btrc-hub/backend/app/controllers/application_controller.rb

class ApplicationController < ActionController::API
  rescue_from ActiveRecord::RecordInvalid, with: :render_record_invalid
  rescue_from ActiveRecord::RecordNotUnique, with: :render_record_not_unique

  before_action :reject_banned_ip_address!
  before_action :authenticate_user
  before_action :reject_banned_user!

  def current_user = @current_user

  private

  def authenticate_user
    code = request.headers['X-Transfer-Code'] || request.headers['HTTP_X_TRANSFER_CODE']
    return if code.blank?

    @current_user = User.find_by(inheritance_code: code)
  end

  def bool? key, default: false
    return default if params[key].nil?

    s = params[key].to_s.strip.downcase
    if default
      !(s.in?(['0', 'false', 'off', 'no']))
    else
      s.in?(['', '1', 'true', 'on', 'yes'])
    end
  end

  def render_bad_request message = 'リクエストが不正です．', field: nil, code: :bad_request
    render_error(:bad_request, message, field:, code:)
  end

  def render_unprocessable_entity message = '入力を確認してください．', field: nil, code: :invalid
    render_error(:unprocessable_entity, message, field:, code:)
  end

  def render_error status, message, field: nil, code: status
    error = { code: code.to_s, message: }
    error[:field] = field.to_s if field.present?

    render json: { errors: [error] }, status:
  end

  def render_model_errors record, status: :unprocessable_entity
    errors =
        record.errors.map do |error|
          { code: error.type.to_s,
            field: error.attribute.to_s,
            message: error.full_message }
        end

    errors = [{ code: 'invalid', message: '入力を確認してください．' }] if errors.empty?

    render json: { errors: }, status:
  end

  def render_record_invalid error
    render_model_errors(error.record)
  end

  def render_record_not_unique _error = nil
    render_unprocessable_entity('既に存在してゐます．', code: :taken)
  end

  def reject_banned_ip_address!
    ip_address = IpAddress.find_by(ip_address: IPAddr.new(request.remote_ip).hton)
    return unless ip_address&.banned?

    head :forbidden
  end

  def reject_banned_user!
    return unless current_user&.banned?

    head :forbidden
  end

  def render_validation_error record = nil, fields: { }, base: []
    errors = { }

    if record
      record.errors.messages.each do |attr, messages|
        errors[attr] ||= []
        errors[attr].concat(messages)
      end
    end

    fields.each do |attr, messages|
      errors[attr] ||= []
      errors[attr].concat(Array(messages))
    end

    base_errors = Array(base) - Array(errors.delete(:base))

    render json: { type: 'validation_error',
                   message: '入力内容を確認してください．',
                   errors:,
                   base_errors: },
           status: :unprocessable_entity
  end
end