require 'digest'
class User < ActiveRecord::Base
  attr_accessor   :password
  attr_accessible :name, :email, :password, :password_confirmation

    email_regex = /\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/i

    validates :name,  :presence => true,
                      :length   => { :maximum => 50 }
    validates :email, :presence   => true,
                      :format     => { :with => email_regex },
                      :uniqueness => { :case_sensitive => false }
    validates :password, :presence => true,
                         :confirmation => true,
                         :length => { :within => 6..40 }

    before_save :encrypt_password

    # Return true if the user's password matches the submitted password.
      def has_password?(submitted_password)
        encrypted_password == encrypt(submitted_password)
      end
      def authenticate(email, submitted_password)
        user = find_by_email(email)
        (user && user.has_password?(submitted_password)) ? user : nil
      end
      def self.authenticate_with_salt(id, cookie_salt)
          user = find_by_id(id)
          (user && user.salt == cookie_salt) ? user : nil
      end
          private

            def encrypt_password
              self.salt = make_salt if new_record?
              self.encrypted_password = encrypt(password)
            end

            def encrypt(string)
              secure_hash("#{salt}--#{string}")
            end

            def make_salt
              secure_hash("#{Time.now.utc}--#{password}")
            end

            def secure_hash(string)
              Digest::SHA2.hexdigest(string)
            end
        end