require 'sha1'

class User < ActiveRecord::Base

  has_many :markets # markets opened by the user
  has_many :trades
  has_many :holdings

  attr_accessor :password
  attr_protected :hashed_password
  validates_uniqueness_of :username 
  validates_confirmation_of :password

  def self.hashed(str)
    SHA1.new(str).to_s
  end

  # If a user matching the credentials is found, returns the user object.
  # If no matching user is found, returns nil.
  def self.authenticate(user_info)
    user = find_by_username(user_info[:username])
    if user && user.hashed_password == hashed(user_info[:password])
      return user
    end
  end

  private
  before_save :update_password

  # Updates the hashed_password if a plain password was provided
  def update_password
    if not password.blank?
      self.hashed_password = self.class.hashed(password)
    end
  end
end