require 'mocha/metaclass'

module Mocha

  class ClassMethod
  
    attr_reader :stubbee, :method
   
    def initialize(stubbee, method)
      @stubbee = stubbee
      @method = RUBY_VERSION < '1.9' ? method.to_s : method.to_sym
    end
  
    def stub
      hide_original_method
      define_new_method
    end
  
    def unstub
      remove_new_method
      restore_original_method
      stubbee.reset_mocha
    end
    
    def mock
      stubbee.mocha
    end
  
    def hide_original_method
      if method_exists?(method)
        begin
          stubbee.__metaclass__.send(:alias_method, hidden_method, method)
        rescue NameError
          # deal with nasties like ActiveRecord::Associations::AssociationProxy
        end
      end
    end
  
    def define_new_method
      stubbee.__metaclass__.class_eval(%{
        def #{method}(*args, &block)
          mocha.method_missing(:#{method}, *args, &block)
        end
      }, __FILE__, __LINE__)
    end
  
    def remove_new_method
      stubbee.__metaclass__.send(:remove_method, method)
    end
  
    def restore_original_method
      if method_exists?(hidden_method)
        begin
          stubbee.__metaclass__.send(:alias_method, method, hidden_method)
          stubbee.__metaclass__.send(:remove_method, hidden_method)
        rescue NameError
          # deal with nasties like ActiveRecord::Associations::AssociationProxy
        end
      end
    end
  
    def hidden_method
      if RUBY_VERSION < '1.9'
        method_name = method.to_s.gsub(/\W/) { |s| "_substituted_character_#{s[0]}_" }
      else
        method_name = method.to_s.gsub(/\W/) { |s| "_substituted_character_#{s.ord}_" }
      end
      hidden_method = "__stubba__#{method_name}__stubba__"
      RUBY_VERSION < '1.9' ? hidden_method.to_s : hidden_method.to_sym
    end  
  
    def eql?(other)
      return false unless (other.class == self.class)
      (stubbee.object_id == other.stubbee.object_id) and (method == other.method)
    end
  
    alias_method :==, :eql?
  
    def to_s
      "#{stubbee}.#{method}"
    end
    
    def method_exists?(method)
      symbol = method.to_sym
      metaclass = stubbee.__metaclass__
      metaclass.public_method_defined?(symbol) || metaclass.protected_method_defined?(symbol) || metaclass.private_method_defined?(symbol)
    end

  end
  
end
