starting with notify

Signed-off-by: Peter Siegmund <developer@mars3142.org>

components/remote_control/capability_service.c

@@ -2,6 +2,10 @@
 #include "esp_log.h"
 #include "storage.h"
 #include <string.h>
+#include <stdlib.h>           // For malloc, free
+#include "host/ble_hs.h"      // For ble_hs_mbuf_from_flat, ble_att_mtu
+#include "host/ble_uuid.h"    // For BLE_ATT_MTU_DFLT (often included via ble_hs.h)
+#include "nimble/nimble_port.h" // For os_mbuf related functions
 
 static const char *TAG_CS = "capability_service";
 
@@ -70,3 +74,83 @@ int capa_char_1979_user_desc(uint16_t con_handle, uint16_t attr_handle, struct b
     os_mbuf_append(ctxt->om, desc, strlen(desc));
     return 0;
 }
+
+void capa_notify_data(uint16_t conn_handle, uint16_t char_val_handle)
+{
+    esp_err_t storage_status = storage_init();
+    if (storage_status != ESP_OK)
+    {
+        ESP_LOGE(TAG_CS, "Notify: Failed to initialize storage: %s", esp_err_to_name(storage_status));
+        return;
+    }
+
+    const char *filename = "/storage/capability.json";
+
+    uint16_t mtu = ble_att_mtu(conn_handle);
+    if (mtu == 0) { // Should not happen for an active connection, fallback
+        ESP_LOGW(TAG_CS, "Notify: ble_att_mtu returned 0, using default MTU %d.", BLE_ATT_MTU_DFLT);
+        mtu = BLE_ATT_MTU_DFLT;
+    }
+
+    // Max payload for notification is MTU - 3 (1 byte opcode for Notification, 2 bytes attribute handle)
+    size_t notify_chunk_size = (mtu > 3) ? (mtu - 3) : (BLE_ATT_MTU_DFLT - 3); // Ensure mtu > 3
+
+    // Further cap by CAPA_READ_CHUNK_SIZE if it's smaller and meant as an upper limit for any single read op
+    if (notify_chunk_size > CAPA_READ_CHUNK_SIZE) {
+        notify_chunk_size = CAPA_READ_CHUNK_SIZE;
+    }
+
+    if (notify_chunk_size == 0) { // Safety check
+        ESP_LOGE(TAG_CS, "Notify: Calculated notify_chunk_size is 0. Aborting.");
+        storage_uninit();
+        return;
+    }
+
+    char *read_buffer = malloc(notify_chunk_size);
+    if (!read_buffer)
+    {
+        ESP_LOGE(TAG_CS, "Notify: Failed to allocate read_buffer (%zu bytes)", notify_chunk_size);
+        storage_uninit();
+        return;
+    }
+
+    ESP_LOGI(TAG_CS, "Notify: Reading capabilities from %s to notify conn %u, attr %u (chunk size %zu, MTU %u)",
+             filename, conn_handle, char_val_handle, notify_chunk_size, mtu);
+
+    FILE *fp = fopen(filename, "r");
+    if (!fp)
+    {
+        ESP_LOGE(TAG_CS, "Notify: Failed to open %s for reading.", filename);
+        free(read_buffer);
+        storage_uninit();
+        return;
+    }
+
+    ssize_t bytes_read;
+    while ((bytes_read = fread(read_buffer, 1, notify_chunk_size, fp)) > 0)
+    {
+        ESP_LOGD(TAG_CS, "Notify: Read %zd bytes from storage for notification", bytes_read);
+
+        struct os_mbuf *om = ble_hs_mbuf_from_flat(read_buffer, bytes_read);
+        if (!om) {
+            ESP_LOGE(TAG_CS, "Notify: Failed to allocate mbuf for notification. Stopping.");
+            break; // Stop sending if mbuf allocation fails
+        }
+
+        int rc = ble_gatts_notify_custom(conn_handle, char_val_handle, om);
+        if (rc != 0) {
+            ESP_LOGE(TAG_CS, "Notify: Error sending notification (rc=%d). Stopping.", rc);
+            // ble_gatts_notify_custom frees 'om' on success or if it takes ownership even on some errors.
+            // If it returns an error where 'om' is not freed, we might need os_mbuf_free_chain(om);
+            // For now, assume NimBLE handles 'om' correctly in error cases like BLE_HS_ENOMEM.
+            break; // Stop if notification fails
+        }
+        ESP_LOGD(TAG_CS, "Notify: Sent %zd bytes successfully.", bytes_read);
+    }
+
+    if (ferror(fp)) { ESP_LOGE(TAG_CS, "Notify: File read error from %s.", filename); }
+    fclose(fp);
+    free(read_buffer);
+    storage_uninit();
+    ESP_LOGI(TAG_CS, "Notify: Finished sending capability data for conn %u.", conn_handle);
+}

components/remote_control/include/capability_service.h

@@ -5,6 +5,7 @@
 
 /// Service Characteristics Callback
 int capa_read(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt *ctxt, void *arg);
+void capa_notify_data(uint16_t conn_handle, uint16_t char_val_handle);
 
 /// Service Characteristics User Description
 int capa_char_1979_user_desc(uint16_t con_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt *ctxt, void *arg);

components/remote_control/remote_control.c

@@ -28,6 +28,9 @@ static const ble_uuid16_t led_service_uuid = BLE_UUID16_INIT(0x1007);
 
 uint8_t ble_addr_type;
 
+// Handle for the capability characteristic value
+static uint16_t g_capa_char_val_handle;
+
 static void ble_app_advertise(void);
 
 static struct ble_gatt_dsc_def char_0xA000_descs[] = {{
@@ -69,6 +72,7 @@ static const struct ble_gatt_svc_def gatt_svcs[] = {
                                                            .uuid = BLE_UUID16_DECLARE(0x1979),
                                                            .flags = BLE_GATT_CHR_F_READ | BLE_GATT_CHR_F_NOTIFY,
                                                            .access_cb = capa_read,
+                                                           .val_handle = &g_capa_char_val_handle,
                                                            .descriptors = char_0x1979_desc,
                                                        },
                                                        {0}},
@@ -118,6 +122,32 @@ static int ble_gap_event(struct ble_gap_event *event, void *arg)
         ble_app_advertise();
         break;
 
+    case BLE_GAP_EVENT_SUBSCRIBE:
+        ESP_LOGI(TAG,
+                 "BLE GAP EVENT SUBSCRIBE conn_handle=%d attr_handle=%d reason=%d "
+                 "prev_notify=%d cur_notify=%d prev_indicate=%d cur_indicate=%d",
+                 event->subscribe.conn_handle, event->subscribe.attr_handle, event->subscribe.reason,
+                 event->subscribe.prev_notify, event->subscribe.cur_notify, event->subscribe.prev_indicate,
+                 event->subscribe.cur_indicate);
+
+        // Check if subscription is for the capability characteristic's CCCD.
+        // The CCCD handle is typically the characteristic value handle + 1.
+        // g_capa_char_val_handle stores the handle of the characteristic value itself.
+        if (event->subscribe.attr_handle == g_capa_char_val_handle + 1)
+        {
+            if (event->subscribe.cur_notify)
+            {
+                ESP_LOGI(TAG, "Client subscribed to capability notifications. Sending data...");
+                // Call the function to send capability data via notifications
+                capa_notify_data(event->subscribe.conn_handle, g_capa_char_val_handle);
+            }
+            else
+            {
+                ESP_LOGI(TAG, "Client unsubscribed from capability notifications.");
+            }
+        }
+        break;
+
     default:
         break;
     }