#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd1(0x27, 16, 2);
LiquidCrystal_I2C lcd2(0x26, 16, 2);

// ====== Przycisk ======
const uint8_t BTN_PIN = 2;

// ====== Odświeżanie LCD bez delay ======
const unsigned long LCD_REFRESH_MS = 200;
unsigned long lastRefreshMs = 0;

// ====== Debounce + pojedyncze naciśnięcie ======
const unsigned long DEBOUNCE_MS = 20;

bool lastRaw = HIGH;
bool stable  = HIGH;
unsigned long lastDebounceMs = 0;

unsigned long clickCount = 0;
bool swapped = false; // false: lcd1=INFO, lcd2=LICZNIK; true: odwrotnie
bool uiDirty = true;

unsigned long uptimeSeconds() {
  return millis() / 1000UL;
}

void printLine(LiquidCrystal_I2C &lcd, uint8_t row, const String &text) {
  lcd.setCursor(0, row);
  String t = text;
  if (t.length() > 16) t = t.substring(0, 16);
  lcd.print(t);
  for (int i = t.length(); i < 16; i++) lcd.print(' ');
}

bool buttonPressedEvent() {
  bool raw = digitalRead(BTN_PIN);

  if (raw != lastRaw) {
    lastRaw = raw;
    lastDebounceMs = millis();
  }

  if (millis() - lastDebounceMs > DEBOUNCE_MS) {
    if (raw != stable) {
      stable = raw;
      if (stable == LOW) return true;  // INPUT_PULLUP: wciśnięty = LOW
    }
  }

  return false;
}

void drawInfo(LiquidCrystal_I2C &lcd) {
  printLine(lcd, 0, "Ekran INFO");
  printLine(lcd, 1, "Kliknij przycisk");
}

void drawCounter(LiquidCrystal_I2C &lcd) {
  unsigned long up = uptimeSeconds();
  printLine(lcd, 0, "Ekran LICZNIK");
  printLine(lcd, 1, "K=" + String(clickCount) + " Up=" + String(up) + "s");
}

void drawUI() {
  if (!swapped) {
    drawInfo(lcd1);
    drawCounter(lcd2);
  } else {
    drawCounter(lcd1);
    drawInfo(lcd2);
  }
}

void setup() {
  Wire.begin();

  lcd1.init(); lcd1.backlight();
  lcd2.init(); lcd2.backlight();

  pinMode(BTN_PIN, INPUT_PULLUP);

  drawUI();
}

void loop() {
  if (buttonPressedEvent()) {
    clickCount++;
    swapped = !swapped;
    uiDirty = true;
  }

  unsigned long now = millis();
  if (uiDirty || (now - lastRefreshMs >= LCD_REFRESH_MS)) {
    lastRefreshMs = now;
    uiDirty = false;
    drawUI();
  }
}