#include <WiFi.h>
#include <WiFiClientSecure.h>
#include <ArduinoJson.h>
#include <time.h>

#define WIFI_SSID "DHANUSH"
#define WIFI_PASSWORD "12345678"
#define BOT_TOKEN "8484728715:AAEafgC3slF9LM_g_bxnCNuramLIhi-XrCo"

const char* telegramHost = "api.telegram.org";
WiFiClientSecure client;
unsigned long lastUpdateId = 0;

const int ledPin = 2; // Change to GPIO 2 or LED_BUILTIN if needed
int ledStatus = 0;

void connectWiFi() {
  Serial.print("Connecting to Wi-Fi");
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nWi-Fi connected.");
  Serial.print("IP: ");
  Serial.println(WiFi.localIP());
}

void syncTime() {
  configTime(0, 0, "pool.ntp.org");
  Serial.print("Synchronizing time");
  time_t now = time(nullptr);
  while (now < 8 * 3600 * 2) {
    delay(500);
    Serial.print(".");
    now = time(nullptr);
  }
  Serial.println(" done.");
}

String getUpdates() {
  String url = "/bot" + String(BOT_TOKEN) + "/getUpdates?offset=" + String(lastUpdateId + 1);
  String payload = "";
  bool jsonStarted = false;

  if (!client.connect(telegramHost, 443)) {
    Serial.println("Connection to Telegram failed");
    return "";
  }

  client.println("GET " + url + " HTTP/1.1");
  client.println("Host: api.telegram.org");
  client.println("Connection: close");
  client.println();

  while (client.connected()) {
    while (client.available()) {
      String line = client.readStringUntil('\n');
      if (line == "\r") {
        jsonStarted = true;
      } else if (jsonStarted) {
        payload += line;
      }
    }
  }
  client.stop();

  Serial.println("Received JSON:");
  Serial.println(payload);
  return payload;
}

void sendMessage(String chat_id, String text) {
  String url = "/bot" + String(BOT_TOKEN) + "/sendMessage";
  String body = "chat_id=" + chat_id + "&text=" + text;

  if (!client.connect(telegramHost, 443)) {
    Serial.println("Connection to Telegram failed");
    return;
  }

  client.println("POST " + url + " HTTP/1.1");
  client.println("Host: api.telegram.org");
  client.println("Content-Type: application/x-www-form-urlencoded");
  client.print("Content-Length: ");
  client.println(body.length());
  client.println();
  client.print(body);

  while (client.connected()) {
    while (client.available()) {
      client.read(); // Ignore response
    }
  }

  client.stop();
}

void handleCommand(String text, String chat_id) {
  if (text == "/ledon") {
    digitalWrite(ledPin, HIGH);
    ledStatus = 1;
    sendMessage(chat_id, "LED is ON");
  } else if (text == "/ledoff") {
    digitalWrite(ledPin, LOW);
    ledStatus = 0;
    sendMessage(chat_id, "LED is OFF");
  } else if (text == "/status") {
    String status = (ledStatus == 1) ? "LED is ON" : "LED is OFF";
    sendMessage(chat_id, status);
  } else if (text == "/start") {
    String welcome = "Welcome!\nCommands:\n/ledon\n/ledoff\n/status";
    sendMessage(chat_id, welcome);
  }
}

void checkTelegram() {
  String payload = getUpdates();
  if (payload == "") return;

  DynamicJsonDocument doc(8192);
  DeserializationError error = deserializeJson(doc, payload);
  if (error) {
    Serial.print("JSON parse failed: ");
    Serial.println(error.c_str());
    return;
  }

  for (JsonObject result : doc["result"].as<JsonArray>()) {
    lastUpdateId = result["update_id"].as<unsigned long>();
    String message_text = result["message"]["text"].as<String>();
    String chat_id = result["message"]["chat"]["id"].as<String>();
    Serial.println("Command: " + message_text);
    handleCommand(message_text, chat_id);
  }
}

void setup() {
  Serial.begin(115200);
  pinMode(ledPin, OUTPUT);
  digitalWrite(ledPin, LOW);

  connectWiFi();
  client.setInsecure();  // Don't verify SSL certificate
  syncTime();
}

void loop() {
  checkTelegram();
  delay(1000); // Poll every 1s
}