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#include <WiFi.h>
#include <WebServer.h>
#include <ESPmDNS.h>
#include <USB.h>
#include <USBHIDKeyboard.h>
// ============================================================
// CONFIG
// ============================================================
struct WifiCred {
  const char* ssid;
  const char* pass;
};
// Add any known networks here.
// Leave empty if you always want hotspot mode.
static WifiCred kKnownNetworks[] = {};
static const int kKnownNetworkCount =
  sizeof(kKnownNetworks) / sizeof(kKnownNetworks[0]);
static const char* AP_SSID = "KeynoteBuddy";
static const char* AP_PASS = "YOUR_PASSWORD_HERE";
static const char* MDNS_NAME = "keynotebuddy-s3";
// How fast repeated commands are allowed (ms)
static const unsigned long kMinKeyIntervalMs = 200;
// ============================================================
// GLOBALS
// ============================================================
WebServer server(80);
USBHIDKeyboard Keyboard;
enum class NetMode {
  WifiSTA,
  HotspotAP
};
static NetMode gNetMode = NetMode::WifiSTA;
static unsigned long gLastKeyTime = 0;
// ============================================================
// WIFI HELPERS
// ============================================================
static bool connectToKnownWifi(uint32_t perNetworkTimeoutMs = 8000) {
  WiFi.mode(WIFI_STA);
  for (int i = 0; i < kKnownNetworkCount; i++) {
    Serial.printf("Trying Wi-Fi: %s\n", kKnownNetworks[i].ssid);
    WiFi.begin(kKnownNetworks[i].ssid, kKnownNetworks[i].pass);
    uint32_t start = millis();
    while (WiFi.status() != WL_CONNECTED &&
           (millis() - start) < perNetworkTimeoutMs) {
      delay(250);
      Serial.print(".");
    }
    Serial.println();
    if (WiFi.status() == WL_CONNECTED) {
      Serial.printf("Connected to %s\n", kKnownNetworks[i].ssid);
      Serial.print("IP: ");
      Serial.println(WiFi.localIP());
      return true;
    }
    WiFi.disconnect(true, true);
    delay(250);
  }
  return false;
}
static void startHotspot() {
  gNetMode = NetMode::HotspotAP;
  WiFi.disconnect(true, true);
  WiFi.mode(WIFI_MODE_NULL);
  delay(300);
  WiFi.mode(WIFI_AP);
  WiFi.setSleep(false);
  delay(500);
  bool ok = WiFi.softAP(AP_SSID, AP_PASS);
  Serial.println(ok ? "Hotspot started." : "Hotspot failed!");
  Serial.print("AP SSID: ");
  Serial.println(AP_SSID);
  Serial.print("AP PASS: ");
  Serial.println(AP_PASS);
  Serial.print("AP IP: ");
  Serial.println(WiFi.softAPIP());
}
static void startWifiOrFallback() {
  if (kKnownNetworkCount > 0 && connectToKnownWifi()) {
    gNetMode = NetMode::WifiSTA;
    if (MDNS.begin(MDNS_NAME)) {
      Serial.printf("mDNS started: http://%s.local/\n", MDNS_NAME);
    } else {
      Serial.println("mDNS failed (not fatal).");
    }
  } else {
    Serial.println("No known Wi-Fi found, falling back to hotspot.");
    startHotspot();
  }
}
// ============================================================
// USB HID HELPERS
// ============================================================
static bool canSendKeyNow() {
  unsigned long now = millis();
  if (now - gLastKeyTime < kMinKeyIntervalMs) {
    return false;
  }
  gLastKeyTime = now;
  return true;
}
static void tapKey(uint8_t keycode) {
  if (!canSendKeyNow()) {
    return;
  }
  Keyboard.press(keycode);
  delay(40);
  Keyboard.releaseAll();
}
static void tapChar(char c) {
  if (!canSendKeyNow()) {
    return;
  }
  Keyboard.press(c);
  delay(40);
  Keyboard.releaseAll();
}
// ============================================================
// HTTP HELPERS
// ============================================================
static void sendBlank() {
  server.send(200, "text/plain", "");
}
static void sendText(const char* text) {
  server.send(200, "text/plain", text);
}
// ============================================================
// HTTP HANDLERS
// ============================================================
static void handleKeyboardIndex() {
  String s;
  s += "Keynote Buddy S3\n\n";
  s += "Mode: ";
  s += (gNetMode == NetMode::HotspotAP) ? "HOTSPOT" : "WIFI";
  s += "\n";
  if (gNetMode == NetMode::HotspotAP) {
    s += "Hotspot SSID: ";
    s += AP_SSID;
    s += "\nHotspot IP: ";
    s += WiFi.softAPIP().toString();
    s += "\n";
  } else {
    s += "SSID: ";
    s += WiFi.SSID();
    s += "\nIP: ";
    s += WiFi.localIP().toString();
    s += "\nRSSI: ";
    s += String(WiFi.RSSI());
    s += " dBm\n";
  }
  s += "\nEndpoints:\n";
  s += "  /keyboard/next\n";
  s += "  /keyboard/previous\n";
  s += "  /keyboard/black\n";
  s += "  /keyboard/white\n";
  s += "  /keyboard/start\n";
  s += "  /keyboard/esc\n";
  server.send(200, "text/plain", s);
}
static void handleNext() {
  // For Keynote on Mac, Right Arrow is usually fine.
  // If needed later, change to tapChar(' ') for Space instead.
  tapKey(KEY_RIGHT_ARROW);
  sendText("next");
}
static void handlePrevious() {
  tapKey(KEY_LEFT_ARROW);
  sendText("previous");
}
static void handleBlack() {
  tapChar('b');
  sendText("black");
}
static void handleWhite() {
  tapChar('w');
  sendText("white");
}
static void handleStart() {
  // Space is often a good "start/advance" key in presentation apps.
  tapChar(' ');
  sendText("start");
}
static void handleEsc() {
  tapKey(KEY_ESC);
  sendText("esc");
}
static void handleNotFound() {
  server.send(404, "text/plain", "");
}
// ============================================================
// SETUP / LOOP
// ============================================================
void setup() {
  Serial.begin(115200);
  delay(1000);
  Serial.println();
  Serial.println("Starting Keynote Buddy S3...");
  // Start network first, while Serial is still stable
  WiFi.setSleep(false);
  delay(300);
  startWifiOrFallback();
  // Routes
  server.on("/", HTTP_GET, handleKeyboardIndex);
  server.on("/keyboard", HTTP_GET, handleKeyboardIndex);
  server.on("/keyboard/next", HTTP_GET, handleNext);
  server.on("/keyboard/previous", HTTP_GET, handlePrevious);
  server.on("/keyboard/black", HTTP_GET, handleBlack);
  server.on("/keyboard/white", HTTP_GET, handleWhite);
  server.on("/keyboard/start", HTTP_GET, handleStart);
  server.on("/keyboard/esc", HTTP_GET, handleEsc);
  server.onNotFound(handleNotFound);
  server.begin();
  Serial.println("HTTP server started.");
  if (gNetMode == NetMode::HotspotAP) {
    Serial.println("Connect iPhone to hotspot and use:");
    Serial.println("  http://192.168.4.1/keyboard");
    Serial.println("  http://192.168.4.1/keyboard/next");
  } else {
    Serial.println("Use:");
    Serial.println("  http://<IP>/keyboard");
    Serial.println("  http://<IP>/keyboard/next");
    Serial.printf("  Optional mDNS: http://%s.local/keyboard\n", MDNS_NAME);
  }
  Serial.flush();
  delay(500);
  // Start USB only after all logging/network setup
  USB.begin();
  delay(200);
  Keyboard.begin();
}
void loop() {
  server.handleClient();
}