require 'logger'
require 'thread'

module Celluloid
  @logger = Logger.new STDERR

  class << self
    attr_accessor :logger # Thread-safe logger class

    def included(klass)
      klass.send :extend, ClassMethods
    end

    # Are we currently inside of an actor?
    def actor?
      !!Thread.current[:actor]
    end

    # Obtain the currently running actor (if one exists)
    def current_actor
      actor = Thread.current[:actor]
      raise NotActorError, "not in actor scope" unless actor
      actor.proxy
    end
    alias_method :current, :current_actor

    # Receive an asynchronous message
    def receive(timeout = nil, &block)
      actor = Thread.current[:actor]
      if actor
        actor.receive(timeout, &block)
      else
        Thread.mailbox.receive(timeout, &block)
      end
    end

    # Sleep letting the actor continue processing messages
    def sleep(interval)
      actor = Thread.current[:actor]
      if actor
        actor.sleep(interval)
      else
        Kernel.sleep interval
      end
    end
  end

  # Class methods added to classes which include Celluloid
  module ClassMethods
    # Create a new actor
    def new(*args, &block)
      proxy = Actor.new(allocate).proxy
      proxy.send(:initialize, *args, &block)
      proxy
    end
    alias_method :spawn, :new

    # Create a new actor and link to the current one
    def new_link(*args, &block)
      current_actor = Celluloid.current_actor
      raise NotActorError, "can't link outside actor context" unless current_actor

      proxy = Actor.new(allocate).proxy
      current_actor.link proxy
      proxy.send(:initialize, *args, &block)
      proxy
    end
    alias_method :spawn_link, :new_link

    # Create a supervisor which ensures an instance of an actor will restart
    # an actor if it fails
    def supervise(*args, &block)
      Supervisor.supervise(self, *args, &block)
    end

    # Create a supervisor which ensures an instance of an actor will restart
    # an actor if it fails, and keep the actor registered under a given name
    def supervise_as(name, *args, &block)
      Supervisor.supervise_as(name, self, *args, &block)
    end

    # Trap errors from actors we're linked to when they exit
    def trap_exit(callback)
      @exit_handler = callback.to_sym
    end

    # Obtain the exit handler for this actor
    attr_reader :exit_handler

    # Configure a custom mailbox factory
    def use_mailbox(klass = nil, &block)
      if block
        define_method(:mailbox_factory, &block)
      else
        define_method(:mailbox_factory) { klass.new }
      end
    end
  end

  #
  # Instance methods
  #

  # Is this actor alive?
  def alive?
    Thread.current[:actor].alive?
  end

  # Raise an exception in caller context, but stay running
  def abort(cause)
    raise AbortError.new(cause)
  end

  # Terminate this actor
  def terminate
    Thread.current[:actor].terminate
  end

  def inspect
    str = "#<Celluloid::Actor(#{self.class}:0x#{object_id.to_s(16)})"
    ivars = instance_variables.map do |ivar|
      "#{ivar}=#{instance_variable_get(ivar).inspect}"
    end

    str << " " << ivars.join(' ') unless ivars.empty?
    str << ">"
  end

  # Send a signal with the given name to all waiting methods
  def signal(name, value = nil)
    Thread.current[:actor].signal name, value
  end

  # Wait for the given signal
  def wait(name)
    Thread.current[:actor].wait name
  end

  # Obtain the current_actor
  def current_actor
    Celluloid.current_actor
  end

  # Obtain the running tasks for this actor
  def tasks
    Thread.current[:actor].tasks.to_a
  end

  # Obtain the Ruby object the actor is wrapping. This should ONLY be used
  # for a limited set of use cases like runtime metaprogramming. Interacting
  # directly with the wrapped object foregoes any kind of thread safety that
  # Celluloid would ordinarily provide you, and the object is guaranteed to
  # be shared with at least the actor thread. Tread carefully.
  def wrapped_object; self; end

  # Obtain the Celluloid::Links for this actor
  def links
    Thread.current[:actor].links
  end

  # Link this actor to another, allowing it to crash or react to errors
  def link(actor)
    actor.notify_link current_actor
    notify_link actor
  end

  # Remove links to another actor
  def unlink(actor)
    actor.notify_unlink current_actor
    notify_unlink actor
  end

  def notify_link(actor)
    links << actor
  end

  def notify_unlink(actor)
    links.delete actor
  end

  # Is this actor linked to another?
  def linked_to?(actor)
    Thread.current[:actor].links.include? actor
  end

  # Receive an asynchronous message via the actor protocol
  def receive(timeout = nil, &block)
    Celluloid.receive(timeout, &block)
  end

  # Sleep while letting the actor continue to receive messages
  def sleep(interval)
    Celluloid.sleep(interval)
  end

  # Call a block after a given interval
  def after(interval, &block)
    Thread.current[:actor].after(interval, &block)
  end

  # Perform a blocking or computationally intensive action inside an
  # asynchronous thread pool, allowing the caller to continue processing other
  # messages in its mailbox in the meantime
  def defer(&block)
    # This implementation relies on the present implementation of
    # Celluloid::Future, which uses an Actor to run the block
    Future.new(&block).value
  end

  # Deprecated, do not use
  def async
    raise "Celluloid#async is defunct. Please use #defer instead"
  end

  # Process async calls via method_missing
  def method_missing(meth, *args, &block)
    # bang methods are async calls
    if meth.to_s.match(/!$/)
      unbanged_meth = meth.to_s.sub(/!$/, '')
      call = AsyncCall.new(@mailbox, unbanged_meth, args, block)

      begin
        Thread.current[:actor].mailbox << call
      rescue MailboxError
        # Silently swallow asynchronous calls to dead actors. There's no way
        # to reliably generate DeadActorErrors for async calls, so users of
        # async calls should find other ways to deal with actors dying
        # during an async call (i.e. linking/supervisors)
      end

      return # casts are async and return immediately
    end

    super
  end
end

require 'celluloid/version'
require 'celluloid/actor_proxy'
require 'celluloid/calls'
require 'celluloid/core_ext'
require 'celluloid/events'
require 'celluloid/fiber'
require 'celluloid/fsm'
require 'celluloid/links'
require 'celluloid/logger'
require 'celluloid/mailbox'
require 'celluloid/receivers'
require 'celluloid/registry'
require 'celluloid/responses'
require 'celluloid/signals'
require 'celluloid/task'
require 'celluloid/timers'
require 'celluloid/thread_pool'

require 'celluloid/actor'
require 'celluloid/future'
require 'celluloid/group'
require 'celluloid/supervisor'