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

// --- Pin Definitions ---
#define DHTPIN 4
#define DHTTYPE DHT22
#define BUTTON_ARRIVAL 25
#define BUTTON_DISPATCH 26

// --- Hardware ---
DHT dht(DHTPIN, DHTTYPE);
LiquidCrystal_I2C lcd(0x27, 16, 2);

// --- Network Credentials ---
const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* mqtt_server = "broker.hivemq.com";
const char* firebaseHost = "https://medisupply-dd526-default-rtdb.firebaseio.com/";

// --- MQTT Client ---
WiFiClient espClient;
PubSubClient client(espClient);

// --- Timing ---
unsigned long lastSensorSend = 0;
unsigned long lastEventSend = 0;
const unsigned long sensorInterval = 10000;  // 10 seconds
const unsigned long eventInterval = 20000;   // 20 seconds

// --- Counters ---
int dispatchedCount = 0;
int receivedCount = 0;

// --- Button Lockouts ---
bool arrivalSent = false;
bool dispatchSent = false;

// --- WiFi Setup ---
void setup_wifi() {
  Serial.print("🔌 Connecting to WiFi...");
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\n✅ WiFi connected");
}

// --- Firebase Send ---
void sendToFirebase(const String& path, const String& jsonPayload) {
  HTTPClient http;
  String url = String(firebaseHost) + path;
  http.begin(url);
  http.addHeader("Content-Type", "application/json");

  int httpCode = http.POST(jsonPayload);
  if (httpCode > 0) {
    String response = http.getString();
    Serial.println("✅ Firebase Response: " + response);
  } else {
    Serial.println("❌ Firebase Error: " + String(httpCode));
  }
  http.end();
}

// --- MQTT Callback (not used, but logged) ---
void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("📥 MQTT Msg [");
  Serial.print(topic);
  Serial.print("]: ");
  for (int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
  }
  Serial.println();
}

// --- MQTT Reconnect ---
void reconnect() {
  while (!client.connected()) {
    Serial.print("🔁 Reconnecting to MQTT...");
    if (client.connect("ESP32Client")) {
      Serial.println("✅ Connected to MQTT broker");
      client.subscribe("medical/supply/command");
    } else {
      Serial.print("❌ Failed (");
      Serial.print(client.state());
      Serial.println(") — retrying in 2s");
      delay(2000);
    }
  }
}

void setup() {
  Serial.begin(115200);
  dht.begin();
  lcd.init();
  lcd.backlight();

  pinMode(BUTTON_ARRIVAL, INPUT_PULLUP);
  pinMode(BUTTON_DISPATCH, INPUT_PULLUP);

  setup_wifi();
  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);

  lcd.setCursor(0, 0);
  lcd.print("System Ready...");
  delay(1500);
  lcd.clear();
}

void loop() {
  if (!client.connected()) reconnect();
  client.loop();

  unsigned long now = millis();

  // --- Handle Arrival ---
  if (digitalRead(BUTTON_ARRIVAL) == LOW && !arrivalSent) {
    arrivalSent = true;
    receivedCount++;

    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Item Received");
    Serial.println("📦 Item Received");

    String payload = "{\"event\":\"arrival\",\"timestamp\":" + String(now) + "}";
    client.publish("medical/supply/event", payload.c_str(), true);
    sendToFirebase("/events.json", payload);

    Serial.println("📤 Sent to MQTT: " + payload);
    delay(500);
  }
  if (digitalRead(BUTTON_ARRIVAL) == HIGH) arrivalSent = false;

  // --- Handle Dispatch ---
  if (digitalRead(BUTTON_DISPATCH) == LOW && !dispatchSent) {
    dispatchSent = true;
    dispatchedCount++;

    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Item Dispatched");
    Serial.println("🚚 Item Dispatched");

    String payload = "{\"event\":\"dispatch\",\"timestamp\":" + String(now) + "}";
    client.publish("medical/supply/event", payload.c_str(), true);
    sendToFirebase("/events.json", payload);

    Serial.println("📤 Sent to MQTT: " + payload);
    delay(500);
  }
  if (digitalRead(BUTTON_DISPATCH) == HIGH) dispatchSent = false;

  // --- Send Temp & Humidity ---
  if (now - lastSensorSend > sensorInterval) {
    lastSensorSend = now;

    float h = dht.readHumidity();
    float t = dht.readTemperature();

    if (!isnan(h) && !isnan(t)) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("Temp: ");
      lcd.print(t, 1);
      lcd.print("C");
      lcd.setCursor(0, 1);
      lcd.print("Hum: ");
      lcd.print(h, 1);
      lcd.print("%");

      String payload = "{\"temperature\":" + String(t, 1) + ",\"humidity\":" + String(h, 1) + "}";
      client.publish("medical/supply/monitor", payload.c_str(), true);
      sendToFirebase("/monitor.json", payload);

      Serial.println("🌡️ Sent to MQTT: " + payload);
    } else {
      Serial.println("⚠️ DHT read failed");
    }
  }

  // --- Send Summary Counts ---
  if (now - lastEventSend > eventInterval) {
    lastEventSend = now;

    String payload = "{\"summary\":{\"dispatched\":" + String(dispatchedCount) +
                     ",\"received\":" + String(receivedCount) + "}}";
    client.publish("medical/supply/summary", payload.c_str(), true);
    sendToFirebase("/summary.json", payload);

    Serial.println("📊 Sent summary to MQTT: " + payload);

    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Total Sent: ");
    lcd.print(dispatchedCount);
    lcd.setCursor(0, 1);
    lcd.print("Total Recv: ");
    lcd.print(receivedCount);
  }
}