#include <WiFi.h>                      // WiFi functions for ESP32
#include <Wire.h>                      // I2C communication for LCD
#include <LiquidCrystal_I2C.h>         // LCD control library

// LCD setup: I2C address 0x27, 20 columns, 4 rows
LiquidCrystal_I2C lcd(0x27, 20, 4);

void setup() {
  Serial.begin(115200);               // Start Serial Monitor for debugging

  lcd.init();                         // Initialize the LCD
  lcd.backlight();                    // Turn on backlight
  lcd.setCursor(0, 0);
  lcd.print("WiFi Scanner...");

  WiFi.mode(WIFI_STA);                // Set ESP32 to Station mode
  WiFi.disconnect();                  // Ensure it disconnects from any network
  delay(100);                         // Allow time for settings to apply
}

void loop() {
  Serial.println("Scanning WiFi networks...");
  
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Scanning...");

  int n = WiFi.scanNetworks();        // Perform WiFi scan
  Serial.println("Scan complete.");

  if (n == 0) {
    Serial.println("No networks found.");
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("No networks found");
  } else {
    Serial.printf("%d networks found:\n", n);

    lcd.clear();
    int maxNetworks = (n > 4) ? 4 : n;  // Limit display to 4 networks

    for (int i = 0; i < maxNetworks; i++) {
      String ssid = WiFi.SSID(i);
      int rssi = WiFi.RSSI(i);

      Serial.printf("%d: %s (%d dBm)\n", i + 1, ssid.c_str(), rssi);

      // Format line for LCD: truncate long SSIDs
      String line = ssid;
      if (line.length() > 10)
        line = line.substring(0, 10);

      line += " ";
      line += String(rssi) + "dBm";

      lcd.setCursor(0, i);            // Set line on LCD (0–3)
      lcd.print(line);
    }
  }

  delay(10000);                       // Wait 10 seconds before next scan
}