module Authentication
  extend ActiveSupport::Concern

  included do
    before_action :set_current_user
    helper_method :current_user, :user_signed_in?
  end

  private

  def current_user
    @current_user ||= User.find_by(id: session[:user_id]) if session[:user_id]
  end

  def user_signed_in?
    current_user.present?
  end

  def require_authentication
    unless user_signed_in?
      redirect_to login_path, alert: "You must be signed in to access this page."
    end
  end

  def require_no_authentication
    if user_signed_in?
      redirect_to root_path, notice: "You are already signed in."
    end
  end

  def sign_in(user)
    reset_session
    session[:user_id] = user.id
    set_rls_user_id(user.id)
  end

  def sign_out
    reset_session
    @current_user = nil
    clear_rls_user_id
  end

  def set_current_user
    if current_user
      set_rls_user_id(current_user.id)
    else
      clear_rls_user_id
    end
  end

  def set_rls_user_id(user_id)
    return unless ActiveRecord::Base.connection.adapter_name == "PostgreSQL"
    ActiveRecord::Base.connection.execute("SET LOCAL app.current_user_id = #{ActiveRecord::Base.connection.quote(user_id)}")
  rescue ActiveRecord::StatementInvalid => e
    Rails.logger.warn("Failed to set RLS user_id: #{e.message}")
    nil
  end

  def clear_rls_user_id
    return unless ActiveRecord::Base.connection.adapter_name == "PostgreSQL"
    ActiveRecord::Base.connection.execute("RESET app.current_user_id")
  rescue ActiveRecord::StatementInvalid => e
    Rails.logger.warn("Failed to clear RLS user_id: #{e.message}")
    nil
  end
end