retrospring/app/models/user.rb

class User < ActiveRecord::Base
  # Include default devise modules. Others available are:
  # :confirmable, :lockable, :timeoutable and :omniauthable
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable,
         :validatable, :authentication_keys => [:login]
  
#   attr_accessor :login
  
  has_many :questions, dependent: :destroy
  has_many :answers, dependent: :destroy
  has_many :comments, dependent: :destroy
  has_many :inboxes, dependent: :destroy
  has_many :active_relationships, class_name: 'Relationship',
                                  foreign_key: 'source_id',
                                  dependent: :destroy
  has_many :passive_relationships, class_name: 'Relationship',
                                   foreign_key: 'target_id',
                                   dependent: :destroy
  has_many :friends,   through: :active_relationships, source: :target
  has_many :followers, through: :passive_relationships, source: :source

  SCREEN_NAME_REGEX = /\A[a-zA-Z0-9_]{1,16}\z/
  
  validates :screen_name, presence: true, format: { with: SCREEN_NAME_REGEX }, uniqueness: { case_sensitive: false }



  def login=(login)
    @login = login
  end

  def login
    @login || self.screen_name || self.email
  end
  
  def self.find_first_by_auth_conditions(warden_conditions)
    conditions = warden_conditions.dup
    if login = conditions.delete(:login)
      where(conditions).where(["lower(screen_name) = :value OR lower(email) = :value", { :value => login.downcase }]).first
    else
      where(conditions).first
    end
  end

  # follows an user.
  def follow(target_user)
    active_relationships.create(target: target_user)

    # increment counts
    increment! :friend_count
    target_user.increment! :follower_count
  end

  def unfollow(target_user)
    active_relationships.find_by(target: target_user).destroy

    # decrement counts
    decrement! :friend_count
    target_user.decrement! :follower_count
  end

  # @return [Boolean] true if +current_user+ is following +target_user+
  def following?(target_user)
    friends.include? target_user
  end
end