# Copyright (c) 2008 Simon Menke
# 
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
# 
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

# Example:
#   recorder = Message::Recorder.new
#   recorder.record.downcase.intern
#   recorder.before do |message_call|
#     p message_call.class # => Message::Recorder::MessageCall
#     !(message_call.subject.nil? or message_callsubject.empty?)
#   end
#   recorder.after do |message_call|
#     p message_call.class # => Message::Recorder::MessageCall
#     p message_call.return_value
#   end
#   recorder.send_to(nil)        # => nil
#   recorder.send_to("")         # => nil
#   recorder.send_to("Mr_Henry") # => :mr_henry
class Message::Recorder
  
  
  # <b>BEFORE CALL FILTER:</b>
  # 
  # Takes a block with one argument of type Message::Recorder::MessageCall
  #   recorder.before { |message_call| ... }
  #   recorder.before :call { |message_call| ... }
  #   recorder.before :call, :my_filter_method
  #   def my_filter_method(message_call)
  #     ...
  #   end
  # if the block returns false the chain will be broken.
  # 
  # <b>BEFORE CHAIN FILTER:</b>
  # 
  # Takes a block with one argument of type Message::Recorder::Message
  #   recorder.before :chain { |message| ... }
  #   recorder.before :chain, :my_filter_method
  #   def my_filter_method(message)
  #     ...
  #   end
  #
  # <b>BEFORE BRANCH FILTER:</b>
  # 
  # Takes a block with one argument of type Message::Recorder::Collector
  #   recorder.before :branch { |collector| ... }
  #   recorder.before :branch, :my_filter_method
  #   def my_filter_method(collector)
  #     ...
  #   end
  def before(*options,&block)
    type     = options.shift if [:call, :chain, :branch].include? options.first
    type   ||= :call
    filter   = block 
    filter ||= method(options.shift)
    case type
    when :call   then before_call_filters   << filter
    when :chain  then before_chain_filters  << filter
    when :branch then before_branch_filters << filter
    end
  end
  
  # <b>AFTER CALL FILTER:</b>
  # 
  # Takes a block with one argument of type Message::Recorder::MessageCall
  #   recorder.after { |message_call| ... }
  #   recorder.after :call { |message_call| ... }
  #   recorder.after :call, :my_filter_method
  #   def my_filter_method(message_call)
  #     ...
  #   end
  # if the block returns false the chain will be broken.
  # 
  # <b>AFTER CHAIN FILTER:</b>
  # 
  # Takes a block with one argument of type Message::Recorder::Message
  #   recorder.after :chain { |message| ... }
  #   recorder.after :chain, :my_filter_method
  #   def my_filter_method(message)
  #     ...
  #   end
  #
  # <b>AFTER BRANCH FILTER:</b>
  # 
  # Takes a block with two arguments of type Message::Recorder::Collector
  #   recorder.after :branch { |original_collector, new_collector| ... }
  #   recorder.after :branch, :my_filter_method
  #   def my_filter_method(original_collector, new_collector)
  #     ...
  #   end
  def after(*options,&block)
    type     = options.shift if [:call, :chain, :branch].include? options.first
    type   ||= :call
    filter   = block 
    filter ||= method(options.shift)
    case type
    when :call   then after_call_filters   << filter
    when :chain  then after_chain_filters  << filter
    when :branch then after_branch_filters << filter
    end
  end
  
  # #record returns a mock object which will store all the messages you send to it.
  def record
    @collector = nil
    collector.collect_messages
  end
  
  # #send_to will send the recorded messages to the #subject.
  def send_to(subject)
    collector.send_to(subject, self)
  end
  
  
  attr_accessor :before_call_filters # :nodoc:
  attr_accessor :after_call_filters  # :nodoc:
  attr_accessor :before_branch_filters # :nodoc:
  attr_accessor :after_branch_filters  # :nodoc:
  attr_accessor :before_chain_filters # :nodoc:
  attr_accessor :after_chain_filters  # :nodoc:
  
  def before_call_filters # :nodoc:
    @before_call_filters ||= []
  end
  
  def after_call_filters # :nodoc:
    @after_call_filters ||= []
  end
  
  def before_branch_filters # :nodoc:
    @before_branch_filters ||= []
  end
  
  def after_branch_filters # :nodoc:
    @after_branch_filters ||= []
  end
  
  def before_chain_filters # :nodoc:
    @before_chain_filters ||= []
  end
  
  def after_chain_filters # :nodoc:
    @after_chain_filters ||= []
  end
  
  def filter_before_call(message_call) # :nodoc:
    before_call_filters.each do |filter|
      should_break = filter.call(message_call)
      return false if should_break === false
    end
    return true
  end
  
  def filter_after_call(message_call) # :nodoc:
    after_call_filters.each do |filter|
      should_break = filter.call(message_call)
      return false if should_break === false
    end
    return true
  end
  
  def filter_before_branch(collector) # :nodoc:
    before_branch_filters.each do |filter|
      filter.call(collector)
    end
  end
  
  def filter_after_branch(original, branch) # :nodoc:
    after_branch_filters.each do |filter|
      filter.call(original, branch)
    end
  end
  
  def filter_before_chain(message) # :nodoc:
    before_chain_filters.each do |filter|
      filter.call(collector)
    end
  end
  
  def filter_after_chain(message) # :nodoc:
    after_chain_filters.each do |filter|
      filter.call(message)
    end
  end
  
  def collector # :nodoc:
    @collector ||= ::Message::Recorder::Collector.new(:recorder => self)
  end
  
end