#include <Arduino.h>
#include <NimBLEDevice.h>
#include <NimBLEAdvertising.h>
#include <FastLED.h>

#include <mbedtls/md.h>
#include <mbedtls/sha256.h>
#include <Preferences.h>
#include <esp_ota_ops.h>
#include <esp_partition.h>
#include <nvs_flash.h>
#include "version.h"

#define RELAY1_PIN  1
#define RELAY2_PIN  2
#define TOUCH1_PIN  8
#define TOUCH2_PIN  6
#define BUTTON_PIN  41
#define LED_PIN     35
#define NUM_LEDS    1

CRGB leds[NUM_LEDS];

#define MAX_CLIENTS 2

#define SERVICE_UUID        "4fafc201-1fb5-459e-8fcc-c5c9c331914b"
#define CHARACTERISTIC_UUID "beb5483e-36e1-4688-b7f5-ea07361f26d8"
#define UUID_CHAR_UUID      "beb5483e-36e1-4688-b7f5-ea07361f26d9"
#define VERSION_UUID        "beb5483e-36e1-4688-b7f5-ea07361f26db"
#define OTA_UUID            "beb5483e-36e1-4688-b7f5-ea07361f26da"

#define HMAC_PKT_SIZE 37
#define OTA_CHUNK_SIZE 500
#define OTA_CMD_START  0x10
#define OTA_CMD_END    0x11
#define OTA_STATUS_ACK 0x00
#define OTA_STATUS_NAK 0x01
#define OTA_STATUS_COMPLETE 0x10
#define OTA_STATUS_ERROR    0x11
#define HMAC_KEY_LEN  32
#define ESP_UUID_LEN  16
#define NVS_NAMESPACE "hmac"
#define NVS_KEY_NAME  "key"
#define NVS_UUID_NAME "uuid"
#define FIRMWARE_VERSION FIRMWARE_VERSION_SERVER

NimBLECharacteristic *pCharacteristic;
bool relay1State = false;
bool relay2State = false;

bool connActive[MAX_CLIENTS] = {false, false};
bool bleRelay1[MAX_CLIENTS] = {false, false};
bool bleRelay2[MAX_CLIENTS] = {false, false};
uint32_t lastSeq[MAX_CLIENTS] = {0, 0};
uint16_t connHandles[MAX_CLIENTS] = {0xFFFF, 0xFFFF};
int connectedCount = 0;

#define STABLE_LED_TIMEOUT_MS 60000
uint32_t connectionStableMs = 0;
uint32_t relayFlashUntil = 0;

bool otaInProgress = false;
esp_ota_handle_t otaHandle = 0;
const esp_partition_t *otaPartition = nullptr;
uint32_t otaExpectedSize = 0;
uint32_t otaWritten = 0;
uint8_t otaExpectedSha[32];
mbedtls_sha256_context otaShaCtx;
bool otaShaStarted = false;
bool otaReady = false;
bool otaEnded = false;
bool otaConfirmed = false;
uint32_t otaEndedAt = 0;
#define OTA_CONFIRM_TIMEOUT_MS 10000

uint8_t hmacKey[HMAC_KEY_LEN];
uint8_t deviceUuid[ESP_UUID_LEN];
bool keyProvisioned = false;
bool uuidProvisioned = false;
Preferences preferences;

static int findClientIdx(uint16_t connHandle) {
    for (int i = 0; i < MAX_CLIENTS; i++) {
        if (connActive[i] && connHandles[i] == connHandle) return i;
    }
    return -1;
}

class MyServerCallbacks : public NimBLEServerCallbacks {
    void onConnect(NimBLEServer *pServer, NimBLEConnInfo &connInfo) override {
        uint16_t handle = connInfo.getConnHandle();
        int slot = -1;
        for (int i = 0; i < MAX_CLIENTS; i++) {
            if (!connActive[i]) {
                slot = i;
                break;
            }
        }
        if (slot >= 0) {
            connHandles[slot] = handle;
            connActive[slot] = true;
            bleRelay1[slot] = false;
            bleRelay2[slot] = false;
            lastSeq[slot] = 0;
            connectedCount++;
            Serial.printf("BLE: device connected (conn=%d, slot=%d, clients=%d/%d, mac=%s)\n",
                          handle, slot, connectedCount, MAX_CLIENTS,
                          connInfo.getAddress().toString().c_str());
        } else {
            Serial.printf("BLE: device connected but no free slot (conn=%d, clients=%d/%d)\n",
                          handle, connectedCount, MAX_CLIENTS);
        }
        pServer->startAdvertising();
    }
    void onDisconnect(NimBLEServer *pServer, NimBLEConnInfo &connInfo, int reason) override {
        uint16_t handle = connInfo.getConnHandle();
        for (int i = 0; i < MAX_CLIENTS; i++) {
            if (connActive[i] && connHandles[i] == handle) {
                connActive[i] = false;
                bleRelay1[i] = false;
                bleRelay2[i] = false;
                lastSeq[i] = 0;
                connHandles[i] = 0xFFFF;
                connectedCount--;
                Serial.printf("BLE: device disconnected (conn=%d, slot=%d, clients=%d/%d, mac=%s)\n",
                              handle, i, connectedCount, MAX_CLIENTS,
                              connInfo.getAddress().toString().c_str());
                break;
            }
        }
    }
};

static bool verifyHmac(const uint8_t *packet, int idx) {
    if (idx < 0 || idx >= MAX_CLIENTS || !connActive[idx]) {
        Serial.printf("BLE: HMAC verify called for invalid idx=%d\n", idx);
        return false;
    }

    uint8_t cmd = packet[0];
    uint32_t seq = ((uint32_t)packet[1] << 24) |
                   ((uint32_t)packet[2] << 16) |
                   ((uint32_t)packet[3] << 8)  |
                   (uint32_t)packet[4];

    if (seq <= lastSeq[idx]) {
        Serial.printf("BLE: replay rejected (seq=%lu, last=%lu, slot=%d)\n", seq, lastSeq[idx], idx);
        return false;
    }

    uint8_t hmacData[5];
    hmacData[0] = cmd;
    hmacData[1] = (seq >> 24) & 0xFF;
    hmacData[2] = (seq >> 16) & 0xFF;
    hmacData[3] = (seq >> 8)  & 0xFF;
    hmacData[4] = seq & 0xFF;

    uint8_t computed[32];
    const mbedtls_md_info_t *mdInfo = mbedtls_md_info_from_type(MBEDTLS_MD_SHA256);
    mbedtls_md_hmac(mdInfo, hmacKey, HMAC_KEY_LEN, hmacData, 5, computed);

    if (memcmp(computed, packet + 5, 32) != 0) {
        Serial.println("BLE: HMAC mismatch");
        return false;
    }

    lastSeq[idx] = seq;
    return true;
}

static bool isHexKey(const String &hex) {
    for (int i = 0; i < hex.length(); i++) {
        char c = hex.charAt(i);
        if (!((c >= '0' && c <= '9') || (c >= 'A' && c <= 'F'))) return false;
    }
    return true;
}

static void parseHexKey(const String &hex, uint8_t *out) {
    for (int i = 0; i < HMAC_KEY_LEN; i++) {
        out[i] = (uint8_t)strtoul(hex.substring(i * 2, i * 2 + 2).c_str(), nullptr, 16);
    }
}

static void otaReset() {
    otaInProgress = false;
    otaHandle = 0;
    otaPartition = nullptr;
    otaExpectedSize = 0;
    otaWritten = 0;
    otaReady = false;
    otaEnded = false;
    otaConfirmed = false;
    if (otaShaStarted) {
        mbedtls_sha256_free(&otaShaCtx);
        otaShaStarted = false;
    }
}

static void sendOtaNotify(NimBLECharacteristic *otaChar, uint8_t status, uint32_t seq) {
    uint8_t buf[5];
    buf[0] = status;
    buf[1] = (seq >> 24) & 0xFF;
    buf[2] = (seq >> 16) & 0xFF;
    buf[3] = (seq >> 8) & 0xFF;
    buf[4] = seq & 0xFF;
    otaChar->setValue(buf, 5);
    bool ok = otaChar->notify();
    if (!ok) {
        Serial.printf("OTA: notify() returned false for status=0x%02X seq=%lu\n", status, seq);
    }
}

static void abortOta(NimBLECharacteristic *otaChar, const char *reason) {
    Serial.printf("OTA: abort — %s\n", reason);
    if (otaHandle != 0) {
        esp_ota_end(otaHandle);
    }
    otaReset();
    sendOtaNotify(otaChar, OTA_STATUS_ERROR, 0);
}

class OtaCharacteristicCallbacks : public NimBLECharacteristicCallbacks {
    void onWrite(NimBLECharacteristic *pChar, NimBLEConnInfo &connInfo) override {
        std::string value = pChar->getValue();
        if (value.empty()) return;
        const uint8_t *data = (const uint8_t *)value.data();
        size_t len = value.length();

        if (len == 5 && data[0] == OTA_CMD_START) {
            if (otaInProgress) {
                esp_ota_end(otaHandle);
                otaReset();
            }
            otaExpectedSize = ((uint32_t)data[1] << 24) | ((uint32_t)data[2] << 16) |
                              ((uint32_t)data[3] << 8)  | (uint32_t)data[4];
            otaPartition = esp_ota_get_next_update_partition(nullptr);
            if (otaPartition == nullptr) {
                Serial.println("OTA: no update partition found");
                sendOtaNotify(pChar, OTA_STATUS_ERROR, 0);
                return;
            }
            esp_err_t err = esp_ota_begin(otaPartition, otaExpectedSize, &otaHandle);
            if (err != ESP_OK) {
                Serial.printf("OTA: begin failed (%d)\n", err);
                sendOtaNotify(pChar, OTA_STATUS_ERROR, 0);
                return;
            }
            otaInProgress = true;
            otaWritten = 0;
            mbedtls_sha256_init(&otaShaCtx);
            mbedtls_sha256_starts_ret(&otaShaCtx, 0);
            otaShaStarted = true;
            digitalWrite(RELAY1_PIN, LOW);
            digitalWrite(RELAY2_PIN, LOW);
            relay1State = false;
            relay2State = false;
            for (int i = 0; i < MAX_CLIENTS; i++) {
                bleRelay1[i] = false;
                bleRelay2[i] = false;
            }
            Serial.printf("OTA: started, expecting %lu bytes\n", otaExpectedSize);
            return;
        }

        if (len == 32 && otaInProgress) {
            memcpy(otaExpectedSha, data, 32);
            uint8_t computedSha[32];
            mbedtls_sha256_finish_ret(&otaShaCtx, computedSha);
            mbedtls_sha256_free(&otaShaCtx);
            otaShaStarted = false;

            Serial.printf("OTA: SHA256 verify — written=%lu expected=%lu\n", otaWritten, otaExpectedSize);
            if (memcmp(computedSha, otaExpectedSha, 32) != 0) {
                Serial.println("OTA: SHA256 mismatch — aborting");
                esp_ota_abort(otaHandle);
                otaReset();
                sendOtaNotify(pChar, OTA_STATUS_ERROR, 0);
                return;
            }

            Serial.println("OTA: SHA256 OK, setting otaReady=true, sending COMPLETE notify");
            otaReady = true;
            sendOtaNotify(pChar, OTA_STATUS_COMPLETE, 0);
            Serial.printf("OTA: COMPLETE notify sent, otaReady=%d, otaConfirmed=%d, otaInProgress=%d\n",
                          otaReady, otaConfirmed, otaInProgress);
            return;
        }

        if (!otaInProgress) {
            Serial.printf("OTA: write ignored — otaInProgress=false (len=%d, data0=0x%02X)\n", len, data[0]);
            return;
        }

        if (len == 1 && data[0] == 0xFF) {
            Serial.printf("OTA: 0xFF received — otaReady=%d, otaEnded=%d, otaConfirmed=%d, otaInProgress=%d\n",
                          otaReady, otaEnded, otaConfirmed, otaInProgress);
            if (!otaEnded) {
                Serial.println("OTA: 0xFF IGNORED — otaEnded is false (esp_ota_end not yet called or failed)");
                return;
            }
            Serial.println("OTA: 0xFF confirm accepted, setting otaConfirmed=true");
            otaConfirmed = true;
            return;
        }

        if (data[0] < 0x10) {
            uint32_t seq = ((uint32_t)data[0] << 24) | ((uint32_t)data[1] << 16) |
                           ((uint32_t)data[2] << 8)  | (uint32_t)data[3];
            size_t dataLen = len - 4;
            mbedtls_sha256_update_ret(&otaShaCtx, data + 4, dataLen);
            unsigned long t0 = micros();
            esp_err_t err = esp_ota_write(otaHandle, data + 4, dataLen);
            unsigned long elapsed = micros() - t0;
            Serial.printf("OTA: chunk %lu write %d bytes in %lu us\n", seq, dataLen, elapsed);
            if (err != ESP_OK) {
                Serial.printf("OTA: write err at seq %lu (%d)\n", seq, err);
                sendOtaNotify(pChar, OTA_STATUS_NAK, seq);
                abortOta(pChar, "write error");
                return;
            }
            otaWritten += dataLen;
            sendOtaNotify(pChar, OTA_STATUS_ACK, seq);
        }
    }
};

class MyCharacteristicCallbacks : public NimBLECharacteristicCallbacks {
    void onWrite(NimBLECharacteristic *pChar, NimBLEConnInfo &connInfo) override {
        if (otaInProgress) return;

        int idx = findClientIdx(connInfo.getConnHandle());
        if (idx < 0) {
            Serial.printf("BLE: write from unknown conn handle %d\n", connInfo.getConnHandle());
            return;
        }

        std::string value = pChar->getValue();
        if (value.length() != HMAC_PKT_SIZE) {
            Serial.printf("BLE: bad packet length %d (expected %d), slot=%d mac=%s\n",
                          (int)value.length(), HMAC_PKT_SIZE, idx,
                          connInfo.getAddress().toString().c_str());
            return;
        }

        const uint8_t *pkt = (const uint8_t *)value.data();

        if (!verifyHmac(pkt, idx)) {
            return;
        }

        uint8_t cmd = pkt[0];
        uint32_t seq = lastSeq[idx];

        if (cmd == 0x01) {
            bleRelay1[idx] = true;
            Serial.printf("BLE: relay1 ON (seq=%lu, slot=%d)\n", seq, idx);
        } else if (cmd == 0x00) {
            bleRelay1[idx] = false;
            Serial.printf("BLE: relay1 OFF (seq=%lu, slot=%d)\n", seq, idx);
        } else if (cmd == 0x02) {
            bleRelay2[idx] = true;
            Serial.printf("BLE: relay2 ON (seq=%lu, slot=%d)\n", seq, idx);
        } else if (cmd == 0x03) {
            bleRelay2[idx] = false;
            Serial.printf("BLE: relay2 OFF (seq=%lu, slot=%d)\n", seq, idx);
        }
    }
};

void setup() {
    Serial.begin(115200);
    delay(2000);
    Serial.println("=== AtomS3 Lite BLE Relay ===");

    FastLED.addLeds<WS2812, LED_PIN, GRB>(leds, NUM_LEDS);

    preferences.begin(NVS_NAMESPACE, true);
    size_t len = preferences.getBytes(NVS_KEY_NAME, hmacKey, HMAC_KEY_LEN);
    size_t uuidLen = preferences.getBytes(NVS_UUID_NAME, deviceUuid, ESP_UUID_LEN);
    preferences.end();

    if (len == HMAC_KEY_LEN) {
        keyProvisioned = true;
        Serial.println("HMAC key loaded from NVS");
    } else {
        keyProvisioned = false;
        Serial.println("No HMAC key provisioned — connect USB and run SET_KEY");
    }

    if (uuidLen == ESP_UUID_LEN) {
        uuidProvisioned = true;
        Serial.print("UUID loaded from NVS: ");
        for (int i = 0; i < ESP_UUID_LEN; i++) Serial.printf("%02X", deviceUuid[i]);
        Serial.println();
    } else {
        uuidProvisioned = false;
        for (int i = 0; i < ESP_UUID_LEN; i++) deviceUuid[i] = (uint8_t)(esp_random() & 0xFF);
        preferences.begin(NVS_NAMESPACE, false);
        preferences.putBytes(NVS_UUID_NAME, deviceUuid, ESP_UUID_LEN);
        preferences.end();
        uuidProvisioned = true;
        Serial.print("Generated new UUID: ");
        for (int i = 0; i < ESP_UUID_LEN; i++) Serial.printf("%02X", deviceUuid[i]);
        Serial.println();
    }

    pinMode(TOUCH1_PIN, INPUT);
    pinMode(TOUCH2_PIN, INPUT);
    pinMode(BUTTON_PIN, INPUT);
    pinMode(RELAY1_PIN, OUTPUT);
    pinMode(RELAY2_PIN, OUTPUT);

    leds[0] = CRGB::Red;
    FastLED.show();
    Serial.println("LED red (no connection), starting BLE...");

    NimBLEDevice::init("SylDa_Server");
    NimBLEDevice::setMTU(248);

    NimBLEServer *pServer = NimBLEDevice::createServer();
    pServer->setCallbacks(new MyServerCallbacks());
    pServer->advertiseOnDisconnect(true);

    NimBLEService *pService = pServer->createService(SERVICE_UUID);
    pCharacteristic = pService->createCharacteristic(
        CHARACTERISTIC_UUID,
        NIMBLE_PROPERTY::WRITE_NR
    );
    pCharacteristic->setCallbacks(new MyCharacteristicCallbacks());

    NimBLECharacteristic *pUuidChar = pService->createCharacteristic(
        UUID_CHAR_UUID,
        NIMBLE_PROPERTY::READ
    );
    pUuidChar->setValue(deviceUuid, ESP_UUID_LEN);

    NimBLECharacteristic *pVersionChar = pService->createCharacteristic(
        VERSION_UUID,
        NIMBLE_PROPERTY::READ
    );
    pVersionChar->setValue(FIRMWARE_VERSION);

    NimBLECharacteristic *pOtaChar = pService->createCharacteristic(
        OTA_UUID,
        NIMBLE_PROPERTY::WRITE_NR | NIMBLE_PROPERTY::NOTIFY
    );
    pOtaChar->setCallbacks(new OtaCharacteristicCallbacks());

    NimBLEAdvertising *pAdvertising = NimBLEDevice::getAdvertising();
    pAdvertising->setName("SylDa_Server");
    pAdvertising->addServiceUUID(SERVICE_UUID);

    NimBLEAdvertisementData scanResp;
    scanResp.setCompleteServices(NimBLEUUID(SERVICE_UUID));
    pAdvertising->setScanResponseData(scanResp);
    pAdvertising->enableScanResponse(true);

    pAdvertising->setMinInterval(32);
    pAdvertising->setMaxInterval(64);
    bool advOk = pAdvertising->start();
    Serial.printf("BLE: advertising started as 'SylDa_Server' (start=%d, isAdv=%d)\n",
                  advOk, pAdvertising->isAdvertising());

    if (keyProvisioned) {
        Serial.print("HMAC Key: ");
        for (int i = 0; i < HMAC_KEY_LEN; i++) {
            Serial.printf("%02X", hmacKey[i]);
        }
        Serial.println();
    } else {
        Serial.println("No HMAC key — use USB SET_KEY to provision");
    }

    Serial.println("Setup done.");
}

void loop() {
    if (!otaInProgress && Serial.available()) {
        static String serialBuf;
        char c = Serial.read();
        serialBuf += c;
        if (c == '\n') {
            serialBuf.trim();
            if (serialBuf == "KEY?") {
                if (keyProvisioned && uuidProvisioned) {
                    Serial.print("DEVICE_ID:");
                    for (int i = 0; i < ESP_UUID_LEN; i++) Serial.printf("%02X", deviceUuid[i]);
                    Serial.println();
                    Serial.print("HMAC_KEY:");
                    for (int i = 0; i < HMAC_KEY_LEN; i++) {
                        Serial.printf("%02X", hmacKey[i]);
                    }
                    Serial.println();
                } else {
                    Serial.println("NO_KEY");
                }
            } else if (serialBuf == "VERSION?") {
                Serial.print("BUILD_NR:");
                Serial.println(FIRMWARE_VERSION);
            } else if (serialBuf.startsWith("SET_KEY:")) {
                String hex = serialBuf.substring(8);
                hex.toUpperCase();
                if (hex.length() == 64 && isHexKey(hex)) {
                    parseHexKey(hex, hmacKey);
                    preferences.begin(NVS_NAMESPACE, false);
                    preferences.putBytes(NVS_KEY_NAME, hmacKey, HMAC_KEY_LEN);
                    preferences.end();
                    keyProvisioned = true;
                    Serial.println("OK");
                    Serial.println("HMAC key stored in NVS");
                } else {
                    Serial.println("ERROR: invalid key format");
                }
            } else if (serialBuf.startsWith("SET_ID:")) {
                String hex = serialBuf.substring(7);
                hex.toUpperCase();
                if (hex.length() == 32 && isHexKey(hex)) {
                    for (int i = 0; i < ESP_UUID_LEN; i++) {
                        deviceUuid[i] = (uint8_t)strtoul(hex.substring(i * 2, i * 2 + 2).c_str(), nullptr, 16);
                    }
                    preferences.begin(NVS_NAMESPACE, false);
                    preferences.putBytes(NVS_UUID_NAME, deviceUuid, ESP_UUID_LEN);
                    preferences.end();
                    uuidProvisioned = true;
                    Serial.println("OK");
                    Serial.println("UUID stored in NVS");
                } else {
                    Serial.println("ERROR: invalid UUID format");
                }
            }
            serialBuf = "";
        }
    }

    if (otaReady) {
        Serial.printf("OTA: loop() processing otaReady — otaWritten=%lu, otaExpectedSize=%lu\n",
                      otaWritten, otaExpectedSize);
        esp_err_t err = esp_ota_end(otaHandle);
        if (err != ESP_OK) {
            Serial.printf("OTA: esp_ota_end failed (%d) — aborting\n", err);
            otaReset();
        } else {
            Serial.println("OTA: esp_ota_end OK, setting otaEnded=true, waiting for 0xFF confirm");
            otaEnded = true;
            otaEndedAt = millis();
        }
        otaReady = false;
        Serial.printf("OTA: otaReady cleared — otaReady=%d, otaEnded=%d, otaConfirmed=%d, otaInProgress=%d\n",
                      otaReady, otaEnded, otaConfirmed, otaInProgress);
    }

    if (otaEnded && !otaConfirmed && (millis() - otaEndedAt > OTA_CONFIRM_TIMEOUT_MS)) {
        Serial.printf("OTA: 0xFF confirm timeout (%lu ms) — discarding update, resuming normal operation\n",
                      millis() - otaEndedAt);
        otaReset();
    }

    if (otaConfirmed) {
        Serial.println("OTA: otaConfirmed=true, setting boot partition");
        esp_err_t err = esp_ota_set_boot_partition(otaPartition);
        if (err != ESP_OK) {
            Serial.printf("OTA: set boot partition failed (%d)\n", err);
        } else {
            leds[0] = CRGB::Green;
            FastLED.show();
            Serial.println("OTA: done, rebooting...");
            delay(500);
            esp_restart();
        }
        otaReset();
    }

    static bool t1Stable = false;
    static bool t2Stable = false;
    static bool btnStable = false;
    static uint32_t t1Change = 0;
    static uint32_t t2Change = 0;
    static uint32_t btnChange = 0;
    #define DEBOUNCE_MS 50
    bool t1Raw = (digitalRead(TOUCH1_PIN) == HIGH);
    bool t2Raw = (digitalRead(TOUCH2_PIN) == HIGH);
    bool btnRaw = (digitalRead(BUTTON_PIN) == LOW);
    if (t1Raw != t1Stable) { t1Change = millis(); t1Stable = t1Raw; }
    if (t2Raw != t2Stable) { t2Change = millis(); t2Stable = t2Raw; }
    if (btnRaw != btnStable) { btnChange = millis(); btnStable = btnRaw; }
    bool t1Active = (millis() - t1Change > DEBOUNCE_MS) && t1Stable;
    bool t2Active = (millis() - t2Change > DEBOUNCE_MS) && t2Stable;
    bool btnActive = (millis() - btnChange > DEBOUNCE_MS) && btnStable;

    if (!otaInProgress) {
        relay1State = t1Active || btnActive ||
                      (connActive[0] && bleRelay1[0]) || (connActive[1] && bleRelay1[1]);
        relay2State = t2Active ||
                      (connActive[0] && bleRelay2[0]) || (connActive[1] && bleRelay2[1]);
    } else {
        relay1State = false;
        relay2State = false;
    }

    CRGB ledColor;

    if (otaInProgress) {
        ledColor = otaEnded
            ? CRGB::Yellow
            : (((millis() / 100) % 2) ? CRGB::Green : CRGB::Black);
    } else {
        if (connectedCount > 0) {
            if (connectionStableMs == 0) connectionStableMs = millis();
        } else {
            connectionStableMs = 0;
        }

        if (connectedCount > 0) {
            ledColor = (millis() - connectionStableMs >= STABLE_LED_TIMEOUT_MS)
                ? CRGB::Black
                : CRGB::Yellow;
        } else {
            ledColor = CRGB::Red;
        }

        static bool lastRelayActive = false;
        bool relayActive = relay1State || relay2State;
        if (relayActive != lastRelayActive) {
            relayFlashUntil = millis() + 150;
        }
        lastRelayActive = relayActive;

        if (millis() < relayFlashUntil) {
            ledColor = CRGB::Green;
        }
    }

    leds[0] = ledColor;

    digitalWrite(RELAY1_PIN, relay1State ? HIGH : LOW);
    digitalWrite(RELAY2_PIN, relay2State ? HIGH : LOW);

    FastLED.show();

    static bool lastRelay1 = false;
    static bool lastRelay2 = false;
    if (relay1State != lastRelay1 || relay2State != lastRelay2) {
        bool anyBle1 = (connActive[0] && bleRelay1[0]) || (connActive[1] && bleRelay1[1]);
        bool anyBle2 = (connActive[0] && bleRelay2[0]) || (connActive[1] && bleRelay2[1]);
        Serial.printf("Relays: R1=%s R2=%s (t1=%s t2=%s btn=%s ble1=%s ble2=%s)\n",
            relay1State ? "ON" : "OFF",
            relay2State ? "ON" : "OFF",
            t1Active ? "YES" : "no",
            t2Active ? "YES" : "no",
            btnActive ? "YES" : "no",
            anyBle1 ? "ON" : "OFF",
            anyBle2 ? "ON" : "OFF");
        lastRelay1 = relay1State;
        lastRelay2 = relay2State;
    }

    static uint32_t heartbeat = 0;
    if (!otaInProgress && millis() - heartbeat > 60000) {
        bool anyBle1 = (connActive[0] && bleRelay1[0]) || (connActive[1] && bleRelay1[1]);
        bool anyBle2 = (connActive[0] && bleRelay2[0]) || (connActive[1] && bleRelay2[1]);
        Serial.printf("[heartbeat] R1=%s R2=%s t1=%s t2=%s btn=%s ble1=%s ble2=%s clients=%d\n",
            relay1State ? "ON" : "OFF",
            relay2State ? "ON" : "OFF",
            t1Active ? "YES" : "no",
            t2Active ? "YES" : "no",
            btnActive ? "YES" : "no",
            anyBle1 ? "ON" : "OFF",
            anyBle2 ? "ON" : "OFF",
            connectedCount);
        heartbeat = millis();
    }

    delay(50);
}