# Adhearsion, open source technology integrator
# Copyright (C) 2006,2007 Jay Phillips
# 
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
# 
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
# 
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

require 'drb'
require 'drb/acl'
require 'thread'

module DRbServerManager
  
  def self.start
    config = CONFIG['drb'] || {}

    permissions = []
    # For greater control over the ACL
    if config['raw_acl']
      permissions = config['raw_acl'].flatten
    else 
      [config['deny']].flatten.each  { |ip| permissions  << "deny"  << ip }
      [config['allow']].flatten.each { |ip| permissions << "allow" << ip }
    end

    # Load the Access Control List
    DRb.install_acl ACL.new(permissions)
    
    host = config['host'] || 'localhost'
    port = config['port'] || 9050
    DRb.start_service "druby://#{host}:#{port}", DRbDoor.new
    
    
    info "Started DRb server on #{DRb.uri}."
    info "DRb Server Access Control List:"
    0.step permissions.length-1, 2 do |i|
      info "   #{permissions[i].upcase} #{permissions[i+1]}"
    end

    $HUTDOWN.hook { DRbServerManager.stop }
  end
  
  def self.stop
    DRb.stop_service
  end
end


# == Using Distributed Ruby (DRb) in Adhearsion
#
# A DRb server works by offering a single object to other Ruby instances
# who wish to use it over TCP. The DRbDoor class is designed to provide
# remote access to the Adhearsion's internals, such as the +PBX+ object,
# helpers' methods, etc.
# 
# == Usage example
#
# Below is an example DRb client which accesses Adhearsion's internals.
#
#    require 'drb'
#    DRb.start_service
#    Adhearsion = DRbObject.new nil, 'druby://localhost:9050'
#    p Adhearsion.PBX.sip_users
#    p Adhearsion.weather 'Dallas, Texas'
#
# Notice the subtle differences above in the two remote DRb procedure calls.
# When calling a method on the DRbDoor (called Adhearsion in the example), the
# target method is inspected to see whether the name meets the Ruby's constant
# syntax: capitalized first letter. The example PBX method actually returns
# the equivalent of Module.const_get(:PBX). When calling a traditionally-formatted
# method (no first capital letter), the return value of that method is evaluated.
class DRbDoor
  
  instance_methods.each { |m| undef_method m unless m =~ /^(__|((private|protected)_methods|to_s|class)$)/ }
  
  
  @@door = Object.new
  class << @@door
    def metaclass() class << self; self; end; end
    def meta_eval(&block) metaclass.instance_eval(&block) end
  end
  
  def method_missing name, *args, &block
    # Check whether it's a constant
    if (?A..?Z).include? name.to_s[0] then Module.const_get name
    else @@door.meta_eval { __send__ name, *args, &block }
    end
  end
  
  def cli(&block) self.instance_eval(&block) end
end