commands_base.rb

require "virtus"

module Commands
  module Base
    def self.included(base)
      base.extend ClassMethods

      base.include Virtus.model
      base.include ActiveModel::Validations
      base.prepend InstanceMethods
    end

    module ClassMethods
      def call(*args)
        new(*args).call
      end
    end

    module InstanceMethods
      def call
        valid? || raise_with_errors(errors)
        super
      end

      protected

      def raise_with_errors(errors)
        raise InvalidDataError.new(errors)
      end
    end
  end
end

commands_commit_user.rb

module Commands
  class CommitUser
    include Base

    attribute :hour, Integer
    attribute :date, Date
    attribute :user
    attribute :project

    validate :check_hour_is_in_working_hours
    validate :check_date_is_in_the_future

    def call
      if commitment
        commitment.update_attributes(project: project)
        commitment
      else
        Models::Commitment.create!(attributes)
      end
    rescue ActiveRecord::RecordInvalid => invalid
      raise_with_errors invalid.record.errors
    end

    protected

    def check_hour_is_in_working_hours
      unless Services::WorkingHours.working_hour?(hour)
        errors.add(:hour, :working_hours)
      end
    end

    def check_date_is_in_the_future
      if date && date < Date.today
        errors.add(:date, :in_future)
      end
    end

    def commitment
      @commitment ||= Models::Commitment.
                      where(attributes.slice(:user, :date, :hour)).first
    end
  end
end

commands_invalid_data_error.rb

module Commands
  class InvalidDataError < RuntimeError
    attr_reader :details

    def initialize(errors = {})
      @details = errors
    end

    def to_s
      super + "\n" + errors_to_s
    end

    def as_json(*args)
      details.map do |attribute, error|
        {
          attribute: attribute,
          reason: error
        }
      end.as_json(*args)
    end

    protected

    def errors_to_s
      buf = ["Errors:"]
      details.each do |attribute, error|
        buf << "* #{attribute}: #{error}"
      end
      buf.join("\n")
    end
  end
end