module Formol
  class Poll < ActiveRecord::Base
    #Exceptions
    class PollException < Exception; end
    class TooManyVotesError < PollException; end
    class UserAlreadyVoter < PollException; end
    class NoOptionProvided < PollException; end
    class TopicLockedError < PollException; end
    class PollExpiredError < PollException; end
    
    #Security
    attr_protected  :topic_id
    attr_readonly   :topic_id
    
    #Virtual attributes
    attr_accessor :poll_vote_ids #to not conflict with has_many :votes
    
    #Default values
    default_value_for :duration,    1.week.to_i
    default_value_for :max_options, 1 #default to single mode
    
    #Associations
    belongs_to  :topic
    
    has_many  :options
    has_many  :votes,   :through    => :options
    has_many  :voters,  :through    => :votes,
                        :class_name => Formol.config.user_class,
                        :uniq       => true

    #Nested attributes
    accepts_nested_attributes_for :options, :limit => 20
                      
    #Validations
    validates :topic,       :presence     => true
    validates :question,    :presence     => true,
                            :length       => {  :in                     => 5..64,
                                                :allow_blank            => true }
    validates :duration,    :presence     => true,
                            :numericality => {  :only_integer           => true,
                                                :greater_than           => 0,
                                                :less_than              => 3.months.to_i,
                                                :allow_blank            => true }
    validates :max_options, :presence     => true,
                            :numericality => {  :only_integer           => true,
                                                :greater_than           => 0,
                                                :less_than_or_equal_to  => Proc.new{ |p| p.options.length },
                                                :allow_blank            => true }
    validates :options,     :length       => { :in                      => 1..20 }
    
    #Normalization
    normalize_attribute :question,  :with => [:squish, :blank]
    
    #Callbacks
    before_validation :setup_options_assoc, :on => :create
    
    #Business methods
    
    def multiple?
      max_options > 1
    end
    
    def single?
      !multiple?
    end
    
    def expired?
      expires_at < Time.now
    end
    
    def expires_at
      created_at + duration.to_i
    end
    
    def voted?(user)
      voters.include?(user)
    end
    
    def vote(user, option_ids)
      option_ids = [option_ids] unless option_ids.respond_to?(:each)
      option_ids.reject!(&:blank?)
      option_ids.compact!
      
      raise NoOptionProvided.new if option_ids.empty?
      raise TooManyVotesError.new if option_ids.length > max_options
      raise UserAlreadyVoter.new if voted?(user)
      raise TopicLockedError.new if topic.locked?
      raise PollExpiredError.new if expired?
      
      options.find(option_ids).to_a.each do |option| #?
        option.votes.create!(:voter => user)
      end
    end
    
    private
    
    #Callback methods
    
    # set poll for each options
    # AR doesn't do it by itself and it ruins validations
    def setup_options_assoc
      options.each do |o|
        o.poll = self
      end
    end
  end
end