commit 82375a196bd98a1685a53ad6f6f603031e84d677
Author: Adrian A. Baumann <ade@adebaumann.com>
Date:   Mon Jun 29 01:06:20 2026 +0200

    Initial commit: rotary dial firmware on ESP32 device framework

diff --git a/README.md b/README.md
new file mode 100644
index 0000000..6307f1e
--- /dev/null
+++ b/README.md
@@ -0,0 +1,99 @@
+# Rotary Dial
+
+ESP32 firmware that reads a pulse-generating telephone rotary dial and publishes the dialled number to Home Assistant over MQTT.
+
+Built on the [ESP32 Device Framework](../Device-Framework).
+
+## How it works
+
+A classic rotary telephone dial generates a burst of pulses as it returns to rest after each digit — one pulse for `1`, two for `2`, …, nine for `9`, ten for `0`. The firmware counts those pulses on a single GPIO pin and assembles digits into a string. When the user stops dialling (2.5 s silence), the complete number is published to MQTT.
+
+Leading zeros are preserved: dialling `07` sends `"07"`, not `"7"`.
+
+## Hardware
+
+| Item | Details |
+|------|---------|
+| MCU | ESP32 (any variant) |
+| Dial | Pulse-generating rotary telephone dial |
+| Pulse pin | GPIO 4 (`DIAL_PIN` in `main.cpp`) |
+| Wiring | Pulse contact between GPIO 4 and GND. Pin uses `INPUT_PULLUP`. |
+
+The pulse contact is normally open. As the dial returns it briefly shorts GPIO 4 to GND on each pulse — the rising edge (release) is what the interrupt counts.
+
+If your dial's contact is normally closed instead, change the interrupt trigger in `setup()` from `RISING` to `FALLING`.
+
+## Building and flashing
+
+```bash
+# Build (S3 DevKit)
+pio run -e esp32-s3-devkitc-1
+
+# Flash
+pio run -e esp32-s3-devkitc-1 --target upload
+
+# Serial monitor (115200 baud)
+pio device monitor
+```
+
+## First-time Wi-Fi setup
+
+On first boot the device opens an access point named **Rotary-Dial**. Connect with any phone or laptop; a captive portal will appear.
+
+1. Enter your Wi-Fi credentials.
+2. Optionally set the **Device hostname** (default: `rotary-dial`).
+3. Save. The device joins your network and restarts.
+
+Reachable at `http://rotary-dial.local` or the IP shown in the serial monitor.
+
+### Factory reset
+
+Power-cycle or press EN **5 times in quick succession** (before boot completes). All settings are cleared and the device restarts into the Wi-Fi portal.
+
+## Web UI
+
+Browse to the device address to configure hostname, authentication, and MQTT.
+
+## MQTT
+
+### Topics
+
+| Direction | Topic | Description |
+|-----------|-------|-------------|
+| Published | `<prefix>/dialed` | Complete dialled number as a string (not retained) |
+| Published | `<prefix>/status` | `online` on connect, `offline` as LWT (retained) |
+
+Default prefix: `dial`
+
+### Home Assistant
+
+On MQTT connect the device publishes a discovery payload so HA automatically creates a **sensor** entity (`sensor.<hostname>_dialed_number`) that shows the last dialled number.
+
+Example automation:
+
+```yaml
+automation:
+  - alias: Act on dialled number
+    trigger:
+      platform: mqtt
+      topic: dial/dialed
+    action:
+      - choose:
+          - conditions:
+              - condition: template
+                value_template: "{{ trigger.payload == '112' }}"
+            sequence:
+              - service: notify.mobile_app
+                data:
+                  message: "Emergency number dialled!"
+```
+
+## Timing constants
+
+Adjust in `main.cpp` if your dial runs faster or slower than standard:
+
+| Constant | Default | Description |
+|----------|---------|-------------|
+| `PULSE_DEBOUNCE_MS` | 15 ms | Minimum time between counted edges |
+| `INTER_PULSE_MS` | 350 ms | Silence after last pulse = digit complete |
+| `INTER_DIGIT_MS` | 2500 ms | Silence after last digit = number complete |
diff --git a/platformio.ini b/platformio.ini
new file mode 100644
index 0000000..5516710
--- /dev/null
+++ b/platformio.ini
@@ -0,0 +1,19 @@
+[env:esp32-s3-devkitc-1]
+platform = espressif32
+board = esp32-s3-devkitc-1
+framework = arduino
+monitor_speed = 115200
+lib_deps =
+	tzapu/WiFiManager@^2.0.17
+	bblanchon/ArduinoJson@^7.0.0
+	knolleary/PubSubClient@^2.8
+
+[env:esp32dev]
+board = esp32dev
+framework = arduino
+platform = espressif32
+monitor_speed = 115200
+lib_deps =
+	tzapu/WiFiManager@^2.0.17
+	bblanchon/ArduinoJson@^7.4.3
+	knolleary/PubSubClient@^2.8
diff --git a/src/main.cpp b/src/main.cpp
new file mode 100644
index 0000000..bd9ec28
--- /dev/null
+++ b/src/main.cpp
@@ -0,0 +1,569 @@
+#include <Arduino.h>
+#include <WiFiManager.h>
+#include <ESPmDNS.h>
+#include <LittleFS.h>
+#include <WebServer.h>
+#include <ArduinoJson.h>
+#include <WiFiClient.h>
+#include <PubSubClient.h>
+
+// ---------------------------------------------------------------------------
+// Framework constants
+// ---------------------------------------------------------------------------
+
+#define HOSTNAME_DEFAULT "rotary-dial"
+#define MQTT_MANUFACTURER "Baumann Enkataleiptics"
+#define AUTH_USERNAME "admin"
+#define MQTT_PROBE_TIMEOUT_MS 400  // keep short: blocks loop()/handleClient() per reconnect attempt
+#define MQTT_PAYLOAD_AVAILABLE "online"
+#define MQTT_PAYLOAD_NOT_AVAILABLE "offline"
+
+// ---------------------------------------------------------------------------
+// Dial constants
+// ---------------------------------------------------------------------------
+
+#define DIAL_PIN          4     // GPIO connected to the pulse contact (to GND)
+#define PULSE_DEBOUNCE_MS 15    // ignore edges faster than this
+#define INTER_PULSE_MS    350   // silence longer than this = digit complete
+#define INTER_DIGIT_MS    2500  // silence longer than this = number complete, publish
+
+struct MqttConfig {
+  bool enabled = false;
+  char host[64] = "";
+  uint16_t port = 1883;
+  char user[32] = "";
+  char pass[32] = "";
+  char prefix[32] = "dial";
+};
+
+struct AuthConfig {
+  bool enabled = false;
+  char pass[32] = "";
+};
+
+static char hostname[64] = HOSTNAME_DEFAULT;
+static MqttConfig mqttCfg;
+static AuthConfig authCfg;
+static WiFiManagerParameter hostnameParam("hostname", "Device hostname", hostname, 63);
+static WebServer server(80);
+static WiFiClient wifiClient;
+static PubSubClient mqttClient(wifiClient);
+static unsigned long mqttReconnectAt = 0;
+
+// ---------------------------------------------------------------------------
+// Dial state
+// ---------------------------------------------------------------------------
+
+static volatile int           dialPulses    = 0;
+static volatile unsigned long dialLastPulse = 0;  // millis() of last counted pulse
+static String                 dialNumber    = "";
+static unsigned long          dialLastDigit = 0;  // millis() of last completed digit
+
+static void IRAM_ATTR onDialPulse() {
+  unsigned long now = millis();
+  if (now - dialLastPulse >= PULSE_DEBOUNCE_MS) {
+    dialPulses++;
+    dialLastPulse = now;
+  }
+}
+
+// ---------------------------------------------------------------------------
+// Config persistence (JSON via LittleFS)
+// ---------------------------------------------------------------------------
+
+static void loadConfig() {
+  Serial.println("[CFG] loading config");
+  if (!LittleFS.exists("/config.json")) { Serial.println("[CFG] no config file"); return; }
+  File f = LittleFS.open("/config.json", "r");
+  if (!f) { Serial.println("[CFG] failed to open"); return; }
+
+  JsonDocument doc;
+  DeserializationError err = deserializeJson(doc, f);
+  f.close();
+  if (err) { Serial.printf("[CFG] parse error: %s\n", err.c_str()); return; }
+
+  if (doc["hostname"].is<const char*>())
+    strlcpy(hostname, doc["hostname"], sizeof(hostname));
+
+  JsonObject mq = doc["mqtt"];
+  if (!mq.isNull()) {
+    mqttCfg.enabled = mq["en"] | false;
+    strlcpy(mqttCfg.host,   mq["host"]   | "", sizeof(mqttCfg.host));
+    mqttCfg.port = mq["port"] | 1883;
+    strlcpy(mqttCfg.user,   mq["user"]   | "", sizeof(mqttCfg.user));
+    strlcpy(mqttCfg.pass,   mq["pass"]   | "", sizeof(mqttCfg.pass));
+    strlcpy(mqttCfg.prefix, mq["prefix"] | "dial", sizeof(mqttCfg.prefix));
+  }
+
+  JsonObject auth = doc["auth"];
+  if (!auth.isNull()) {
+    authCfg.enabled = auth["en"] | false;
+    strlcpy(authCfg.pass, auth["pass"] | "", sizeof(authCfg.pass));
+  }
+
+  Serial.printf("[CFG] loaded hostname=%s mqtt_en=%d\n", hostname, mqttCfg.enabled);
+}
+
+static void saveConfig() {
+  JsonDocument doc;
+  doc["hostname"] = hostname;
+
+  JsonObject mq = doc["mqtt"].to<JsonObject>();
+  mq["en"]     = mqttCfg.enabled;
+  mq["host"]   = mqttCfg.host;
+  mq["port"]   = mqttCfg.port;
+  mq["user"]   = mqttCfg.user;
+  mq["pass"]   = mqttCfg.pass;
+  mq["prefix"] = mqttCfg.prefix;
+
+  JsonObject auth = doc["auth"].to<JsonObject>();
+  auth["en"]   = authCfg.enabled;
+  auth["pass"] = authCfg.pass;
+
+  File f = LittleFS.open("/config.json", "w");
+  if (f) {
+    serializeJson(doc, f);
+    f.close();
+    Serial.printf("[CFG] saved hostname=%s mqtt_en=%d\n", hostname, mqttCfg.enabled);
+  } else {
+    Serial.println("[CFG] save failed");
+  }
+}
+
+// ---------------------------------------------------------------------------
+// MQTT
+// ---------------------------------------------------------------------------
+
+static void mqttPublishDialed(const String& number) {
+  if (!mqttCfg.enabled || !mqttClient.connected()) return;
+  char topic[128];
+  snprintf(topic, sizeof(topic), "%s/dialed", mqttCfg.prefix);
+  mqttClient.publish(topic, number.c_str(), false);  // not retained — it's an event
+  Serial.printf("[DIAL] published %s -> %s\n", topic, number.c_str());
+}
+
+static void mqttCallback(char* topic, byte* payload, unsigned int len) {
+  // Dial is output-only; no incoming commands.
+  String val;
+  for (unsigned i = 0; i < len; i++) val += (char)payload[i];
+  Serial.printf("[MQTT] rcvd topic=%s payload=%s\n", topic, val.c_str());
+}
+
+static void mqttPublishDiscovery() {
+  if (!mqttCfg.enabled || !mqttClient.connected()) return;
+
+  uint8_t mac[6];
+  WiFi.macAddress(mac);
+  char devId[32];
+  snprintf(devId, sizeof(devId), "esp32_%02x%02x%02x", mac[3], mac[4], mac[5]);
+  String objId = String(devId) + "_dialed";
+
+  JsonDocument doc;
+  doc["unique_id"]             = objId;
+  doc["name"]                  = "Dialed Number";
+  doc["state_topic"]           = String(mqttCfg.prefix) + "/dialed";
+  doc["availability_topic"]    = String(mqttCfg.prefix) + "/status";
+  doc["payload_available"]     = MQTT_PAYLOAD_AVAILABLE;
+  doc["payload_not_available"] = MQTT_PAYLOAD_NOT_AVAILABLE;
+  doc["device"]["identifiers"][0] = devId;
+  doc["device"]["name"]        = hostname;
+  doc["device"]["manufacturer"] = MQTT_MANUFACTURER;
+  doc["device"]["model"]       = "Rotary Dial";
+
+  char topic[128];
+  snprintf(topic, sizeof(topic), "homeassistant/sensor/%s/config", objId.c_str());
+  char payload[512];
+  serializeJson(doc, payload, sizeof(payload));
+  bool ok = mqttClient.publish(topic, payload, true);
+  Serial.printf("[MQTT] discovery %s ok=%d\n", topic, ok);
+}
+
+static void mqttSubscribe() {
+  // Dial is output-only; nothing to subscribe to.
+}
+
+static bool mqttConnect() {
+  if (!mqttCfg.enabled || strlen(mqttCfg.host) == 0) {
+    Serial.printf("[MQTT] connect skipped en=%d host=%d\n",
+      mqttCfg.enabled, strlen(mqttCfg.host) > 0);
+    return false;
+  }
+
+  char clientId[32];
+  {
+    uint8_t mac[6];
+    WiFi.macAddress(mac);
+    snprintf(clientId, sizeof(clientId), "esp32-%02x%02x%02x", mac[3], mac[4], mac[5]);
+  }
+
+  char statusTopic[128];
+  snprintf(statusTopic, sizeof(statusTopic), "%s/status", mqttCfg.prefix);
+
+  mqttClient.setServer(mqttCfg.host, mqttCfg.port);
+  mqttClient.setCallback(mqttCallback);
+  mqttClient.setBufferSize(1024);
+
+  // Pass NULL for empty credentials so the broker treats it as an anonymous
+  // connection rather than an empty-string login (which some brokers reject).
+  const char* user = strlen(mqttCfg.user) > 0 ? mqttCfg.user : nullptr;
+  const char* pass = strlen(mqttCfg.pass) > 0 ? mqttCfg.pass : nullptr;
+
+  Serial.printf("[MQTT] connecting to %s:%d as %s\n", mqttCfg.host, mqttCfg.port, clientId);
+  bool ok = mqttClient.connect(clientId, user, pass,
+                               statusTopic, 0, true, MQTT_PAYLOAD_NOT_AVAILABLE);
+
+  if (ok) {
+    Serial.printf("[MQTT] connected to %s:%d\n", mqttCfg.host, mqttCfg.port);
+    mqttClient.publish(statusTopic, MQTT_PAYLOAD_AVAILABLE, true);
+    mqttSubscribe();
+    mqttPublishDiscovery();
+  } else {
+    Serial.printf("[MQTT] failed rc=%d\n", mqttClient.state());
+  }
+  return ok;
+}
+
+static void mqttLoop() {
+  if (!mqttCfg.enabled || strlen(mqttCfg.host) == 0) return;
+
+  if (!mqttClient.connected()) {
+    unsigned long now = millis();
+    if (now > mqttReconnectAt) {
+      Serial.printf("[MQTT] probing %s:%d\n", mqttCfg.host, mqttCfg.port);
+      WiFiClient probe;
+      bool reachable = probe.connect(mqttCfg.host, mqttCfg.port, MQTT_PROBE_TIMEOUT_MS);
+      probe.stop();
+
+      if (reachable) {
+        Serial.println("[MQTT] probe OK, connecting");
+        if (mqttConnect()) mqttReconnectAt = 0;
+        else mqttReconnectAt = now + 30000;
+      } else {
+        Serial.println("[MQTT] probe failed, retry in 30s");
+        mqttReconnectAt = now + 30000;
+      }
+    }
+  } else {
+    mqttClient.loop();
+  }
+}
+
+// ---------------------------------------------------------------------------
+// Dial processing
+// ---------------------------------------------------------------------------
+
+static void dialLoop() {
+  unsigned long now = millis();
+
+  // Snapshot volatile state atomically
+  noInterrupts();
+  int pulses = dialPulses;
+  unsigned long lastPulse = dialLastPulse;
+  interrupts();
+
+  // Burst silence exceeded → digit complete
+  if (pulses > 0 && (now - lastPulse) >= INTER_PULSE_MS) {
+    noInterrupts();
+    dialPulses = 0;
+    interrupts();
+
+    // 10 pulses = digit '0'; 1–9 pulses = digits '1'–'9'
+    char digit = '0' + (pulses >= 10 ? 0 : pulses);
+    dialNumber += digit;
+    dialLastDigit = now;
+    Serial.printf("[DIAL] digit=%c number_so_far=%s\n", digit, dialNumber.c_str());
+  }
+
+  // Number complete when no further digits arrive within the timeout
+  if (dialNumber.length() > 0 && (now - dialLastDigit) >= INTER_DIGIT_MS) {
+    Serial.printf("[DIAL] complete number=%s\n", dialNumber.c_str());
+    mqttPublishDialed(dialNumber);
+    dialNumber = "";
+  }
+}
+
+// ---------------------------------------------------------------------------
+// mDNS
+// ---------------------------------------------------------------------------
+
+static void startMDNS() {
+  if (MDNS.begin(hostname)) {
+    Serial.printf("mDNS: %s.local\n", hostname);
+    MDNS.addService("http", "tcp", 80);
+  } else {
+    Serial.println("mDNS start failed");
+  }
+}
+
+// ---------------------------------------------------------------------------
+// Web helpers
+// ---------------------------------------------------------------------------
+
+static String escHtml(const String& s) {
+  String out;
+  for (unsigned i = 0; i < s.length(); i++) {
+    char c = s.charAt(i);
+    switch (c) {
+      case '&':  out += "&amp;";  break;
+      case '<':  out += "&lt;";   break;
+      case '>':  out += "&gt;";   break;
+      case '\'': out += "&#39;";  break;
+      case '"':  out += "&quot;"; break;
+      default:   out += c;
+    }
+  }
+  return out;
+}
+
+static bool requireAuth() {
+  if (!authCfg.enabled) return true;
+  if (server.authenticate(AUTH_USERNAME, authCfg.pass)) return true;
+  server.requestAuthentication();
+  return false;
+}
+
+// ---------------------------------------------------------------------------
+// Web handlers
+// ---------------------------------------------------------------------------
+
+static void handleRoot() {
+  if (!requireAuth()) { Serial.println("[HTTP] GET / -> 401"); return; }
+  Serial.println("[HTTP] GET /");
+
+  String authSection;
+  {
+    String checked = authCfg.enabled ? " checked" : "";
+    const char* passHint = strlen(authCfg.pass) > 0 ? "set &#8212; leave blank to keep" : "enter password";
+
+    authSection +=
+      "<fieldset><legend>Security</legend>"
+      "<div class=row>"
+        "<label class=tgl-lbl>Require password</label>"
+        "<label class=switch><input type=checkbox name=auth_en" + checked + "><span class=slid></span></label>"
+      "</div>"
+      "<div class=row><label>Password</label><input name=auth_pass type=password placeholder='" + String(passHint) + "'></div>"
+      "</fieldset>";
+  }
+
+  String mqttSection;
+  {
+    char portStr[8];
+    snprintf(portStr, sizeof(portStr), "%u", mqttCfg.port);
+    String checked = mqttCfg.enabled ? " checked" : "";
+    String hostVal = escHtml(mqttCfg.host);
+    String userVal = escHtml(mqttCfg.user);
+    String prefVal = escHtml(mqttCfg.prefix);
+    const char* passHint = strlen(mqttCfg.pass) > 0 ? "set &#8212; leave blank to keep" : "enter password";
+
+    mqttSection +=
+      "<fieldset><legend>MQTT</legend>"
+      "<div class=row>"
+        "<label class=tgl-lbl>Enable</label>"
+        "<label class=switch><input type=checkbox name=mqtt_en" + checked + "><span class=slid></span></label>"
+      "</div>"
+      "<div class=row><label>Broker</label><input name=mqtt_host value='" + hostVal + "'></div>"
+      "<div class=row><label>Port</label><input name=mqtt_port type=number value=" + String(portStr) + "></div>"
+      "<div class=row><label>User</label><input name=mqtt_user value='" + userVal + "'></div>"
+      "<div class=row><label>Pass</label><input name=mqtt_pass type=password placeholder='" + String(passHint) + "'></div>"
+      "<div class=row><label>Prefix</label><input name=mqtt_prefix value='" + prefVal + "'></div>"
+      "</fieldset>";
+  }
+
+  String html;
+  html.reserve(3072);
+  html += "<!DOCTYPE html><html><head><meta charset=utf-8>";
+  html += "<meta name=viewport content='width=device-width,initial-scale=1'><title>Rotary Dial</title><style>";
+  html += "*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}";
+  html += "body{font-family:-apple-system,BlinkMacSystemFont,\"Segoe UI\",Roboto,Oxygen,Ubuntu,sans-serif;background:#f2f4f8;color:#1a1a2e;display:flex;justify-content:center;align-items:flex-start;min-height:100vh;padding:24px 16px}";
+  html += ".card{background:#fff;border-radius:12px;box-shadow:0 4px 24px rgba(0,0,0,.08);padding:32px;width:100%;max-width:560px}";
+  html += "h1{font-size:24px;margin-bottom:4px}.sub{color:#666;font-size:14px;margin-bottom:24px}";
+  html += ".info{background:#f8f9fc;border-radius:8px;padding:12px 16px;margin-bottom:20px;font-size:14px}";
+  html += ".info div{display:flex;justify-content:space-between;padding:4px 0}.info div span:first-child{color:#666}";
+  html += "label{display:block;font-size:14px;font-weight:600;margin-bottom:4px}";
+  html += "input{width:100%;padding:9px 12px;border:1px solid #d1d5db;border-radius:8px;font-size:14px;outline:none;transition:border-color .2s;margin-bottom:12px}";
+  html += "input:focus{border-color:#4361ee;box-shadow:0 0 0 3px rgba(67,97,238,.15)}";
+  html += "fieldset{border:1px solid #e5e7eb;border-radius:10px;padding:16px;margin-bottom:16px}";
+  html += "legend{font-weight:600;font-size:14px;padding:0 6px;color:#4361ee}";
+  html += "fieldset .row{display:flex;gap:8px;align-items:center;margin-bottom:8px}";
+  html += "fieldset .row label{width:70px;margin-bottom:0;flex-shrink:0}";
+  html += "fieldset .row input{margin-bottom:0}";
+  html += ".btn{width:100%;margin-top:8px;padding:12px;background:#4361ee;color:#fff;border:none;border-radius:8px;font-size:15px;font-weight:600;cursor:pointer;transition:background .2s}";
+  html += ".btn:hover{background:#3651d4}.mac{font-size:12px;color:#999;text-align:center;margin-top:20px}";
+  html += ".tgl-lbl{margin-bottom:0!important;line-height:18px}.switch{position:relative;display:inline-block;width:32px;height:18px;margin-left:auto;flex-shrink:0}fieldset .row label.switch{width:32px}";
+  html += ".switch input{opacity:0;width:0;height:0;margin-bottom:0}.slid{position:absolute;cursor:pointer;top:0;left:0;right:0;bottom:0;background:#ccc;border-radius:18px;transition:.3s}";
+  html += ".slid::before{content:\"\";position:absolute;height:14px;width:14px;left:2px;top:2px;background:#fff;border-radius:50%;transition:.3s;box-shadow:0 1px 3px rgba(0,0,0,.2)}";
+  html += ".switch input:checked+.slid{background:#4361ee}.switch input:checked+.slid::before{transform:translateX(14px)}";
+  html += "</style></head><body><div class=card>";
+  html += "<h1>Rotary Dial</h1><div class=sub>Configuration</div><div class=info>";
+  html += "<div><span>Hostname</span><span>" + String(hostname) + "</span></div>";
+  html += "<div><span>IP</span><span>" + WiFi.localIP().toString() + "</span></div></div>";
+  html += "<form action=/config method=post>";
+  html += "<label>Hostname</label><input name=hostname value='" + String(hostname) + "'>";
+  html += authSection;
+  html += mqttSection;
+  html += "<button class=btn type=submit>Save</button></form>";
+  html += "<div class=mac>" + WiFi.macAddress() + "</div></div>";
+  html += "</body></html>";
+  server.send(200, "text/html", html);
+  Serial.printf("[HTTP] GET / -> 200 (%u bytes)\n", html.length());
+}
+
+static void handleConfig() {
+  if (!requireAuth()) { Serial.println("[HTTP] POST /config -> 401"); return; }
+  Serial.println("[HTTP] POST /config");
+
+  if (server.hasArg("hostname")) {
+    String val = server.arg("hostname");
+    val.trim();
+    if (val.length() > 0)
+      val.toCharArray(hostname, sizeof(hostname));
+  }
+
+  // Persist connection fields regardless of enable checkbox so edits made while
+  // disabling MQTT aren't discarded.
+  if (server.hasArg("mqtt_host"))
+    strlcpy(mqttCfg.host, server.arg("mqtt_host").c_str(), sizeof(mqttCfg.host));
+  if (server.hasArg("mqtt_port"))
+    mqttCfg.port = server.arg("mqtt_port").toInt();
+  if (server.hasArg("mqtt_user"))
+    strlcpy(mqttCfg.user, server.arg("mqtt_user").c_str(), sizeof(mqttCfg.user));
+  if (server.hasArg("mqtt_pass") && server.arg("mqtt_pass").length() > 0)
+    strlcpy(mqttCfg.pass, server.arg("mqtt_pass").c_str(), sizeof(mqttCfg.pass));
+  if (server.hasArg("mqtt_prefix"))
+    strlcpy(mqttCfg.prefix, server.arg("mqtt_prefix").c_str(), sizeof(mqttCfg.prefix));
+
+  mqttCfg.enabled = server.hasArg("mqtt_en");
+  Serial.printf("[HTTP] mqtt enabled=%d host=%s port=%u user=%s prefix=%s\n",
+    mqttCfg.enabled, mqttCfg.host, mqttCfg.port, mqttCfg.user, mqttCfg.prefix);
+
+  if (server.hasArg("auth_en")) {
+    if (server.hasArg("auth_pass") && server.arg("auth_pass").length() > 0)
+      strlcpy(authCfg.pass, server.arg("auth_pass").c_str(), sizeof(authCfg.pass));
+    authCfg.enabled = strlen(authCfg.pass) > 0;
+    Serial.printf("[HTTP] auth enabled=%d\n", authCfg.enabled);
+  } else {
+    authCfg.enabled = false;
+    Serial.println("[HTTP] auth disabled");
+  }
+
+  saveConfig();
+
+  // let mqttLoop handle reconnection to avoid blocking the HTTP handler
+  if (mqttClient.connected()) mqttClient.disconnect();
+  mqttReconnectAt = 0;
+
+  server.sendHeader("Location", "/", true);
+  server.send(303);
+}
+
+static void startServer() {
+  server.on("/", handleRoot);
+  server.on("/config", HTTP_POST, handleConfig);
+  server.begin();
+  Serial.println("HTTP server started");
+}
+
+// ---------------------------------------------------------------------------
+// Factory reset (rapid reset 5x within a few seconds)
+// ---------------------------------------------------------------------------
+
+static void factoryReset() {
+  Serial.println("[BOOT] factory reset triggered!");
+
+  strlcpy(hostname, HOSTNAME_DEFAULT, sizeof(hostname));
+  hostnameParam.setValue(hostname, strlen(hostname));
+
+  authCfg.enabled = false;
+  authCfg.pass[0] = '\0';
+
+  mqttCfg.enabled = false;
+  mqttCfg.host[0] = '\0';
+  mqttCfg.port = 1883;
+  mqttCfg.user[0] = '\0';
+  mqttCfg.pass[0] = '\0';
+  strlcpy(mqttCfg.prefix, "dial", sizeof(mqttCfg.prefix));
+
+  saveConfig();
+
+  Serial.println("[BOOT] factory reset complete, restarting...");
+  delay(200);
+  ESP.restart();
+}
+
+static void checkFactoryReset() {
+  const int THRESHOLD = 5;
+  int count = 0;
+  File f = LittleFS.open("/reset_count", "r");
+  if (f) {
+    count = f.parseInt();
+    f.close();
+  }
+  count++;
+  if (count >= THRESHOLD) {
+    LittleFS.remove("/reset_count");
+    Serial.printf("[BOOT] reset count %d, triggering factory reset\n", count);
+    factoryReset();
+    return;
+  }
+  f = LittleFS.open("/reset_count", "w");
+  if (f) {
+    f.print(count);
+    f.close();
+    Serial.printf("[BOOT] reset count %d/%d\n", count, THRESHOLD);
+  }
+}
+
+// ---------------------------------------------------------------------------
+// Setup & loop
+// ---------------------------------------------------------------------------
+
+void setup() {
+  Serial.begin(115200);
+  Serial.println("\n\n=== Rotary Dial boot ===");
+  LittleFS.begin(true);
+
+  loadConfig();
+  hostnameParam.setValue(hostname, strlen(hostname));
+
+  checkFactoryReset();
+
+  // Reset-counter settle window: if the device stays powered past this point it
+  // wasn't a rapid power-cycle, so clear the counter before the (possibly
+  // indefinitely blocking) WiFi portal.
+  delay(3000);
+  LittleFS.remove("/reset_count");
+
+  pinMode(DIAL_PIN, INPUT_PULLUP);
+  attachInterrupt(digitalPinToInterrupt(DIAL_PIN), onDialPulse, RISING);
+
+  Serial.println("[WIFI] starting WiFiManager");
+  WiFiManager wm;
+  wm.setTitle("Rotary Dial");
+
+  wm.addParameter(&hostnameParam);
+  wm.setSaveParamsCallback([]() {
+    strlcpy(hostname, hostnameParam.getValue(), sizeof(hostname));
+    saveConfig();
+  });
+
+  if (!wm.autoConnect("Rotary-Dial")) {
+    Serial.println("[WIFI] failed, restarting");
+    ESP.restart();
+  }
+  Serial.printf("[WIFI] connected, IP: %s\n", WiFi.localIP().toString().c_str());
+
+  strlcpy(hostname, hostnameParam.getValue(), sizeof(hostname));
+  saveConfig();
+  startServer();
+  startMDNS();
+  mqttReconnectAt = 0;
+
+  Serial.printf("[BOOT] ready at http://%s.local or http://%s\n",
+                hostname, WiFi.localIP().toString().c_str());
+}
+
+void loop() {
+  server.handleClient();
+  mqttLoop();
+  dialLoop();
+}