class User < ActiveRecord::Base
  attr_accessible :email,
                  :email_confirmation,
                  :password,
                  :password_confirmation,
                  :username

  attr_accessor :password, :password_confirmation, :email_confirmation

  belongs_to :group

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

  validates :username,  :presence => true,
                        :length => { :maximum => 25 },
                        :format => { :with => name_regex }

  validates :password, :length => { :in => 5..20 }
  validates :password, :confirmation => true
  validates :password_confirmation, :presence => true

  validates :email, :confirmation => true,
                    :uniqueness => { :case_sensitive => false },
                    :format => { :with => email_regex }
  validates :email_confirmation, :presence => true

  before_save :encrypt_password

  def self.authenticate(email, submitted_password)
    user = find_by_email(email)
    return nil if user.nil?
    return user if user.has_password?(submitted_password)
  end

  def self.authenticate_with_salt(id, cookie_salt)
    user = find_by_id(id)
    return nil if user.nil?
    return user if user.salt == cookie_salt
  end

  def has_password?(string)
    password_hash == encrypt(string)
  end

  def role?(s)
    group.nil? || new_record? ? false : group.groupname.to_sym == s
  end

  private

    def encrypt_password
      self.salt = generate_salt if new_record?
      self.password_hash = encrypt(password)
    end

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

    def generate_salt
      secure_hash("#{Time.now.utc}:#{password}")
    end

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