namespace Smoll.Ex4.Commands {
    interface ICommand{
        void Perform(List<IScriptable> stack);
    }

    class PushNumberCommand : ICommand
    {
        public double self;
        public PushNumberCommand(double value) {
            self = value;
        }

        public void Perform(List<IScriptable> stack)
        {
            stack.Add(new Number(self));;
        }
    }

    class PushStringCommand : ICommand
    {
        public string self;
        public PushStringCommand(string value) {
            self = value;
        }

        public void Perform(List<IScriptable> stack)
        {
            stack.Add(new Commands.String(self));;
        }
    }

    class PushAtomCommand : ICommand
    {
        public string self;
        public PushAtomCommand(string value) {
            self = value;
        }

        public void Perform(List<IScriptable> stack)
        {
            stack.Add(new Commands.Atom(self));;
        }
    }

    class AddNumberCommand : ICommand
    {
        public void Perform(List<IScriptable> stack)
        {
            if(! stack.TakeLast(2).All(x => x is Ex4.Commands.Number)) {
                throw new Exception("Bad arguments to add as numbers");
            }
            var ret = stack.TakeLast(2).Cast<Ex4.Commands.Number>().Select(x => x.value).Sum();
            stack.RemoveAt(stack.Count - 1);
            stack.RemoveAt(stack.Count - 1);
            stack.Add(new Number(ret));
        }
    }

    class PrintCommand : ICommand
    {
        public void Perform(List<IScriptable> stack)
        {
            var ret = stack.Last();
            stack.RemoveAt(stack.Count - 1);
            System.Console.Out.Write(ret.ToString());
        }
    }

    class CompositeCommand : ICommand
    {
        List<ICommand> executable;
        public CompositeCommand(List<ICommand> executable) {
            this.executable = executable;
        }

        public void Perform(List<IScriptable> stack)
        {
            foreach (var item in executable)
            {
                item.Perform(stack);
            }
        }
    }
}