ozfortress/citadel

class User
  class NameChange < ApplicationRecord
    belongs_to :user, autosave: true
    belongs_to :approved_by, class_name: 'User', optional: true
    belongs_to :denied_by, class_name: 'User', optional: true

    validates :name, presence: true, length: { in: 1..64 }

    validate :unique_name, on: :create
    validate :only_one_request_per_user, on: :create
    validate :name_not_already_used, on: :create

    scope :pending, -> { where(approved_by: nil, denied_by: nil) }
    scope :approved, -> { where.not(approved_by: nil) }

    def pending?
      !approved_by && !denied_by
    end

    def approve(user, approved)
      if approved
        self.approved_by = user
        self.user.update!(name: name)
      else
        self.denied_by = user
      end
      save
    end

    private

    def unique_name
      return if user.blank? || name.blank?

      errors.add(:name, 'Must be different to the current name') if pending? && user.name == name
    end

    def only_one_request_per_user
      return if user.blank?

      errors.add(:name, 'A name request is already pending') unless user.names.pending.empty?
    end

    def name_not_already_used
      return if name.blank?

      if pending? && (User.where(name: name).exists? ||
                      NameChange.pending.where(name: name).exists?)
        errors.add(:name, 'Must be unique')
      end
    end
  end
end