#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <DHT.h>
#include <ESP8266WiFi.h>
#include <PubSubClient.h>

// Konfigurasi LCD
LiquidCrystal_I2C lcd(0x27, 16, 2);

// Konfigurasi DHT11
#define DHTPIN 2     // GPIO2 (D4)
#define DHTTYPE DHT11
DHT dht(DHTPIN, DHTTYPE);

// Konfigurasi MQ135
#define MQ135_PIN A0
float R0 = 76.63;    // Nilai default, akan dikalibrasi ulang

// Konfigurasi Buzzer dan LED
#define BUZZER_PIN 12     // GPIO12 (D6)
#define LED_PIN 14        // GPIO14 (D5) - Pin untuk LED indikator (diubah ke D5)
#define CO2_THRESHOLD 90  // Threshold CO2 dalam ppm
#define TEMP_THRESHOLD 30   // Threshold suhu dalam °C
#define HUMID_THRESHOLD 80  // Threshold kelembaban dalam %

// Konfigurasi WiFi dan MQTT
const char* ssid = "SKK - STUDENT";
const char* password = "";
const char* mqtt_server = "103.124.138.170";
const int mqtt_port = 1883;
const char* mqtt_user = "USER_MQTT";
const char* mqtt_pass = "PASS_MQTT";
const char* topic_temp = "sensor/temperature";
const char* topic_humid = "sensor/humidity";
const char* topic_co2 = "sensor/co2";
const char* topic_control = "sensor/control";
const char* topic_status = "sensor/status";
const char* topic_alert = "sensor/alert";

WiFiClient espClient;
PubSubClient client(espClient);

// Variabel status sistem
bool systemEnabled = true;
unsigned long lastSensorUpdate = 0;
const long sensorInterval = 60000; // Interval pengiriman data sensor (ms)

void setup_wifi() {
  delay(10);
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.begin(ssid, password);

  lcd.clear();
  lcd.print("Connecting WiFi");
  
  while (WiFi.status() != WL_CONNECTED) {
    for(int i=0; i<10; i++) {
      delay(500);
      Serial.print(".");
      lcd.print(".");
    }
    lcd.clear();
    lcd.print("Retrying WiFi...");
  }

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
  
  lcd.clear();
  lcd.print("WiFi Connected");
  lcd.setCursor(0, 1);
  lcd.print(WiFi.localIP());
  delay(2000);
}

void reconnect() {
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    
    if (client.connect("ESP8266Client", mqtt_user, mqtt_pass)) {
      Serial.println("connected");
      client.subscribe(topic_control);
      Serial.println("Subscribed to control topic");
      client.publish(topic_status, systemEnabled ? "ON" : "OFF", true);
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      
      lcd.clear();
      lcd.print("MQTT Fail");
      lcd.setCursor(0, 1);
      lcd.print("Retrying...");
      
      delay(5000);
    }
  }
}

void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");

  char message[length+1];
  for (int i = 0; i < length; i++) {
    message[i] = (char)payload[i];
  }
  message[length] = '\0';
  Serial.println(message);

  if (String(topic) == topic_control) {
    if (strcmp(message, "ON") == 0) {
      systemEnabled = true;
      noTone(BUZZER_PIN); // Matikan buzzer saat sistem dihidupkan
      digitalWrite(LED_PIN, LOW); // Matikan LED
      lcd.clear();
      lcd.print("System ON");
      client.publish(topic_status, "ON", true);
      Serial.println("System turned ON");
      delay(1000);
    } 
    else if (strcmp(message, "OFF") == 0) {
      systemEnabled = false;
      noTone(BUZZER_PIN); // Matikan buzzer saat sistem dimatikan
      digitalWrite(LED_PIN, LOW); // Matikan LED
      lcd.clear();
      lcd.print("System OFF");
      client.publish(topic_status, "OFF", true);
      Serial.println("System turned OFF");
      delay(1000);
    }
  }
}
//mengubah waktu kalibrasi
void calibrateR0() {
  if (!systemEnabled) return;
  
  Serial.println("Kalibrasi MQ135 dimulai...");
  lcd.clear();
  lcd.print("Kalibrasi MQ135");
  lcd.setCursor(0, 1);
  lcd.print("Udara bersih 5m");
  //rubah pada waktu 300
  for(int i = 0; i < 300; i++) {
    delay(1000);
    if(i % 30 == 0) {
      Serial.print(".");
      lcd.print(".");
    }
    if (!systemEnabled) {
      Serial.println("Kalibrasi dibatalkan!");
      lcd.clear();
      lcd.print("Kalibrasi");
      lcd.setCursor(0, 1);
      lcd.print("Dibatalkan");
      delay(2000);
      return;
    }
  }
  
  Serial.println("\nMengambil sampel...");
  float sum = 0;
  int validReadings = 0;
  
  for (int i = 0; i < 100; i++) {
    int rawValue = analogRead(MQ135_PIN);
    if(rawValue < 50 || rawValue > 1000) {
      continue;
    }
    
    float sensor_volt = rawValue * (3.3 / 1023.0);
    float RS_air = (3.3 - sensor_volt) / sensor_volt;
    sum += RS_air;
    validReadings++;
    delay(100);
    
    if (!systemEnabled) {
      Serial.println("Kalibrasi dibatalkan!");
      lcd.clear();
      lcd.print("Kalibrasi");
      lcd.setCursor(0, 1);
      lcd.print("Dibatalkan");
      delay(2000);
      return;
    }
  }

  if(validReadings < 50) {
    Serial.println("Gagal kalibrasi: Pembacaan tidak stabil");
    lcd.clear();
    lcd.print("Gagal Kalibrasi!");
    delay(3000);
    return;
  }
  
  R0 = sum / validReadings;
  Serial.print("R0 terkalibrasi: ");
  Serial.println(R0);
  
  lcd.clear();
  lcd.print("Kalibrasi Selesai");
  lcd.setCursor(0, 1);
  lcd.print("R0: ");
  lcd.print(R0);
  delay(3000);
}

void controlBuzzerAndLED(float temperature, float humidity, float co2) {
  bool alertCondition = false;
  String alertMessage = "";
  
  if (co2 > CO2_THRESHOLD && co2 > 0) {
    alertCondition = true;
    alertMessage += "CO2 tinggi! ";
    Serial.println("Peringatan: Level CO2 melebihi threshold!");
  }
  
  if (temperature > TEMP_THRESHOLD && temperature > 0) {
    alertCondition = true;
    alertMessage += "Suhu tinggi! ";
    Serial.println("Peringatan: Suhu melebihi threshold!");
  }
  
  if (humidity > HUMID_THRESHOLD && humidity > 0) {
    alertCondition = true;
    alertMessage += "Kelembaban tinggi! ";
    Serial.println("Peringatan: Kelembaban melebihi threshold!");
  }
  
  if (alertCondition && systemEnabled) {
    tone(BUZZER_PIN, 1000);  // Frekuensi 1 kHz
    digitalWrite(LED_PIN, HIGH);  // Nyalakan LED
    lcd.setCursor(15, 0);
    lcd.print("!");
    
    if (alertMessage.length() > 0) {
      client.publish(topic_alert, alertMessage.c_str());
    }
  } else {
    noTone(BUZZER_PIN);
    digitalWrite(LED_PIN, LOW);  // Matikan LED
    lcd.setCursor(15, 0);
    lcd.print(" ");
  }
}

void readAndSendSensorData() {
  if (!systemEnabled) {
    noTone(BUZZER_PIN);
    digitalWrite(LED_PIN, LOW);
    return;
  }

  float humidity = dht.readHumidity();
  float temperature = dht.readTemperature();
  int rawValue = analogRead(MQ135_PIN);
  
  float sensor_volt = rawValue * (3.3 / 1023.0);
  float RS_gas = (3.3 - sensor_volt) / sensor_volt;
  float ratio = RS_gas / R0;
  float ppm_CO2 = 116.6020682 * pow(ratio, -2.769034857);
  
  float corrected_ppm = ppm_CO2;
  if (!isnan(temperature) && !isnan(humidity)) {
    corrected_ppm = ppm_CO2 * (1.0 + 0.0005*(25-temperature) + 0.0002*humidity);
  }
  
  if (isnan(humidity)) humidity = -1;
  if (isnan(temperature)) temperature = -1;
  if(rawValue < 50 || rawValue > 1000) corrected_ppm = -1;

  controlBuzzerAndLED(temperature, humidity, corrected_ppm);

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("S:");
  lcd.print(systemEnabled ? "ON " : "OFF");
  lcd.print(" T:");
  lcd.print(temperature >= 0 ? temperature : -1, 1);
  lcd.print("C");
  
  lcd.setCursor(0, 1);
  lcd.print("H:");
  lcd.print(humidity >= 0 ? humidity : -1, 0);
  lcd.print("% CO2:");
  if(corrected_ppm < 0) {
    lcd.print("Err");
  } else {
    lcd.print(corrected_ppm, 0);
  }

  char tempStr[10], humidStr[10], co2Str[10];
  dtostrf(temperature, 4, 2, tempStr);
  dtostrf(humidity, 4, 2, humidStr);
  dtostrf(corrected_ppm, 4, 0, co2Str);
  
  client.publish(topic_temp, tempStr);
  client.publish(topic_humid, humidStr);
  client.publish(topic_co2, co2Str);
  
  Serial.print("Temperature: ");
  Serial.print(tempStr);
  Serial.print("C | Humidity: ");
  Serial.print(humidStr);
  Serial.print("% | CO2: ");
  Serial.print(co2Str);
  Serial.println("ppm");
}

void setup() {
  Serial.begin(115200);
  
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(LED_PIN, OUTPUT);
  digitalWrite(BUZZER_PIN, LOW);
  digitalWrite(LED_PIN, LOW);
  
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Starting System...");
  
  dht.begin();
  
  int testVal = analogRead(MQ135_PIN);
  if(testVal < 50) {
    Serial.println("ERROR: Sensor MQ135 tidak terdeteksi!");
    lcd.clear();
    lcd.print("MQ135 Error!");
    while(1) { 
      delay(1000);
      Serial.println("Periksa koneksi dan reset board");
    }
  }
  
  setup_wifi();
  
  client.setServer(mqtt_server, mqtt_port);
  client.setCallback(callback);
  
  calibrateR0();
  
  lcd.clear();
}

void loop() {
  if (!client.connected()) {
    reconnect();
  }
  client.loop();

  lcd.setCursor(3, 0);
  lcd.print(systemEnabled ? "ON " : "OFF");

  unsigned long currentMillis = millis();
  if (currentMillis - lastSensorUpdate >= sensorInterval && systemEnabled) {
    lastSensorUpdate = currentMillis;
    readAndSendSensorData();
  }
  
  delay(100);
}