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

/* LCD I2C 20x4 setup */
LiquidCrystal_I2C lcd(0x27, 20, 4);  // Use 0x3F if 0x27 doesn't work

/* Keypad setup */
const byte KEYPAD_ROWS = 4;
const byte KEYPAD_COLS = 4;
byte rowPins[KEYPAD_ROWS] = {5, 4, 3, 2};
byte colPins[KEYPAD_COLS] = {A3, A2, A1, A0};

char keys[KEYPAD_ROWS][KEYPAD_COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, KEYPAD_ROWS, KEYPAD_COLS);

/* Preset Messages */
String messages[10] = {
  "", // placeholder for index 0
  "HELLO",
  "HOW'S THE SITUATION?",
  "YOUR EST TIME TO ARRIVE?",
  "WE WILL SEND YOU BACKUP",
  "GO BACK UP",
  "GO MORE DEEPER",
  "GO TO LEFT",
  "GO TO RIGHT",
  "BE CAREFUL"
};

String selectedMessage = "";
bool messageReady = false;

void showSplashScreen() {
  lcd.setCursor(2, 1);
  lcd.print("UNDERWATER IR COMMS");
  lcd.setCursor(4, 2);
  lcd.print("SYSTEM READY");
  delay(2000);
  lcd.clear();
}

void displayMenu() {
  lcd.setCursor(0, 0);
  lcd.print("Press 1-9 to choose");
  lcd.setCursor(0, 1);
  lcd.print("Msg, #: Send, *:Clr");
}

void sendMessage() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Sending Message:");
  lcd.setCursor(0, 1);
  lcd.print(selectedMessage);

  // Simulated IR send (via Serial)
  Serial.print("IR SEND: ");
  Serial.println(selectedMessage);

  lcd.setCursor(0, 3);
  lcd.print("Status: Transmitted");
  delay(3000);

  selectedMessage = "";
  lcd.clear();
  displayMenu();
}

void setup() {
  Wire.begin();
  lcd.init();
  lcd.backlight();  // <- ✅ FIXED THIS LINE
  Serial.begin(9600);
  showSplashScreen();
  displayMenu();
}

void loop() {
  char key = keypad.getKey();
  if (key) {
    if (key >= '1' && key <= '9') {
      int index = key - '0';
      selectedMessage = messages[index];
      lcd.setCursor(0, 2);
      lcd.print("Selected:            ");
      lcd.setCursor(10, 2);
      lcd.print(key);
    } else if (key == '#') {
      if (selectedMessage.length() > 0) {
        sendMessage();
      }
    } else if (key == '*') {
      selectedMessage = "";
      lcd.setCursor(0, 2);
      lcd.print("Selection cleared    ");
    }
  }
}