# Copyright: Copyright (c) 2004  Nicolas Despres. All rights reserved.
# Author: Nicolas Despres  <polrop@lrde.epita.fr>.
# License: Gnu General Public License.

# $LastChangedBy: ertai $
# $Id: observable_pool.rb 186 2005-04-03 00:07:45Z ertai $


require 'observable'
require 'thread'


module ObservablePool

  class Observer
    include Observable

    attr_reader :observable

    def initialize(observable, mutex)
      @observable = observable
      @observable.add_observer(self)
      @mutex = mutex
    end

    def update(*args, &block)
      @mutex.synchronize do
        changed
        notify_observers(@observable, *args, &block)
      end
    end

    def method_missing(meth, *args, &block)
      @observable.send(meth, *args, &block)
    end

  end # class Observer

  def add_observable(observable)
    unless observable.is_a?(Observable)
      raise(ArgumentError, "observable object must be Observale")
    end
    @observable_peer_mutex = Mutex.new unless defined? @observable_peer_mutex
    @observable_peers = {} unless defined? @observable_peers
    sync_observer = Observer.new(observable, @observable_peer_mutex)
    @observable_peers[observable] = sync_observer
    @global_observer_peers = [] unless defined? @global_observer_peers
    @global_observer_peers.each do |observer|
      sync_observer.add_observer(observer)
    end
    sync_observer
  end

  def add_observables(*observables)
    observables.each { |observable| add_observable(observable) }
  end

  def delete_observable(observable)
    @observable_peers.delete(observable) if defined? @observable_peers
  end

  def delete_observables
    @observable_peers.clear if defined? @observable_peers
  end

  def observable(observable)
    @observable_peers[observable] if defined? @observable_peers
  end

  def observable?(observable)
    @observable_peers.has_key?(observable) if defined? @observable_peers
  end

  def list_observables
    if defined? @observable_peers
      @observable_peers.keys
    else
      []
    end
  end

  def list_observables_observed(observer)
    observables = []
    if defined? @observable_peers
      @observable_peers.each do |observable, obsv|
        if obsv.list_observers.include?(observer)
          observables << observable
        end
      end
    end
    observables
  end

  def count_observables
    if defined? @observable_peers
      @observable_peers.size
    else
      0
    end
  end

  def each_observables(&block)
    if defined? @observable_peers
      @observable_peers.each do |observable, observer|
        block[observable, observer]
      end
    end
  end

  def list_all_observers
    observers = []
    if defined? @observable_peers
      @observable_peers.each do |observable, observer|
        observers += observer.list_observers
      end
    end
    observers.uniq
  end

  def count_all_observers
    list_observers.size
  end

  def add_global_observer(observer)
    if defined? @observable_peers
      @observable_peers.each do |observable, obsv|
        obsv.add_observer(observer) unless observable.observer?(observer)
      end
    end
    @global_observer_peers = [] unless defined? @global_observer_peers
    @global_observer_peers << observer
  end

  def add_global_observers(*observers)
    observers.each { |observer| add_global_observer(observer) }
  end

  def delete_global_observer(observer)
    if defined? @observable_peers
      @observable_peers.each do |observable, obsv|
        obsv.delete_observer(observer)
      end
    end
    @global_observer_peers.delete(observer) if defined? @global_observer_peers
  end

  def delete_global_observers
    if defined? @global_observer_peers
      @global_observer_peers.dup.each do |global_observer|
        delete_global_observer(global_observer)
      end
    end
  end

  def list_global_observers
    if defined? @global_observer_peers
      @global_observer_peers.dup
    else
      []
    end
  end

  def count_global_observers
    if defined? @global_observer_peers
      @globale.observer_peers.size
    else
      0
    end
  end

  def global_observer?(observer)
    if defined? @global_observer_peers
      @global_observer_peers.include?(observer)
    else
      false
    end
  end

end # class ObservablePool


if defined? TEST_MODE or __FILE__ == $0


require 'test/unit/ui/yaml/testrunner'


class ObservablePoolTest < Test::Unit::TestCase

  class Notifier
    include Observable

  end

  class NotifierPool
    include ObservablePool

  end

  class Obsv

    attr_reader :last_msg

    def initialize
      @last_msg = nil
    end

    def update(*args, &block)
      @last_msg = args
    end

  end

  def test_simple
    n1 = Notifier.new
    n2 = Notifier.new
    o1 = Obsv.new
    o2 = Obsv.new
    o3 = Obsv.new
    op = NotifierPool.new
    assert_equal(0, op.count_observables)
    assert_equal([], op.list_observables)
    op.add_observables(n1)
    op.add_observable(n2)
    op.observable(n2).add_observers(o1, o3)
    assert_equal(2, op.count_observables)
    [ n1, n2 ].each { |x| assert(op.list_observables.include?(x)) }
    assert_equal(1, n1.count_observers)
    assert_equal([], n1.list_observers[0].list_observers)
    assert_equal(1, n2.count_observers)
    assert_equal(2, n2.list_observers[0].count_observers)
    [o1, o3].each do |x|
      assert(n2.list_observers[0].list_observers.include?(x),
             "#{x} not observer")
    end
    op.observable(n1).add_observers(o2, o3)
    assert_equal(2, op.observable(n1).count_observers)
    [o1, o2, o3].each do |x|
      assert(op.list_all_observers.include?(x), "#{x} not observer")
    end
    n2.changed
    n2.notify_observers('msg2')
    assert_equal([ n2, 'msg2'], o1.last_msg)
    assert_nil(o2.last_msg)
    assert_equal([ n2, 'msg2'], o3.last_msg)
    n1.changed
    n1.notify_observers('msg1')
    assert_equal([n2, 'msg2'], o1.last_msg)
    assert_equal([n1, 'msg1'], o2.last_msg)
    assert_equal([n1, 'msg1'], o3.last_msg)
    [n1, n2].each do |x|
      assert(op.list_observables_observed(o3).include?(x), "#{x} not observer")
    end
  end

  def test_global_observer
    n1 = Notifier.new
    n2 = Notifier.new
    n3 = Notifier.new
    o1 = Obsv.new
    o2 = Obsv.new
    o3 = Obsv.new
    op = NotifierPool.new
    assert_equal(0, op.count_global_observers)
    assert_equal([], op.list_global_observers)
    op.add_observables(n1)
    op.add_observable(n2)
    op.observable(n1).add_observers(o1)
    op.observable(n2).add_observers(o2)
    op.add_global_observers(o3)
    [o1, o3].each do |x|
      assert(n1.list_observers[0].list_observers.include?(x),
             "#{x} not observer")
    end
    [o2, o3].each do |x|
      assert(n2.list_observers[0].list_observers.include?(x),
             "#{x} not observer")
    end
    assert_equal([o3], op.list_global_observers)
    op.add_observable(n3)
    assert([o3], n3.list_observers[0].list_observers)
    op.delete_global_observers
    assert_equal([], op.list_global_observers)
    assert([], n3.list_observers[0].list_observers)
    assert([o2], n2.list_observers[0].list_observers)
    assert([o1], n1.list_observers[0].list_observers)
  end

end # class ObservablePoolTest


end