session.rb

class Session < ApplicationRecord
  belongs_to :conference
  belongs_to :stage
  has_many :assignments
  has_many :users, through: :assignments
  has_many :session_speakers, dependent: :destroy
  has_many :speakers, through: :session_speakers

  scope :scheduled, -> { where(status: 'scheduled') }
  scope :future, -> { where(starts_at: Time.now..) }

  validates :ref_id, uniqueness: { scope: :conference_id }

  after_update :notify_if_changed

  self.implicit_order_column = :starts_at

  def to_param
    ref_id
  end

  def starts_at
    super.in_time_zone(conference.time_zone)
  end

  def ends_at
    super.in_time_zone(conference.time_zone)
  end

  def is_interpreted?
    is_relevant?
  end

  def is_relevant?
    RelevantStage.exists?(stage:)
  end

  def translators_needed?
    is_interpreted? && assignments.length < 2
  end

  def backup_needed?
    return false
  end

  def assignees?
    assignments.length.positive?
  end

  private

  def notify_if_changed
    return if new_record?
    if saved_changes.present?
      ActiveSupport::Notifications.instrument("session.updated", record: self, changes: saved_changes)
    end
  end
end