gem 'delegate_cached'

class ThruHike < ApplicationRecord
  belongs_to :hiker, inverse_of: :thru_hikes
  belongs_to :trail, inverse_of: :thru_hikes

  delegate_cached :name, to: :hiker, prefix: true # 'hiker_name' column required on thru_hikes table
  delegate_cached :name, to: :trail               # 'name' column required on thru_hikes tables
end

class ThruHike < ApplicationRecord
  belongs_to :hiker, inverse_of: :thru_hikes
  belongs_to :trail, inverse_of: :thru_hikes

  delegate_cached :name, to: :hiker, prefix: true # 'hiker_name' column required on thru_hikes table
  delegate_cached :name, to: :trail               # 'name' column required on thru_hikes tables

  # This callback added by delegate_cached
  before_save :set_delegate_cached_value_for_hiker_name

  # This method added by delegate_cached
  def set_delegate_cached_value_for_hiker_name
    return unless hiker
    self['hiker_name'] = hiker.name
  end

  # This method added by delegate_cached
  def update_delegate_cached_value_for_hiker_name
    update(hiker_name: hiker.name)
  end

  # This method added by delegate_cached and overrides the ActiveRecord accessor
  # Cached value is returned unless nil. When nil, update the value from the
  # delegated_to model. To disable updating, use the update_when_nil = false option
  def hiker_name
    unless self['hiker_name'].nil?
      return self['hiker_name']
    end
    update_delegate_cached_value_for_hiker_name
    hiker.name
  end
end

class Hiker < ApplicationRecord
  has_many :thru_hikes, inverse_of: :hiker

  # This callback added by delegate_cached
  # To disable the callback, use the skip_callback = true option
  after_save :update_delegate_cached_value_for_thru_hikes_hiker_name, if: :name_changed?

  # This method added by delegate_cached
  def update_delegate_cached_value_for_thru_hikes_hiker_name
    ThruHike.where(hiker_id: id)
            .update_all(hiker_name: name)
  end
end

class Trail < ApplicationRecord
  has_many :thru_hikes, inverse_of: :trail

  # This callback added by delegate_cached
  # To disable the callback, use the skip_callback = true option
  after_save :update_delegate_cached_value_for_thru_hikes_name, if: :name_changed?

  # This method added by delegate_cached
  def update_delegate_cached_value_for_thru_hikes_name
    ThruHike.where(hiker_id: id)
            .update_all(name: name)
  end
end