#include <M5StickCPlus2.h>

// -1 if error
int a = 0;
int b = 0;
int targetResult = 0;

enum class Operator{
    plus,
    minus,
    mult
};

void initRandomSeed(){
    randomSeed(millis());
}

String generateQuestion(){
    Operator oper = static_cast<Operator>(random(0, 3));
    switch (oper)
    {
        case Operator::plus:
            a = random(0, 15);
            b = random(1, 15);

            targetResult = a + b;
            return String(a) + "+" + String(b) + " = ?";

        case Operator::minus:
            do
            {
                a = random(15, 30);
                b = random(0, 15);

                targetResult = a - b;
            } while (targetResult <= 0);
            return String(a) + "-" + String(b) + "= ?";

        case Operator::mult:
            a = random(0, 10);
            b = random(1, 10);

            targetResult = a * b;
            return String(a) + "*" + String(b) + "= ?";

        default:
            Serial.println("Failed to create math question");
            return "Error";
    }
}