Lambda Function for BT Beacon to MQTT Broadcast for Home Assistant mqtt_room

device.yml

        - lambda: |-
            if (x.get_ibeacon().has_value()) {
                std::string uuid;
                esp_bt_uuid_t raw_uuid = x.get_ibeacon().value().get_uuid().get_uuid();
                char sbuf[64];
                char *bpos = sbuf;
                switch (raw_uuid.len) {
                    case ESP_UUID_LEN_128:
                        for (int8_t i = 0; i <= 15; i++) {
                            sprintf(bpos, "%02x", raw_uuid.uuid.uuid128[i]);
                            bpos += 2;
                            if (i == 6 || i == 8 || i == 10 || i == 12)
                                  sprintf(bpos++, "-");
                        }
                        sbuf[47] = '\0';
                        uuid.assign(sbuf);
                        break;
                    default:
                        uuid = x.get_ibeacon().value().get_uuid().to_string();
                        std::transform(uuid.begin(), uuid.end(), uuid.begin(), [](unsigned char c){ return std::tolower(c); });
                        break;
                }
                
                char mbuf[32] = {0};
                sprintf(mbuf, "-%hu-%hu", x.get_ibeacon().value().get_major(), x.get_ibeacon().value().get_minor());
                uuid.append(mbuf);
                int8_t tx_power = x.get_ibeacon().value().get_signal_power();
                if (tx_power >= 100) {
                  tx_power = -69;
                }
                
                float dist = pow(10, (float)(tx_power - x.get_rssi()) / (10 * 2));
                
                if (dist < 30) {
                    ESP_LOGD("ble_adv", "Sending MQTT room update for '%s' (%s): %.03fm (%d rssi, %d sigpow)",
                             x.get_name().c_str(), uuid.c_str(), dist, x.get_rssi(), tx_power);
                    id(mqtt_client).publish_json(id(room_topic), [=](JsonObject root) {
                        root["id"] = uuid;
                        root["name"] = x.get_name();
                        root["distance"] = dist;
                        root["rssi"] = x.get_rssi();
                        root["tx_power"] = tx_power;
                    });
                } else {
                    ESP_LOGD("ble_adv", "Skipping MQTT room update for '%s' (%s): %.03fm (%d rssi, %d sigpow)",
                             x.get_name().c_str(), uuid.c_str(), dist, x.get_rssi(), tx_power);
                }
            }