#!/usr/bin/env ruby
# .NET-style events in Ruby.

require 'date'

# BEGIN .NET-style events in Ruby
class Event
	def initialize
		@event_handlers = {}
	end
	def add_handler(*event_handlers, &block)
		event_handlers.each do |event_handler|
			@event_handlers[event_handler.to_s] = event_handler
		end
		if block
			@event_handlers[block.to_s] = block
			block.to_s
		end
	end
	def remove_handler(*event_handlers)

		event_handlers.each do |event_handler|
			@event_handlers.delete(event_handler.to_s)
		end
	end

	def raise_event(sender, eventArgs)
    @event_handlers.each do |key, handler|
       Thread.new { handler.call(sender, eventArgs) }
     end
	end
end

class EventArgs
	@@empty = EventArgs.new
	def EventArgs.empty
		@@empty
	end
end

# END .NET-style events in Ruby

# BEGIN More Ruby-like .NET-style events in Ruby
module Events
	def self.included(base)
		base.extend ClassMethods
	end
	module ClassMethods
		def has_events *events
			events.each do |event|
				class_eval <<-"EOF"
					def on_#{event}(*handlers, &block)
						@#{event}_handlers ||= {}
						handlers.each do |handler|
							@#{event}_handlers[handler.to_s] = handler
						end
						if block
							@#{event}_handlers[block.to_s] = block
							return block.to_s
						end
					end
					def delete_#{event}(*handlers)
						handlers.each do |handler|
							@#{event}_handlers.delete(handler.to_s)
						end
					end
					protected
					def #{event}(*args)
						@#{event}_handlers ||= {}
						@#{event}_handlers.each do |key, handler|
							Thread.new { handler.call *args }
						end
					end
				EOF
			end
		end
	end
end
#END More Ruby-like .NET-style events in Ruby


class FireAlarmActivatedEventArgs < EventArgs
	attr_reader :time
	attr_reader :room
	def initialize(time, room)
		@time = time
		@room = room
	end
end

class OldBuilding
	attr_reader :fire_alarm_activated
	def initialize
		@fire_alarm_activated = Event.new
	end
	def set_on_fire
		@fire_alarm_activated.raise_event self, FireAlarmActivatedEventArgs.new(DateTime.now, rand(60))
	end
	def evacuate
		puts "Evacuating building #{self.object_id}.\n"
	end
end

class NewBuilding
	include Events
	has_events :fire_alarm_activated, :sprinkler_activated

	def set_on_fire
		room = rand(60)
		fire_alarm_activated self, DateTime.now, room
		sprinkler_activated self, DateTime.now, room
	end
end

class Program
	def initialize
		@old_building = OldBuilding.new
		@new_building = NewBuilding.new
	end
	def on_fire_alarm_activated(sender, eventArgs)
		puts "Fire detected in building #{sender.object_id}, room #{eventArgs.room}, at #{eventArgs.time}.\n"
		puts "Calling fire department.\n"
		sender.evacuate
	end
	def main(*args)
		puts "\n"
		@old_building.fire_alarm_activated.add_handler method(:on_fire_alarm_activated)
		@old_building.fire_alarm_activated.add_handler { |sender, eventArgs| puts "It burns, it burns in room #{eventArgs.room}.\n" }
		@old_building.set_on_fire

		@new_building.on_fire_alarm_activated { |building, time, room| puts "Fire detected in building #{building.object_id}, room #{room}, at #{time}.\n" }
		@new_building.on_sprinkler_activated { |building, time, room| puts "Sprinkler activated in room #{room} at #{time}.\n" }
		@new_building.on_fire_alarm_activated { |building, time, room| puts "Evacuating bulding #{building.object_id}.\n" }
		10.times do
			sleep 1;
			@new_building.set_on_fire
		end
		sleep 0.2
		puts "\n"
	end
end

Program.new().main()

# This is an abomination. I know. Don't judge. It's just an example. Piss off.