class ActiveSupport::Cache::MemCacheStore

def self.build_mem_cache(*addresses) # :nodoc:
  addresses = addresses.flatten
  options = addresses.extract_options!
  addresses = ["localhost:11211"] if addresses.empty?
  pool_options = retrieve_pool_options(options)
  if pool_options.empty?
    Dalli::Client.new(addresses, options)
  else
    ensure_connection_pool_added!
    ConnectionPool.new(pool_options) { Dalli::Client.new(addresses, options.merge(threadsafe: false)) }
  end
end

def self.supports_cache_versioning?
  true
end

def clear(options = nil)
  rescue_error_with(nil) { @data.with { |c| c.flush_all } }
end

def decrement(name, amount = 1, options = nil)
  options = merged_options(options)
  instrument(:decrement, name, amount: amount) do
    rescue_error_with nil do
      @data.with { |c| c.decr(normalize_key(name, options), amount, options[:expires_in]) }
    end
  end
end

def delete_entry(key, options)
  rescue_error_with(false) { @data.with { |c| c.delete(key) } }
end

def deserialize_entry(raw_value)
  if raw_value
    entry = Marshal.load(raw_value) rescue raw_value
    entry.is_a?(Entry) ? entry : Entry.new(entry)
  end
end

def increment(name, amount = 1, options = nil)
  options = merged_options(options)
  instrument(:increment, name, amount: amount) do
    rescue_error_with nil do
      @data.with { |c| c.incr(normalize_key(name, options), amount, options[:expires_in]) }
    end
  end
end

def initialize(*addresses)
  addresses = addresses.flatten
  options = addresses.extract_options!
  super(options)
  unless [String, Dalli::Client, NilClass].include?(addresses.first.class)
    raise ArgumentError, "First argument must be an empty array, an array of hosts or a Dalli::Client instance."
  end
  if addresses.first.is_a?(Dalli::Client)
    @data = addresses.first
  else
    mem_cache_options = options.dup
    UNIVERSAL_OPTIONS.each { |name| mem_cache_options.delete(name) }
    @data = self.class.build_mem_cache(*(addresses + [mem_cache_options]))
  end
end

def normalize_key(key, options)
  key = super.dup
  key = key.force_encoding(Encoding::ASCII_8BIT)
  key = key.gsub(ESCAPE_KEY_CHARS) { |match| "%#{match.getbyte(0).to_s(16).upcase}" }
  key = "#{key[0, 213]}:md5:#{ActiveSupport::Digest.hexdigest(key)}" if key.size > 250
  key
end

def read_entry(key, options)
  rescue_error_with(nil) { deserialize_entry(@data.with { |c| c.get(key, options) }) }
end

def read_multi_entries(names, options)
  keys_to_names = Hash[names.map { |name| [normalize_key(name, options), name] }]
  raw_values = @data.with { |c| c.get_multi(keys_to_names.keys) }
  values = {}
  raw_values.each do |key, value|
    entry = deserialize_entry(value)
    unless entry.expired? || entry.mismatched?(normalize_version(keys_to_names[key], options))
      values[keys_to_names[key]] = entry.value
    end
  end
  values
end

def rescue_error_with(fallback)
  yield
rescue Dalli::DalliError => e
  logger.error("DalliError (#{e}): #{e.message}") if logger
  fallback
end

def stats
  @data.with { |c| c.stats }
end

def write_entry(key, entry, options)
  method = options && options[:unless_exist] ? :add : :set
  value = options[:raw] ? entry.value.to_s : entry
  expires_in = options[:expires_in].to_i
  if expires_in > 0 && !options[:raw]
    # Set the memcache expire a few minutes in the future to support race condition ttls on read
    expires_in += 5.minutes
  end
  rescue_error_with false do
    @data.with { |c| c.send(method, key, value, expires_in, options) }
  end
end