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

// --- WiFi Settings ---
const char* ssid     = "floflo";
const char* password = "florence";

// --- Azure MQTT Settings ---
const char* mqtt_server = "mqtt-test2.southeastasia-1.ts.eventgrid.azure.net";
const int mqtt_port = 8883;

const char* mqtt_clientID = "my-device";

// Azure Event Grid may require username (often the client ID)
const char* mqtt_username = "my-device";
// Password might be a SAS token or empty for cert-based auth
const char* mqtt_password = "";

// // --- Complete Certificate Chain ---
// // Root CA
static const char root_ca[] PROGMEM = R"EOF(
-----BEGIN CERTIFICATE-----
 -----END CERTIFICATE-----
)EOF";

//Intermediate CA
static const char intermediate_ca[] PROGMEM = R"EOF(
-----BEGIN CERTIFICATE-----
-----END CERTIFICATE-----
)EOF";

// Device Certificate
static const char device_cert[] PROGMEM = R"EOF(
-----BEGIN CERTIFICATE-----
-----END CERTIFICATE-----
)EOF";

// Device Private Key
static const char device_key[] PROGMEM = R"EOF(
-----BEGIN PRIVATE KEY-----
-----END PRIVATE KEY-----

)EOF";

// -------------Establish WiFi Connection-----------------------

// Secure WiFi client
WiFiClientSecure espClient;

// MQTT client
PubSubClient client(espClient);

// Connection status tracking
unsigned long lastReconnectAttempt = 0;
bool mqttConnected = false;

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

  WiFi.begin(ssid, password);
  int attempts = 0;
  while (WiFi.status() != WL_CONNECTED && attempts < 20) {
    delay(500);
    Serial.print(".");
    attempts++;
  }
  
  if (WiFi.status() == WL_CONNECTED) {
    Serial.println("");
    Serial.println("WiFi connected");
    Serial.print("IP address: ");
    Serial.println(WiFi.localIP());
  } else {
    Serial.println("");
    Serial.println("WiFi connection failed!");
  }
}

void reconnect() {
  if (millis() - lastReconnectAttempt < 5000) {
    return; // Don't retry too frequently
  }
  lastReconnectAttempt = millis();
  
  Serial.print("Connecting to Azure MQTT...");
  
  // Try to connect with username/password (may be required for Azure Event Grid)
  if (client.connect(mqtt_clientID, mqtt_username, mqtt_password)) {
    Serial.println("connected!");
    mqttConnected = true;
    
    // Subscribe to any topics if needed
    // client.subscribe("my-device/commands");
    
  } else {
    Serial.print("failed, rc=");
    Serial.print(client.state());
    Serial.println();
    
    // Print more detailed error information
    switch(client.state()) {
      case -4: Serial.println("Connection timeout"); break;
      case -3: Serial.println("Connection lost"); break;
      case -2: Serial.println("Connect failed"); break;
      case -1: Serial.println("Disconnected"); break;
      case 1: Serial.println("Bad protocol"); break;
      case 2: Serial.println("Bad client ID"); break;
      case 3: Serial.println("Unavailable"); break;
      case 4: Serial.println("Bad credentials"); break;
      case 5: Serial.println("Unauthorized"); break;
    }
    mqttConnected = false;
  }
}

void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");
  for (unsigned int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
  }
  Serial.println();
}


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

  setup_wifi();

  if (WiFi.status() != WL_CONNECTED) {
    Serial.println("WiFi not connected, halting...");
    while(1) delay(1000);
  }

  // Configure TLS certificates
  // For a complete chain, you might need to concatenate certificates
  // espClient.setCACert(root_ca);
  espClient.setCACert(intermediate_ca);
  espClient.setCertificate(device_cert);
  espClient.setPrivateKey(device_key);
  
  // Optional: Enable certificate verification
  client.setServer(mqtt_server, mqtt_port);
  client.setCallback(callback);
  
  // Set a reasonable timeout
  client.setSocketTimeout(15);
  
  Serial.println("Setup complete");
}

void loop() {
  // Ensure WiFi is still connected
  if (WiFi.status() != WL_CONNECTED) {
    Serial.println("WiFi disconnected, reconnecting...");
    setup_wifi();
    return;
  }

  // Handle MQTT connection
  if (!client.connected()) {
    mqttConnected = false;
    reconnect();
  } else {
    client.loop();
    
    // Only send telemetry if connected
    if (mqttConnected) {
      // Create a more structured payload
      String payload = "{\"deviceId\":\"my-device\",\"temperature\":38.0,\"timestamp\":" + String(millis()) + "}";
      
      // Use Azure Event Grid compatible topic format
      String topic = "my-device/telemetry/temperature";
      
      bool published = client.publish(topic.c_str(), payload.c_str());
      
      if (published) {
        Serial.println("Telemetry sent: " + payload);
      } else {
        Serial.println("Failed to publish telemetry");
      }
    }
  }

  delay(10000); // Send every 10 seconds instead of 5
}