#include <WiFi.h>
#include <PubSubClient.h>
#include <ESP32Servo.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

// 🔹 OLED
Adafruit_SSD1306 lcd(128, 64, &Wire, -1);

// 🔹 WiFi (Wokwi)
const char* ssid = "Wokwi-GUEST";
const char* password = "";

// 🔹 MQTT
const char* mqtt_server = "broker.emqx.io";

// 🔹 Pins capteur A
#define TRIG_A 5
#define ECHO_A 18

// 🔹 Servo
#define SERVO_PIN 13
Servo myServo;

// 🔹 MQTT
WiFiClient espClient;
PubSubClient client(espClient);

// 🔹 Etat
bool lastState = false;

// 🔹 Fonction distance
long readDistance(int trig, int echo) {
  digitalWrite(trig, LOW);
  delayMicroseconds(2);
  digitalWrite(trig, HIGH);
  delayMicroseconds(10);
  digitalWrite(trig, LOW);
  return pulseIn(echo, HIGH) * 0.034 / 2;
}

// 🔹 Affichage OLED
void displayOLED(String line1, String line2) {
  lcd.clearDisplay();
  lcd.setTextSize(1);
  lcd.setTextColor(SSD1306_WHITE);
  lcd.setCursor(0, 0);
  lcd.println(line1);
  lcd.setCursor(0, 16);
  lcd.println(line2);
  lcd.display();
}

// 🔹 WiFi
void setup_wifi() {
  Serial.print("Connexion WiFi...");
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(300);
    Serial.print(".");
  }
  Serial.println("\nWiFi connecté !");
}

// 🔹 MQTT callback
void callback(char* topic, byte* payload, unsigned int length) {
  String msg = "";
  for (int i = 0; i < length; i++) {
    msg += (char)payload[i];
  }
  Serial.print("MQTT reçu: ");
  Serial.println(msg);

  if (String(topic) == "parking/barriere/cmd") {
    if (msg == "OPEN") {
      myServo.write(90);
    } else if (msg == "CLOSE") {
      myServo.write(0);
    }
  }
}

// 🔹 MQTT reconnect
void reconnect() {
  while (!client.connected()) {
    Serial.print("Connexion MQTT...");
    if (client.connect("ESP32ClientZainab")) {
      Serial.println("OK");
      client.subscribe("parking/barriere/cmd");
    } else {
      Serial.println("Erreur...");
      delay(2000);
    }
  }
}

// 🔹 Setup
void setup() {
  Serial.begin(115200);

  pinMode(TRIG_A, OUTPUT);
  pinMode(ECHO_A, INPUT);

  // Servo
  myServo.attach(SERVO_PIN);
  myServo.write(0);

  // OLED
  if (!lcd.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println("OLED non trouvé !");
    while (true);
  }
  displayOLED("Smart Parking", "Initialisation...");
  delay(2000);

  // WiFi + MQTT
  setup_wifi();
  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);
}

// 🔹 Loop
void loop() {
  if (!client.connected()) {
    reconnect();
  }
  client.loop();

  long distance = readDistance(TRIG_A, ECHO_A);
  bool currentState = (distance < 10);

  // 🔹 MQTT envoi si changement
  if (currentState != lastState) {
    if (currentState) {
      client.publish("parking/placeA/status", "occupee");
      Serial.println("Etat: OCCUPEE");
    } else {
      client.publish("parking/placeA/status", "libre");
      Serial.println("Etat: LIBRE");
    }
    lastState = currentState;
  }

  // 🔹 OLED affichage
  if (currentState) {
    displayOLED("Place A:", "OCCUPEE");
  } else {
    displayOLED("Place A:", "LIBRE");
  }

  delay(500);
}