#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 32
#define OLED_RESET -1

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

#define BTN_MODE 12
#define BTN_SET 14

int mode = 0;
unsigned long lastDebounce = 0;

// Simulação de tempo (relógio interno)
unsigned long baseMillis = 0;
int simHour = 12;
int simMin = 0;
int simDay = 14;
int simMonth = 5;

// Cronômetro
bool chronoRunning = false;
unsigned long chronoStart = 0;
unsigned long chronoTime = 0;

// Soneca
bool sleeping = false;
unsigned long sleepStart = 0;

void setup() {
  pinMode(BTN_MODE, INPUT_PULLUP);
  pinMode(BTN_SET, INPUT_PULLUP);

  Wire.begin(21, 22);
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.clearDisplay();
  display.setTextColor(SSD1306_WHITE);
  display.setTextSize(1);
  baseMillis = millis();
}

void loop() {
  unsigned long nowMillis = millis();

  // Atualiza hora simulada (1 min a cada 5s)
  if (nowMillis - baseMillis >= 5000) {
    baseMillis = nowMillis;
    simMin++;
    if (simMin >= 60) {
      simMin = 0;
      simHour++;
      if (simHour >= 24) {
        simHour = 0;
        simDay++;
        if (simDay > 31) {
          simDay = 1;
          simMonth++;
          if (simMonth > 12) simMonth = 1;
        }
      }
    }
  }

  display.clearDisplay();
  display.setCursor(0, 0);
  display.println("== YenWatch Mini ==");

  switch (mode) {
    case 0: // Hora
      display.setCursor(20, 16);
      if (simHour < 10) display.print("0");
      display.print(simHour);
      display.print(":");
      if (simMin < 10) display.print("0");
      display.print(simMin);
      break;

    case 1: // Data
      display.setCursor(20, 16);
      if (simDay < 10) display.print("0");
      display.print(simDay);
      display.print("/");
      if (simMonth < 10) display.print("0");
      display.print(simMonth);
      break;

    case 2: { // Cronômetro
      unsigned long elapsed = chronoRunning ? (nowMillis - chronoStart + chronoTime) : chronoTime;
      int mins = (elapsed / 60000);
      int secs = (elapsed / 1000) % 60;

      display.setCursor(20, 16);
      if (mins < 10) display.print("0");
      display.print(mins);
      display.print(":");
      if (secs < 10) display.print("0");
      display.print(secs);
      break;
    }

    case 3: { // Soneca
      if (!sleeping) {
        sleeping = true;
        sleepStart = nowMillis;
      }

      display.setCursor(20, 16);
      display.println("Dormindo...");

      if (nowMillis - sleepStart >= 10000) {
        sleeping = false;
        mode = 0;
      }
      break;
    }
  }

  display.display();

  // Debounce dos botões
  if (nowMillis - lastDebounce > 200) {
    if (digitalRead(BTN_MODE) == LOW) {
      mode = (mode + 1) % 4;
      lastDebounce = nowMillis;
    }

    if (digitalRead(BTN_SET) == LOW) {
      lastDebounce = nowMillis;
      if (mode == 1) {
        simDay++;
        if (simDay > 31) {
          simDay = 1;
          simMonth++;
          if (simMonth > 12) simMonth = 1;
        }
      }
      else if (mode == 2) {
        if (!chronoRunning) {
          chronoRunning = true;
          chronoStart = nowMillis;
        } else {
          chronoRunning = false;
          chronoTime += nowMillis - chronoStart;
        }
      }
    }
  }
}