require "permalink/string_ext"

module SimplesIdeias
  module Permalink
    def self.included(base)
      base.extend ClassMethods

      class << base
        attr_accessor :has_permalink_options
      end
    end

    module ClassMethods
      # has_permalink :title
      # has_permalink :title, :to => :custom_permalink_field
      # has_permalink :title, :to => :permalink, :to_param => [:id, :permalink]
      # has_permalink :title, :unique => true
      def has_permalink(from, options={})
        options = {
          :to => :permalink,
          :to_param => [:id, :permalink],
          :unique => false
        }.merge(options)

        self.has_permalink_options = {
          :from_column_name => from,
          :to_column_name => options[:to],
          :to_param => [options[:to_param]].flatten,
          :unique => options[:unique]
        }

        include SimplesIdeias::Permalink::InstanceMethods

        before_validation :create_permalink
        before_save :create_permalink
      end
    end

    module InstanceMethods
      def to_param
        to_param_option = self.class.has_permalink_options[:to_param]

        to_param_option.compact.collect do |name|
          if respond_to?(name)
            send(name).to_s
          else
            name.to_s
          end
        end.reject(&:blank?).join('-')
      end

      private
      def next_available_permalink(_permalink)
        the_permalink = _permalink

        if self.class.has_permalink_options[:unique]
          suffix = 2

          while self.class.first(:conditions => {to_permalink_name => the_permalink}, :select => self.class.primary_key)
            the_permalink = "#{_permalink}-#{suffix}"
            suffix += 1
          end
        end

        the_permalink
      end

      def from_permalink_name
        self.class.has_permalink_options[:from_column_name]
      end

      def to_permalink_name
        self.class.has_permalink_options[:to_column_name]
      end

      def from_permalink_value
        read_attribute(from_permalink_name)
      end

      def to_permalink_value
        read_attribute(to_permalink_name)
      end

      def create_permalink
        unless from_permalink_value.blank? || !to_permalink_value.blank?
          write_attribute(to_permalink_name, next_available_permalink(from_permalink_value.to_s.to_permalink))
        end
      end
    end
  end
end

ActiveRecord::Base.send(:include, SimplesIdeias::Permalink)