using System.Collections.Generic;

namespace Amogulator.Suslang;

public interface Value {
    string valueString();
}

public class IntValue : Value {
    public int value;

    public string valueString() => $"{this.value}";
}

public class FloatValue : Value {
    public double value;

    public string valueString() => $"{this.value}";
}

public class VM {
    private int pc = 0;
    private List<Operation> program;
    public Stack<Value> stack = new();

    public VM(List<Operation> program) {
        this.program = program;
    }

    public void evaluate() {
        while (this.pc < this.program.Count) {
            switch (this.program[this.pc]) {
                case PushIntOperation op:
                    this.stack.Push(new IntValue() { value = op.value });
                    break;
                case PushFloatOperation op:
                    this.stack.Push(new FloatValue() { value = op.value });
                    break;
                case AddIntOperation:
                    this.stack.Push(new IntValue() { value = ((IntValue) this.stack.Pop()).value + ((IntValue) this.stack.Pop()).value });
                    break;
                case SubtractIntOperation:
                    this.stack.Push(new IntValue() { value = ((IntValue) this.stack.Pop()).value - ((IntValue) this.stack.Pop()).value });
                    break;
                case MultiplyIntOperation:
                    this.stack.Push(new IntValue() { value = ((IntValue) this.stack.Pop()).value * ((IntValue) this.stack.Pop()).value });
                    break;
                case DivideIntOperation:
                    this.stack.Push(new IntValue() { value = ((IntValue) this.stack.Pop()).value / ((IntValue) this.stack.Pop()).value });
                    break;
                case ModuloIntOperation:
                    this.stack.Push(new IntValue() { value = ((IntValue) this.stack.Pop()).value % ((IntValue) this.stack.Pop()).value });
                    break;
                case AddFloatOperation:
                    this.stack.Push(new FloatValue() { value = ((FloatValue) this.stack.Pop()).value + ((FloatValue) this.stack.Pop()).value });
                    break;
                case SubtractFloatOperation:
                    this.stack.Push(new FloatValue() { value = ((FloatValue) this.stack.Pop()).value - ((FloatValue) this.stack.Pop()).value });
                    break;
                case MultiplyFloatOperation:
                    this.stack.Push(new FloatValue() { value = ((FloatValue) this.stack.Pop()).value * ((FloatValue) this.stack.Pop()).value });
                    break;
                case DivideFloatOperation:
                    this.stack.Push(new FloatValue() { value = ((FloatValue) this.stack.Pop()).value / ((FloatValue) this.stack.Pop()).value });
                    break;
                case ModuloFloatOperation:
                    this.stack.Push(new FloatValue() { value = ((FloatValue) this.stack.Pop()).value % ((FloatValue) this.stack.Pop()).value });
                    break;
                default:
                    break;
            }
            this.pc += 1;
        }
    }
}