#include <WiFi.h>
#include <HTTPClient.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <ESP32Servo.h>

// ---------------- WIFI (WOKWI) ---------------- //
const char* ssid = "Wokwi-GUEST";
const char* password = "";

// ---------------- CLOUD RL ---------------- //
String serverURL = "https://xxxxx.ngrok-free.app/predict";

// ---------------- PINS ---------------- //
#define LATCH_PIN 5
#define CLOCK_PIN 18
#define DATA_PIN 19
#define SERVO_PIN 23

// ---------------- OBJECTS ---------------- //
LiquidCrystal_I2C lcd(0x27, 16, 2);
Servo gateServo;

// ---------------- VARIABLES ---------------- //
int totalSlots = 20;
int slotStatus[20];

unsigned long lastReconnect = 0;

// ---------------- WIFI CONNECT ---------------- //
void connectWiFi() {

  Serial.println("\n🔌 Connecting to Wokwi WiFi...");

  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("\n✅ WiFi Connected!");
  Serial.print("IP: ");
  Serial.println(WiFi.localIP());
}

// ---------------- READ SLOTS ---------------- //
void readSlots() {

  digitalWrite(LATCH_PIN, LOW);
  delayMicroseconds(5);
  digitalWrite(LATCH_PIN, HIGH);

  for (int i = 0; i < totalSlots; i++) {
    slotStatus[i] = digitalRead(DATA_PIN);

    digitalWrite(CLOCK_PIN, HIGH);
    delayMicroseconds(5);
    digitalWrite(CLOCK_PIN, LOW);
  }
}

// ---------------- COUNT FREE ---------------- //
int getFreeSlots() {

  int freeCount = 0;

  for (int i = 0; i < totalSlots; i++) {
    if (slotStatus[i] == 0)
      freeCount++;
  }

  return freeCount;
}

// ---------------- CLOUD RL ---------------- //
String getCloudDecision(int freeSlots) {

  if (WiFi.status() != WL_CONNECTED) {
    Serial.println("❌ WiFi Lost");
    return "ERROR";
  }

  HTTPClient http;
  http.setTimeout(5000);

  http.begin(serverURL);
  http.addHeader("Content-Type", "application/json");

  // ✅ CORRECT RL FORMAT
  String json = "{\"state\":[" + String(freeSlots) + ",0,0,0]}";

  Serial.println("\n📤 Sending: " + json);

  int code = http.POST(json);

  if (code > 0) {

    String res = http.getString();
    http.end();

    Serial.println("🌐 Response: " + res);

    if (res.indexOf("\"action\":1") >= 0)
      return "OPEN";
    else
      return "CLOSE";
  }

  http.end();
  Serial.println("❌ Cloud Error");
  return "ERROR";
}

// ---------------- GATE CONTROL ---------------- //
void controlGate(String decision) {

  if (decision == "OPEN") {
    gateServo.write(90);
    Serial.println("🚗 Gate OPEN");
  } 
  else {
    gateServo.write(0);
    Serial.println("⛔ Gate CLOSE");
  }
}

// ---------------- LCD ---------------- //
void updateLCD(int freeSlots, String status) {

  lcd.clear();

  lcd.setCursor(0, 0);
  lcd.print("Free: ");
  lcd.print(freeSlots);

  lcd.setCursor(0, 1);
  lcd.print("Gate: ");
  lcd.print(status);
}

// ---------------- SETUP ---------------- //
void setup() {

  Serial.begin(115200);

  pinMode(LATCH_PIN, OUTPUT);
  pinMode(CLOCK_PIN, OUTPUT);
  pinMode(DATA_PIN, INPUT);

  lcd.init();
  lcd.backlight();

  gateServo.attach(SERVO_PIN);
  gateServo.write(0);

  connectWiFi();
}

// ---------------- LOOP ---------------- //
void loop() {

  readSlots();

  int freeSlots = getFreeSlots();

  String decision = getCloudDecision(freeSlots);

  // fallback safety only (NO spam logs)
  if (decision == "ERROR") {
    decision = (freeSlots > 5) ? "OPEN" : "CLOSE";
  }

  controlGate(decision);
  updateLCD(freeSlots, decision);

  Serial.print("Free Slots: ");
  Serial.print(freeSlots);
  Serial.print(" | Decision: ");
  Serial.println(decision);

  delay(2000);
}