Remove arduino-esp32 dependency, modernise WiFi and SPI compat

- Replace Arduino WiFi.h in Networking.cpp with native esp_wifi/esp_netif;
  uses event-driven connect with FreeRTOS EventGroup and 30 s timeout
- Remove initArduino() / Arduino.h from main.cpp
- Remove deprecated arduino-esp32 submodule (was uninitialized and marked
  deprecated since it was first added in Dec 2021)
- rc522.h: guard VSPI_HOST → SPI3_HOST for ESP-IDF 5.x compatibility
- WebInterface.cpp: drop redundant esp_wifi.h (esp_netif.h is sufficient)
- CMakeLists.txt: add esp_wifi + nvs_flash to REQUIRES

https://claude.ai/code/session_01MhAnh68DPNnTjcKqjNYDmk

.gitmodules

@@ -1,7 +0,0 @@
-[submodule "device/components/esp-idf-rc522"]
-	path = device/components/esp-idf-rc522
-	url = git@github.com:sweidac/esp-idf-rc522.git
-
-[submodule "device/components/arduino-esp32"]
-	path = device/components/arduino-esp32
-	url = https://github.com/espressif/arduino-esp32.git

device/components/esp-idf-rc522/CMakeLists.txt

@@ -0,0 +1,4 @@
+idf_component_register(
+    SRCS "rc522.c"
+    INCLUDE_DIRS "."
+)

device/components/esp-idf-rc522/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2019 Alija Bobija
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

device/components/esp-idf-rc522/component.mk

@@ -0,0 +1 @@
+COMPONENT_ADD_INCLUDEDIRS := .

device/components/esp-idf-rc522/rc522.c

@@ -0,0 +1,746 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "esp_system.h"
+#include "driver/spi_master.h"
+#include "soc/gpio_struct.h"
+#include "driver/gpio.h"
+#include "esp_timer.h"
+#include "esp_log.h"
+
+#include "rc522.h"
+
+static const char* TAG = "ESP-RC522";
+
+struct rc522 {
+    bool running;
+    rc522_config_t* config;
+    spi_device_handle_t spi;
+    TaskHandle_t task_handle;
+    bool scan_started;
+    uint8_t* lastSerialNumber;
+};
+
+typedef struct rc522* rc522_handle_t;
+
+static rc522_handle_t hndl = NULL;
+
+#define rc522_fw_version() rc522_read(0x37)
+
+bool rc522_is_inited() {
+    return hndl != NULL;
+}
+
+static esp_err_t rc522_spi_init() {
+    if(! hndl || ! hndl->config) {
+        ESP_LOGE(TAG, "Fail to init SPI. Invalid handle");
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    if(hndl->spi) {
+        ESP_LOGW(TAG, "SPI already initialized");
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    spi_bus_config_t buscfg = {
+        .miso_io_num = hndl->config->miso_io,
+        .mosi_io_num = hndl->config->mosi_io,
+        .sclk_io_num = hndl->config->sck_io,
+        .quadwp_io_num = -1,
+        .quadhd_io_num = -1
+    };
+
+    spi_device_interface_config_t devcfg = {
+        .clock_speed_hz = 5000000,
+        .mode = 0,
+        .spics_io_num = hndl->config->sda_io,
+        .queue_size = 7,
+        .flags = SPI_DEVICE_HALFDUPLEX
+    };
+
+    esp_err_t err = spi_bus_initialize(hndl->config->spi_host_id, &buscfg, 0);
+
+    if(err != ESP_OK) {
+        return err;
+    }
+
+    err = spi_bus_add_device(hndl->config->spi_host_id, &devcfg, &hndl->spi);
+
+    if(err != ESP_OK) {
+        spi_bus_free(hndl->config->spi_host_id);
+        hndl->spi = NULL;
+    }
+
+    return err;
+}
+
+static esp_err_t rc522_write_n(uint8_t addr, uint8_t n, uint8_t *data) {
+    uint8_t* buffer = (uint8_t*) malloc(n + 1);
+    buffer[0] = (addr << 1) & 0x7E;
+
+    for (uint8_t i = 1; i <= n; i++) {
+        buffer[i] = data[i-1];
+    }
+
+    spi_transaction_t t;
+    memset(&t, 0, sizeof(t));
+
+    t.length = 8 * (n + 1);
+    t.tx_buffer = buffer;
+
+    esp_err_t ret = spi_device_transmit(hndl->spi, &t);
+
+    free(buffer);
+
+    return ret;
+}
+
+static esp_err_t rc522_write(uint8_t addr, uint8_t val) {
+    return rc522_write_n(addr, 1, &val);
+}
+
+static uint8_t* rc522_read_n(uint8_t addr, uint8_t n) {
+    if (n <= 0) {
+        return NULL;
+    }
+
+    spi_transaction_t t;
+    memset(&t, 0, sizeof(t));
+
+    uint8_t* buffer = (uint8_t*) malloc(n);
+
+    t.flags = SPI_TRANS_USE_TXDATA;
+    t.length = 8;
+    t.tx_data[0] = ((addr << 1) & 0x7E) | 0x80;
+    t.rxlength = 8 * n;
+    t.rx_buffer = buffer;
+
+    esp_err_t ret = spi_device_transmit(hndl->spi, &t);
+    assert(ret == ESP_OK);
+
+    return buffer;
+}
+
+static uint8_t rc522_read(uint8_t addr) {
+    uint8_t* buffer = rc522_read_n(addr, 1);
+    uint8_t res = buffer[0];
+    free(buffer);
+
+    return res;
+}
+
+static esp_err_t rc522_set_bitmask(uint8_t addr, uint8_t mask) {
+    return rc522_write(addr, rc522_read(addr) | mask);
+}
+
+static esp_err_t rc522_clear_bitmask(uint8_t addr, uint8_t mask) {
+    return rc522_write(addr, rc522_read(addr) & ~mask);
+}
+
+static esp_err_t rc522_antenna_on() {
+    esp_err_t ret;
+
+    if(~ (rc522_read(0x14) & 0x03)) {
+        ret = rc522_set_bitmask(0x14, 0x03);
+
+        if(ret != ESP_OK) {
+            return ret;
+        }
+    }
+
+    return rc522_write(0x26, 0x60); // 43dB gain
+}
+
+static void rc522_task(void* arg);
+
+esp_err_t rc522_init(rc522_config_t* config) {
+    if(! config) {
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    if(hndl) {
+        ESP_LOGW(TAG, "Already initialized");
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    if(! (hndl = calloc(1, sizeof(struct rc522)))) {
+        return ESP_ERR_NO_MEM;
+    }
+
+    if(! (hndl->config = calloc(1, sizeof(rc522_config_t)))) {
+        rc522_destroy();
+        return ESP_ERR_NO_MEM;
+    }
+
+    // copy config considering defaults
+    hndl->config->callback         = config->callback;
+    hndl->config->ndef_callback    = config->ndef_callback;
+    hndl->config->miso_io          = config->miso_io == 0 ? RC522_DEFAULT_MISO : config->miso_io;
+    hndl->config->mosi_io          = config->mosi_io == 0 ? RC522_DEFAULT_MOSI : config->mosi_io;
+    hndl->config->sck_io           = config->sck_io == 0 ? RC522_DEFAULT_SCK : config->sck_io;
+    hndl->config->sda_io           = config->sda_io == 0 ? RC522_DEFAULT_SDA : config->sda_io;
+    hndl->config->spi_host_id      = config->spi_host_id == 0 ? RC522_DEFAULT_SPI_HOST : config->spi_host_id;
+    hndl->config->scan_interval_ms = config->scan_interval_ms < 50 ? RC522_DEFAULT_SCAN_INTERVAL_MS : config->scan_interval_ms;
+    hndl->config->task_stack_size  = config->task_stack_size == 0 ? RC522_DEFAULT_TACK_STACK_SIZE : config->task_stack_size;
+    hndl->config->task_priority    = config->task_priority == 0 ? RC522_DEFAULT_TACK_STACK_PRIORITY : config->task_priority;
+
+    esp_err_t err = rc522_spi_init();
+
+    if(err != ESP_OK) {
+        rc522_destroy();
+        return err;
+    }
+
+    // ---------- RW test ------------
+    const uint8_t test_addr = 0x24, test_val = 0x25;
+    for(uint8_t i = test_val; i < test_val + 2; i++) {
+        if((err = rc522_write(test_addr, i)) != ESP_OK || rc522_read(test_addr) != i) {
+            ESP_LOGE(TAG, "RW test fail");
+            rc522_destroy();
+            return err;
+        }
+    }
+    // ------- End of RW test --------
+
+    rc522_write(0x01, 0x0F);
+    rc522_write(0x2A, 0x8D);
+    rc522_write(0x2B, 0x3E);
+    rc522_write(0x2D, 0x1E);
+    rc522_write(0x2C, 0x00);
+    rc522_write(0x15, 0x40);
+    rc522_write(0x11, 0x3D);
+
+    rc522_antenna_on();
+
+    hndl->running = true;
+    if (xTaskCreate(rc522_task, "rc522_task", hndl->config->task_stack_size, NULL, hndl->config->task_priority, &hndl->task_handle) != pdTRUE) {
+        ESP_LOGE(TAG, "Fail to create rc522 task");
+        rc522_destroy();
+        return err;
+    }
+
+    if(err != ESP_OK) {
+        ESP_LOGE(TAG, "Fail to create timer");
+        rc522_destroy();
+        return err;
+    }
+
+    ESP_LOGI(TAG, "Initialized (firmware: 0x%x)", rc522_fw_version());
+    return ESP_OK;
+}
+
+uint64_t rc522_sn_to_u64(uint8_t* sn) {
+    if(!sn) {
+        return 0;
+    }
+
+    uint64_t result = 0;
+    for(int i = 4; i >= 0; i--) {
+        result |= ((uint64_t) sn[i] << (i * 8));
+    }
+
+    return result;
+}
+
+/* Returns pointer to dynamically allocated array of two element */
+static uint8_t* rc522_calculate_crc(uint8_t *data, uint8_t n) {
+    rc522_clear_bitmask(0x05, 0x04);
+    rc522_set_bitmask(0x0A, 0x80);
+
+    rc522_write_n(0x09, n, data);
+
+    rc522_write(0x01, 0x03);
+
+    uint8_t i = 255;
+    uint8_t nn = 0;
+
+    for(;;) {
+        nn = rc522_read(0x05);
+        i--;
+
+        if(! (i != 0 && ! (nn & 0x04))) {
+            break;
+        }
+    }
+
+    uint8_t* res = (uint8_t*) malloc(2);
+
+    res[0] = rc522_read(0x22);
+    res[1] = rc522_read(0x21);
+
+    return res;
+}
+
+static uint8_t* rc522_card_write(uint8_t cmd, uint8_t *data, uint8_t n, uint8_t* res_n) {
+    uint8_t *result = NULL;
+    uint8_t irq = 0x00;
+    uint8_t irq_wait = 0x00;
+    uint8_t last_bits = 0;
+    uint8_t nn = 0;
+
+    if(cmd == 0x0E) {
+        irq = 0x12;
+        irq_wait = 0x10;
+    }
+    else if(cmd == 0x0C) {
+        irq = 0x77;
+        irq_wait = 0x30;
+    }
+
+    rc522_write(0x02, irq | 0x80);
+    rc522_clear_bitmask(0x04, 0x80);
+    rc522_set_bitmask(0x0A, 0x80);
+    rc522_write(0x01, 0x00);
+
+    rc522_write_n(0x09, n, data);
+
+    rc522_write(0x01, cmd);
+
+    if(cmd == 0x0C) {
+        rc522_set_bitmask(0x0D, 0x80);
+    }
+
+    uint16_t i = 1000;
+
+    for(;;) {
+        nn = rc522_read(0x04);
+        i--;
+
+        if(! (i != 0 && (((nn & 0x01) == 0) && ((nn & irq_wait) == 0)))) {
+            break;
+        }
+    }
+
+    rc522_clear_bitmask(0x0D, 0x80);
+
+    if(i != 0) {
+        if((rc522_read(0x06) & 0x1B) == 0x00) {
+            if(cmd == 0x0C) {
+                nn = rc522_read(0x0A);
+                last_bits = rc522_read(0x0C) & 0x07;
+
+                if (last_bits != 0) {
+                    *res_n = (nn - 1) + last_bits;
+                } else {
+                    *res_n = nn;
+                }
+
+                result = (uint8_t*) malloc(*res_n);
+
+                for(i = 0; i < *res_n; i++) {
+                    result[i] = rc522_read(0x09);
+                }
+            }
+        }
+    }
+
+    return result;
+}
+
+static uint8_t* rc522_request(uint8_t* res_n) {
+    uint8_t* result = NULL;
+    rc522_write(0x0D, 0x07);
+
+    uint8_t req_mode = 0x26;
+    result = rc522_card_write(0x0C, &req_mode, 1, res_n);
+
+    if(*res_n * 8 != 0x10) {
+        free(result);
+        return NULL;
+    }
+
+    return result;
+}
+
+static uint8_t* rc522_anticoll() {
+    uint8_t res_n;
+
+    rc522_write(0x0D, 0x00);
+    uint8_t* result = rc522_card_write(0x0C, (uint8_t[]) { 0x93, 0x20 }, 2, &res_n);
+
+    if(result && res_n != 5) { // all cards/tags serial numbers is 5 bytes long (?)
+        free(result);
+        return NULL;
+    }
+
+    return result;
+}
+
+/* Send HALT and clear crypto bit. Card will only respond to WUPA after this. */
+static void rc522_halt_card() {
+    uint8_t buf[] = { 0x50, 0x00, 0x00, 0x00 };
+    uint8_t* crc = rc522_calculate_crc(buf, 2);
+    buf[2] = crc[0];
+    buf[3] = crc[1];
+    free(crc);
+
+    uint8_t res_n;
+    uint8_t* res = rc522_card_write(0x0C, buf, 4, &res_n);
+    free(res);
+    rc522_clear_bitmask(0x08, 0x08);
+}
+
+static uint8_t* rc522_get_tag() {
+    uint8_t* result = NULL;
+    uint8_t* res_data = NULL;
+    uint8_t res_data_n;
+
+    res_data = rc522_request(&res_data_n);
+
+    if(res_data != NULL) {
+        free(res_data);
+        result = rc522_anticoll();
+        /* NOTE: card is NOT halted here — caller must call rc522_halt_card() */
+    }
+
+    return result;
+}
+
+/* URI prefix table for NDEF URI records (RFC 3986 shortened forms) */
+static const char* const RC522_URI_PREFIXES[] = {
+    "",              /* 0x00 no prefix */
+    "http://www.",   /* 0x01 */
+    "https://www.",  /* 0x02 */
+    "http://",       /* 0x03 */
+    "https://",      /* 0x04 */
+    "tel:",          /* 0x05 */
+    "mailto:",       /* 0x06 */
+    "ftp://anonymous:anonymous@", /* 0x07 */
+    "ftp://ftp.",    /* 0x08 */
+    "ftps://",       /* 0x09 */
+    "sftp://",       /* 0x0A */
+    "smb://",        /* 0x0B */
+    "nfs://",        /* 0x0C */
+    "ftp://",        /* 0x0D */
+    "dav://",        /* 0x0E */
+    "news:",         /* 0x0F */
+    "telnet://",     /* 0x10 */
+    "imap:",         /* 0x11 */
+    "rtsp://",       /* 0x12 */
+    "urn:",          /* 0x13 */
+    "pop:",          /* 0x14 */
+    "sip:",          /* 0x15 */
+    "sips:",         /* 0x16 */
+    "tftp:",         /* 0x17 */
+    "btspp://",      /* 0x18 */
+    "btl2cap://",    /* 0x19 */
+    "btgoep://",     /* 0x1A */
+    "tcpobex://",    /* 0x1B */
+    "irdaobex://",   /* 0x1C */
+    "file://",       /* 0x1D */
+    "urn:epc:id:",   /* 0x1E */
+    "urn:epc:tag:",  /* 0x1F */
+    "urn:epc:pat:",  /* 0x20 */
+    "urn:epc:raw:",  /* 0x21 */
+    "urn:epc:",      /* 0x22 */
+    "urn:nfc:",      /* 0x23 */
+};
+#define RC522_URI_PREFIX_COUNT (sizeof(RC522_URI_PREFIXES) / sizeof(RC522_URI_PREFIXES[0]))
+
+/* Parse an NDEF message TLV block and extract the first URI record URL.
+ * Returns heap-allocated null-terminated URL string, or NULL if not found. */
+static char* rc522_parse_ndef_url(const uint8_t* data, int len) {
+    int i = 0;
+
+    while(i < len) {
+        uint8_t tlv_type = data[i++];
+
+        if(tlv_type == 0xFE) break;  /* Terminator TLV */
+        if(tlv_type == 0x00) continue; /* Null TLV — no length byte */
+
+        if(i >= len) break;
+
+        /* Read TLV length (1 or 3 bytes) */
+        uint16_t tlv_len;
+        if(data[i] == 0xFF) {
+            i++;
+            if(i + 1 >= len) break;
+            tlv_len = ((uint16_t)data[i] << 8) | data[i + 1];
+            i += 2;
+        } else {
+            tlv_len = data[i++];
+        }
+
+        if(tlv_type != 0x03 || tlv_len == 0 || i + (int)tlv_len > len) {
+            i += tlv_len;
+            continue;
+        }
+
+        /* Parse NDEF record header */
+        uint8_t header   = data[i++];
+        uint8_t tnf      = header & 0x07;
+        bool    sr       = (header & 0x10) != 0; /* Short Record */
+        bool    il       = (header & 0x08) != 0; /* ID Length present */
+
+        if(i >= len) break;
+        uint8_t type_len = data[i++];
+
+        uint32_t payload_len;
+        if(sr) {
+            if(i >= len) break;
+            payload_len = data[i++];
+        } else {
+            if(i + 3 >= len) break;
+            payload_len = ((uint32_t)data[i] << 24) | ((uint32_t)data[i+1] << 16)
+                        | ((uint32_t)data[i+2] << 8)  | data[i+3];
+            i += 4;
+        }
+
+        uint8_t id_len = 0;
+        if(il) {
+            if(i >= len) break;
+            id_len = data[i++];
+        }
+
+        /* Only handle Well-Known URI records (TNF=0x01, Type='U') */
+        if(tnf == 0x01 && type_len == 1 && i < len && data[i] == 0x55) {
+            i++;        /* skip type byte 'U' */
+            i += id_len; /* skip optional ID */
+
+            if(payload_len > 0 && i < len) {
+                uint8_t prefix_code = data[i++];
+                payload_len--;
+
+                const char* prefix     = (prefix_code < RC522_URI_PREFIX_COUNT) ? RC522_URI_PREFIXES[prefix_code] : "";
+                size_t      prefix_len = strlen(prefix);
+                size_t      body_len   = (payload_len < (uint32_t)(len - i)) ? payload_len : (uint32_t)(len - i);
+
+                if(prefix_len + body_len > 255) body_len = 255 - prefix_len;
+
+                char* url = (char*) malloc(prefix_len + body_len + 1);
+                if(!url) return NULL;
+
+                memcpy(url, prefix, prefix_len);
+                memcpy(url + prefix_len, data + i, body_len);
+                url[prefix_len + body_len] = '\0';
+                return url;
+            }
+        }
+
+        /* Skip over this record */
+        i += type_len + id_len + (int)payload_len;
+    }
+
+    return NULL;
+}
+
+/* Wake a halted card with WUPA (0x52), perform cascade anticollision (CL1 + optional CL2),
+ * SELECT the card, read pages 4–15 of user memory (NDEF area), parse, then halt.
+ * Returns heap-allocated URL string or NULL.  Card is always left in HALT state on return. */
+static char* rc522_read_ndef_url() {
+    uint8_t res_n;
+
+    /* WUPA: wake halted card — identical bit-framing to REQA but byte is 0x52 */
+    rc522_write(0x0D, 0x07);
+    uint8_t wupa_cmd = 0x52;
+    uint8_t* atqa = rc522_card_write(0x0C, &wupa_cmd, 1, &res_n);
+    if(!atqa || res_n * 8 != 0x10) {
+        free(atqa);
+        return NULL;
+    }
+    free(atqa);
+
+    /* CL1 anti-collision */
+    rc522_write(0x0D, 0x00);
+    uint8_t* cl1 = rc522_card_write(0x0C, (uint8_t[]){ 0x93, 0x20 }, 2, &res_n);
+    if(!cl1 || res_n != 5) {
+        free(cl1);
+        rc522_halt_card();
+        return NULL;
+    }
+
+    bool cascade = (cl1[0] == 0x88); /* cascade tag byte indicates 7-byte UID */
+
+    /* CL1 SELECT */
+    uint8_t sel1[9] = { 0x93, 0x70, cl1[0], cl1[1], cl1[2], cl1[3], cl1[4] };
+    uint8_t* crc = rc522_calculate_crc(sel1, 7);
+    sel1[7] = crc[0]; sel1[8] = crc[1]; free(crc);
+    uint8_t sel_n;
+    uint8_t* sak1 = rc522_card_write(0x0C, sel1, 9, &sel_n);
+    free(cl1);
+    if(!sak1) {
+        rc522_halt_card();
+        return NULL;
+    }
+    free(sak1);
+
+    if(cascade) {
+        /* CL2 anti-collision */
+        rc522_write(0x0D, 0x00);
+        uint8_t* cl2 = rc522_card_write(0x0C, (uint8_t[]){ 0x95, 0x20 }, 2, &res_n);
+        if(!cl2 || res_n != 5) {
+            free(cl2);
+            rc522_halt_card();
+            return NULL;
+        }
+
+        /* CL2 SELECT */
+        uint8_t sel2[9] = { 0x95, 0x70, cl2[0], cl2[1], cl2[2], cl2[3], cl2[4] };
+        crc = rc522_calculate_crc(sel2, 7);
+        sel2[7] = crc[0]; sel2[8] = crc[1]; free(crc);
+        uint8_t* sak2 = rc522_card_write(0x0C, sel2, 9, &sel_n);
+        free(cl2);
+        if(!sak2) {
+            rc522_halt_card();
+            return NULL;
+        }
+        free(sak2);
+    }
+
+    /* Card is now SELECTED. Verify NDEF capability container at page 3.
+     * For NTAG/MIFARE Ultralight the NDEF magic byte is 0xE1 at CC[0]. */
+    uint8_t read_cc[4] = { 0x30, 0x03 };
+    crc = rc522_calculate_crc(read_cc, 2);
+    read_cc[2] = crc[0]; read_cc[3] = crc[1]; free(crc);
+
+    uint8_t* cc_data = rc522_card_write(0x0C, read_cc, 4, &res_n);
+    if(!cc_data || res_n < 4 || cc_data[0] != 0xE1) {
+        free(cc_data);
+        rc522_halt_card();
+        return NULL;
+    }
+    free(cc_data);
+
+    /* Read NDEF user pages 4–15 (12 pages × 4 bytes = 48 bytes).
+     * READ command (0x30) returns 16 bytes (4 pages) per call. */
+    uint8_t ndef_buf[48];
+    int     ndef_len = 0;
+
+    for(uint8_t page = 4; page <= 12; page += 4) { /* 3 reads × 16 bytes = 48 bytes */
+        uint8_t read_cmd[4] = { 0x30, page };
+        crc = rc522_calculate_crc(read_cmd, 2);
+        read_cmd[2] = crc[0]; read_cmd[3] = crc[1]; free(crc);
+
+        uint8_t* page_data = rc522_card_write(0x0C, read_cmd, 4, &res_n);
+        if(!page_data || res_n < 16) {
+            free(page_data);
+            break;
+        }
+
+        int copy = (48 - ndef_len < 16) ? 48 - ndef_len : 16;
+        memcpy(ndef_buf + ndef_len, page_data, copy);
+        ndef_len += copy;
+        free(page_data);
+    }
+
+    rc522_halt_card();
+
+    if(ndef_len == 0) return NULL;
+    return rc522_parse_ndef_url(ndef_buf, ndef_len);
+}
+
+esp_err_t rc522_start(rc522_start_args_t start_args) {
+    esp_err_t err = rc522_init(&start_args);
+    return err != ESP_OK ? err : rc522_start2();
+}
+
+esp_err_t rc522_start2() {
+    if(! hndl) { return ESP_ERR_INVALID_STATE; }
+
+    hndl->scan_started = true;
+
+    return ESP_OK;
+}
+
+esp_err_t rc522_pause() {
+    if(! hndl) { return ESP_ERR_INVALID_STATE; }
+
+    if(! hndl->scan_started) {
+        return ESP_OK;
+    }
+
+    hndl->scan_started = false;
+
+    return ESP_OK;
+}
+
+void rc522_destroy() {
+    if(! hndl) { return; }
+
+    rc522_pause(); // stop timer
+    hndl->running = false; // task will delete itself
+
+    if(hndl->spi) {
+        spi_bus_remove_device(hndl->spi);
+        spi_bus_free(hndl->config->spi_host_id);
+        hndl->spi = NULL;
+    }
+
+    free(hndl->config);
+    hndl->config = NULL;
+
+    free(hndl);
+    hndl = NULL;
+}
+
+static bool isSameSerialNumber(uint8_t* one, uint8_t* other) {
+    if (one == NULL && other == NULL) {
+        return true;
+    }
+
+    if (one == NULL || other == NULL) {
+        return false;
+    }
+
+    return one[0] == other[0]
+        && one[1] == other[1]
+        && one[2] == other[2]
+        && one[3] == other[3]
+        && one[4] == other[4];
+}
+
+static void rc522_task(void* arg) {
+    while(hndl->running) {
+        if(!hndl->scan_started) {
+            vTaskDelay(100 / portTICK_PERIOD_MS);
+            continue;
+        }
+
+        uint8_t* serial_no = rc522_get_tag(); /* card NOT halted yet */
+
+        if(!isSameSerialNumber(serial_no, hndl->lastSerialNumber)) {
+            rc522_tag_callback_t  cb      = hndl->config->callback;
+            rc522_ndef_callback_t ndef_cb = hndl->config->ndef_callback;
+
+            if(serial_no == NULL) {
+                free(hndl->lastSerialNumber);
+                hndl->lastSerialNumber = NULL;
+
+                if(cb)      cb(NULL);
+                if(ndef_cb) ndef_cb(NULL, NULL);
+            } else {
+                if(!hndl->lastSerialNumber) {
+                    hndl->lastSerialNumber = malloc(5);
+                }
+                memcpy(hndl->lastSerialNumber, serial_no, 5);
+
+                if(cb) cb(serial_no);
+
+                if(ndef_cb) {
+                    /* rc522_read_ndef_url() handles HALT internally after reading */
+                    char* url = rc522_read_ndef_url();
+                    ndef_cb(serial_no, url);
+                    if(url) free(url);
+                } else {
+                    rc522_halt_card();
+                }
+            }
+        } else if(serial_no != NULL) {
+            /* Same card still present — halt it again to prevent continuous REQA responses */
+            rc522_halt_card();
+        }
+
+        int delay_ms = hndl->config->scan_interval_ms;
+        if(serial_no != NULL) {
+            free(serial_no);
+            serial_no = NULL;
+            delay_ms *= 2;
+        }
+
+        vTaskDelay(delay_ms / portTICK_PERIOD_MS);
+    }
+
+    vTaskDelete(NULL);
+}

device/components/esp-idf-rc522/rc522.h

@@ -0,0 +1,98 @@
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "driver/spi_master.h"
+
+#define RC522_DEFAULT_MISO                 (25)
+#define RC522_DEFAULT_MOSI                 (23)
+#define RC522_DEFAULT_SCK                  (19)
+#define RC522_DEFAULT_SDA                  (22)
+/* VSPI_HOST was renamed to SPI3_HOST in ESP-IDF 5.0 */
+#ifdef VSPI_HOST
+#  define RC522_DEFAULT_SPI_HOST           (VSPI_HOST)
+#else
+#  define RC522_DEFAULT_SPI_HOST           (SPI3_HOST)
+#endif
+#define RC522_DEFAULT_SCAN_INTERVAL_MS     (125)
+#define RC522_DEFAULT_TACK_STACK_SIZE      (4 * 1024)
+#define RC522_DEFAULT_TACK_STACK_PRIORITY  (4)
+
+typedef void(*rc522_tag_callback_t)(uint8_t*);
+
+/* Called when a tag is detected (url != NULL) or removed (sn == NULL, url == NULL).
+ * url is the NDEF URI record content, or NULL if no NDEF was found on the tag.
+ * The caller must NOT free sn or url — they are freed by the library. */
+typedef void(*rc522_ndef_callback_t)(uint8_t* sn, const char* url);
+
+typedef struct {
+    int miso_io;                    /*<! MFRC522 MISO gpio (Default: 25) */
+    int mosi_io;                    /*<! MFRC522 MOSI gpio (Default: 23) */
+    int sck_io;                     /*<! MFRC522 SCK gpio  (Default: 19) */
+    int sda_io;                     /*<! MFRC522 SDA gpio  (Default: 22) */
+    spi_host_device_t spi_host_id;  /*<! Default VSPI_HOST (SPI3) */
+    rc522_tag_callback_t callback;  /*<! Called with 5-byte serial number, or NULL when tag removed */
+    rc522_ndef_callback_t ndef_callback; /*<! Called with (sn, url) on tag change; url may be NULL */
+    uint16_t scan_interval_ms;      /*<! How fast will ESP32 scan for nearby tags, in miliseconds. Default: 125ms */
+    size_t task_stack_size;         /*<! Stack size of rc522 task (Default: 4 * 1024) */
+    uint8_t task_priority;          /*<! Priority of rc522 task (Default: 4) */
+} rc522_config_t;
+
+typedef rc522_config_t rc522_start_args_t;
+
+/**
+ * @brief Initialize RC522 module.
+ *        To start scanning tags - call rc522_resume or rc522_start2 function.
+ * @param config Configuration
+ * @return ESP_OK on success
+ */
+esp_err_t rc522_init(rc522_config_t* config);
+
+/**
+ * @brief Convert serial number (array of 5 bytes) to uint64_t number
+ * @param sn Serial number
+ * @return Serial number in number representation. If fail, 0 will be retured
+ */
+uint64_t rc522_sn_to_u64(uint8_t* sn);
+
+/**
+ * @brief Check if RC522 is inited
+ * @return true if RC522 is inited
+ */
+bool rc522_is_inited();
+
+/**
+ * @brief This function will call rc522_init function and immediately start to scan tags by calling rc522_resume function.
+ * @param start_args Configuration
+ * @return ESP_OK on success
+ */
+esp_err_t rc522_start(rc522_start_args_t start_args);
+
+/**
+ * @brief Start to scan tags. If already started, ESP_OK will just be returned.
+ * @return ESP_OK on success
+ */
+esp_err_t rc522_start2();
+
+/**
+ * @brief Start to scan tags. If already started, ESP_OK will just be returned.
+ * @return ESP_OK on success
+ */
+#define rc522_resume() rc522_start2()
+
+/**
+ * @brief Pause scan tags. If already paused, ESP_OK will just be returned.
+ * @return ESP_OK on success
+ */
+esp_err_t rc522_pause();
+
+/**
+ * @brief Destroy RC522 and free all resources
+ */
+void rc522_destroy();
+
+#ifdef __cplusplus
+}
+#endif

device/main/AudioPlayer.cpp

@@ -1,24 +1,40 @@
 #include "AudioPlayer.hpp"
 
-#include <iostream>
 #include <esp_player_wrapper.h>
 #include "audio_setup.h"
-#include <string>
+#include <esp_log.h>
+
+static const char* TAG = "AudioPlayer";
 
 AudioPlayer::AudioPlayer() {
     playerHandle = setup_player(NULL, NULL);
-    esp_player_init(playerHandle);
+    esp_player_init((esp_audio_handle_t)playerHandle);
-
+    esp_audio_vol_set((esp_audio_handle_t)playerHandle, 50);
-    esp_audio_vol_set(playerHandle, 50);
 }
 
-void AudioPlayer::play(std::string uri, int position = 0) {
+bool AudioPlayer::isHttpUri(const std::string& uri) const {
+    return uri.rfind("http://", 0) == 0 || uri.rfind("https://", 0) == 0;
+}
+
+bool AudioPlayer::isLastUri(const std::string& uri) const {
+    return lastUri == uri;
+}
+
+void AudioPlayer::play(const std::string& uri) {
     if(isLastUri(uri)) {
         esp_player_music_resume();
-    } else {
+        return;
+    }
+
     esp_player_music_stop();
-        esp_player_sdcard_music_play(uri.c_str(), position);
+    lastUri = uri;
-        lastUri = std::string(uri);
+
+    if(isHttpUri(uri)) {
+        ESP_LOGI(TAG, "Streaming: %s", uri.c_str());
+        esp_player_http_music_play(uri.c_str(), 0);
+    } else {
+        ESP_LOGI(TAG, "Playing local: %s", uri.c_str());
+        esp_player_sdcard_music_play(uri.c_str(), 0);
     }
 }
 
@@ -26,14 +42,25 @@ void AudioPlayer::pause() {
     esp_player_music_pause();
 }
 
-bool AudioPlayer::isLastUri(std::string uri) {
+void AudioPlayer::stop() {
-    return lastUri == uri;
+    esp_player_music_stop();
+    lastUri.clear();
 }
 
-int AudioPlayer::getPosition() {
+int AudioPlayer::getVolume() {
-    int position;
+    int vol = 0;
+    esp_player_vol_get(&vol);
+    return vol;
+}
 
-    esp_player_pos_get(&position);
+void AudioPlayer::setVolume(int vol) {
+    if(vol < 0)   vol = 0;
+    if(vol > 100) vol = 100;
+    esp_audio_vol_set((esp_audio_handle_t)playerHandle, vol);
+}
 
-    return position;
+bool AudioPlayer::isPlaying() const {
+    esp_audio_state_t state;
+    if(esp_player_state_get(&state) != ESP_OK) return false;
+    return state.status == AUDIO_STATUS_RUNNING;
 }

device/main/AudioPlayer.hpp

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <string>
+#include <esp_player_wrapper.h>
 
 class AudioPlayer {
     void* playerHandle;
@@ -9,10 +10,20 @@ class AudioPlayer {
 public:
     AudioPlayer();
 
-		void play(std::string uri, int position);
+    /* Play URI. http:// / https:// URIs stream via HTTP; anything else plays from SD card.
+     * Re-placing the same URI resumes rather than restarting. */
+    void play(const std::string& uri);
+
     void pause();
-		int getPosition();
+    void stop();
+
+    int  getVolume();
+    void setVolume(int vol);
+
+    bool isPlaying() const;
+    const std::string& getCurrentUri() const { return lastUri; }
 
 private:
-		bool isLastUri(std::string uri);
+    bool isHttpUri(const std::string& uri) const;
+    bool isLastUri(const std::string& uri) const;
 };

device/main/BluetoothInterface.cpp

@@ -0,0 +1,25 @@
+#include "BluetoothInterface.hpp"
+#include <esp_log.h>
+
+static const char* TAG = "Bluetooth";
+
+BluetoothInterface::BluetoothInterface() {
+    ESP_LOGI(TAG, "BT interface created (stub — not yet enabled)");
+}
+
+bool BluetoothInterface::setEnabled(bool on) {
+    if(on == enabled) return enabled;
+
+    if(on) {
+        /* TODO: initialize Bluedroid stack, register A2DP sink callbacks,
+         *       switch audio pipeline output from I2S codec to BT stream.
+         * Requires CONFIG_BT_ENABLED=y and esp_bt / esp_a2dp components. */
+        ESP_LOGW(TAG, "BT enable requested — not yet implemented");
+        enabled = false; /* keep false until implemented */
+    } else {
+        ESP_LOGI(TAG, "BT disable requested");
+        enabled = false;
+    }
+
+    return enabled;
+}

device/main/BluetoothInterface.hpp

@@ -0,0 +1,19 @@
+#pragma once
+
+/* Stub for Bluetooth A2DP speaker mode.
+ * When enabled the ESP32 advertises itself as a BT audio sink so a phone
+ * can pair and route music through the Kidsbox speaker.
+ * Full implementation requires the esp_bt + esp_a2dp components to be
+ * added to the build and CONFIG_BT_ENABLED=y in sdkconfig. */
+class BluetoothInterface {
+public:
+    BluetoothInterface();
+
+    bool isEnabled() const { return enabled; }
+
+    /* Toggle BT speaker mode on/off.  Returns whether BT is now enabled. */
+    bool setEnabled(bool on);
+
+private:
+    bool enabled = false;
+};

device/main/CMakeLists.txt

@@ -1,2 +1,12 @@
-idf_component_register(SRCS "Networking.cpp" "main.cpp" "WebInterface.cpp" "RFIDInterface.cpp" "audio_setup.c" "AudioPlayer.cpp" "TagPlayerControl.cpp" "Tag.cpp"
+idf_component_register(SRCS
-    INCLUDE_DIRS ".")
+        "main.cpp"
+        "Networking.cpp"
+        "WebInterface.cpp"
+        "RFIDInterface.cpp"
+        "AudioPlayer.cpp"
+        "TagPlayerControl.cpp"
+        "CacheManager.cpp"
+        "BluetoothInterface.cpp"
+        "audio_setup.c"
+    INCLUDE_DIRS "."
+    REQUIRES esp_http_client esp_netif esp_wifi nvs_flash)

device/main/CacheManager.cpp

@@ -0,0 +1,205 @@
+#include "CacheManager.hpp"
+
+#include <esp_log.h>
+#include <esp_http_client.h>
+#include <freertos/FreeRTOS.h>
+#include <freertos/task.h>
+#include <sys/stat.h>
+#include <dirent.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <string>
+#include <functional>
+
+static const char* TAG = "CacheManager";
+
+struct DownloadArgs {
+    std::string url;
+    std::function<void(bool)> onComplete;
+};
+
+CacheManager::CacheManager() {
+    mkdir(CACHE_DIR, 0777);
+}
+
+/* djb2 hash of the URL, returned as 8-char hex string */
+std::string CacheManager::urlToKey(const std::string& url) const {
+    uint32_t hash = 5381;
+    for(char c : url) {
+        hash = ((hash << 5) + hash) ^ (uint8_t)c;
+    }
+    char buf[9];
+    snprintf(buf, sizeof(buf), "%08lx", (unsigned long)hash);
+    return std::string(buf);
+}
+
+std::string CacheManager::urlExtension(const std::string& url) const {
+    /* Strip query/fragment before looking for extension */
+    size_t qs = url.find('?');
+    std::string path = (qs != std::string::npos) ? url.substr(0, qs) : url;
+
+    size_t dot = path.rfind('.');
+    size_t slash = path.rfind('/');
+
+    if(dot != std::string::npos && (slash == std::string::npos || dot > slash)) {
+        std::string ext = path.substr(dot); /* includes the dot */
+        if(ext.size() <= 5) return ext;     /* ignore suspiciously long "extensions" */
+    }
+    return ".mp3"; /* sensible default */
+}
+
+std::string CacheManager::keyToPath(const std::string& key, const std::string& ext) const {
+    return std::string(CACHE_DIR) + "/" + key + ext;
+}
+
+/* Find any file in CACHE_DIR whose name starts with key */
+std::string CacheManager::findFileByKey(const std::string& key) const {
+    DIR* dir = opendir(CACHE_DIR);
+    if(!dir) return "";
+
+    struct dirent* entry;
+    while((entry = readdir(dir)) != NULL) {
+        std::string name(entry->d_name);
+        if(name.rfind(key, 0) == 0) {
+            closedir(dir);
+            return std::string(CACHE_DIR) + "/" + name;
+        }
+    }
+    closedir(dir);
+    return "";
+}
+
+std::string CacheManager::getCachedPath(const std::string& url) const {
+    if(url.empty()) return "";
+    std::string key  = urlToKey(url);
+    std::string path = findFileByKey(key);
+    if(!path.empty()) {
+        ESP_LOGI(TAG, "Cache hit: %s -> %s", url.c_str(), path.c_str());
+    }
+    return path;
+}
+
+void CacheManager::downloadTask(void* arg) {
+    auto* dl = static_cast<DownloadArgs*>(arg);
+
+    ESP_LOGI(TAG, "Downloading: %s", dl->url.c_str());
+
+    CacheManager cm;
+    std::string key  = cm.urlToKey(dl->url);
+    std::string ext  = cm.urlExtension(dl->url);
+    std::string path = cm.keyToPath(key, ext);
+
+    esp_http_client_config_t cfg = {};
+    cfg.url            = dl->url.c_str();
+    cfg.timeout_ms     = 30000;
+    cfg.buffer_size    = 4096;
+
+    esp_http_client_handle_t client = esp_http_client_init(&cfg);
+    esp_err_t err = esp_http_client_open(client, 0);
+
+    bool success = false;
+
+    if(err == ESP_OK) {
+        int content_len = esp_http_client_fetch_headers(client);
+        (void)content_len;
+
+        FILE* f = fopen(path.c_str(), "wb");
+        if(f) {
+            char buf[4096];
+            int read_len;
+            while((read_len = esp_http_client_read(client, buf, sizeof(buf))) > 0) {
+                fwrite(buf, 1, read_len, f);
+            }
+            fclose(f);
+            success = (read_len == 0); /* 0 = clean EOF */
+            if(!success) {
+                remove(path.c_str());
+                ESP_LOGE(TAG, "Download error, partial file deleted");
+            } else {
+                ESP_LOGI(TAG, "Cached to %s", path.c_str());
+            }
+        } else {
+            ESP_LOGE(TAG, "Cannot open cache file: %s (errno %d)", path.c_str(), errno);
+        }
+    } else {
+        ESP_LOGE(TAG, "HTTP open failed: %s", esp_err_to_name(err));
+    }
+
+    esp_http_client_cleanup(client);
+
+    if(dl->onComplete) dl->onComplete(success);
+
+    delete dl;
+    vTaskDelete(NULL);
+}
+
+void CacheManager::downloadAsync(const std::string& url, std::function<void(bool)> onComplete) {
+    if(url.empty()) return;
+
+    auto* args = new DownloadArgs{ url, onComplete };
+    xTaskCreate(downloadTask, "cache_dl", 8192, args, 3, NULL);
+}
+
+std::vector<CacheEntry> CacheManager::listEntries() const {
+    std::vector<CacheEntry> entries;
+
+    DIR* dir = opendir(CACHE_DIR);
+    if(!dir) return entries;
+
+    struct dirent* entry;
+    while((entry = readdir(dir)) != NULL) {
+        if(entry->d_name[0] == '.') continue;
+
+        std::string name(entry->d_name);
+        std::string full = std::string(CACHE_DIR) + "/" + name;
+
+        struct stat st;
+        size_t size = 0;
+        if(stat(full.c_str(), &st) == 0) size = st.st_size;
+
+        /* Key is filename without extension */
+        size_t dot = name.rfind('.');
+        std::string key = (dot != std::string::npos) ? name.substr(0, dot) : name;
+
+        entries.push_back({ key, /*url unknown*/"", full, size });
+    }
+    closedir(dir);
+    return entries;
+}
+
+bool CacheManager::deleteEntry(const std::string& key) {
+    std::string path = findFileByKey(key);
+    if(path.empty()) return false;
+    return remove(path.c_str()) == 0;
+}
+
+void CacheManager::deleteAll() {
+    DIR* dir = opendir(CACHE_DIR);
+    if(!dir) return;
+
+    struct dirent* entry;
+    while((entry = readdir(dir)) != NULL) {
+        if(entry->d_name[0] == '.') continue;
+        std::string full = std::string(CACHE_DIR) + "/" + entry->d_name;
+        remove(full.c_str());
+    }
+    closedir(dir);
+    ESP_LOGI(TAG, "Cache cleared");
+}
+
+size_t CacheManager::totalBytes() const {
+    size_t total = 0;
+    DIR* dir = opendir(CACHE_DIR);
+    if(!dir) return 0;
+
+    struct dirent* entry;
+    while((entry = readdir(dir)) != NULL) {
+        if(entry->d_name[0] == '.') continue;
+        std::string full = std::string(CACHE_DIR) + "/" + entry->d_name;
+        struct stat st;
+        if(stat(full.c_str(), &st) == 0) total += st.st_size;
+    }
+    closedir(dir);
+    return total;
+}

device/main/CacheManager.hpp

@@ -0,0 +1,46 @@
+#pragma once
+
+#include <string>
+#include <vector>
+#include <functional>
+
+struct CacheEntry {
+    std::string key;     /* hex hash of the URL */
+    std::string url;
+    std::string path;    /* full SD card path */
+    size_t      size;    /* file size in bytes, 0 if unknown */
+};
+
+class CacheManager {
+public:
+    CacheManager();
+
+    /* Returns the SD-card path for url if cached, or empty string if not. */
+    std::string getCachedPath(const std::string& url) const;
+
+    /* Enqueue an async FreeRTOS task that downloads url and caches it.
+     * onComplete is called (from the download task) when done or on error. */
+    void downloadAsync(const std::string& url, std::function<void(bool success)> onComplete = nullptr);
+
+    /* List all cached entries. */
+    std::vector<CacheEntry> listEntries() const;
+
+    /* Delete a single cache entry by key (hex hash). Returns true if deleted. */
+    bool deleteEntry(const std::string& key);
+
+    /* Delete the entire cache directory. */
+    void deleteAll();
+
+    /* Total bytes used by cache. */
+    size_t totalBytes() const;
+
+private:
+    static constexpr const char* CACHE_DIR = "/sdcard/cache";
+
+    std::string urlToKey(const std::string& url) const;
+    std::string urlExtension(const std::string& url) const;
+    std::string keyToPath(const std::string& key, const std::string& ext) const;
+    std::string findFileByKey(const std::string& key) const;
+
+    static void downloadTask(void* arg);
+};

device/main/Networking.cpp

@@ -1,15 +1,89 @@
 #include "Networking.hpp"
 
-#include "WiFi.h"
+#include <esp_log.h>
+#include <esp_wifi.h>
+#include <esp_event.h>
+#include <esp_netif.h>
+#include <nvs_flash.h>
+#include <freertos/FreeRTOS.h>
+#include <freertos/event_groups.h>
+#include <string.h>
+
+static const char* TAG = "Networking";
+
+static EventGroupHandle_t s_wifi_event_group;
+static const int CONNECTED_BIT = BIT0;
+static int s_retries = 0;
+
+static void wifi_event_handler(void*, esp_event_base_t base, int32_t id, void* data) {
+    if(base == WIFI_EVENT && id == WIFI_EVENT_STA_START) {
+        esp_wifi_connect();
+    } else if(base == WIFI_EVENT && id == WIFI_EVENT_STA_DISCONNECTED) {
+        if(s_retries < CONFIG_ESP_MAXIMUM_RETRY) {
+            esp_wifi_connect();
+            s_retries++;
+            ESP_LOGI(TAG, "Reconnect attempt %d/%d", s_retries, CONFIG_ESP_MAXIMUM_RETRY);
+        } else {
+            ESP_LOGW(TAG, "Could not connect after %d attempts", CONFIG_ESP_MAXIMUM_RETRY);
+        }
+    } else if(base == IP_EVENT && id == IP_EVENT_STA_GOT_IP) {
+        ip_event_got_ip_t* ev = (ip_event_got_ip_t*)data;
+        ESP_LOGI(TAG, "Connected. IP: " IPSTR, IP2STR(&ev->ip_info.ip));
+        s_retries = 0;
+        xEventGroupSetBits(s_wifi_event_group, CONNECTED_BIT);
+    }
+}
 
 void Networking::connectWifi() {
-	WiFi.begin(CONFIG_ESP_WIFI_SSID, CONFIG_ESP_WIFI_PASSWORD);
+    /* NVS is required by the WiFi driver */
-
+    esp_err_t err = nvs_flash_init();
-    while (WiFi.status() != WL_CONNECTED) {
+    if(err == ESP_ERR_NVS_NO_FREE_PAGES || err == ESP_ERR_NVS_NEW_VERSION_FOUND) {
-        delay(1000);
+        nvs_flash_erase();
-        Serial.println("Waiting for connection...");
+        nvs_flash_init();
     }
 
-    Serial.println("Connected.");
+    err = esp_netif_init();
-    Serial.println(WiFi.localIP());
+    if(err != ESP_OK && err != ESP_ERR_INVALID_STATE) {
+        ESP_LOGE(TAG, "esp_netif_init: %s", esp_err_to_name(err));
+    }
+
+    err = esp_event_loop_create_default();
+    if(err != ESP_OK && err != ESP_ERR_INVALID_STATE) {
+        ESP_LOGE(TAG, "esp_event_loop_create_default: %s", esp_err_to_name(err));
+    }
+
+    esp_netif_create_default_wifi_sta();
+
+    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
+    esp_wifi_init(&cfg);
+
+    s_wifi_event_group = xEventGroupCreate();
+    s_retries = 0;
+
+    esp_event_handler_instance_t inst_any, inst_ip;
+    esp_event_handler_instance_register(WIFI_EVENT, ESP_EVENT_ANY_ID,    wifi_event_handler, NULL, &inst_any);
+    esp_event_handler_instance_register(IP_EVENT,   IP_EVENT_STA_GOT_IP, wifi_event_handler, NULL, &inst_ip);
+
+    wifi_config_t wifi_cfg = {};
+    strncpy((char*)wifi_cfg.sta.ssid,     CONFIG_ESP_WIFI_SSID,     sizeof(wifi_cfg.sta.ssid)     - 1);
+    strncpy((char*)wifi_cfg.sta.password, CONFIG_ESP_WIFI_PASSWORD, sizeof(wifi_cfg.sta.password) - 1);
+    wifi_cfg.sta.threshold.authmode = WIFI_AUTH_WPA2_PSK;
+
+    esp_wifi_set_mode(WIFI_MODE_STA);
+    esp_wifi_set_config(WIFI_IF_STA, &wifi_cfg);
+    esp_wifi_start();
+
+    EventBits_t bits = xEventGroupWaitBits(s_wifi_event_group, CONNECTED_BIT,
+                                           pdFALSE, pdFALSE, pdMS_TO_TICKS(30000));
+    if(!(bits & CONNECTED_BIT)) {
+        ESP_LOGW(TAG, "WiFi not connected after 30 s — continuing without network");
+    }
+
+    vEventGroupDelete(s_wifi_event_group);
+    s_wifi_event_group = NULL;
+}
+
+bool Networking::isConnected() const {
+    wifi_ap_record_t ap;
+    return esp_wifi_sta_get_ap_info(&ap) == ESP_OK;
 }

device/main/Networking.hpp

@@ -1,9 +1,10 @@
-#ifndef _NETWORKING_HPP
+#pragma once
-#define _NETWORKING_HPP
 
 class Networking {
 public:
+    /* Connects to the WiFi configured in Kconfig (CONFIG_ESP_WIFI_SSID / _PASSWORD).
+     * Blocks up to 30 s, then returns regardless of connection state. */
     void connectWifi();
-};
 
-#endif
+    bool isConnected() const;
+};

device/main/RFIDInterface.cpp

@@ -10,35 +10,58 @@
 
 static const char* TAG = "rfid";
 
-static char* lastTagId = (char*)malloc(26 * sizeof(char));
+static char lastTagId[26];
-static std::function<void(char*)> callback;
+static std::function<void(char*)>                       legacyCallback;
+static std::function<void(const char*, const char*)>    ndefCallback;
 
 static char* getLastTagId() {
     return lastTagId;
 }
 
+static void onUidCallback(uint8_t* sn) {
+    if(sn == NULL) {
+        ESP_LOGI(TAG, "Tag removed");
+        lastTagId[0] = '\0';
+        if(legacyCallback) legacyCallback(NULL);
+    } else {
+        snprintf(lastTagId, sizeof(lastTagId),
+                 "%#x_%#x_%#x_%#x_%#x", sn[0], sn[1], sn[2], sn[3], sn[4]);
+        ESP_LOGI(TAG, "Tag UID: %s", lastTagId);
+        if(legacyCallback) legacyCallback(lastTagId);
+    }
+}
+
+static void onNdefCallback(uint8_t* sn, const char* url) {
+    if(!ndefCallback) return;
+
+    if(sn == NULL) {
+        ndefCallback(NULL, NULL);
+        return;
+    }
+
+    /* Format UID same way as above */
+    char uid[26];
+    snprintf(uid, sizeof(uid),
+             "%#x_%#x_%#x_%#x_%#x", sn[0], sn[1], sn[2], sn[3], sn[4]);
+
+    if(url) {
+        ESP_LOGI(TAG, "NDEF URL on %s: %s", uid, url);
+    } else {
+        ESP_LOGI(TAG, "No NDEF on %s", uid);
+    }
+
+    ndefCallback(uid, url);
+}
+
 RFIDInterface::RFIDInterface() {
     startConfig = (rc522_start_args_t){
         .miso_io     = 12,
         .mosi_io     = 13,
         .sck_io      = 23,
         .sda_io      = 18,
-        .callback    = [](uint8_t* sn) {
+        .spi_host_id = (spi_host_device_t)0,
-                if (sn == NULL) {
+        .callback    = onUidCallback,
-                    ESP_LOGI(TAG, "Tag removed");
+        .ndef_callback = onNdefCallback,
-
-                    if (callback) {
-                        callback(NULL);
-                    }
-                } else { // serial number is always 5 bytes long
-                    sprintf(lastTagId, "%#x_%#x_%#x_%#x_%#x", sn[0], sn[1], sn[2], sn[3], sn[4]);
-                    ESP_LOGI(TAG, "tag id: %s", lastTagId);
-
-                    if (callback) {
-                        callback(getLastTagId());
-                    }
-                }
-            }
     };
 }
 
@@ -55,10 +78,13 @@ void RFIDInterface::registerWebResources(WebInterface* interface) {
             return ESP_OK;
         }
     };
-
     interface->registerResource(&config);
 }
 
+void RFIDInterface::registerTagCallback(std::function<void(const char*, const char*)> cb) {
+    ndefCallback = cb;
+}
+
 void RFIDInterface::registerTagChangeCallback(std::function<void(char*)> cb) {
-    callback = cb;
+    legacyCallback = cb;
 }

device/main/RFIDInterface.hpp

@@ -12,7 +12,15 @@ class RFIDInterface {
     RFIDInterface();
     void start();
     void registerWebResources(WebInterface* interface);
-		void registerTagChangeCallback(std::function<void(char*)>);
+
+    /* Callback receives (uid_string, url_or_null):
+     *   uid == NULL  → tag removed
+     *   url == NULL  → tag placed but no NDEF URI found (use uid for local lookup)
+     *   url != NULL  → tag placed with NDEF URI */
+    void registerTagCallback(std::function<void(const char* uid, const char* url)> cb);
+
+    /* Legacy: only fires with UID string (NULL on removal). Kept for compatibility. */
+    void registerTagChangeCallback(std::function<void(char*)> cb);
 };
 
 #endif

device/main/Tag.cpp

@@ -1,199 +0,0 @@
-#include "Tag.hpp"
-
-#include <iostream>
-#include <fstream>
-#include <string>
-
-#include <cJSON.h>
-
-#define BASE_PATH "/sdcard/internal/";
-
-/**
- * {
- * 		tagId : "xa5_x1f_x13_xaa_x00",
- * 		playlist : [
- * 			"file://sdcard/music_intro.mp3",
- * 			"file://sdcard/audiobook_chapter1.mp3",
- * 			"file://sdcard/audiobook_chapter2.mp3"
- * 		],
- * 		currentIndex : 0,
- * 		currentPosition : 1234 // the position as returned by the player. can be frames, can be ms or anything
- * }
- */
-
-Tag::Tag() {}
-
-Tag::Tag(char* tagId): Tag(std::string(tagId)) {
-
-}
-
-Tag::Tag(std::string tagId): tagId(tagId) {
-	this->playlist = std::vector<std::string>();
-}
-
-void Tag::setCurrentPosition(uint32_t fileIndex, uint32_t position) {
-	this->currentFileIndex = fileIndex;
-	this->currentFilePosition = position;
-}
-
-int Tag::getCurrentPosition() {
-	return this->currentFilePosition;
-}
-
-std::string Tag::getNextLink() {
-	return this->playlist.at(this->currentFileIndex);
-}
-
-bool Tag::isLinked() {
-	return ! this->playlist.empty();
-}
-
-void Tag::read() {
-	std::string contents;
-
-	try {
-		contents = readFileContents();
-	} catch (std::invalid_argument& e){
-		std::cout << "Execption while reading tag-file: " << e.what() << "\n";
-
-		write();
-		return;
-	}
-
-	cJSON* data = cJSON_Parse(contents.c_str());
-
-	char* tagId = cJSON_GetObjectItem(data, "tagId")->valuestring;
-
-	int currentIndex = cJSON_GetObjectItem(data, "currentIndex")->valueint;
-
-	if (currentIndex < 0) {
-		std::cout << "Bad file index, must be >= 0, was: " << currentIndex << "\n";
-		currentIndex = 0;
-	}
-
-	this->currentFileIndex = currentIndex;
-
-	int currentFilePosition = cJSON_GetObjectItem(data, "currentPosition")->valueint;
-
-	if (currentFilePosition < 0) {
-		std::cout << "Bad file position, must be >= 0, was: " << currentFilePosition << "\n";
-		currentFilePosition = 0;
-	}
-
-	this->currentFilePosition = 0;
-
-	cJSON* playlist = cJSON_GetObjectItem(data, "playlist");
-
-	if (playlist) {
-		int playlistLength = cJSON_GetArraySize(playlist);
-
-		for (int i = 0; i < playlistLength; i++) {
-			cJSON* item = cJSON_GetArrayItem(playlist, i);
-
-			// each item is just an URL
-			this->playlist.push_back(std::string(item->valuestring));
-		}
-	}
-
-	cJSON_Delete(data);
-}
-
-void Tag::write() {
-	std::string contents = createFileContents();
-
-	std::cout << contents << std::endl;
-
-	std::string filePath = getFilePath();
-
-	std::ofstream file(filePath);
-
-	if (! file.is_open()) {
-		std::cout << "Error opening file for tag " << tagId << " before writing";
-
-		char* errorName;
-
-		switch (errno) {
-			case EACCES:
-				errorName = "EACCESS";
-				break;
-			case ENOENT:
-				errorName = "ENOENT";
-				break;
-			default:
-				errorName = "not parsed";
-		}
-
-		std::cout << errorName << "\n";
-	}
-
-	file << contents << std::endl;
-	
-	file.close();
-}
-
-std::string Tag::createFileContents() {
-	cJSON* root = cJSON_CreateObject();
-	cJSON* playlist;
-
-	cJSON_AddStringToObject(root, "tagId", this->tagId.c_str());
-	cJSON_AddNumberToObject(root, "currentIndex", this->currentFileIndex);
-	cJSON_AddNumberToObject(root, "currentPosition", this->currentFilePosition);
-	playlist = cJSON_AddArrayToObject(root, "playlist");
-	
-	for (auto& link: this->playlist) {
-		cJSON_AddItemToArray(playlist, cJSON_CreateString(link.c_str()));
-	}
-
-	char* json = cJSON_Print(root);
-	cJSON_Delete(root); // playlist is also free'd
-
-	std::cout << json << std::endl;
-
-	return std::string(json);
-}
-
-std::string Tag::readFileContents() {
-	std::string filePath = getFilePath();
-
-	std::fstream file(filePath);
-
-	if (! file) {
-		std::cout << "Error opening file for tag " << tagId;
-
-		char* errorName;
-
-		switch (errno) {
-			case EACCES:
-				errorName = "EACCESS";
-				break;
-			case ENOENT:
-				errorName = "ENOENT";
-				break;
-			default:
-				errorName = "not parsed";
-		}
-
-		std::cout << errorName << "\n";
-
-		file.close();
-		throw std::invalid_argument(errorName);
-	}
-
-	std::string line;
-	std::string content;
-
-	while(getline(file, line)) {
-		content.append(line);
-	}
-
-	file.close();
-
-	return content;
-}
-
-std::string Tag::getFilePath() {
-	std::string filePath = BASE_PATH;
-	filePath.append(tagId);
-
-	return filePath;
-}

device/main/Tag.hpp

@@ -1,28 +0,0 @@
-#pragma once
-
-#include <string>
-#include <vector>
-
-class Tag {
-	private:
-		std::string tagId{""};
-		std::vector<std::string> playlist;
-		uint32_t currentFileIndex{0};
-		uint32_t currentFilePosition{0};
-
-	public:
-		Tag();
-		Tag(std::string tagId);
-		Tag(char* tagId);
-		void read();
-		void write();
-		bool isLinked();
-		std::string getNextLink();
-		void setCurrentPosition(uint32_t fileIndex, uint32_t position);
-		int getCurrentPosition();
-
-	private:
-		std::string createFileContents();
-		std::string readFileContents();
-		std::string getFilePath();
-};

device/main/TagPlayerControl.cpp

@@ -1,41 +1,71 @@
 #include "TagPlayerControl.hpp"
 
-#include "AudioPlayer.hpp"
+#include <esp_log.h>
-#include "Tag.hpp"
-
-#include <iostream>
 #include <fstream>
 #include <string>
-#include <memory>
-
-#include <esp_log.h>
 
 static const char* TAG = "TagPlayerControl";
 
-TagPlayerControl::TagPlayerControl(std::shared_ptr<AudioPlayer> player)
+TagPlayerControl::TagPlayerControl(std::shared_ptr<AudioPlayer>  player,
-	: audioPlayer(player) {
+                                   std::shared_ptr<CacheManager> cache)
-}
+    : audioPlayer(player), cacheManager(cache) {}
 
-void TagPlayerControl::onTagChanged(char* tagId) {
+void TagPlayerControl::onTagChanged(const char* uid, const char* url) {
-	if (tagId == NULL) {
+    if(uid == NULL) {
-		// tag has been removed. stop playback
+        ESP_LOGI(TAG, "Tag removed — pausing");
         audioPlayer->pause();
-		storePosition();
+        lastUid.clear();
+        return;
+    }
+
+    lastUid = std::string(uid);
+
+    if(url != NULL && url[0] != '\0') {
+        ESP_LOGI(TAG, "Tag %s -> URL: %s", uid, url);
+        playUrl(std::string(url));
     } else {
-		playTag(tagId);
+        ESP_LOGI(TAG, "Tag %s -> no NDEF, trying local mapping", uid);
+        playLocalTag(std::string(uid));
     }
 }
 
-void TagPlayerControl::playTag(char* tagId) {
+void TagPlayerControl::playUrl(const std::string& url) {
-	currentTag = Tag(tagId);
+    /* Check cache first; if found play local file to avoid re-downloading */
-	currentTag.read();
+    std::string cached = cacheManager->getCachedPath(url);
-
+    if(!cached.empty()) {
-	if (currentTag.isLinked()) {
+        audioPlayer->play(cached);
-		audioPlayer->play(currentTag.getNextLink(), currentTag.getCurrentPosition());
+        return;
-	}
     }
 
-void TagPlayerControl::storePosition() {
+    /* Stream via HTTP and cache in background for future plays */
-	currentTag.setCurrentPosition(0, audioPlayer->getPosition());
+    audioPlayer->play(url);
-	currentTag.write();
+
+    cacheManager->downloadAsync(url, [url](bool success) {
+        if(success) {
+            ESP_LOGI("TagPlayerControl", "Cached for next play: %s", url.c_str());
+        }
+    });
+}
+
+void TagPlayerControl::playLocalTag(const std::string& uid) {
+    std::string mappingPath = std::string("/sdcard/internal/") + uid;
+    std::fstream file(mappingPath);
+
+    if(!file) {
+        ESP_LOGW(TAG, "No mapping file for tag %s at %s", uid.c_str(), mappingPath.c_str());
+        return;
+    }
+
+    std::string line, content;
+    while(getline(file, line)) {
+        content.append(line);
+    }
+    file.close();
+
+    if(content.empty()) {
+        ESP_LOGW(TAG, "Empty mapping file for tag %s", uid.c_str());
+        return;
+    }
+
+    audioPlayer->play(content);
 }

device/main/TagPlayerControl.hpp

@@ -1,19 +1,25 @@
 #pragma once
 
 #include <memory>
+#include <string>
 #include "AudioPlayer.hpp"
-#include "Tag.hpp"
+#include "CacheManager.hpp"
 
 class TagPlayerControl {
     std::shared_ptr<AudioPlayer>  audioPlayer;
-	Tag currentTag;
+    std::shared_ptr<CacheManager> cacheManager;
+
+    std::string lastUid;
 
 public:
-		TagPlayerControl(std::shared_ptr<AudioPlayer> player);
+    TagPlayerControl(std::shared_ptr<AudioPlayer> player,
+                     std::shared_ptr<CacheManager> cache);
 
-		void onTagChanged(char* tagId);
+    /* Called by RFIDInterface. uid == NULL means tag removed.
+     * url is the NDEF URI from the tag, or NULL if no NDEF record was found. */
+    void onTagChanged(const char* uid, const char* url);
 
 private:
-		void playTag(char* tagId);
+    void playUrl(const std::string& url);
-		void storePosition();
+    void playLocalTag(const std::string& uid);
 };

device/main/WebInterface.cpp

@@ -1,79 +1,69 @@
 #include "WebInterface.hpp"
+#include "AudioPlayer.hpp"
+#include "CacheManager.hpp"
 
 #include <esp_http_server.h>
 #include <esp_log.h>
-#include "esp_vfs.h"
+#include <esp_vfs.h>
 #include <board.h>
-#include "periph_sdcard.h"
+#include <periph_sdcard.h>
-#include <errno.h>
+#include <esp_system.h>
-
+#include <esp_netif.h>
 #include <fcntl.h>
-#include "esp_system.h"
+#include <errno.h>
+#include <string.h>
+#include <dirent.h>
+#include <sys/stat.h>
+#include <string>
+#include <sstream>
 
 static const char* TAG = "WebInterface";
 
 #define FILE_PATH_MAX   (ESP_VFS_PATH_MAX + 128)
 #define SCRATCH_BUFSIZE (10240)
+#define CHECK_FILE_EXTENSION(f, ext) (strcasecmp(&(f)[strlen(f) - strlen(ext)], (ext)) == 0)
 
-#define CHECK_FILE_EXTENSION(filename, ext) (strcasecmp(&filename[strlen(filename) - strlen(ext)], ext) == 0)
+typedef struct {
-
-typedef struct rest_server_context {
     char base_path[ESP_VFS_PATH_MAX + 1];
     char scratch[SCRATCH_BUFSIZE];
 } rest_server_context_t;
 
-WebInterface::WebInterface() {
+/* ── helpers ──────────────────────────────────────────────────────────── */
 
-}
+static esp_err_t set_content_type(httpd_req_t* req, const char* filepath) {
-
-void WebInterface::start() {
-	initSD();
-	server = start_webserver();
-}
-
-void WebInterface::finishResourceRegistrations() {
-	registerFileServer();
-}
-
-void WebInterface::initSD() {
-	esp_periph_config_t periph_cfg = DEFAULT_ESP_PERIPH_SET_CONFIG();
-	esp_periph_set_handle_t set = esp_periph_set_init(&periph_cfg);
-
-	// Initialize SD Card peripheral
-	if (audio_board_sdcard_init(set, SD_MODE_1_LINE) == ESP_FAIL) {
-		ESP_LOGE(TAG, "Sdcard not mounted");
-	} else {
-		ESP_LOGI(TAG, "SDCard mounted");
-	}
-}
-
-/* Set HTTP response content type according to file extension */
-esp_err_t set_content_type_from_file(httpd_req_t *req, const char *filepath)
-{
     const char* type = "text/plain";
-	if (CHECK_FILE_EXTENSION(filepath, ".html")) {
+    if(CHECK_FILE_EXTENSION(filepath, ".html")) type = "text/html";
-		type = "text/html";
+    else if(CHECK_FILE_EXTENSION(filepath, ".js"))  type = "application/javascript";
-	} else if (CHECK_FILE_EXTENSION(filepath, ".js")) {
+    else if(CHECK_FILE_EXTENSION(filepath, ".css")) type = "text/css";
-		type = "application/javascript";
+    else if(CHECK_FILE_EXTENSION(filepath, ".png")) type = "image/png";
-	} else if (CHECK_FILE_EXTENSION(filepath, ".css")) {
+    else if(CHECK_FILE_EXTENSION(filepath, ".ico")) type = "image/x-icon";
-		type = "text/css";
+    else if(CHECK_FILE_EXTENSION(filepath, ".svg")) type = "image/svg+xml";
-	} else if (CHECK_FILE_EXTENSION(filepath, ".png")) {
+    else if(CHECK_FILE_EXTENSION(filepath, ".json"))type = "application/json";
-		type = "image/png";
-	} else if (CHECK_FILE_EXTENSION(filepath, ".ico")) {
-		type = "image/x-icon";
-	} else if (CHECK_FILE_EXTENSION(filepath, ".svg")) {
-		type = "text/xml";
-	}
     return httpd_resp_set_type(req, type);
 }
 
-/* Send HTTP response with the contents of the requested file */
+static void send_json(httpd_req_t* req, const std::string& json) {
-esp_err_t rest_common_get_handler(httpd_req_t *req)
+    httpd_resp_set_type(req, "application/json");
-{
+    httpd_resp_set_hdr(req, "Access-Control-Allow-Origin", "*");
-	char filepath[FILE_PATH_MAX];
+    httpd_resp_sendstr(req, json.c_str());
+}
 
-	rest_server_context_t *rest_context = (rest_server_context_t *)req->user_ctx;
+static void send_json_ok(httpd_req_t* req) {
-	strlcpy(filepath, rest_context->base_path, sizeof(filepath));
+    send_json(req, "{\"ok\":true}");
+}
+
+static void send_json_error(httpd_req_t* req, const char* msg) {
+    std::string body = std::string("{\"error\":\"") + msg + "\"}";
+    httpd_resp_set_status(req, "400 Bad Request");
+    send_json(req, body);
+}
+
+/* ── static file handler ──────────────────────────────────────────────── */
+
+static esp_err_t rest_common_get_handler(httpd_req_t* req) {
+    char filepath[FILE_PATH_MAX];
+    rest_server_context_t* ctx = (rest_server_context_t*)req->user_ctx;
+    strlcpy(filepath, ctx->base_path, sizeof(filepath));
 
     if(req->uri[strlen(req->uri) - 1] == '/') {
         strlcat(filepath, "/index.html", sizeof(filepath));
@@ -83,100 +73,218 @@ esp_err_t rest_common_get_handler(httpd_req_t *req)
 
     int fd = open(filepath, O_RDONLY);
     if(fd == -1) {
-		ESP_LOGE(TAG, "Failed to open file : %s. Errno: %d", filepath, errno);
+        ESP_LOGE(TAG, "Failed to open %s (errno %d)", filepath, errno);
-		/* Respond with 500 Internal Server Error */
+        httpd_resp_send_err(req, HTTPD_404_NOT_FOUND, "File not found");
-
-		char responseError[255];
-		char* error_name;
-
-		switch (errno)
-		{
-			case EACCES:
-				error_name = "EACCESS";
-				break;
-			case ENOENT:
-				error_name = "ENOENT";
-				break;
-			default:
-				error_name = "not parsed";
-		}
-
-		sprintf(responseError, "Failed to read existing file. %d => %s", errno, error_name);
-
-		httpd_resp_send_err(req, HTTPD_500_INTERNAL_SERVER_ERROR, responseError);
         return ESP_FAIL;
     }
 
-	set_content_type_from_file(req, filepath);
+    set_content_type(req, filepath);
 
-	char *chunk = rest_context->scratch;
+    char* chunk = ctx->scratch;
-	ssize_t read_bytes;
+    ssize_t n;
-	do {
+    while((n = read(fd, chunk, SCRATCH_BUFSIZE)) > 0) {
-		/* Read file in chunks into the scratch buffer */
+        if(httpd_resp_send_chunk(req, chunk, n) != ESP_OK) {
-		read_bytes = read(fd, chunk, SCRATCH_BUFSIZE);
-		if (read_bytes == -1) {
-			ESP_LOGE(TAG, "Failed to read file : %s", filepath);
-		} else if (read_bytes > 0) {
-			/* Send the buffer contents as HTTP response chunk */
-			if (httpd_resp_send_chunk(req, chunk, read_bytes) != ESP_OK) {
             close(fd);
-				ESP_LOGE(TAG, "File sending failed!");
-				/* Abort sending file */
             httpd_resp_sendstr_chunk(req, NULL);
-				/* Respond with 500 Internal Server Error */
+            httpd_resp_send_err(req, HTTPD_500_INTERNAL_SERVER_ERROR, "Send error");
-				httpd_resp_send_err(req, HTTPD_500_INTERNAL_SERVER_ERROR, "Failed to send file");
             return ESP_FAIL;
         }
     }
-	} while (read_bytes > 0);
-	/* Close file after sending complete */
     close(fd);
-	ESP_LOGI(TAG, "File sending complete");
-	/* Respond with an empty chunk to signal HTTP response completion */
     httpd_resp_send_chunk(req, NULL, 0);
     return ESP_OK;
 }
 
+/* ── API handlers (use shared_ptrs captured from WebInterface) ──────── */
 
-httpd_handle_t WebInterface::start_webserver(void) {
+/* GET /api/info — device info JSON */
-	httpd_handle_t server = NULL;
+static AudioPlayer*  g_audio   = nullptr;
+static CacheManager* g_cache   = nullptr;
+
+static esp_err_t api_info_handler(httpd_req_t* req) {
+    /* Get device IP */
+    esp_netif_ip_info_t ip_info = {};
+    esp_netif_t* netif = esp_netif_get_handle_from_ifkey("WIFI_STA_DEF");
+    if(netif) esp_netif_get_ip_info(netif, &ip_info);
+
+    char ip_str[16] = "0.0.0.0";
+    snprintf(ip_str, sizeof(ip_str), IPSTR, IP2STR(&ip_info.ip));
+
+    int vol = g_audio ? g_audio->getVolume() : 0;
+    bool playing = g_audio ? g_audio->isPlaying() : false;
+    size_t cache_bytes = g_cache ? g_cache->totalBytes() : 0;
+
+    /* Free heap */
+    uint32_t free_heap = esp_get_free_heap_size();
+
+    std::ostringstream json;
+    json << "{"
+         << "\"ip\":\"" << ip_str << "\","
+         << "\"volume\":" << vol << ","
+         << "\"playing\":" << (playing ? "true" : "false") << ","
+         << "\"cacheBytes\":" << cache_bytes << ","
+         << "\"freeHeap\":" << free_heap
+         << "}";
+
+    send_json(req, json.str());
+    return ESP_OK;
+}
+
+/* GET /api/storage — list cached files as JSON array */
+static esp_err_t api_storage_get_handler(httpd_req_t* req) {
+    if(!g_cache) { send_json(req, "[]"); return ESP_OK; }
+
+    auto entries = g_cache->listEntries();
+    std::ostringstream json;
+    json << "[";
+    for(size_t i = 0; i < entries.size(); i++) {
+        if(i > 0) json << ",";
+        json << "{\"key\":\"" << entries[i].key << "\","
+             << "\"size\":" << entries[i].size << "}";
+    }
+    json << "]";
+    send_json(req, json.str());
+    return ESP_OK;
+}
+
+/* DELETE /api/storage?key=<hex> — delete one entry, or all if no key */
+static esp_err_t api_storage_delete_handler(httpd_req_t* req) {
+    if(!g_cache) { send_json_ok(req); return ESP_OK; }
+
+    char key_buf[32] = {};
+    if(httpd_req_get_url_query_str(req, key_buf, sizeof(key_buf)) == ESP_OK) {
+        char key[32] = {};
+        if(httpd_query_key_value(key_buf, "key", key, sizeof(key)) == ESP_OK && key[0]) {
+            bool ok = g_cache->deleteEntry(std::string(key));
+            if(!ok) { send_json_error(req, "key not found"); return ESP_OK; }
+        } else {
+            g_cache->deleteAll();
+        }
+    } else {
+        g_cache->deleteAll();
+    }
+    send_json_ok(req);
+    return ESP_OK;
+}
+
+/* POST /api/playback body: action=play|pause|stop|volume&value=<0-100> */
+static esp_err_t api_playback_handler(httpd_req_t* req) {
+    char buf[128] = {};
+    int len = httpd_req_recv(req, buf, sizeof(buf) - 1);
+    if(len <= 0) { send_json_error(req, "empty body"); return ESP_OK; }
+    buf[len] = '\0';
+
+    char action[16] = {};
+    httpd_query_key_value(buf, "action", action, sizeof(action));
+
+    if(!g_audio) { send_json_error(req, "audio not ready"); return ESP_OK; }
+
+    if(strcmp(action, "pause") == 0) {
+        g_audio->pause();
+    } else if(strcmp(action, "stop") == 0) {
+        g_audio->stop();
+    } else if(strcmp(action, "volume") == 0) {
+        char val_str[8] = {};
+        httpd_query_key_value(buf, "value", val_str, sizeof(val_str));
+        int vol = atoi(val_str);
+        g_audio->setVolume(vol);
+    } else {
+        send_json_error(req, "unknown action");
+        return ESP_OK;
+    }
+
+    send_json_ok(req);
+    return ESP_OK;
+}
+
+/* GET /api/bluetooth — returns BT status (stub) */
+static esp_err_t api_bluetooth_get_handler(httpd_req_t* req) {
+    send_json(req, "{\"enabled\":false,\"note\":\"bluetooth not yet implemented\"}");
+    return ESP_OK;
+}
+
+/* POST /api/bluetooth body: enabled=true|false (stub) */
+static esp_err_t api_bluetooth_post_handler(httpd_req_t* req) {
+    send_json(req, "{\"ok\":false,\"note\":\"bluetooth not yet implemented\"}");
+    return ESP_OK;
+}
+
+/* ── WebInterface ────────────────────────────────────────────────────── */
+
+WebInterface::WebInterface() {}
+
+void WebInterface::start() {
+    initSD();
+    server = start_webserver();
+}
+
+void WebInterface::finishResourceRegistrations() {
+    registerApiHandlers();
+    registerFileServer();
+}
+
+void WebInterface::initSD() {
+    esp_periph_config_t periph_cfg = DEFAULT_ESP_PERIPH_SET_CONFIG();
+    esp_periph_set_handle_t set = esp_periph_set_init(&periph_cfg);
+
+    if(audio_board_sdcard_init(set, SD_MODE_1_LINE) == ESP_FAIL) {
+        ESP_LOGE(TAG, "SDCard not mounted");
+    } else {
+        ESP_LOGI(TAG, "SDCard mounted");
+    }
+}
+
+httpd_handle_t WebInterface::start_webserver() {
     httpd_config_t config = HTTPD_DEFAULT_CONFIG();
     config.lru_purge_enable = true;
     config.uri_match_fn     = httpd_uri_match_wildcard;
+    config.max_uri_handlers = 16;
 
-	// Start the httpd server
+    httpd_handle_t srv = NULL;
-	ESP_LOGI(TAG, "Starting server on port: '%d'", config.server_port);
+    ESP_LOGI(TAG, "Starting server on port %d", config.server_port);
-	if (httpd_start(&server, &config) == ESP_OK) {
+    if(httpd_start(&srv, &config) == ESP_OK) return srv;
-		return server;
-	}
 
-
+    ESP_LOGE(TAG, "Failed to start server");
-	ESP_LOGI(TAG, "Error starting server!");
     return NULL;
 }
 
 void WebInterface::registerResource(httpd_uri_t* config) {
-	ESP_LOGI(TAG, "Register resource on path %s", config->uri);
+    if(!server) return;
+    ESP_LOGI(TAG, "Register %s", config->uri);
     httpd_register_uri_handler(server, config);
 }
 
-void WebInterface::registerFileServer() {
+void WebInterface::registerApiHandlers() {
-	rest_server_context_t *fileContext = (rest_server_context_t*)calloc(1, sizeof(rest_server_context_t));
+    /* Expose singletons to the static C handlers */
+    g_audio = audioPlayer.get();
+    g_cache = cacheManager.get();
 
-	if (! fileContext) {
+    httpd_uri_t info  = { "/api/info",       HTTP_GET,    api_info_handler,             nullptr };
-		ESP_LOGE(TAG, "No memory for rest context");
+    httpd_uri_t stg_g = { "/api/storage",    HTTP_GET,    api_storage_get_handler,      nullptr };
-		return;
+    httpd_uri_t stg_d = { "/api/storage",    HTTP_DELETE, api_storage_delete_handler,   nullptr };
+    httpd_uri_t pb    = { "/api/playback",   HTTP_POST,   api_playback_handler,         nullptr };
+    httpd_uri_t bt_g  = { "/api/bluetooth",  HTTP_GET,    api_bluetooth_get_handler,    nullptr };
+    httpd_uri_t bt_p  = { "/api/bluetooth",  HTTP_POST,   api_bluetooth_post_handler,   nullptr };
+
+    registerResource(&info);
+    registerResource(&stg_g);
+    registerResource(&stg_d);
+    registerResource(&pb);
+    registerResource(&bt_g);
+    registerResource(&bt_p);
 }
 
-	strlcpy(fileContext->base_path, "/sdcard/www", sizeof(fileContext->base_path));    
+void WebInterface::registerFileServer() {
+    rest_server_context_t* ctx = (rest_server_context_t*)calloc(1, sizeof(rest_server_context_t));
+    if(!ctx) { ESP_LOGE(TAG, "No memory for file server context"); return; }
 
-	/* URI handler for getting web server files */
+    strlcpy(ctx->base_path, "/sdcard/www", sizeof(ctx->base_path));
-	httpd_uri_t common_get_uri = {
+
+    httpd_uri_t file_uri = {
         .uri     = "/*",
         .method  = HTTP_GET,
         .handler = rest_common_get_handler,
-		.user_ctx = fileContext
+        .user_ctx = ctx
     };
-	
+    registerResource(&file_uri);
-	registerResource(&common_get_uri);
 }

device/main/WebInterface.hpp

@@ -2,12 +2,23 @@
 #define _WEB_INTERFACE_HPP
 
 #include <esp_http_server.h>
+#include <memory>
+#include <functional>
+
+class AudioPlayer;
+class CacheManager;
 
 class WebInterface {
     httpd_handle_t server = NULL;
+    std::shared_ptr<AudioPlayer>  audioPlayer;
+    std::shared_ptr<CacheManager> cacheManager;
 
 public:
     WebInterface();
+
+    void setAudioPlayer(std::shared_ptr<AudioPlayer> p)   { audioPlayer  = p; }
+    void setCacheManager(std::shared_ptr<CacheManager> c) { cacheManager = c; }
+
     void start();
     void finishResourceRegistrations();
     void registerResource(httpd_uri_t* config);
@@ -16,7 +27,7 @@ class WebInterface {
 private:
     httpd_handle_t start_webserver();
     void registerFileServer();
-		//esp_err_t hello_get_handler(httpd_req_t *req); 
+    void registerApiHandlers();
 };
 
 #endif

device/main/main.cpp

@@ -1,12 +1,11 @@
-#include "Arduino.h"
-
 #include "Networking.hpp"
 #include "WebInterface.hpp"
 #include "RFIDInterface.hpp"
 #include "AudioPlayer.hpp"
 #include "TagPlayerControl.hpp"
+#include "CacheManager.hpp"
+#include "BluetoothInterface.hpp"
 
-#include <iostream>
 #include <memory>
 
 extern "C" {
@@ -16,29 +15,39 @@ extern "C" {
 Networking         networking;
 WebInterface       webInterface;
 RFIDInterface      rfid;
+BluetoothInterface bluetooth;
 
-std::shared_ptr<AudioPlayer> audioPlayer; // initialize here, because the ctor does init stuff that fails when executed before `app_main()`
+/* Shared objects — must be heap-allocated after app_main() starts the scheduler */
-
+std::shared_ptr<AudioPlayer>    audioPlayer;
+std::shared_ptr<CacheManager>   cacheManager;
 std::shared_ptr<TagPlayerControl> tagPlayerControl;
 
 void app_main(void) {
-    initArduino();
+    /* SD card must be mounted first — other components depend on it */
-
     webInterface.initSD();
 
-/*   networking.connectWifi();
+    /* Network — non-blocking with 30 s timeout */
-    webInterface.start();
+    networking.connectWifi();
 
+    /* Audio pipeline — must run after scheduler is up */
+    audioPlayer  = std::make_shared<AudioPlayer>();
+    cacheManager = std::make_shared<CacheManager>();
+
+    /* Wire web interface to audio/cache for API endpoints */
+    webInterface.setAudioPlayer(audioPlayer);
+    webInterface.setCacheManager(cacheManager);
+
+    /* Start HTTP server and register API + static-file handlers */
+    webInterface.start();
     rfid.registerWebResources(&webInterface);
     webInterface.finishResourceRegistrations();
-*/
 
-    audioPlayer = std::make_shared<AudioPlayer>();
+    tagPlayerControl = std::make_shared<TagPlayerControl>(audioPlayer, cacheManager);
-    tagPlayerControl = std::make_shared<TagPlayerControl>(audioPlayer);
 
+    /* RFID must start after the audio player (hardware init order constraint) */
     rfid.start();
 
-    rfid.registerTagChangeCallback([tagPlayerControl](char* tagId) {
+    rfid.registerTagCallback([](const char* uid, const char* url) {
-        tagPlayerControl->onTagChanged(tagId);
+        tagPlayerControl->onTagChanged(uid, url);
     });
 }

www/index.html

@@ -1,17 +1,59 @@
-<html>
+<!DOCTYPE html>
+<html lang="en">
 <head>
+  <meta charset="UTF-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1">
   <title>Kidsbox</title>
-		<link rel="stylesheet" src="styles.css">
+  <link rel="stylesheet" href="styles.css">
 </head>
 <body>
-		<h1>Hi, I'm a File!</h1>
+  <header>
+    <h1>&#127911; Kidsbox</h1>
+  </header>
 
-		<section class="rfid">
+  <main>
-			<h3>RFID-ID</h3>
+    <section class="card" id="section-playback">
-			<div class="rfid-id"></div>
+      <h2>Now Playing</h2>
-			<button class="rfid-refresh">refresh</button>
+      <div class="track-uri" id="track-uri">—</div>
+      <div class="playback-controls">
+        <button class="btn btn-primary"   id="btn-pause" disabled>Pause</button>
+        <button class="btn btn-secondary" id="btn-stop"  disabled>Stop</button>
+      </div>
+      <div class="volume-row">
+        <label for="volume-slider">Volume</label>
+        <input type="range" id="volume-slider" min="0" max="100" value="50">
+        <span id="volume-label">50</span>
+      </div>
     </section>
 
+    <section class="card" id="section-info">
+      <h2>Device Info</h2>
+      <table class="info-table">
+        <tr><th>IP Address</th><td id="info-ip">—</td></tr>
+        <tr><th>Status</th><td id="info-playing">—</td></tr>
+        <tr><th>Cache Used</th><td id="info-cache">—</td></tr>
+        <tr><th>Free Heap</th><td id="info-heap">—</td></tr>
+      </table>
+      <button class="btn btn-secondary" id="btn-refresh-info">Refresh</button>
+    </section>
+
+    <section class="card" id="section-storage">
+      <h2>Storage</h2>
+      <div class="storage-header">
+        <span id="storage-summary">Loading…</span>
+        <button class="btn btn-danger" id="btn-clear-cache">Clear All</button>
+      </div>
+      <ul class="cache-list" id="cache-list"></ul>
+    </section>
+
+    <section class="card" id="section-bluetooth">
+      <h2>Bluetooth Speaker</h2>
+      <p class="bt-status" id="bt-status">Disabled</p>
+      <button class="btn btn-secondary" id="btn-bt-toggle">Enable</button>
+      <p class="note">Pair your phone to play music through the Kidsbox speaker.</p>
+    </section>
+  </main>
+
   <script src="main.js"></script>
 </body>
 </html>

www/main.js

@@ -1,13 +1,152 @@
-console.log('hi');
+'use strict';
 
-const elements = {};
+/* ── helpers ──────────────────────────────────────────────────────────── */
 
-elements.rfidId = document.querySelector('.rfid-id');
+function fmt_bytes(n) {
-elements.rfidRefresh = document.querySelector('.rfid-refresh');
+  if (n < 1024) return n + ' B';
+  if (n < 1024 * 1024) return (n / 1024).toFixed(1) + ' KB';
+  return (n / (1024 * 1024)).toFixed(1) + ' MB';
+}
 
-elements.rfidRefresh.addEventListener('click', async () => {
+async function api(method, path, body) {
-	const response = await fetch('/rfid'),
+  const opts = { method };
-		rfidId = await response.text();
+  if (body) {
+    opts.headers = { 'Content-Type': 'application/x-www-form-urlencoded' };
+    opts.body = body;
+  }
+  const res = await fetch(path, opts);
+  return res.json();
+}
 
-	elements.rfidId.innerText = rfidId;
+/* ── device info ──────────────────────────────────────────────────────── */
+
+async function refreshInfo() {
+  try {
+    const d = await api('GET', '/api/info');
+    document.getElementById('info-ip').textContent      = d.ip ?? '—';
+    document.getElementById('info-playing').textContent = d.playing ? 'Playing' : 'Stopped';
+    document.getElementById('info-cache').textContent   = fmt_bytes(d.cacheBytes ?? 0);
+    document.getElementById('info-heap').textContent    = fmt_bytes(d.freeHeap ?? 0);
+
+    document.getElementById('track-uri').textContent = d.currentUri || '—';
+    document.getElementById('btn-pause').disabled = !d.playing;
+    document.getElementById('btn-stop').disabled  = !d.playing;
+
+    const vol = d.volume ?? 50;
+    document.getElementById('volume-slider').value  = vol;
+    document.getElementById('volume-label').textContent = vol;
+  } catch (e) {
+    console.error('Failed to fetch /api/info', e);
+  }
+}
+
+/* ── storage ──────────────────────────────────────────────────────────── */
+
+async function refreshStorage() {
+  try {
+    const entries = await api('GET', '/api/storage');
+    const list    = document.getElementById('cache-list');
+    const summary = document.getElementById('storage-summary');
+
+    list.innerHTML = '';
+
+    if (!Array.isArray(entries) || entries.length === 0) {
+      summary.textContent = 'No cached files';
+      return;
+    }
+
+    let total = 0;
+    entries.forEach(e => {
+      total += e.size ?? 0;
+      const li  = document.createElement('li');
+      const key = document.createElement('span');
+      key.className   = 'cache-key';
+      key.textContent = e.key;
+      const sz        = document.createElement('span');
+      sz.className    = 'cache-size';
+      sz.textContent  = fmt_bytes(e.size ?? 0);
+      const del       = document.createElement('button');
+      del.className   = 'btn btn-danger';
+      del.style.cssText = 'padding:.2rem .5rem;font-size:.75rem';
+      del.textContent = '✕';
+      del.addEventListener('click', () => deleteEntry(e.key));
+      li.append(key, sz, del);
+      list.appendChild(li);
+    });
+
+    summary.textContent =
+      `${entries.length} file${entries.length !== 1 ? 's' : ''} — ${fmt_bytes(total)}`;
+  } catch (e) {
+    console.error('Failed to fetch /api/storage', e);
+  }
+}
+
+async function deleteEntry(key) {
+  await api('DELETE', `/api/storage?key=${encodeURIComponent(key)}`);
+  refreshStorage();
+}
+
+async function clearCache() {
+  if (!confirm('Delete all cached files?')) return;
+  await api('DELETE', '/api/storage');
+  refreshStorage();
+}
+
+/* ── playback ─────────────────────────────────────────────────────────── */
+
+async function sendPlayback(action, value) {
+  const body = value !== undefined
+    ? `action=${action}&value=${encodeURIComponent(value)}`
+    : `action=${action}`;
+  await api('POST', '/api/playback', body);
+  refreshInfo();
+}
+
+/* ── bluetooth ────────────────────────────────────────────────────────── */
+
+async function refreshBt() {
+  try {
+    const d = await api('GET', '/api/bluetooth');
+    const status = document.getElementById('bt-status');
+    const btn    = document.getElementById('btn-bt-toggle');
+    if (d.enabled) {
+      status.textContent = 'Enabled';
+      status.style.color = '#48bb78';
+      btn.textContent    = 'Disable';
+    } else {
+      status.textContent = 'Disabled';
+      status.style.color = '#a0aec0';
+      btn.textContent    = 'Enable';
+    }
+  } catch (e) {
+    console.error('Failed to fetch /api/bluetooth', e);
+  }
+}
+
+async function toggleBt() {
+  const enabled = document.getElementById('bt-status').textContent === 'Enabled';
+  await api('POST', '/api/bluetooth', `enabled=${!enabled}`);
+  refreshBt();
+}
+
+/* ── init ─────────────────────────────────────────────────────────────── */
+
+document.addEventListener('DOMContentLoaded', () => {
+  refreshInfo();
+  refreshStorage();
+  refreshBt();
+
+  document.getElementById('btn-refresh-info').addEventListener('click', refreshInfo);
+  document.getElementById('btn-clear-cache').addEventListener('click', clearCache);
+  document.getElementById('btn-bt-toggle').addEventListener('click', toggleBt);
+  document.getElementById('btn-pause').addEventListener('click', () => sendPlayback('pause'));
+  document.getElementById('btn-stop').addEventListener('click',  () => sendPlayback('stop'));
+
+  const slider = document.getElementById('volume-slider');
+  const label  = document.getElementById('volume-label');
+  slider.addEventListener('input',  () => { label.textContent = slider.value; });
+  slider.addEventListener('change', () => sendPlayback('volume', slider.value));
+
+  /* Auto-refresh info every 5 s while page is visible */
+  setInterval(() => { if (!document.hidden) refreshInfo(); }, 5000);
 });

www/styles.css

@@ -0,0 +1,125 @@
+*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
+
+body {
+  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
+  background: #f0f4f8;
+  color: #1a202c;
+  min-height: 100vh;
+}
+
+header {
+  background: #2d3748;
+  color: #fff;
+  padding: 1rem 1.5rem;
+}
+
+header h1 {
+  font-size: 1.5rem;
+  font-weight: 700;
+}
+
+main {
+  max-width: 700px;
+  margin: 1.5rem auto;
+  padding: 0 1rem;
+  display: flex;
+  flex-direction: column;
+  gap: 1.25rem;
+}
+
+.card {
+  background: #fff;
+  border-radius: 10px;
+  box-shadow: 0 2px 8px rgba(0,0,0,.08);
+  padding: 1.25rem 1.5rem;
+}
+
+.card h2 {
+  font-size: 1rem;
+  font-weight: 600;
+  text-transform: uppercase;
+  letter-spacing: .05em;
+  color: #718096;
+  margin-bottom: 1rem;
+}
+
+/* Playback */
+.track-uri {
+  font-size: .9rem;
+  color: #4a5568;
+  word-break: break-all;
+  min-height: 1.2em;
+  margin-bottom: .75rem;
+}
+
+.playback-controls {
+  display: flex;
+  gap: .5rem;
+  margin-bottom: 1rem;
+}
+
+.volume-row {
+  display: flex;
+  align-items: center;
+  gap: .75rem;
+}
+
+.volume-row label { font-size: .875rem; color: #718096; white-space: nowrap; }
+.volume-row input  { flex: 1; }
+#volume-label      { font-size: .875rem; width: 2rem; text-align: right; }
+
+/* Buttons */
+.btn {
+  padding: .45rem .9rem;
+  border: none;
+  border-radius: 6px;
+  font-size: .875rem;
+  font-weight: 600;
+  cursor: pointer;
+  transition: opacity .15s;
+}
+
+.btn:disabled { opacity: .45; cursor: not-allowed; }
+.btn:not(:disabled):hover { opacity: .85; }
+
+.btn-primary   { background: #4299e1; color: #fff; }
+.btn-secondary { background: #e2e8f0; color: #2d3748; }
+.btn-danger    { background: #fc8181; color: #fff; }
+
+/* Device info */
+.info-table { width: 100%; border-collapse: collapse; margin-bottom: .75rem; }
+.info-table th, .info-table td { padding: .35rem .5rem; text-align: left; font-size: .875rem; }
+.info-table th { color: #718096; width: 40%; }
+.info-table tr:not(:last-child) th,
+.info-table tr:not(:last-child) td { border-bottom: 1px solid #edf2f7; }
+
+/* Storage */
+.storage-header {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  margin-bottom: .75rem;
+  font-size: .875rem;
+  color: #4a5568;
+}
+
+.cache-list { list-style: none; }
+
+.cache-list li {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  padding: .4rem 0;
+  border-bottom: 1px solid #edf2f7;
+  font-size: .875rem;
+}
+
+.cache-list li:last-child { border-bottom: none; }
+
+.cache-list .cache-key { font-family: monospace; color: #4a5568; }
+.cache-list .cache-size { color: #a0aec0; }
+
+/* Bluetooth */
+.bt-status { font-weight: 600; margin-bottom: .5rem; }
+#btn-bt-toggle { margin-bottom: .5rem; }
+.note { font-size: .8rem; color: #a0aec0; }