module Scrivito

# this class is the server-side equivalent of the JavaScript class `cms_field_element`
class CmsFieldTag < Struct.new(
    :view_context, :editing_context, :obj_or_widget, :field_name
  )

  def options
    formatted_options = {}
    raw_options.each do |key, value|
      formatted_options["data-scrivito-#{key}"] = value
    end

    formatted_options
  end

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

  def default_content
    calculate_content_and_modification
    @content_and_modification.first
  end

  def modification_info
    calculate_content_and_modification
    @content_and_modification.second
  end

  private

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

  def raw_options
    return {} unless inplace_editing_allowed?

    options = {
      'private-field-workspace-id' => current_workspace_id,
      'field-name'                 => field_name,
      'field-obj-class'            => obj_or_widget.obj_class_name,
      'field-type'                 => field_type,
    }

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

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

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

    if field_type == 'widget'
      valid_widget_classes = obj_or_widget.valid_widget_classes_for(field_name.to_s)
      if valid_widget_classes
        options['private-field-widget-allowed-classes'] = valid_widget_classes.to_json
      end
    end

    options
  end

  def comparison
    editing_context.comparison
  end

  def current_value
    obj_or_widget[field_name]
  end

  def current_workspace_id
    Workspace.current.id
  end

  FIELD_TYPES_WITH_ORIGINAL_CONTENT = %w[
    enum
    html
    multienum
    reference
    referencelist
    string
    text
  ]

  def inplace_editing_allowed?
    editing_context.authenticated_editor?
  end

  def original_content(field_type, field_value)
    case field_type
    when 'reference' then field_value.try(:id)
    when 'referencelist' then field_value.map(&:id)
    else field_value
    end
  end

end

end