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

#define SDA 21
#define SCL 22

#define BUT_UP 26
#define BUT_DN 27

LiquidCrystal_I2C lcd(0x27, 16, 2);


byte arrows[8] =  {0b00100,0b01110,0b11111,0b00000,0b11111,0b01110,0b00100,0b00000};

// Textové pole: [index][řádek]
const char* text[][2] = {
                      //xxxxxxxxxxxxxxx 
  {"Stopwatch  12:30", "(0-12hod [0])"},
  {"Stopwatch    off", "(0-12hod [0])"},
  {"15:30 15.11.2025", "[0] set date/time"},
  {"WiFi          on", "SSID: SUNREG Wi"}
  };

int textIndex = 0;
const int textCount = sizeof(text) / sizeof(text[0]);

void setup() {
  Serial.begin(115200);

  pinMode(BUT_UP, INPUT_PULLUP);
  pinMode(BUT_DN, INPUT_PULLUP);

  Wire.begin(SDA, SCL);
  lcd.init();
  lcd.backlight();


  lcd.createChar(0, arrows);      // sipky up down symbol

  showTextOnLcd(textIndex);
}

void loop() {
  // Tlačítko UP
  if (digitalRead(BUT_UP) == LOW) {
    textIndex++;
    if (textIndex >= textCount) textIndex = 0;
    showTextOnLcd(textIndex);
    delay(300);
  }

  // Tlačítko DOWN
  if (digitalRead(BUT_DN) == LOW) {
    textIndex--;
    if (textIndex < 0) textIndex = textCount - 1;
    showTextOnLcd(textIndex);
    delay(300);
  }
}

void showTextOnLcd(int num) {
  lcd.clear();

  lcd.setCursor(0, 0);
  printWithSpecials(text[num][0]);

  lcd.setCursor(0, 1);
  printWithSpecials(text[num][1]);
}


void printWithSpecials(const char* str) {
  int i = 0;

  while (str[i] != '\0' && i < 16) {
    if (str[i] == '[' && str[i+2] == ']' && isdigit(str[i+1])) {
      int index = str[i+1] - '0'; // převod ASCII čísla na int
      lcd.write(index);
      i += 3; // přeskočíme "[x]"
    } else {
      lcd.print(str[i]);
      i++;
    }
  }
}