#include <WiFi.h>
#include <HTTPClient.h>
#include "DHT.h"
#include "ThingSpeak.h"

// Wi-Fi Credentials
const char* ssid = "Wokwi-GUEST";  
const char* password = "";

// ThingSpeak Credentials
const char* THINGSPEAK_API_KEY = "D88QSHNQJZSM9SZI";  
unsigned long THINGSPEAK_CHANNEL_ID = 2838022;  

// Twilio Credentials (for SMS Alerts)
const char* TWILIO_SID = "ACfa444b0fc581e0e3c17088d0f406c3ce";  
const char* TWILIO_AUTH_TOKEN = "5a2d7e830d8765218864167c37c78238";  
const char* TWILIO_PHONE_NUMBER = "+16402303109";  
const char* YOUR_PHONE_NUMBER = "+916369474178";  

// Sensor and Buzzer Setup
#define DHTPIN 4        
#define DHTTYPE DHT22   
DHT dht(DHTPIN, DHTTYPE);

#define DOOR_SENSOR_PIN 5   // Push button for fridge door
#define BUZZER_PIN 19       // Buzzer connected to GPIO19

bool fridgeDoorOpen = false;
unsigned long doorOpenStartTime = 0;
const unsigned long DOOR_OPEN_THRESHOLD = 60000;  // 60 sec

WiFiClient client;

// Alert tracking variables
bool doorAlertSent = false;
bool tempAlertSent = false;
bool humidityAlertSent = false;

unsigned long lastDoorAlertTime = 0;
unsigned long lastTempAlertTime = 0;
unsigned long lastHumidityAlertTime = 0;
const unsigned long ALERT_COOLDOWN = 600000;  // 10 minutes cooldown

void setup() {
    Serial.begin(115200);
    
    WiFi.begin(ssid, password);
    Serial.print("Connecting to Wi-Fi...");
    while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.print(".");
    }
    Serial.println("\nConnected to Wi-Fi!");

    dht.begin();
    pinMode(DOOR_SENSOR_PIN, INPUT_PULLUP);
    pinMode(BUZZER_PIN, OUTPUT);
    digitalWrite(BUZZER_PIN, LOW);

    ThingSpeak.begin(client);
}

void loop() {
    float temperature = dht.readTemperature();
    float humidity = dht.readHumidity();
    
    if (isnan(temperature) || isnan(humidity)) {
        Serial.println("Failed to read from DHT sensor!");
        return;
    }

    bool doorStatus = digitalRead(DOOR_SENSOR_PIN) == LOW;  
    if (doorStatus) {
        if (!fridgeDoorOpen) {
            fridgeDoorOpen = true;
            doorOpenStartTime = millis();
        }
    } else {
        fridgeDoorOpen = false;
    }

    sendToThingSpeak(temperature, humidity, fridgeDoorOpen);
    handleAlerts(temperature, humidity);

    delay(30000);
}

void sendToThingSpeak(float temperature, float humidity, bool doorStatus) {
    if (WiFi.status() == WL_CONNECTED) {
        ThingSpeak.setField(1, temperature);
        ThingSpeak.setField(2, humidity);
        ThingSpeak.setField(3, doorStatus ? 1 : 0);

        int responseCode = ThingSpeak.writeFields(THINGSPEAK_CHANNEL_ID, THINGSPEAK_API_KEY);
        if (responseCode == 200) {
            Serial.println("Data sent to ThingSpeak!");
        } else {
            Serial.println("ThingSpeak Error: " + String(responseCode));
        }
    }
}

void handleAlerts(float temperature, float humidity) {
    unsigned long currentMillis = millis();
    bool alertActive = false;

    // Fridge Door Alert
    if (fridgeDoorOpen && (currentMillis - doorOpenStartTime > DOOR_OPEN_THRESHOLD)) {
        if (!doorAlertSent || (currentMillis - lastDoorAlertTime > ALERT_COOLDOWN)) {
            sendSMSAlert("Fridge Door Open Too Long! Close it ASAP!");
            doorAlertSent = true;
            lastDoorAlertTime = currentMillis;
        }
        alertActive = true;
    } else if (doorAlertSent) {
        sendSMSAlert("Fridge Door Issue Resolved.");
        doorAlertSent = false;
    }

    // Temperature Alert
    if (temperature > 10) {
        if (!tempAlertSent || (currentMillis - lastTempAlertTime > ALERT_COOLDOWN)) {
            sendSMSAlert("Temperature Alert! Fridge is warming: " + String(temperature) + "°C");
            tempAlertSent = true;
            lastTempAlertTime = currentMillis;
        }
        alertActive = true;
    } else if (tempAlertSent) {
        sendSMSAlert("Temperature Back to Normal.");
        tempAlertSent = false;
    }

    // Humidity Alert
    if (humidity > 80) {
        if (!humidityAlertSent || (currentMillis - lastHumidityAlertTime > ALERT_COOLDOWN)) {
            sendSMSAlert("Humidity Alert! Too much moisture: " + String(humidity) + "%");
            humidityAlertSent = true;
            lastHumidityAlertTime = currentMillis;
        }
        alertActive = true;
    } else if (humidityAlertSent) {
        sendSMSAlert("Humidity Back to Normal.");
        humidityAlertSent = false;
    }

    // Control Buzzer
    if (alertActive) {
        digitalWrite(BUZZER_PIN, HIGH); // Buzzer ON
    } else {
        digitalWrite(BUZZER_PIN, LOW); // Buzzer OFF
    }
}

void sendSMSAlert(String message) {
    if (WiFi.status() == WL_CONNECTED) {
        HTTPClient http;
        String url = "https://api.twilio.com/2010-04-01/Accounts/" + String(TWILIO_SID) + "/Messages.json";
        
        String postData = "To=" + String(YOUR_PHONE_NUMBER) +
                          "&From=" + String(TWILIO_PHONE_NUMBER) +
                          "&Body=" + message;

        http.begin(url);
        http.setAuthorization(TWILIO_SID, TWILIO_AUTH_TOKEN);
        http.addHeader("Content-Type", "application/x-www-form-urlencoded");
        
        int responseCode = http.POST(postData);
        if (responseCode > 0) {
            Serial.println("SMS Sent: " + message);
        } else {
            Serial.println("SMS Failed!");
        }
        http.end();
    }
}