module FaultInjection
  
  class FaultConditionBase
	attr_accessor :error_class
	attr_accessor :message
	attr_accessor :probability
	attr_accessor :limit_times

	def initialize
	  @probability ||= 1
	  @limit_times ||= -1
	end
	
	def should_raise_on(*args)
	  return false if @limit_times == 0
	  
	  b = _should_raise_on(*args)

	  if @probability < 1
		b = b && rand(0) < @probability
	  end

	  @limit_times -= 1 if b

	  b
	end

	private
	
	def _should_raise_on(*args)
	  false
	end
  end
  
  class FaultConditionLine < FaultConditionBase
	attr_accessor :file
	attr_accessor :line
	
	def initialize(file,line,prob=1)
	  @file = file
	  @line = line
	  self.probability = prob

	  if @line <= 0
		raise ArgumentError,"line number must be greater than 0."
	  end

	  if prob < 0 or prob > 1
		raise ArgumentError, "Probability must be between 0 and 1."
	  end
	  
	  super()
	end

	private
	def _should_raise_on *args
	  if args.size == 2
		file,line = *args
		reg = Regexp.new(Regexp.escape(@file) + '$')
		return reg.match(file) && line == @line
		
	  else
		false
	  end
	end
  end

  class FaultConditionCall < FaultConditionBase
	# representing method chain(callee first)
	#   [ [class,'method_name'],
	#     [class,'method_name'],
	#              ...
	#     [class,'method_name'] ]
	attr_accessor :stack_pattern

	def initialize
	  @stack_pattern = []

	  super()
	end

	def add_callee(klass,method)
	  @stack_pattern.unshift [klass,method]
	end

	private
	def _should_raise_on *args
	  return false if @stack_pattern.nil? or @stack_pattern.size == 0
	  
	  if args[0].instance_of? Array
		stack = args[0]
		#STDERR.puts @stack_pattern.map{|e| "#{e[0]}##{e[1]}"}.join("\n")
		
		return false if stack.size < @stack_pattern.size

		@stack_pattern.each_index do |i|
		  e = @stack_pattern[i]
		  b = stack[-i-1]
		  return false if e[0] != b[0].to_s.to_sym or e[1] != b[1].to_sym
		end
		
		true
	  else
		false
	  end
	end
  end
end