module Linkr::Models
  
  class Link < Base
    PER_PAGE = 25
    has_many :comments; has_many :votes
    validates_presence_of   :user, :url, :title
    validates_uniqueness_of :url, :title
    attr_accessor :description
    def after_create
      comments.create :body => description, :user => user unless description.blank?
      Vote.for self.user, self, :up
    end
    class << self
      def find_all_by_score(tag=nil, page=1)
        timestamp_func = ActiveRecord::Base.connection.adapter_name == "MySQL" ? 'UNIX_TIMESTAMP' : 'julianday'
        find :all, :order => "round(#{timestamp_func}(created_at)) desc, score desc, created_at desc",
             :limit => PER_PAGE, :offset => (page-1)*page, :conditions => tag ? ["tags like ?", "%#{tag}%"] : nil
      end
      def find_all_by_date(tag=nil, page=1)
        find :all, :order => 'created_at desc', :limit => PER_PAGE, :offset => (page-1)*page,
             :conditions => tag ? ["tags like ?", "%#{tag}%"] : nil
      end
      def find_tags
        (Link.find(:all).collect { |l| l.tags.to_s.split }).flatten.uniq.sort
      end
      def search(query)
        (find(:all, :conditions => ['title LIKE ?', "%#{query}%"]) +
             Comment.find(:all, :conditions => ['body LIKE ?', "%#{query}%"]).collect(&:link)).
             uniq.sort_by(&:created_at).reverse
      end
      def tag_count(tag)
        Link.count :conditions => ["tags like ? ", "%#{tag}%"]
      end
      def tag_cloud
        cloud = {}
        find_tags.each do |tag|
          cloud[tag] = tag_count tag
        end
        cloud
      end
    end
  end
  
  class Comment < Base
    belongs_to :link
    validates_presence_of :link_id, :body, :user
  end
  
  class Vote < Base
    belongs_to :link
    def to_s; self.direction == 1 ? 'up' : 'down' end
    def after_save
      self.link.score += self.direction
      self.link.update
    end
    def self.for(user, link, direction)
      vote = Vote.find_by_user_and_link_id(user, link)
      dir = direction.to_sym == :up ? 1 : -1
      if vote
        return if vote.direction == dir
        vote.update_attribute :direction, dir
      else
        Vote.create :user => user, :link => link, :direction => dir
      end
    end
  end
  
  class InitSchema < V 1
    def self.up
      create_table :linkr_links do |t|
        t.column :title, :string, :limit => 100
        t.column :url, :string, :limit => 255
        t.column :tags, :string
        t.column :user, :string
        t.column :score, :integer, :default => 0
        t.column :created_at, :datetime
      end
      create_table :linkr_comments do |t|
        t.column :link_id, :integer
        t.column :user, :string
        t.column :created_at, :datetime
        t.column :body, :text
      end
      create_table :linkr_votes do |t|
        t.column :user, :string
        t.column :link_id, :integer
        t.column :direction, :integer
      end
    end
  end
end