# This store uses Memcache as it's backing.
# The configuration for this should look something like this:
#  my_awesome_cache_options:
#    debug: false
#    store: memcache
#    marshall_method: none
#    default_expiry: <%= 24.hours %>
#    store_options:  
#      c_threshold: 10_000
#      compression: true
#      debug: false
#      readonly: false
#      urlencode: false
#    logging:
#      logger_1:
#        type: file
#        file: log/memcached.log
#    servers:
#      - 127.0.0.1:11211
class Cachetastic::Stores::Memcache < Cachetastic::Stores::Base
  
  def setup
    self.conn = MemCache.new(self.servers, self.store_options.merge({:namespace => self.namespace}))
    self.version = self.get_version(self.name)
  end
  
  def set(key, value, expiry = 0)
    self.conn.set(key, value, expiry)
  end
  
  def delete(key, delay = 0)
    self.conn.delete(key, delay)
  end
  
  def get(key)
    self.conn.get(key)
  end
  
  def expire_all
    self.increment_version(self.name)
  end
  
  def inspect
    self.conn.inspect + " <version: #{self.version}> #{self.conn.stats.inspect}"
  end
  
  def valid?
    begin
      return (self.conn.active? && self.version == self.get_version(self.name))
    rescue Exception => e
      puts e.message
      puts e.backtrace.join("\n")
      return false
    end
  end
  
  protected
  attr_accessor :conn
  attr_accessor :version
  
  def namespace
    v = self.get_version(self.name)
    return "#{name}.#{v}"
  end
  
  def ns_versions
    ivar_cache do
      ns_conn = MemCache.new(self.servers, self.store_options.merge({:namespace => :namespace_versions}))
    end
  end
  
  def increment_version(name)
    name = name.to_s
    v = get_version(name)
    self.ns_versions.set(name, v + 1)
  end

  def get_version(name)
    name = name.to_s
    v = self.ns_versions.get(name)
    if v.nil?
      self.ns_versions.set(name, 1)
      v = 1
    end
    v
  end
  
end