#pragma once
#include <WiFi.h>         
#include <PubSubClient.h> 
#include <Wire.h>         
#include <LiquidCrystal_I2C.h> 
#include <DHT.h>          
#include <time.h>         
#include <esp_system.h>   

#define BUTTON_PIN 15     
#define LED1_PIN 19      
#define LED2_PIN 18       
#define DHTPIN 26      
#define DHTTYPE DHT22     
#define BUZZER_PIN 4    
#define GAS_PIN 34      
#define PIR_PIN 27       

const float TEMP_THRESHOLD_C = 20.0; 
const float TEMP_THRESHOLD_F = 68.0;  
const float HUMIDITY_THRESHOLD = 70.0;
const int GAS_THRESHOLD = 4000;     
const unsigned long MOTION_DELAY = 5000; 

const char* ssid = "Wokwi-GUEST";  
const char* password = "";      
const char* mqtt_server = "broker.hivemq.com"; 

const char* mqtt_topic_pub = "IoT/Warehouse room1/sensor";  
const char* mqtt_topic_time = "IoT/Warehouse room1/time";     
const char* mqtt_topic_sub = "IoT/Warehouse room1/command";  
const char* mqtt_topic_alarm = "IoT/Warehouse room1/alarm";    
const char* mqtt_topic_lwt = "IoT/Warehouse room1/status";   
const char* mqtt_topic_motion = "IoT/Warehouse room1/motion";  

WiFiClient espClient;                 
PubSubClient client(espClient);      
DHT dht(DHTPIN, DHTTYPE);            
LiquidCrystal_I2C lcd(0x27, 20, 4);   

bool led1State = false, led2State = false; 
unsigned long lastMsg = 0, lastDisplayChange = 0,  
             alarmStartTime = 0, lastBuzzerToggle = 0;
const long publishInterval = 3000, displayInterval = 3000;
int displayState = 0;  
char msg[100];       
bool welcomeDisplayed = false, isAlarm = false,  
     motionDetected = false, motionStateChanged = false;
unsigned long lastMotionTime = 0;  
int buttonState, lastButtonState = HIGH;  
unsigned long lastDebounceTime = 0, debounceDelay = 50; 
bool restartTriggered = false;
uint8_t dot[] = {0x0E, 0x0A, 0x0E, 0x00, 0x00, 0x00, 0x00, 0x00}; 

void setup_wifi() {
  Serial.println("Connecting to WiFi...");
  WiFi.begin(ssid, password); 
  
  int wifiRetry = 0;
  while (WiFi.status() != WL_CONNECTED && wifiRetry < 10) { 
    Serial.print(".");
    delay(500);  
    wifiRetry++;
  }
  
  if (WiFi.status() == WL_CONNECTED) Serial.println("\nWiFi connected!");
  else { 
    Serial.println("\nWiFi failed! Restarting...");
    esp_restart();
  }
}

int readGasLevel() { return analogRead(GAS_PIN); }  

void handlePIR() {
  bool currentMotion = digitalRead(PIR_PIN) == HIGH;  
  
  if (currentMotion) {  
    lastMotionTime = millis();  
    if (!motionDetected) {  
      motionDetected = true;
      motionStateChanged = true; 
      Serial.println("Motion detected!");
      client.publish(mqtt_topic_motion, "detected");  
    }
  } else if (motionDetected && millis() - lastMotionTime > MOTION_DELAY) { 
    motionDetected = false;
    motionStateChanged = true;  
    Serial.println("Motion stopped");
    client.publish(mqtt_topic_motion, "stopped"); 
  }
}

void displayWelcome() { 
  if (!welcomeDisplayed) { 
    lcd.clear();
    lcd.print("Hi,Welcome!");
    lcd.setCursor(0, 1);  
    lcd.print("Warehouse1,");
    lcd.setCursor(0, 2);  
    lcd.print("By Group3!");
    welcomeDisplayed = true; 
    delay(2000);  
  }
}

void displayDateTime() {
  struct tm timeinfo;  
  if (getLocalTime(&timeinfo)) { 
    char dtbuf[21];
    strftime(dtbuf, sizeof(dtbuf), "%Y-%m-%d %H:%M:%S", &timeinfo);  
    
    lcd.clear();
    lcd.print("DateTime:");
    lcd.setCursor(0, 1);
    lcd.print(dtbuf);  
      
    if (millis() - lastMsg >= publishInterval) { 
      lastMsg = millis();
      client.publish(mqtt_topic_time, dtbuf);
    }
  } else { 
    lcd.clear();
    lcd.print("Time sync lost!");
  }
}

void displaySensorData() {
  unsigned long start = millis();
  float h = dht.readHumidity(); 
  float c = dht.readTemperature();  
  float f = dht.readTemperature(true); 
  int gas = readGasLevel();  
  
  if (millis() - start > 1000) {  
    lcd.clear();
    lcd.print("Sensor Timeout!");
    return;
  }
  
  if (isnan(h) || isnan(c) || isnan(f)) {
    Serial.println(F("DHT read failed!"));
    lcd.clear();
    lcd.print("Sensor Error!");
    return;
  }

  Serial.printf("Hum: %.1f%%  Temp: %.1f°C / %.1f°F  Gas: %d  Motion: %s\n", 
               h, c, f, gas, motionDetected ? "Yes" : "No");

  bool tempAlarm = c > TEMP_THRESHOLD_C; 
  bool humAlarm = h > HUMIDITY_THRESHOLD; 
  bool gasAlarm = gas > GAS_THRESHOLD;  
  
  if (tempAlarm || humAlarm || gasAlarm) { 
    isAlarm = true;
    alarmStartTime = millis();  
    
    lcd.clear();
    lcd.print("ALARM!");
    lcd.setCursor(0, 1);
    if (tempAlarm) lcd.print("Temp Over!");
    else if (humAlarm) lcd.print("Humidity Over!");
    else lcd.print("Gas Over!");  
    
    lcd.setCursor(0, 2);  
    if (tempAlarm) {
      lcd.print(String(c));lcd.write(0);lcd.print("C > ");
      lcd.print(String(TEMP_THRESHOLD_C));lcd.write(0);lcd.print("C");
    } else if (humAlarm) {
      lcd.print(String(h) + "% > " + String(HUMIDITY_THRESHOLD) + "%");
    } else {
      lcd.print(String(gas) + " > " + String(GAS_THRESHOLD));
    }
    
    lcd.setCursor(0, 3);  
    lcd.print("Motion: ");
    lcd.print(motionDetected ? "Detected" : "None");
    
    char alarmMsg[100];
    snprintf(alarmMsg, sizeof(alarmMsg), "Alarm: %s %.1f%s",
             tempAlarm ? "Temp" : humAlarm ? "Humidity" : "Gas",
             tempAlarm ? c : humAlarm ? h : (float)gas,
             tempAlarm ? "C" : humAlarm ? "%" : "");
    client.publish(mqtt_topic_alarm, "ON");
  } else {  
    isAlarm = false;
    digitalWrite(BUZZER_PIN, LOW);  
    
    lcd.clear();
    lcd.setCursor(0, 0); 
    lcd.print("Humidity: "); lcd.print(h, 1); lcd.print("%");
    
    lcd.setCursor(0, 1);  
    lcd.print("Temp: "); lcd.print(c, 1); lcd.write(0); lcd.print("C/"); 
    lcd.print(f, 1); lcd.write(0); lcd.print("F");

    lcd.setCursor(0, 2); 
    lcd.print("Gas Level: "); lcd.print(gas);

    lcd.setCursor(0, 3); 
    lcd.print("Motion: "); lcd.print(motionDetected ? "Detected" : "None");

    if (millis() - lastMsg >= publishInterval) {
      lastMsg = millis();
      snprintf(msg, sizeof(msg), 
               "{\"temp_c\": %.1f, \"temp_f\": %.1f, \"hum\": %.1f, \"gas\": %d, \"motion\": %s}", 
               c, f, h, gas, motionDetected ? "true" : "false");
      client.publish(mqtt_topic_pub, msg);
    }
  }
}

void callback(char* topic, byte* payload, unsigned int length) { 
  payload[length] = 0;
  String command = String((char*)payload);
  command.toUpperCase();  
  Serial.print("MQTT: "); Serial.println(command);
  
  if (command == "RESTART") {
    Serial.println("Restart command");
    blinkAndRestart();  
  }
}

void controlBuzzer(bool enable) { 
  static int buzzerPattern = 0; 
  unsigned long now = millis();

  if (enable && now - lastBuzzerToggle >= 500) {  
    lastBuzzerToggle = now;
    buzzerPattern = (buzzerPattern + 1) % 4; 
    switch (buzzerPattern) { 
      case 0: tone(BUZZER_PIN, 1000); break;  
      case 1: tone(BUZZER_PIN, 1500); break;  
      case 2: tone(BUZZER_PIN, 2000); break;  
      case 3: noTone(BUZZER_PIN); break;    
    }
  } else if (!enable) noTone(BUZZER_PIN); 
}

void blinkAndRestart() {
  lcd.clear();
  lcd.print("Restarting..."); 
  
  for (int i = 0; i < 3; i++) { 
    digitalWrite(LED2_PIN, LOW);
    delay(300);
    digitalWrite(LED2_PIN, HIGH);
    delay(300);
  }
  
  client.publish(mqtt_topic_lwt, "restarting", true); 
  delay(250);  
  esp_restart();  
}

void handleButton() {
  int reading = digitalRead(BUTTON_PIN);

  if (reading != lastButtonState) lastDebounceTime = millis(); 
  if (millis() - lastDebounceTime > debounceDelay && reading != buttonState) {
    buttonState = reading;
    if (buttonState == LOW && !restartTriggered) { 
      restartTriggered = true;
      Serial.println("Button: Restart");
      blinkAndRestart();  
    }
  }
  lastButtonState = reading;  
}

void reconnect() {
  if (client.connected()) return; 

  Serial.println("Connecting to MQTT...");
  if (client.connect("ESP32ClientDevice", mqtt_topic_lwt, 0, true, "offline")) {
    Serial.println("MQTT connected!");
    client.publish(mqtt_topic_lwt, "online", true);  
    client.subscribe(mqtt_topic_sub);  
    delay(500);
  } else {  
    Serial.print("MQTT failed (");
    Serial.print(client.state());  
    Serial.println("), retry in 5s...");
    delay(5000);
  }
}

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

  pinMode(BUTTON_PIN, INPUT_PULLUP);  
  pinMode(LED1_PIN, OUTPUT);
  pinMode(LED2_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(GAS_PIN, INPUT);
  pinMode(PIR_PIN, INPUT);           
  digitalWrite(LED1_PIN, LOW);  
  digitalWrite(LED2_PIN, HIGH); 
  digitalWrite(BUZZER_PIN, LOW);
  
  lcd.init();
  lcd.backlight();
  lcd.createChar(0, dot);  
  lcd.clear();
  lcd.print("Initializing...");
  delay(1000);

  dht.begin();  
  setup_wifi();  
  
  client.setServer(mqtt_server, 1883);  
  client.setCallback(callback); 
  client.setKeepAlive(120);  
  client.setSocketTimeout(5000); 

  configTime(8 * 3600, 0, "pool.ntp.org"); 
  struct tm timeinfo;
  int timeRetry = 0;
  while (!getLocalTime(&timeinfo) && timeRetry < 5) {  
    Serial.println("Waiting for time...");
    delay(1000);
    timeRetry++;
  }
  if (timeRetry < 5) { 
    Serial.println("Time synced");
    displayWelcome();  
    lastDisplayChange = millis();
    lastMsg = 0;
  } else Serial.println("Time sync failed!");  

  Serial.println("Entering loop");
}

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

  unsigned long now = millis();

  if (isAlarm) { 
    controlBuzzer(true); 
    if (now - lastBuzzerToggle >= 250) {  
      lastBuzzerToggle = now;
      digitalWrite(LED1_PIN, !digitalRead(LED1_PIN)); 
    }
    if (now - alarmStartTime > 15000) {  
      isAlarm = false;
      digitalWrite(BUZZER_PIN, LOW);
      digitalWrite(LED1_PIN, led1State);
      client.publish(mqtt_topic_alarm, "OFF");     
    }
  }

  if (motionStateChanged && !isAlarm && !restartTriggered) {
    motionStateChanged = false;
    if (displayState == 1) displayDateTime();
    else if (displayState == 2) displaySensorData();
  }

  if (now - lastDisplayChange >= displayInterval && !isAlarm && !restartTriggered) {
    lastDisplayChange = now;
    displayState = (displayState + 1) % 3;
    switch (displayState) {
      case 0: displayWelcome(); break;
      case 1: displayDateTime(); break;
      case 2: displaySensorData(); break;
    }
  }
}