obdev/app/models/employer.rb

class Employer < ApplicationRecord
  # Direct association with participants
  has_many :direct_participants, class_name: 'Participant'

  # Association through EmployerRecord
  has_many :employer_records
  has_many :indirect_participants, through: :employer_records, source: :participant

  # Association with Workers through direct_participants
  has_many :workers, through: :direct_participants

  # Other methods...
  def full_name
    "#{first_name} #{last_name}"
  end

  
  validate :unique_as_participant
  validates :ssn, uniqueness: true, allow_blank: true, presence: true
  validates :tin, uniqueness: true, allow_blank: true, presence: true
  
  private
  
  def unique_as_participant
    # Check if there's a Participant with the same details
      existing_participant = Participant.find_by(ssn: ssn)
      if existing_participant && (existing_participant.id != id)
        errors.add(:base, 'A participant with the same SSN already exists')
      end
    end
  end