module Scrivito

# This class is the server-side equivalent of the JavaScript +cms_field_element+ class.
class CmsFieldTag < Struct.new(:view, :tag_name, :obj_or_widget, :editing_options)
  FIELD_TYPES_WITH_ORIGINAL_CONTENT = %w[
    binary
    date
    enum
    float
    html
    integer
    link
    linklist
    multienum
    reference
    referencelist
    string
    stringlist
  ]

  include TagRenderer

  def initialize(*args)
    super
    assert_valid_attribute
  end

  def content(&block)
    if field_type == 'widgetlist'
      raise ArgumentError, 'No block allowed for widgetlist fields' if block_given?
      modifications = modification_info || []
      rendered_widgets = default_content.each_with_index.map do |widget, index|
        WidgetTag.new(view, widget, placement_modification: modifications[index],
          render_context: widget_render_context, inner_tag: inner_tag).render
      end
      view.safe_join(rendered_widgets)
    else
      attribute_renderer = AttributeValueRenderer.new(view)
      block_given? ? view.capture { yield } : attribute_renderer.render(default_content, field_type)
    end
  end

  def options
    return {} unless authenticated_editor?

    options = {
      'field-name'                   => field_name,
      'field-obj-class'              => obj_or_widget.obj_class,
      'field-type'                   => field_type,
      'private-editor'               => editing_options[:editor],
      'private-field-allowed-values' => valid_values,
      'private-field-workspace-id'   => current_workspace_id,
    }

    modification = comparison.modification_for_attribute(obj_or_widget, field_name)
    if modification == Modification::EDITED && field_type != 'widgetlist'
      options['field-modification'] = modification
    end

    if obj_or_widget.kind_of?(BasicWidget)
      options['private-field-obj-id'] = obj_or_widget.obj.id
      options['private-field-widget-id'] = obj_or_widget.id
    else
      options['private-field-obj-id'] = obj_or_widget.id
    end

    if FIELD_TYPES_WITH_ORIGINAL_CONTENT.include?(field_type)
      original_value = view.scrivito_value(current_value)
      original_content = original_content(field_type, original_value, current_value)
      encoded_content = Base64.strict_encode64(MultiJson.encode(original_content))
      options['private-field-original-content'] = encoded_content
    end

    if field_type == 'widgetlist'
      options["private-field-widget-inner-tag"] = inner_tag
      options['private-field-widget-allowed-classes'] = build_valid_widget_classes.to_json
      options['private-field-widget-template'] = widget_render_context
    end

    options
  end

  def modification_info
    calculate_content_and_modification
    @content_and_modification.second
  end

  private

  def build_valid_widget_classes
    obj_or_widget.valid_widget_ruby_classes_for(field_name).map do |widget_class|
      widget_class = widget_class.to_s
      {
        name: widget_class,
        description: description_for_widget_class(widget_class),
      }
    end
  end

  def widget_render_context
    editing_options[:widget_render_context] || WidgetTag::DEFAULT_RENDER_CONTEXT
  end

  def field_name
    editing_options[:field_name]
  end

  def inner_tag
    editing_options[:inner_tag] || WidgetTag::DEFAULT_TAG
  end

  def field_type
    @field_type ||= obj_or_widget.type_of_attribute(field_name)
  end

  def description_for_widget_class(class_name)
    class_name.constantize.description_for_editor
  end

  def default_content
    calculate_content_and_modification
    @content_and_modification.first
  end

  def calculate_content_and_modification
    @content_and_modification ||=
      comparison.diff_for(obj_or_widget, field_name) || [current_value, nil]
  end

  def comparison
    editing_context.comparison
  end

  def current_value
    obj_or_widget[field_name]
  end

  def current_workspace_id
    Workspace.current.id
  end

  def authenticated_editor?
    editing_context.authenticated_editor?
  end

  def editing_context
    EditingContextMiddleware.from_request(view.request)
  end

  def original_content(field_type, field_value, raw_value)
    if %w[
      binary
      date
      reference
      referencelist
    ].include?(field_type)
      ClientAttributeSerializer.serialize_custom_attr_value(field_type, raw_value)
    else
      ClientAttributeSerializer.serialize_custom_attr_value(field_type, field_value)
    end
  end

  def valid_values
    MultiJson.encode(obj_or_widget.attribute_definitions[field_name].try(:values) || [])
  end

  def assert_valid_attribute
    unless obj_or_widget.has_attribute?(field_name)
      raise ScrivitoError, "Unknown attribute #{field_name} for #{obj_or_widget.obj_class}"
    end
  end
end

end