
  end
  if value.blank? && options[:prompt]
    option_tags = content_tag_string('option', prompt_text(options[:prompt]), :value => '') + "\n" + option_tags
  end
  option_tags
end

def initialize(object_name, method_name, template_object, options = {})
  @object_name, @method_name = object_name.to_s.dup, method_name.to_s.dup
  @template_object = template_object
  @object_name.sub!(/\[\]$/,"") || @object_name.sub!(/\[\]\]$/,"]")
  @object = retrieve_object(options.delete(:object))
  @options = options
  @auto_index = Regexp.last_match ? retrieve_autoindex(Regexp.last_match.pre_match) : nil
end

def name_and_id_index(options)
  options.key?("index") ?  options.delete("index") || "" : @auto_index
end

def placeholder_required?(html_options)
  # See https://html.spec.whatwg.org/multipage/forms.html#attr-select-required
  html_options["required"] && !html_options["multiple"] && html_options.fetch("size", 1).to_i == 1
end

def render
  raise NotImplementedError, "Subclasses must implement a render method"
end

def retrieve_autoindex(pre_match)
  object = self.object || @template_object.instance_variable_get("@#{pre_match}")
  if object && object.respond_to?(:to_param)
    object.to_param
  else
    raise ArgumentError, "object[] naming but object param and @object var don't exist or don't respond to to_param: #{object.inspect}"
  end
end

def retrieve_object(object)
  if object
    object
  elsif @template_object.instance_variable_defined?("@#{@object_name}")
    @template_object.instance_variable_get("@#{@object_name}")
  end
rescue NameError
  # As @object_name may contain the nested syntax (item[subobject]) we need to fallback to nil.
  nil
end

def sanitized_method_name
  @sanitized_method_name ||= @method_name.sub(/\?$/,"")
end

def sanitized_object_name
  @sanitized_object_name ||= @object_name.gsub(/\]\[|[^-a-zA-Z0-9:.]/, "_").sub(/_$/, "")
end

def sanitized_value(value)
  value.to_s.gsub(/\s/, "_").gsub(/[^-\w]/, "").downcase
end

def select_content_tag(option_tags, options, html_options)
  html_options = html_options.stringify_keys
  add_default_name_and_id(html_options)
  if placeholder_required?(html_options)
    raise ArgumentError, "include_blank cannot be false for a required field." if options[:include_blank] == false
    options[:include_blank] ||= true unless options[:prompt]
  end
  value = options.fetch(:selected) { value(object) }
  select = content_tag("select", add_options(option_tags, options, value), html_options)
  if html_options["multiple"] && options.fetch(:include_hidden, true)
    tag("input", :disabled => html_options["disabled"], :name => html_options["name"], :type => "hidden", :value => "") + select
  else
    select
  end
end

def tag_id(index = nil)
  # a little duplication to construct less strings
  if index
    "#{sanitized_object_name}_#{index}_#{sanitized_method_name}"
  else
    "#{sanitized_object_name}_#{sanitized_method_name}"
  end
end

def tag_name(multiple = false, index = nil)
  # a little duplication to construct less strings
  if index
    "#{@object_name}[#{index}][#{sanitized_method_name}]#{"[]" if multiple}"
  else
    "#{@object_name}[#{sanitized_method_name}]#{"[]" if multiple}"
  end
end

def value(object)
  object.public_send @method_name if object
end

def value_before_type_cast(object)
  unless object.nil?
    method_before_type_cast = @method_name + "_before_type_cast"
    if value_came_from_user?(object) && object.respond_to?(method_before_type_cast)
      object.public_send(method_before_type_cast)
    else
      value(object)
    end
  end
end

def value_came_from_user?(object)
  method_name = "#{@method_name}_came_from_user?"
  !object.respond_to?(method_name) || object.public_send(method_name)
end