#include <WiFi.h>
#include <PubSubClient.h>
#include <LiquidCrystal_I2C.h>
#include "DHT.h"
#include <HTTPClient.h>

// ===================
// WIFI SETTINGS
// ===================
const char* WIFI_SSID = "Wokwi-GUEST";
const char* WIFI_PASS = "";

// ===================
// MQTT SETTINGS
// ===================
const char* MQTT_BROKER = "test.mosquitto.org";
const int   MQTT_PORT   = 1883;

// MQTT Topics
const char* MQTT_ALERT  = "home/security/alert";
const char* MQTT_RESET  = "home/security/reset";
const char* MQTT_TEMP   = "home/security/temperature";
const char* MQTT_HUM    = "home/security/humidity";
const char* MQTT_ARM    = "home/security/arm";
const char* MQTT_DISARM = "home/security/disarm";

// ===================
// TELEGRAM BOT
// ===================

String TELEGRAM_TOKEN   = "8084100234:AAH1BqrTHzB9Qufmsc3VKp4XDjtqoZuy9iE";
String TELEGRAM_CHAT_ID = "5704271859"; 

// ===================
// PIN DEFINITIONS
// ===================
#define PIR_PIN     15
#define BUZZER_PIN  13
#define LED_RED     27
#define LED_GREEN   26
#define LDR_PIN     34
#define LIGHT_LED   25

// DHT22
#define DHTPIN  4
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);

// ===================
// LCD
// ===================
LiquidCrystal_I2C lcd(0x27, 16, 2);

// ===================
// GLOBALS
// ===================
WiFiClient espClient;
PubSubClient client(espClient);

bool alarmActive      = false;
bool tempAlarmActive  = false;
bool systemArmed      = false;
bool pirReady         = false;
unsigned long pirStartTime;

float TEMP_LIMIT = 28.0;   // ✅ Lowered so Wokwi can trigger temp alert

// ===================
// LCD Flicker Fix
// ===================
String lastLCD1 = "";
String lastLCD2 = "";

void lcdUpdate(String l1, String l2 = "") {
  if (l1 != lastLCD1 || l2 != lastLCD2) {
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print(l1);
    lcd.setCursor(0, 1);
    lcd.print(l2);
    lastLCD1 = l1;
    lastLCD2 = l2;
  }
}

// ===================
// TELEGRAM ALERT (with URL encoding fix)
// ===================
void sendTelegram(String message) {
  if (WiFi.status() == WL_CONNECTED) {
    HTTPClient http;

    // ✅ Encode special characters
    message.replace(" ", "%20");
    message.replace("!", "%21");
    message.replace("🔥", "%F0%9F%94%A5");

    String url = "https://api.telegram.org/bot" + TELEGRAM_TOKEN +
                 "/sendMessage?chat_id=" + TELEGRAM_CHAT_ID +
                 "&text=" + message;

    http.begin(url);
    http.GET();
    http.end();
  }
}

// ===================
// MQTT CALLBACK
// ===================
void mqttCallback(char* topic, byte* payload, unsigned int length) {
  String cmd;
  for (int i = 0; i < length; i++) cmd += (char)payload[i];

  cmd.trim();
  cmd.toLowerCase();
  String t = String(topic);

  // RESET
  if (t == MQTT_RESET && cmd == "reset") {
    alarmActive = false;
    tempAlarmActive = false;
    noTone(BUZZER_PIN);
    digitalWrite(LED_RED, LOW);

    client.publish(MQTT_ALERT, "System Reset");
    sendTelegram("System%20RESET");

    lcdUpdate("System Reset");
    delay(1500);
    lcdUpdate(systemArmed ? "System Armed" : "System Disarmed");
  }

  // ARM
  else if (t == MQTT_ARM && cmd == "arm") {
    systemArmed = true;
    alarmActive = false;
    tempAlarmActive = false;
    noTone(BUZZER_PIN);
    digitalWrite(LED_RED, LOW);

    client.publish(MQTT_ALERT, "System Armed");
    sendTelegram("System%20ARMED");

    lcdUpdate("System Armed");
  }

  // DISARM
  else if (t == MQTT_DISARM && cmd == "disarm") {
    systemArmed = false;
    alarmActive = false;
    tempAlarmActive = false;
    noTone(BUZZER_PIN);
    digitalWrite(LED_RED, LOW);

    client.publish(MQTT_ALERT, "System Disarmed");
    sendTelegram("System%20DISARMED");

    lcdUpdate("System Disarmed");
  }
}

// ===================
// WIFI + MQTT
// ===================
void connectWiFi() {
  WiFi.begin(WIFI_SSID, WIFI_PASS);
  while (WiFi.status() != WL_CONNECTED) delay(300);
}

void connectMQTT() {
  while (!client.connected()) {
    if (client.connect("ESP32-Security")) {
      client.subscribe(MQTT_RESET);
      client.subscribe(MQTT_ARM);
      client.subscribe(MQTT_DISARM);
    }
    delay(500);
  }
}

// ===================
// SETUP
// ===================
void setup() {
  Serial.begin(115200);

  pinMode(PIR_PIN, INPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(LED_RED, OUTPUT);
  pinMode(LED_GREEN, OUTPUT);
  pinMode(LDR_PIN, INPUT);
  pinMode(LIGHT_LED, OUTPUT);

  digitalWrite(LED_GREEN, HIGH);

  dht.begin();

  lcd.init();
  lcd.backlight();
  lcdUpdate("System Disarmed");

  pirStartTime = millis();

  connectWiFi();
  client.setServer(MQTT_BROKER, MQTT_PORT);
  client.setCallback(mqttCallback);
  connectMQTT();
}

// ===================
// LOOP
// ===================
void loop() {
  if (!client.connected()) connectMQTT();
  client.loop();

  // PIR warm-up
  if (!pirReady && millis() - pirStartTime > 5000) pirReady = true;

  // Read sensors
  int motion   = digitalRead(PIR_PIN);
  float temp   = dht.readTemperature();
  float hum    = dht.readHumidity();
  int ldrValue = analogRead(LDR_PIN);

  String lightStatus = (ldrValue < 2000) ? "Dark" : "Light";

  // Light LED control
  digitalWrite(LIGHT_LED, (lightStatus == "Dark") ? HIGH : LOW);

  // Publish sensor data
  client.publish(MQTT_TEMP, String(temp).c_str());
  client.publish(MQTT_HUM,  String(hum).c_str());
  //================================
  // Wait before publishing again
  delay(3500);  // Publish every 5 seconds
  //=============================

  // ✅ AUTO-CLEAR TEMP ALARM
  if (tempAlarmActive && temp <= TEMP_LIMIT && systemArmed) {
    tempAlarmActive = false;
    alarmActive = false;
    noTone(BUZZER_PIN);
    digitalWrite(LED_RED, LOW);

    client.publish(MQTT_ALERT, "Temperature Normal");
    sendTelegram("Temperature%20Normal");

    lcdUpdate("TEMP NORMAL");
    delay(500);
  }

  // ✅ ALARM ACTIVE → freeze display
  if (alarmActive) {
    tone(BUZZER_PIN, 1000);
    digitalWrite(LED_RED, HIGH);

    if (tempAlarmActive)
      lcdUpdate("TEMP ALERT!");
    else
      lcdUpdate("MOTION ALERT!");

    return;
  }

  // ✅ DISARMED → normal display
  if (!systemArmed) {
    lcdUpdate("LDR:" + lightStatus + " D",
              "T:" + String(temp) + " H:" + String(hum));
    return;
  }

  // ✅ ARMED → normal display
  lcdUpdate("LDR:" + lightStatus + " A",
            "T:" + String(temp) + " H:" + String(hum));

  // ✅ MOTION ALARM
  if (pirReady && motion == HIGH) {
    alarmActive = true;
    tempAlarmActive = false;

    client.publish(MQTT_ALERT, "Motion Detected!");
    sendTelegram("%E2%9A%A0%EF%B8%8F%20Motion%20Detected");

    lcdUpdate("MOTION ALERT!");
    return;
  }

  // ✅ TEMP ALARM
  if (temp > TEMP_LIMIT) {
    alarmActive = true;
    tempAlarmActive = true;

    client.publish(MQTT_ALERT, "High Temperature!");
    sendTelegram("%F0%9F%94%A5%20High%20Temperature");

    lcdUpdate("TEMP ALERT!");
    return;
  }
}