#include <fstream>
#include <iostream>
#include <array>

#include "utils.h"

#define MIN_VALUE 1
#define MAX_VALUE 10
#define MAX_TRIES 3
#define QUESTIONS 10
#define PENALTY_POINTS 3
#define POINTS_PER_ANSWER 10

using namespace std;

const char* format[] = {
  "? x %d = %d",
  "%d x ? = %d",
  "%d x %d = ?",
  "? x ? = %d"
};

int next() {
  return MIN_VALUE + rand() % (MAX_VALUE - MIN_VALUE + 1);
}

array<int, 3> getEquation() {
  int a = next(), b = next();
  return {a, b, a * b};
}

int getCode(array<int, 3> equation) {
  return stoi(
    to_string(equation[0]) +
    to_string(equation[1]) +
    to_string(equation[2])
  );
}

// TODO: ESP32 Wroom Sound Implementation
int buzzer(int attempts) {
  cout << "BUZZER: " << MAX_TRIES - attempts << " attempts remaining" << endl;
  return PENALTY_POINTS;
}

// g++ main.cpp -o main; ./main
int main() {
  // Initialize memory and variables scoping
  int memory[QUESTIONS];
  fill(memory, memory + QUESTIONS, -1);
  srand(time(NULL));
  int input, counter = 0, currentPoints = 0;
  // Solve as many questions as defined
  while (counter < QUESTIONS) {
    // Generate equation and "hash"
    array<int, 3> nums = getEquation();
    memory[counter] = getCode(nums);
    int option = rand() % 4;
    // Allow different formats for the same equation
    memory[counter] *= 10;
    memory[counter] += option;
    // Overwrite duplicate equation code
    while (hasDuplicates(memory)) {
      nums = getEquation();
      memory[counter] = getCode(nums);
      memory[counter] *= 10;
      memory[counter] += option;
    }
    // printArray(memory);
    int points = POINTS_PER_ANSWER, attempts = 0;
    // One free variable
    if (option < 3) {
      int expected = nums[option];
      // Shift values to format
      for (int i = option; i < 2; i++) {
        nums[i] = nums[i + 1];
      }
      do {
        printf(format[option], nums[0], nums[1]);
        cout << endl << "? = ";
        cin >> input;
        if (input == expected) { // User solved the equation
          cout << "OK" << endl;
          counter++;
          currentPoints += points;
          cout << "Points: " << currentPoints << endl;
          break;
        } else { // User failed
          points -= buzzer(++attempts);
        }
      } while (attempts < MAX_TRIES);
    // Two free variables
    } else {
      do {
        printf(format[option], nums[2]);
        cout << endl << "? = ";
        cin >> input;
        // The equation code is ignored, the user "redefines" it
        if (nums[2] % input == 0 && input <= MAX_VALUE) {
          int expected = nums[2] / input;
          memory[counter] = stoi(
            to_string(input) + to_string(expected) +
            to_string(nums[2]) + to_string(option)
          );
          cout << "? = ";
          cin >> input;
          if (input == expected) {
            cout << "OK" << endl;
            counter++;
            currentPoints += points;
            cout << "Points: " << currentPoints << endl;
            break;
          } else {
            points -= buzzer(++attempts);
          }
        } else {
          points -= buzzer(++attempts);
        }
      } while (attempts < MAX_TRIES);
    }
  }
  return 0;
}