require 'digest/sha1'

class User < ActiveRecord::Base
  attr_accessor :new_password

  validates_presence_of     :name
  validates_presence_of     :email
  validates_uniqueness_of   :email

  validates_presence_of     :new_password,              :if => :password_required?
  validates_presence_of     :new_password_confirmation, :if => :password_required?
  validates_confirmation_of :new_password,              :if => :password_required?

  has_url_name

  # Users are authenticated with an email/password combination
  # by default
  def self.authenticate(email, password)
    user = self.find(:first, :conditions => ["lower(email) = lower(?)", email])
    return nil if user.nil?
    user if user.password == encrypt(password, user.salt)
  end

  def to_param
    url_name
  end

  def self.find_by_param(*args)
    find_by_url_name *args
  end


  def remember_me
    self.remember_token_expires_at = 2.weeks.from_now.utc
    self.remember_token            = encrypt("#{email}--#{remember_token_expires_at}")
    save(false)
  end

  def forget_me
    self.remember_token_expires_at = nil
    self.remember_token            = nil
    save(false)
  end


  # Encrypts the password with the user salt
  def encrypt(password)
    self.class.encrypt(password, salt)
  end

  def self.encrypt(password, salt)
    Digest::SHA1.hexdigest("#{salt}#{password}")
  end

  protected

  def before_validation_with_password_hashing
    return unless password_required?
    self.salt = generate_salt
    self.password = encrypt(new_password)
  end
  alias_method_chain :before_validation, :password_hashing

  def before_create_with_salt_generation
    unless self.salt && self.salt.size == 10
      self.salt = generate_salt
    end
    before_create_without_salt_generation
  end
  alias_method_chain :before_create, :salt_generation


  def generate_salt
    chars = ('0'..'9').to_a + ('a'..'z').to_a + ('A'..'Z').to_a
    s = []
    10.times{ s << chars[rand(chars.size)] }
    return s.join
  end

  def password_required?
    !new_password.blank?
  end
end