/*
  Infotainment System in City Railway - Wokwi IoT Simulation
  Author: armanyrs + Copilot
*/

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

LiquidCrystal_I2C LCD(0x27, 16, 2);

#define BTN_PIN 39   // VN pin (with external pullup)
#define BUZZER_PIN 13

const char* stations[] = {"Depok", "Manggarai", "Jakarta Kota"};
const int numStations = sizeof(stations) / sizeof(stations[0]);

enum State {
  SHOW_ROUTE,          // Animasi rute berjalan
  SHOW_WARNING         // Peringatan pintu, buzzer aktif
};

State state = SHOW_ROUTE; // Mulai langsung animasi rute
bool nextIsOpen = false;  // Siklus: tutup → buka → tutup → buka dst

int currentStation = 0;
int direction = 1; // 1: forward, -1: backward

unsigned long lastDebounceTime = 0;
const unsigned long debounceDelay = 50;
bool lastButtonState = false;
bool buttonState = false;

unsigned long lastAnimTime = 0;
const unsigned long animSpeed = 150; // ms per scroll step

String routeText = "";
int routeOffset = 0;
unsigned long warningShownAt = 0;
const unsigned long warningDuration = 1200;

void setup() {
  Serial.begin(115200);
  pinMode(BTN_PIN, INPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  LCD.init();
  LCD.backlight();
  welcomeScreen();
  delay(1500);

  updateRouteText();
  displayRouteText(true);
}

void loop() {
  handleButton();
  handleState();
}

// Button press handler with debounce logic
void handleButton() {
  bool reading = !digitalRead(BTN_PIN); // LOW when pressed
  if (reading != lastButtonState) {
    lastDebounceTime = millis();
  }

  if ((millis() - lastDebounceTime) > debounceDelay) {
    if (reading != buttonState) {
      buttonState = reading;
      if (buttonState && state == SHOW_ROUTE) { // Button pressed, hanya saat animasi rute
        // Masuk mode warning
        state = SHOW_WARNING;
        warningShownAt = millis();
        LCD.clear();
        if (nextIsOpen) {
          advanceStation();
          LCD.setCursor(0, 0);
          LCD.print("Pintu dibuka");
        } else {
          LCD.setCursor(0, 0);
          LCD.print("Pintu ditutup");
        }
        soundBuzzer();
        nextIsOpen = !nextIsOpen; // Ganti siklus tutup/buka
      }
    }
  }
  lastButtonState = reading;
}

// State handler: animasi rute atau warning pintu
void handleState() {
  if (state == SHOW_ROUTE) {
    handleAnimation();
  } else if (state == SHOW_WARNING) {
    // Tunggu warning selesai, lalu kembali ke animasi rute
    if (millis() - warningShownAt > warningDuration) {
      LCD.clear();
      updateRouteText();
      displayRouteText(true);
      state = SHOW_ROUTE;
    }
  }
}

// Buzzer: beep 3x
void soundBuzzer() {
  for (int i = 0; i < 3; i++) {
    digitalWrite(BUZZER_PIN, HIGH);
    delay(120);
    digitalWrite(BUZZER_PIN, LOW);
    delay(120);
  }
}

// Advance route station and handle direction
void advanceStation() {
  currentStation += direction;
  if (currentStation >= numStations - 1) {
    direction = -1;
  } else if (currentStation <= 0) {
    direction = 1;
  }
}

// Prepare scrolling route text
void updateRouteText() {
  int nextStation = currentStation + direction;
  routeText = String(stations[currentStation]) + " -> " + String(stations[nextStation]);
  routeText = "    " + routeText + "    "; // pad for smooth scroll
  routeOffset = 0;
}

// Animate route text: scroll from right to left
void handleAnimation() {
  if (millis() - lastAnimTime > animSpeed) {
    lastAnimTime = millis();
    displayRouteText(false);
  }
}

// Show route text at current offset
void displayRouteText(bool reset) {
  if (reset) routeOffset = 0;
  LCD.setCursor(0, 0);
  LCD.print("Rute Kereta:    ");
  LCD.setCursor(0, 1);
  int txtLen = routeText.length();
  if (routeOffset + 16 <= txtLen) {
    LCD.print(routeText.substring(routeOffset, routeOffset + 16));
  } else {
    LCD.print(routeText.substring(routeOffset));
    for (int i = 0; i < 16 - (txtLen - routeOffset); i++) LCD.print(" ");
  }
  routeOffset++;
  if (routeOffset > txtLen - 16) {
    routeOffset = 0;
  }
}

// Initial welcome screen
void welcomeScreen() {
  LCD.setCursor(0, 0);
  LCD.print("Infotainment");
  LCD.setCursor(0, 1);
  LCD.print("City Railway");
}