strategy_decorator_cake.rb

module Component
    def operation
        raise "Component error"
    end
end

module Decorator
    include Component
    def initialize(component)
        @component = component
    end
    
    def operation
        @component.operation
    end
    
    def remove
        return @component
    end

end

class Sprinkles
    include Decorator
    def operation
        puts "Sprinkles added"
        super
    end
end

class Fruit
    include Decorator
    def operation
        puts "Fruit added"
        super
    end
end

class Cake
    include Component
    
    def initialize(strategy)
        @strategy = strategy
    end
    
    def operation
        @strategy.execute
    end
    
    def change_strategy(strategy)
        @strategy = strategy
    end
end


module CookingStrategy
    def execute
        raise "CookingStrategy error"
    end
end

class Oven
    include CookingStrategy
    def execute
        puts "Oven cooked"
    end
end

class Microwave
    include CookingStrategy
    def execute
        puts "Microwave cooked"
    end
end


# use strategy
oven_strategy = Oven.new
cake = Cake.new(oven_strategy)
cake.operation

# swap strategy
microwave_strategy = Microwave.new
cake.change_strategy(microwave_strategy)
cake.operation

# add decorators
cake = Sprinkles.new(Fruit.new(cake))
cake.operation

# remove decorator
cake = cake.remove
cake.operation

# remove decorator
cake = cake.remove
cake.operation