#include <WiFi.h>
#include <PubSubClient.h>
#include <DHT.h>

const char* ssid = "Wokwi-GUEST";      // WiFi SSID
const char* password = "";

// Azure IoT Hub connection string
const char* connectionString = "HostName=HealthcareBot.azure-devices.net;DeviceId=ESP32;SharedAccessKey=o5L9hqkOrTu3XDgUUGLkdc0WD0OrYqu3LAIoTFxRmsE="; // connection string

// Sensor pin definitions
#define DHTPIN 15         // Pin where the DHT22 is connected
#define PIRPIN 13         // Pin where the PIR sensor is connected
#define LDRPIN 14         // Digital pin where the LDR is connected 
#define LEDPIN 25         // Pin where the LED is connected
#define TEMPPIN 32       // Analog pin where the LM35/TMP36 is connected 

// DHT Sensor
#define DHTTYPE DHT22   // DHT22 (AM2302)
DHT dht(DHTPIN, DHTTYPE);

// Wi-Fi client and MQTT client
WiFiClient espClient;
PubSubClient client(espClient);

// State variables
bool sendingMessage = true;  // Start sending messages by default
int messageId = 0;
unsigned long lastMsgTime = 0;

// Function to parse the connection string
void parseConnectionString(const char* connStr, char* hostName, char* deviceId, char* deviceKey) {
  char* token;
  char* rest = const_cast<char*>(connStr);
  while ((token = strtok_r(rest, ";", &rest))) {
    if (strncmp(token, "HostName=", 9) == 0) {
      strcpy(hostName, token + 9);
    } else if (strncmp(token, "DeviceId=", 9) == 0) {
      strcpy(deviceId, token + 9);
    } else if (strncmp(token, "SharedAccessKey=", 16) == 0) {
      strcpy(deviceKey, token + 16);
    }
  }
}

// Function to blink the LED
void blinkLED() {
  digitalWrite(LEDPIN, HIGH);  // Turn LED on
  delay(500);                  // Wait 500 ms
  digitalWrite(LEDPIN, LOW);   // Turn LED off
}

// Callback when a message is received
void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");
  
  // Print message content
  for (int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
  }
  Serial.println();
  
  blinkLED();
}

// Reconnect to MQTT broker
void reconnect() {
  // Parse the connection string
  char hostName[100], deviceId[100], deviceKey[100];
  parseConnectionString(connectionString, hostName, deviceId, deviceKey);

  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    // Client ID for MQTT connection
    String clientId = String("ESP8266Client-") + String(deviceId);

    if (client.connect(clientId.c_str(), deviceId, deviceKey)) {
      Serial.println("connected");
      client.subscribe("devices/healthcarebot/messages/devicebound/#");  // Subscribe to device-specific messages
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}

// Setup function
void setup() {
  // Start the serial communication
  Serial.begin(115200);

  // Initialize the DHT sensor
  dht.begin();

  // Initialize pins
  pinMode(LEDPIN, OUTPUT);
  pinMode(PIRPIN, INPUT);

  // Connect to Wi-Fi
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to WiFi...");
  }
  Serial.println("Connected to WiFi");

  // Parse the connection string
  char hostName[100];
  parseConnectionString(connectionString, hostName, nullptr, nullptr);

  // Set the MQTT server and callback function
  client.setServer(hostName, 1883);
  client.setCallback(callback);
}

// Function to get and send the sensor data
void sendMessage() {
  if (!sendingMessage) return;

  messageId++;
  float humidity = dht.readHumidity();
  float dhtTemperature = dht.readTemperature();
  int ldrValue = analogRead(LDRPIN);
  bool motionDetected = digitalRead(PIRPIN);

  // Read the temperature from LM35/TMP36
  int tempValue = analogRead(TEMPPIN);
  // Convert the analog reading (which ranges from 0 - 4095) to a voltage (0 - 3.3V for ESP32)
  float voltage = tempValue * (3.3 / 4095.0);
  // Convert the voltage to temperature (assuming 10mV per degree Celsius for TMP36)
  float lm35Temperature = (voltage - 0.5) * 100.0; // For TMP36
  // float lm35Temperature = voltage * 100.0; // For LM35, uncomment if using LM35 sensor

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

  // Create JSON payload
  String payload = "{";
  payload += "\"messageId\":"; payload += messageId; payload += ",";
  payload += "\"deviceId\":\"ESP8266 Client\",";
  payload += "\"dhtTemperature\":"; payload += dhtTemperature; payload += ",";
  payload += "\"lm35Temperature\":"; payload += lm35Temperature; payload += ",";
  payload += "\"humidity\":"; payload += humidity; payload += ",";
  payload += "\"lightLevel\":"; payload += ldrValue; payload += ",";
  payload += "\"motionDetected\":"; payload += motionDetected;
  payload += "}";

  // Publish to the IoT Hub
  Serial.print("Sending message: ");
  Serial.println(payload);

  if (client.publish("devices/your-device-id/messages/events/", payload.c_str())) {
    Serial.println("Message sent to Azure IoT Hub");
    blinkLED();
  } else {
    Serial.println("Failed to send message to Azure IoT Hub");
  }
}

// Main loop function
void loop() {
  // Reconnect if disconnected
  if (!client.connected()) {
    reconnect();
  }
  client.loop();

  // Send a message every 2 seconds
  unsigned long now = millis();
  if (now - lastMsgTime > 2000) {
    lastMsgTime = now;
    sendMessage();
  }
}