obdev/app/models/participant.rb

class Participant < ApplicationRecord
  # Associations
  belongs_to :employer, optional: false
  has_many :employments
  has_many :workers, through: :employments
  has_many :service_contracts
  has_many :vendors, through: :service_contracts
  has_many :employer_records
  has_many :employers, through: :employer_records
  has_and_belongs_to_many :programs
  has_many :bank_accounts, as: :owner

  # Validations
  validates :first_name, :last_name, :ssn, presence: true
  validates :ssn, uniqueness: { message: "SSN is already taken by another participant" }, unless: :ssn_already_taken_by_employer?
  validates :employer_id, presence: true

  def full_name
    "#{first_name} #{last_name}"
  end

  private

  def ssn_already_taken_by_employer?
    # Check if the SSN already exists in the Employer model, excluding the current participant's employer
    Employer.where.not(id: employer_id).exists?(ssn: ssn)
  end
end