#include <WiFi.h>
#include <RTClib.h>
#include <DHTesp.h>
#include <ThingSpeak.h>
#include <LiquidCrystal_I2C.h>
#include <ESP32Servo.h>

// ----- Pin Definitions -----
#define MQ2_AOUT_PIN      35
#define MQ2_DOUT_PIN      34
#define GASLIGHT_PIN      26
#define DHTPIN            18
#define REDLEDPIN         12
#define ORANGELEDPIN      13
#define GREENLEDPIN       14
#define PERSON_TRIG_PIN   19
#define PERSON_ECHO_PIN   4
#define SERVO_PIN         23

// ----- WiFi & ThingSpeak -----
char ssid[] = "Wokwi-GUEST";
char pass[] = "";
WiFiClient client;
unsigned long channelID = 3027723;
const char* writeAPIKey = "TM9PHV4E6Q6GG6TG";

// ----- Global Objects -----
LiquidCrystal_I2C lcd(0x27, 16, 2);
DHTesp dht;
RTC_DS3231 rtc;
Servo radarServo;

// ----- Radar Servo Scan -----
const int centerAngle = 90;
const int scanDelay = 20;
const int objectThreshold = 30;
bool scanningRight = true;
int currentAngle = centerAngle;

int statusCode;

// ----- Function Prototypes -----
void connectWiFi();
long readDistanceCM();
void displayLCD(float temp, float humi, DateTime now);
void controlLEDs(float temp, float humi);
void gasSensorCheck();
void radarScan();
void uploadToThingSpeak(float temp, float humi, int gasValue, long distance);

void setup() {
  Serial.begin(115200);
  Serial.println("System Starting...");

  dht.setup(DHTPIN, DHTesp::DHT22);
  lcd.init();
  lcd.backlight();

  pinMode(REDLEDPIN, OUTPUT);
  pinMode(ORANGELEDPIN, OUTPUT);
  pinMode(GREENLEDPIN, OUTPUT);
  pinMode(GASLIGHT_PIN, OUTPUT);
  pinMode(MQ2_DOUT_PIN, INPUT);
  pinMode(MQ2_AOUT_PIN, INPUT);
  pinMode(PERSON_TRIG_PIN, OUTPUT);
  pinMode(PERSON_ECHO_PIN, INPUT);

  radarServo.attach(SERVO_PIN);
  radarServo.write(centerAngle);
  delay(1000);

  if (!rtc.begin()) {
    Serial.println("RTC initialization failed!");
    while (1);
  }
  if (rtc.lostPower()) {
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
  }

  lcd.setCursor(0, 0);
  lcd.print("Welcome to");
  lcd.setCursor(0, 1);
  lcd.print("Smart World");
  delay(3000);
  lcd.clear();

  connectWiFi();
  ThingSpeak.begin(client);

  Serial.println("Smart Envi Robot Initialized");
}

void loop() {
  if (WiFi.status() != WL_CONNECTED) {
    connectWiFi();
  }

  TempAndHumidity data = dht.getTempAndHumidity();
  float temp = data.temperature;
  float humi = data.humidity;

  if (isnan(humi) || isnan(temp)) {
    Serial.println("Failed to read from DHT sensor!");
    return;
  }

  DateTime now = rtc.now();
  displayLCD(temp, humi, now);
  controlLEDs(temp, humi);
  gasSensorCheck();
  radarScan();

  int gasAnalog = analogRead(MQ2_AOUT_PIN);
  long distance = readDistanceCM();

  uploadToThingSpeak(temp, humi, gasAnalog, distance);

  delay(2000); // delay between readings
}

void connectWiFi() {
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, pass);
  Serial.print("Connecting to WiFi");
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.print(".");
  }
  Serial.println("\nConnected to WiFi.");
}

long readDistanceCM() {
  digitalWrite(PERSON_TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(PERSON_TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(PERSON_TRIG_PIN, LOW);

  long duration = pulseIn(PERSON_ECHO_PIN, HIGH, 30000);
  return duration * 0.034 / 2;
}

void displayLCD(float temp, float humi, DateTime now) {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.printf("T:%.1fC H:%.1f%%", temp, humi);

  lcd.setCursor(0, 1);
  lcd.printf("%02d/%02d/%d %02d:%02d", now.day(), now.month(), now.year(), now.hour(), now.minute());

  Serial.printf("Humidity: %.1f %%\n", humi);
  Serial.printf("Temperature: %.1f ºC\n", temp);
  Serial.println("-----");
}

void controlLEDs(float temp, float humi) {
  digitalWrite(REDLEDPIN, LOW);
  digitalWrite(ORANGELEDPIN, LOW);
  digitalWrite(GREENLEDPIN, LOW);

  if (temp >= 70 && humi <= 30) {
    digitalWrite(REDLEDPIN, HIGH);
    Serial.println("Warning: You're in danger");
  } else if (temp >= 30 && temp <= 70 && humi >= 30 && humi <= 60) {
    digitalWrite(GREENLEDPIN, HIGH);
    Serial.println("You're fine");
  } else if (temp < 30 && humi > 60) {
    digitalWrite(ORANGELEDPIN, HIGH);
    Serial.println("Caution: Low temp/high humidity");
  }
}

void gasSensorCheck() {
  int analogValue = analogRead(MQ2_AOUT_PIN);
  int gasDigital = digitalRead(MQ2_DOUT_PIN);

  Serial.printf("Analog Gas Value: %d | Digital Trigger: %s\n", analogValue, gasDigital == HIGH ? "🚨 Detected" : "Safe");

  digitalWrite(GASLIGHT_PIN, gasDigital == HIGH ? HIGH : LOW);
}

void radarScan() {
  radarServo.write(currentAngle);
  delay(scanDelay);

  long distance = readDistanceCM();
  Serial.printf("Angle: %d°, Distance: %ld cm\n", currentAngle, distance);

  if (distance > 0 && distance < objectThreshold) {
    Serial.println("🔍 Object detected within 30cm!");
    delay(2000);
    radarServo.write(centerAngle);
    Serial.println("↩️ Returning to center");
    delay(1000);
    scanningRight = true;
    currentAngle = centerAngle;
    return;
  }

  if (scanningRight) {
    currentAngle += 2;
    if (currentAngle >= 180) {
      scanningRight = false;
      currentAngle = 180;
    }
  } else {
    currentAngle -= 2;
    if (currentAngle <= 0) {
      scanningRight = true;
      currentAngle = 0;
    }
  }
}

void uploadToThingSpeak(float temp, float humi, int gasValue, long distance) {
  ThingSpeak.setField(1, temp);
  ThingSpeak.setField(2, humi);
  ThingSpeak.setField(3, gasValue);
  ThingSpeak.setField(4, distance);

  statusCode = ThingSpeak.writeFields(channelID, writeAPIKey);
  if (statusCode == 200) {
    Serial.println("✅ Channel update successful.");
  } else {
    Serial.printf("❌ Problem Writing data. HTTP error: %d\n", statusCode);
  }
}