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

// ================== SENSOR SETTINGS ==================
#define DHTPIN 2
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);

// ================== LCD SETTINGS =====================
LiquidCrystal_I2C lcd(0x27, 20, 4);

// ================== OUTPUT PINS ======================
#define FAN_PIN        3
#define HEATER_PIN     4
#define HUMIDIFIER_PIN 5

// ================== CONTROL THRESHOLDS ===============
#define TEMP_HIGH     27
#define TEMP_LOW      25
#define HUMIDITY_LOW  65
#define HUMIDITY_HIGH 75
#define HUMIDITY_FAN  80

// ================== STATE FLAGS ======================
bool fanState = false;
bool heaterState = false;
bool humidifierState = false;

// ================== BANNER (row 0 fallback) ==========
char bannerMessage[] = " MANTIS CLIMATE CONTROL ";
int bannerIndex = 0;
unsigned long lastBannerScroll = 0;
const int bannerDelay = 400;

// ================== TIMERS ===========================
unsigned long lastSensorRead = 0;
const int sensorInterval = 5000;

// ================== HEARTBEAT ========================
bool heartbeatState = false;
unsigned long lastHeartbeat = 0;

// ================== UPTIME ===========================
unsigned long lastUptimeUpdate = 0;

// ================== EVENT SCROLLER (row 0) ===========
String eventMessage = "";
int eventIndex = 0;
unsigned long lastEventScroll = 0;
const int eventScrollDelay = 400;
bool eventActive = false;

// ================== STATUS SCROLLER (row 3) ==========
String statusMessage = "";
int statusIndex = 0;
unsigned long lastStatusScroll = 0;
const int statusScrollDelay = 400;

void setup() {
  Serial.begin(9600);
  dht.begin();
  lcd.init();
  lcd.backlight();

  // Boot splash
  lcd.setCursor(0,0); lcd.print(" MANTIS CLIMATE ");
  lcd.setCursor(0,1); lcd.print("     CONTROL     ");
  delay(1000);

  lcd.setCursor(0,3); lcd.print("Booting: ");
  for (int i=0; i<10; i++) {
    lcd.setCursor(9+i, 3);
    lcd.write(byte(255));
    delay(200);
  }

  lcd.setCursor(0,2);
  lcd.print("   System Ready!   ");
  delay(2000);
  lcd.clear();

  pinMode(FAN_PIN, OUTPUT);
  pinMode(HEATER_PIN, OUTPUT);
  pinMode(HUMIDIFIER_PIN, OUTPUT);

  digitalWrite(FAN_PIN, LOW);
  digitalWrite(HEATER_PIN, LOW);
  digitalWrite(HUMIDIFIER_PIN, LOW);

  Serial.println(F("\n=== MANTIS CLIMATE CONTROL READY ==="));
}

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

  // ---------- Sensor Read ----------
  static float humidity = NAN, temperature = NAN;
  static bool prevFan = false, prevHeater = false, prevHumidifier = false;

  if (now - lastSensorRead >= sensorInterval) {
    lastSensorRead = now;
    humidity = dht.readHumidity();
    temperature = dht.readTemperature();

    if (isnan(humidity) || isnan(temperature)) {
      lcd.setCursor(0,1);
      lcd.print("Sensor Error!       ");
      Serial.println(F("⚠️  Sensor read failed"));
      return;
    }

    // Control logic
    fanState        = (temperature > TEMP_HIGH || humidity > HUMIDITY_FAN);
    heaterState     = (temperature < TEMP_LOW);
    humidifierState = (humidity < HUMIDITY_LOW);
    if (humidity > HUMIDITY_HIGH) humidifierState = false;

    digitalWrite(FAN_PIN, fanState);
    digitalWrite(HEATER_PIN, heaterState);
    digitalWrite(HUMIDIFIER_PIN, humidifierState);

    // Detect changes → trigger event
    if (fanState != prevFan) {
      eventMessage = fanState ? ">>> FAN TURNED ON <<< " : ">>> FAN TURNED OFF <<< ";
      eventIndex = 0; eventActive = true;
    }
    if (heaterState != prevHeater) {
      eventMessage = heaterState ? ">>> HEATER TURNED ON <<< " : ">>> HEATER TURNED OFF <<< ";
      eventIndex = 0; eventActive = true;
    }
    if (humidifierState != prevHumidifier) {
      eventMessage = humidifierState ? ">>> HUMIDIFIER TURNED ON <<< " : ">>> HUMIDIFIER TURNED OFF <<< ";
      eventIndex = 0; eventActive = true;
    }

    prevFan = fanState;
    prevHeater = heaterState;
    prevHumidifier = humidifierState;

    // Serial Debug
    Serial.print("🌡 Temp: "); Serial.print(temperature,1); Serial.print("°C  ");
    Serial.print("💧 Humidity: "); Serial.print(humidity,0); Serial.print("%  |  ");
    Serial.print("Fan: "); Serial.print(fanState ? "ON " : "OFF");
    Serial.print(" | Heater: "); Serial.print(heaterState ? "ON " : "OFF");
    Serial.print(" | Humidifier: "); Serial.println(humidifierState ? "ON" : "OFF");

    // Update LCD (Temp + Humidity)
    lcd.setCursor(0,1);
    lcd.print("Temp: ");
    lcd.print(temperature,1);
    lcd.print((char)223);
    lcd.print("C   ");

    lcd.setCursor(0,2);
    lcd.print("Humidity: ");
    lcd.print(humidity,0);
    lcd.print("%   ");

    // Build status message for scrolling
    statusMessage = " Fan:" + String(fanState ? "ON " : "OFF") +
                    " | Heat:" + String(heaterState ? "ON " : "OFF") +
                    " | Humid:" + String(humidifierState ? "ON " : "OFF") + " ";
    statusIndex = 0;
  }

  // ---------- Row 0: Event OR Banner ----------
  if (eventActive) {
    if (now - lastEventScroll >= eventScrollDelay) {
      lastEventScroll = now;
      lcd.setCursor(0,0);
      int len = eventMessage.length();
      for (int i=0; i<20; i++) {
        char c = eventMessage[(eventIndex + i) % len];
        lcd.print(c);
      }
      eventIndex++;
      if (eventIndex >= len) {
        eventActive = false; // done scrolling once
      }
    }
  } else {
    if (now - lastBannerScroll >= bannerDelay) {
      lastBannerScroll = now;
      int len = strlen(bannerMessage);
      lcd.setCursor(0,0);
      for (int i=0; i<20; i++) {
        lcd.print(bannerMessage[(bannerIndex + i) % len]);
      }
      bannerIndex = (bannerIndex + 1) % len;
    }
  }

  // ---------- Heartbeat Blink (top-right corner of row 0) ----------
  if (now - lastHeartbeat >= 1000 && !eventActive) {
    lastHeartbeat = now;
    heartbeatState = !heartbeatState;
    lcd.setCursor(19,0);
    lcd.print(heartbeatState ? "*" : " ");
  }

  // ---------- Uptime (always in row 2, right side) ----------
  if (now - lastUptimeUpdate >= 60000) {
    lastUptimeUpdate = now;
    unsigned long minutes = now / 60000;
    unsigned long hours = minutes / 60;
    minutes = minutes % 60;
    lcd.setCursor(14,2);
    char buf[6];
    snprintf(buf, sizeof(buf), "%02lu:%02lu", hours, minutes);
    lcd.print(buf);
  }

  // ---------- Row 3: Always scrolling status ----------
  if (now - lastStatusScroll >= statusScrollDelay && statusMessage.length() > 0) {
    lastStatusScroll = now;
    lcd.setCursor(0,3);
    int len = statusMessage.length();
    for (int i=0; i<20; i++) {
      char c = statusMessage[(statusIndex + i) % len];
      lcd.print(c);
    }
    statusIndex = (statusIndex + 1) % len;
  }
}