class DialogImportValidator
  class BlankFileError < StandardError; end
  class ImportNonYamlError < StandardError; end
  class InvalidDialogFieldTypeError < StandardError; end
  class InvalidDialogVersionError < StandardError; end
  class ParsedNonDialogYamlError < StandardError; end
  class ParsedNonDialogError < StandardError; end

  def initialize(dialog_field_association_validator = DialogFieldAssociationValidator.new)
    @dialog_field_association_validator = dialog_field_association_validator
  end

  def determine_validity(import_file_upload)
    potential_dialogs = YAML.safe_load(import_file_upload.uploaded_content, :permitted_classes => [Symbol])
    raise BlankFileError unless potential_dialogs

    check_dialogs_for_validity(potential_dialogs)
  rescue Psych::SyntaxError
    raise ImportNonYamlError
  end

  def determine_dialog_validity(dialog)
    check_dialog_for_validity(dialog)
  rescue ParsedNonDialogYamlError
    raise ParsedNonDialogError, 'Not a valid dialog'
  end

  private

  def check_dialogs_for_validity(dialogs)
    dialogs.each do |dialog|
      check_dialog_for_validity(dialog)
    end
  rescue TypeError
    raise ParsedNonDialogYamlError
  end

  def check_dialog_for_validity(dialog)
    raise ParsedNonDialogYamlError unless dialog['dialog_tabs']
    raise InvalidDialogVersionError if dialog['export_version'].present? && dialog['export_version'] > DialogImportService::CURRENT_DIALOG_VERSION

    check_dialog_tabs_for_validity(dialog['dialog_tabs'])
  rescue TypeError
    raise ParsedNonDialogYamlError
  end

  def check_dialog_tabs_for_validity(dialog_tabs)
    dialog_tabs.each do |dialog_tab|
      raise ParsedNonDialogYamlError unless dialog_tab["dialog_groups"]

      check_dialog_groups_for_validity(dialog_tab["dialog_groups"])
    end
  end

  def check_dialog_groups_for_validity(dialog_groups)
    dialog_groups.each do |dialog_group|
      raise ParsedNonDialogYamlError unless dialog_group["dialog_fields"]

      check_dialog_fields_for_validity(dialog_group["dialog_fields"])
    end
  end

  def check_dialog_fields_for_validity(dialog_fields)
    dialog_fields.each do |dialog_field|
      raise InvalidDialogFieldTypeError unless valid_dialog_field_type?(dialog_field["type"])

      check_dialog_associations_for_validity(dialog_fields)
    end
  end

  def check_dialog_associations_for_validity(dialog_fields)
    associations = {}
    dialog_fields.each { |df| associations.merge!(df["name"] => df["dialog_field_responders"]) if df["dialog_field_responders"].present? }
    if associations.present?
      associations.each_key { |k|  @dialog_field_association_validator.check_for_circular_references(associations, k) }
    end
  end

  def valid_dialog_field_type?(type)
    DialogField::DIALOG_FIELD_TYPES.include?(type) || type.nil? || type == "DialogFieldDynamicList"
  end
end
